Chunlei Shi

Bo Peng

Research on Key Technology of Grid Cell Division Method in Rural Community

Keywords: management, grid cell division, village community

des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

As the market economy continues to develop, village society presents a diversified development trend, along with the development of the towns, village members appeared stratified society, dispatch phenomenon, which leads to differences complicate the values and interests of the main interests of the village community sources of. The village society of pluralism, diversity is bound to induce complex social needs, social conflicts and problems, the improper disposal may cause discontent among the members of the village community, and even leads to mass incidents [START_REF] Lu | Cooperative service: Innovation Mode of Rural Social Management [J][END_REF]. For China, a vast country with a large agricultural population, the role of towns and villages in the county of socio-economic development can not be ignored. Facing the new situation and the new problems of rural society, rural grassroots government's public service still follow the tradition of fragmentation, the fragmented nature of resource allocation and administrative work, this kind of government management model is clearly not meet the requirements of the village social development. Particularly in industrialized, urban reform orientation of the development process, long-term adherence to the "urban bias" in public policyoriented, leading to a serious shortage of village public services. How in the new rural governance system effectively extend the management and service functions of government to farmers, covering the entire villages is a new topic in the new situation of grass-roots social management innovation. Thus, according to the new characteristics of rural community development, the research on the method of new village community governance haves important theoretical significance and practical significance [START_REF] Huang | Governance of New Rural Communitese in the Context of Urbanization[END_REF].

Grid management is a new management model ,which was worked out in the construction of China's urban grass-roots social management in recent years, it mainly refers to in accordance with certain criteria the community are divided into a plurality of mesh, as the basis of the IT and grid coordination mechanisms, the sharing of resources between the grid and efficient exchange of information, and ultimately achieve the optimal allocation of resources, improve the efficiency of the new management thinking for the community management [START_REF] Gao | The Study of China's Urban Community Grid Management[END_REF], to solve community information due to the work and information integration across sectors shared problems brought [START_REF] Fountain | Building the Virtual State Information Technology and Institutional Change[END_REF]. Grid management centralized dynamic management, fine management and flat management, the use of digital management technology, from the perspective of social management, to integration of social wealth and resources, eliminate information silos, to achieve information sharing and coordination office, can greatly improve the efficiency of community management, saving management costs, laid the basis for innovative community management model [START_REF] Chen | The Research on Lucheng Town Community Grid Management[END_REF][6]. Therefore, exploring for grid management model for village communities has great significance in urban and rural dual economic structure and build a new socialist countryside construction.

Grid Cell Division

Grid Cell division is the basis of geographical network applications.It has a relatively large workload.The first step in constructing the grid management system is to divide each grid cell, there must be some criteria for the classification constructed so that for standard each grid cell's construction and management, in order to facilitate the implementation of grid management.

Village space meshing has rules division and irregular division. Village spatial data is complexity and variety, space meshing will directly affect the entire village grid system and the management based on this. Geography meshing should give full consideration to the workload of each mesh grid administrators, and should be divided according to the village space form, and should consider the integrated grid area, the number of households within the grid, the number of towns and villages within the grid and other parts of factors. In this paper, three division methods are proposed according to the administrative divisions, road blocks and regular grid.

Principle of Grid Cell Division and Geographical Elements

The division of the grid cell should follow the principle of a statutory basis , territorial management, geographical distribution, the convenience of management, space and relative stability. Space grid with rectangular shape is appropriate, and the ratio of length to width should not be too large,meanwhile,it should avoid the appearance of "7" shape or "concave" shape of the space grid.

The division of the grid cell should be in accordance with the layout of the village lanes, courtyards and open spaces, rivers, mountains, lakes and other natural geography. References to the standard of the relevant grid division recomm ended by the construction department can give the following method for the division of geographical elements.Geographical elements mentioned here may not be comprehensive, in the implementation should be flexible to grasp.

(1) Boundary. Spatial grid can not cross the township, village, administrative boundaries.

(2) Settlement places. In general, considering the ownership relations,put the buildings which have a wall or have unified label on the topographic map in a spatial grid. A building which is inconsistent with the ownership should be based on the adjacent relationship, as far as possible subdivided into a grid with rules shape.

(3) Hilly area. According to its boundary (the slope bottom or the bottom of the slope),in principle, hilly area is divided into an independent space grid . If there is a high degree of highway in the middle of the mountain, it can be divided into several mountainous areas in accordance with the road. In the boundary of the mountain division, first consider the river and road at the bottom of the slope,if existing rivers and roads divide the mountain and other according to the roads and the rivers.Otherwise, to divide the sideline according to the steep ridge or the fence, etc. In addition, lakes, reservoirs and rivers in the mountains and small area residents and other features are generally no longer to be divided, and as a part of the mountain space grid [START_REF] Li | Plotting of City Spatial Grid Based on Field Mode[END_REF].

(4) Waters. It mainly includes linear rivers and lakes, reservoirs, etc. To make the central line of the river as the boundary of the space grid(If the river is the boundary of the administrative division, treatment by administrative divisions), and according to the grid object distribution, the river can be divided into the appropriate space grid. For relatively large reservoirs and lakes generally divided separately, if the area is lesser, which can consider a merger with the surrounding terrain for the same space grid.

Grid Cell Division Method

According to the Administrative Divisions

Administrative divisions are in the area of the state to facilitate the administration and hierarchically divided region, also known as administrative region.In the villages and towns, the village is primary mass self-government organizations of the villagers elected by the villagers, it is the township (town) the next level of administrative division, setting up a villagers' committee, and accepting the guidance of the administrative authority at the next higher level. Space grid division, which is according to the township (town) -the village of the administrative rank level division. The first step is to meet the needs of villages and towns management departments, do the division of "rough" class level. Township and village boundaries are certain legal boundaries, and once determined it is difficult to be amended, unless the authorities to modify the boundary line. The second step is to meet the needs of rural management and other functional departments, do the division of "fine" class level. Comprehensive analysis is needed to determine the size of the smallest unit grid, which is division of rural space grid by the comprehensive analysis of the survey report, multiple data source graphics overlay, contrast, and field survey. In the area of the villages and towns, the geographical elements are diverse. The division of the region is actually a partition of the geographical elements..

The basic idea of the geographic grid according to the administrative division is that village as the unit. According to the territorial management, geographical distribution, the status quo management, convenient management, integrity management objects, etc. The town is divided into a number of geographic grid units. The geographic grid divided according to the administration should follow the following principles.

(1)The division of the grid cell should be carried out according to the statutory topographic survey data, the scale should generally be with l / 500 advisable, but should not be less than l / 2000. When dividing grid cell, the larger the scale, the grid line to be more accurate, and management object is more accurate positioning.

(2)The maximum boundary of the unit grid is the villages boundary, and one village has a grid at least.

(3) The division of the grid should be adapted to the current situation, and not split more than ten thousand square meters of independent courtyard,division of the units of the independent courtyard. In the actual process of separating, the area of the unit grid may be reached tens of thousands of square meters.

(4) The division of the grid must enable service behavior to be easily realized, in the process of information service, whether considering the traffic tools, or consideration to the problem of rural politics of rapid processing, etc., all requirements can be easily arrived at the scene.

(5)Building can't be split.Otherwise the description of the location of the management object will be ambiguous.Villages and towns management object can't be split.Otherwise you will produce the phenomenon such as cross or management absence. Unit within the grid management object number is roughly balanced, for the implementation of the management behavior, evaluation and so on, are very necessary.

(6) The splicing between the elements of the grid must be seamless splicing, and can not overlap, otherwise it will inevitably produce the phenomenon such as cross or management absence.

According to the Road Blocks

In the villages and towns, block plays a very vital role in traffic.It also divides the village into different areas. Block itself is a kind of irregular geographic grid, therefore, it can be divided into geographical grid based on block elements. The basic idea of dividing geographic grid according to the road block division is that in the block formed between the main road as the basic unit in the towns and villages, in each block unit which is divided into irregular geographic grid according to the actual geographical distribution and non-trunk, the roads should be divided as an independent unit grid. The geographic grid separated according to the road blocks should follow the following principles.

(1)The division of the unit grid should be carried out according to the statutory topographic survey data, the scale should generally with l / 500 advisable, but should not be less than l / 2000. 1 / 500 l / 1000 and l / 2000 are three kinds of scale topographic survey data can be used to divide the unit grid.

(2)The maximum boundary of the unit grid is the boundary of the road block, and one block has at least one unit grid.

(3) The division of the grid unit to be carried out in accordance with the layout of the village lanes, courtyards and public green space, square, bridge, open space, rivers, mountains, lakes and other natural geography.

(4) The division of the grid should maintain the integrity of the independent courtyard, and do not split the larger detached courtyard. In the actual process of dividing, the area of the unit grid may be reached tens of thousands of square meters.

(5) The division of the grid must enable service behavior to be easily realize, in the process of information service, whether considering the traffic tools, or consideration to the problem of rural politics of rapid processing, etc., all requirements can be easily arrived at the scene.

(6)Building can't be split, otherwise the description of the location of the management objective will be ambiguous;Villages and towns management object can't be split, otherwise you will produce the phenomenon such as cross or management absence. Unit within the grid management object number is approximately balanced, for the implementation of the management behavior, evaluation and so on, are very necessary. [START_REF] Li | Plotting of City Spatial Grid Based on Field Mode[END_REF]The splicing between the elements of the grid must be seamless splicing, and can not overlap, otherwise it will inevitably produce the phenomenon such as cross or management absence. [START_REF] Zhu | GIS Study on the Gridding of Vector Polygon in GIS[END_REF]The road as an independent unit grid to be divided.

According to the Regular grid

Regular grid square is a kind of geographic data model, namely, can express geographic information as a series of grid cells, which are of the same size and align by rows and cols. The first step of dividing geographic grid is to divide the large scale map into regular grid square by with a certain distance. These grid squares are composed of a regular geographic grid.Each geographic grid determines its location by the coordinates of its center point. If necessary, geographic grid can be subdivided according to the actual surface intensity, such as sparse objects without the need of mesh subdivision, but intensive surface features can be subdivided into geographic grid according to the needs, from high level to low level of different thickness. Geographic grid , divided by regular grid square , whose properties should be determined, because of their different properties contribute several algorithms in the following:

(1)Central Point Method, Central point method is the most simple method of properties discrimination. The core idea of Central point method is taking the attribute values of the central point in source regions as the attribute value of the entire grid area for each grid. Central point method is applicable to the geographical elements with continuous distribution characteristics. In the practical application, there may be the center point of the grid area falls on the boundary of many source regions and can't determine the position ownership of the center point. Then require combined with other methods, or directly by analysts, according to the experience and the need to clarify the properties.

(2) Preponderant Area Method, Preponderant area method takes the attribute value of the source region, which is the largest component of the grid region, determines the value of the entire grid area. It can be applied to the case of a finer classification and smaller grid [START_REF] Zhu | GIS Study on the Gridding of Vector Polygon in GIS[END_REF].

(3) Weightiness Method, Weightiness method according to the importance of the non-homologous region in the area of the grid, the most significant source region is chosen to decide the attribute value of the grid area. It is suitable for the region with special meaning and less area.

Analysis and Comparison

According to the division of administrative division the geographic grid, makes the information of towns and villages in the space forming three levels, and clearly determine the responsibility of village management at each level. The first level is townships (towns). The responsible person in the village management is the township (town) government. The second level is the village, the responsible person is the village committee; The third level is the geographical grid unit, the responsible person is a special geographic grid unit management personnel. Geographical grid encoding is the same with administrative divisions encoding. There is no phenomenon road and road intersection because of the management cross or management defects. The disadvantage is that the data is not easy to manage, and the flexibility is not high. According to road blocks divide geographical grid, blocks network on the map has an obvious boundary, thereby dividing the grid cells relatively easy, and take the road as a separate grid may avoid road cross management or management vacancy phenomenon. The disadvantage is that according to the district road network divide geographical grid may be conflict with the administrative divisions. For example, two different villages or groups (teams) in the region are likely to be divided into a geographic grid unit, resulting in conflict with administrative divisions. Correspondingly, the geographical grid encoding and the grid components encoding conflict with the administrative divisions encoding. The intersection of the road can cause the phenomenon of the management across or management absence. The road unit grid and the grid of the adjacent units need to be equipped with the management personnel, which will cause the waste of human resources.

Geographic grid divided in accordance with the square grid is a regular grid, is contributing to store the geographic space information, management and spatial analysis, but it can't guarantee the surface features' integrity. Many surface features are split in different geographic grids, even the relatively larger independent courtyard will be split in several unit grids. That will easily cause the management across or management absence. And the properties in a single grid are not sole. There may be a number of different properties in the grid.

Conclusions

The new model of rural grid management is still at the stage of theoretical exploring and researching. This paper discusses the grid partition technology in the village and town grid management, and gives out the specific principles and method of grid division. In the implementation of the actual grid partition should according to the characteristics of local topography and the village or town planning layout, combined with the advantages and disadvantages of various divide method, considering each management subject of convergence after grid partition to avoid the fracture of management services rights, finally archive success of covering the whole management and full service in village management grid construction and operation process.


Mingxi Shao

Xiumei Zhang

Bingguo Liu

Changyong Shao
email: dshaochangyong@cau.edu.cn

Aisheng Ma

Shousheng Zhang

Sheng Liu

Yujie Liu

Lijing Zhao
email: izhaolijing008@163.com

Lin Dong

Research on the Digital Machine for Killing the Larva of Longicorn Beetle with Microwave Based on the Arduino

Keywords: pulse microwave, The microwave oven, The arduino, DS18B20 temperature sensor, Silicon controlled rectifier

de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

Longicorn beetle is a kind of widespread occurrence of pests worldwide, is the floorboard of the superfamily coleoptera leaf beetle cerambycidae insects and their host variety, damage is extensive, such as forestry, garden trees and fruit trees were infect it, next, because it has a way of life of concealed, natural enemy species less, low interference by natural factors, etc, so control is very difficult, often cause harm in a cabin myself, even the deforestation. Longicorn larvae of vermicular, can crawl into life within two years, at the beginning of hatched larvae in the bark of feeding, with the increase of age, namely greater in phloem and xylem in feeding, trees conducting tissue damage, leading to death. Sawyer neutralising the commonly used method at present is mainly chemical method, namely: by dimethoate and dichlorvos highly toxic pesticides into wormholes, purpose of pesticides.

The shortcomings of this approach is that as the longicorn larvae to become resistant to treatment, result in applying pesticide concentration increasing, the environmental pollution is more and more serious, at the same time, also cause serious damage to human and animal health. Therefore, attempts to make the field technicians physical methods neutralising the longicorn, but so far, there is still no good insecticidal equipment or physical insecticidal method can achieve the effect of neutralising the sawyer, high efficiency, high killing rate.

Microwave is a kind of can make the material in the inland waters molecules to vibrate and generate heat, therefore, in our already use microwave oven to heat food in the kitchen, and hotel, the hotel has to be used for drying, sterilization equipment, the effect is obvious.

Currently used in the microwave oven is infrared temperature detection device, the thermal stability of the sensor of the device, though, but as a result of microwave heating from the inside out, at this time of the infrared temperature sensor, temperature is only the surface temperature were collected and the internal temperature of the heated material difference is very big. At the same time, because now the microwave equipment for microwave magnetron is realized by using a timer to control, but this method reduces the life of a microwave magnetron, also have impact on control system. Based on the above problems, in this paper, after studying, put forward a new kind of kill longicorn larvae of automatic control system. This design USES the arduino as the control core, DS18B20 temperature acquisition module for the temperature control unit for soil temperature and the temperature detection, closed-loop control to realize interpolation, interpolation signal transmission to the SCR to magnetron microwave output control.

Microwave Kill the Larva of Longicorn Beetle Composition Of the System

Microwave kill the larva of longicorn beetle system main structures is shown in Figure 1: Fig. 1. the digital machine for killing the larva of longicorn beetle 1), Magnetron and cavity, adopts the structure combining a snap button.

2), Install the ring frame 12 groups of magnetron pulse current of capacitor and transformer and support. Type a panasonic m210-2 M1, maximum output power 900 w. Capacitor using the treasure chang 2100 v 1 u f microwave special capacitance, 12 groups of transformer the GAL -700 -e -1 s. 36 sets of SCR control on rectangular frame is divided into three groups of 12 groups of magnetron.

3), This system USES through the 12 v supply to the output transformer for power supply way of wind cold short of 12 groups of fans. 4), The control of this system adopts the arduino and touch key as the core controller to realize automatic control. 5), Temperature detection and feedback system USES DS18B20 temperature acquisition module, the detection of light soil and the internal temperature of the trunk, closed-loop control to realize interpolation. 6), Because the microwave will cause certain damage to human body, the closed loop type is adopted stainless steel sheet to prevent overflow, microwave scattering and in use process, made up of closed loop cavity surrounded the trunk or the roots of the soil.

Microwave Kill the larva of Longicorn Beetle of Electrical Control System

Microwave kill the larva of longicorn beetle control system is shown in Figure 2, through the picture you can see, the control unit is mainly the arduino and relevant input and output unit, temperature display, SCR, temperature sensor and controlled object.

Arduino port circuit design

According to the control requirements of the system, need eight digital output port and four analog input ports and three analog output port. In order to meet this requirement, choose the Arduino UNO platform, this platform is the core of ATmega328 processing chip, a total of 14 digital input/output: 6 road PWM output port, no.6 analog input port, all the way ICSP header, a 16 MHZ crystal oscillator, a power switch, Intelligent module Touchscreen

Control

Magnetron heating system

Transmission system

Cooling circulation system

A USB interface and a reset button. In the AREF new added two pin: SCL and SDA, support the I2C interface; Increase IOREF and reserve a pin, control panel can be compatible with 5 V and 3.3 V supply voltage.

Microwave kill longicorn larvae circuit design of the system

Choose intelligent thyristor control insecticidal machine heating unit, this system USES MJYS -JL -450 type intelligent thyristor, thyristor module of the input signal of current 4 ma -20 ma, or 0 to 5 v voltage, control principle are shown in Figure 3 below.

Device name

The The system control method is as follows:

1) use the arduino form PWM pulse signal timing control function, low level is the input signal is 4 ma thyristor, magnetron no microwave power is zero at this time; High electricity at ordinary times, silicon controlled rectifier input signal to 20 ma, microwave magnetron, at this time a single power 900 w.

2) power regulation. Through the change of the PWM duty cycle of the signal, when the duty ratio is less than 1, can activate the microwave magnetron output. So you can through the PWM pulse width modulation pulse rate and silicon controlled rectifier input signal to change the output power of microwave insecticidal machine.

Microwave kill longicorn larvae temperature control circuit design of the system

In the system of the temperature feedback collection unit adopts the digital temperature sensor DS18B20, the module will be collected the temperature of the analog signal into digital signal, the sensor includes a NTC thermometer element and a resistive touch wet element. DS18B20 temperature detection range in -55 ~ + 125 ℃, in -10 ~ + 85 ℃ accuracy of + / -5 ℃. In each bucket cover the bottom with a DS18B20, soil temperature signal collected and processed output PWM pulse signal, control thyristor module, change the power magnetron, achieve control of the temperature.

Microwave kill root nematode system software design

This system adopts the aiduino as processing core, the main program includes the main program, subprogram, temperature acquisition and practical program, microwave control instruction, fault alarm procedures, etc.

Microwave kill root nematode system temperature and pulse microwave control program

The core of this system is for the control of temperature and microwave power, the soil temperature DS18B20 temperature sensor acquisition and processing, the input signal to the arduino Atmel AVR ATmega328 processing, after processing by its send a pulse signal to the thyristor module change magnetron power to implement automatic regulation for temperature. This system has two kinds of manual and automatic operation mode. Automatic mode, the use of pid algorithm, and calculate the duty ratio, through the arduino central processing unit and output control signal, through intelligent thyristor adjust the duty ratio of pulse signal, change the power of microwave magnetron to for temperature control. When malfunction or insecticidal effect is not ideal the need for manual operation, the operator can be manually opened according to the actual temperature heating, namely in setting an interrupt program, through the manual button at the bottom of the screen to switch to the program change PMW duty ratio to change the role of the magnetron power. This system program design flow chart as shown in Figure 4:

Figure 4 system program design flow chart

This system adopted by the arduino as the core control unit, by controlling the output power of microwave pulse duty ratio control, and adopted the DS18B20 temperature sensor to collect signal and output control signal so that a complete output, execution, feedback, to perform a closed-loop control.

START

Kill Longicorn Larvae of the Mechanical Mechanism of Microwave Insecticidal Machine Design

Neutralising the longicorn larvae of microwave insecticidal machine structure

The device including the telescopic rod, the top of the telescopic rod connected to the hull, microwave transmitter and controller installed in the shell, shell on the inside of the board to open hole, the inside of the shell plate respectively hinged on both ends the first arc baffle plate and a second reflex arc plate, the first arc baffle in the hinge parts setting first contact pressure, the second arc baffle in the hinge position setting the second contact pressure, the first arc the outer end of the baffle plate and a second reflex arc plate edge set opening snap button, the first baffle plate and a second reflex arc arc plate forming a circular cavity microwave irradiation after closure, hole and cavity microwave irradiation are interlinked, first arc baffle wall by first fittings installed first microwave leak proof brush, the second arc baffle wall brush through the second fittings installed the second microwave leak proof. The invention by microwave irradiation sawyer will kill, makes the killing rate of 100%, and characterized by the good insecticidal effect. The mechanical structure as follows in Figure 5:

Structure of microwave irradiation

Mentioned in the present invention arc baffle the end of the opening and closing the structure of the snap button as shown in figure 7, the structure for optimizing structure, opening and closing of the snap button for concrete structure: the first reflex arc plate convex block set the end of July 23, 23 on both sides of the convex block with 29 arc grooves, the second arc baffle grooves set the end of June 22, respectively on the 22 of the two grooves inside open half spherical tank 24, 24, respectively, on both sides of the opening half spherical tank is set to half spherical tank 24 raised near the center of the block is 26, each half spherical tank are installed within 24 28, spring spring 28 end connected to the spherical bead 25, 25 set on spherical beads baffle ring 27, baffle ring located in the half spherical tank within 24, 27 and 26 limit stop. When the contact pressure affected by external force, fit two curved reflector, two spherical bead 25 at arc grooves in the 29, implement two arc fit reflex plate.

Figure 6 the structure of the snap button

Microwave insecticidal machine when using this design, the two pressure contact and collision tree trunk to make two reflex arc plate automatically closed, there will be a wormhole trunk as well in the closed two curved reflector formed the circular microwave irradiation cavity, at this point, the four microwave leak proof brush also closed with arc baffle ring shape formation, the two curved reflector closed after the formation of the circular cavity microwave irradiation to seal. Open microwave transmitter irradiation longicorn larvae, under the action of microwave irradiation, generate a lot of heat and moisture in the trunk at the same time, the longicorn larvae molecules under the action of microwave electromagnetic field produced deformation and vibration, make the function of the cell membrane produces change, until the cell membrane rupture, produce non-thermal effect, superposition of non-thermal effect and the heat generated by the trunk longicorn larvae were culling.

The Insecticidal Effect of Microwave Neutralising the Longicorn Larvae System

This design of neutralising the longicorn larvae microwave insecticidal machine, when use pull telescopic rod according to the height of trees to the length of the need, the microwave irradiation cavity into the trunk of a stem borer pest lateral, microwave irradiation cavity around the trunk and the cavity is closed, intermittent open microwave transmitter, the microwave irradiation cumulative time reaching 3 to 4 minutes, neutralising the longicorn larvae reached 100%, and trees 45 to 60 days, the continuous observation trees to normal growth, and before using microwave extermination are exactly the same, without any exception. The effect is according to the statistical data from experiment base. The applicant in the five years of poplar 1000 f to do the test, the poplar sawyer about 70% less trees are infection, the tree appear a large number of wormholes, peeling bark, longhorn beetle larvae into the depths of the trunk for 15 to 20 centimeters, the wormhole distribution within the limits of the upper 20 centimeters, was disseminated trees can be divided into two groups. Using the present invention insecticidal machine will fit with the trunk of the wormhole surrounded in microwave irradiation cavity, the first set of open microwave transmitter 60 seconds to stop and check the longicorn larvae death in about 31% and 60 seconds to stop and open the microwave transmitter, check the longicorn larvae death in about 70% and the third open microwave transmitter illuminate is 60 seconds, check the longicorn larvae insect body burst, all died. Continuous observation was light trees 45 to 60 days, tree growth all normal. By microwave irradiation at the same time, the second group of 80 seconds to stop and check the longicorn larvae death cases, 3 times, total radiation light 80 seconds after the stop check every time, when the third time after irradiation, check all longicorn larvae were killed, 45 to 60 days continuous observation by microwave irradiation trees, tree growth situation is the same as the first group, without any exception. The irradiation method, in the trunk of the wormhole within the scope of the upper 20 cm mobile microwave transmitter, repeat the above test method, inspection longhorn beetle larva mortality rates were 100%, and no impact for the growth of trees.

Figure 2 control system 3 . 1

 31 Figure 2 control system

Figure 3

 3 Figure 3 Microwave kill longicorn larvae circuit

Figure 5 mechanical structure 1 .

 1 Figure 5 mechanical structure 1.the cavity 2.connecting rod 3. The control panel 4variable pressure control panel 5.wire6.microwave reflector 30. universal joint.

  number

			Rated power (KW)
	Magnetron	90	0.9
	Intelligent thyristor	48	0.05
	cooling tower fan	1	1.1
	water pump	2	2.2
	elevator	1	0.75
	oil pump	1	0.37
	conveyor	1	2.2


Jian Zhou

Fengrong Zhang
email: bfrzhang@cau.edu.cn

Yan Xu

Yang Gao

Xiaoyu Zhao
email: ezhaoxiaoyu1992@sina.com

Relationship between Vegetation Coverage and Rural Settlements and Anti-desertification Strategies in Horqin Left Back Banner, Inner Mongolia, China

Keywords: Vegetation coverage, NDVI, Rural settlements, Anti-desertification, Horqin Left Back Banner (HLBB)

This paper investigated the relationship between vegetation coverage and rural settlements in Horqin Left Back Banner. There are 4 spatial patterns about the relationship between vegetation coverage and rural settlements, including high region-low region, high region-low region-high region, high region-low region-high region-low region, and high region. Around rural settlements, land is used as cultivated land and vegetation coverage is high. The overlap effect of overgrazing and extensive cultivation creates the first low region of vegetation coverage. With increasing distance from rural settlements, human disturbance to vegetation growth decreases, vegetation coverage increases, and the high region appears again. The second low region of vegetation coverage is caused by the overgrazing of another rural settlement. At the border region of 2 adjacent villages, 3 different conditions are presented with the vegetation coverage and rural settlements. In the first condition, vegetation coverage is low and is located at the intersection of both low regions of the 2 rural settlements. In the second condition, the vegetation coverage is high and is located at the intersection of both high regions of the 2 rural settlements. In the third condition, vegetation coverage is low and is located at the intersection of both low regions of the 2 rural settlements. According to the changing patterns and reasons for such patterns, we present strategies for antidesertification, including banning grazing, stopping extensive cultivation, promoting optimal choice of sand-fixation plant, and clarifying land property rights.

Introduction

Desertification, defined in the Convention to Combat Desertification and Drought in 1994 as "land degradation in arid, semiarid and dry sub-humid areas resulting from various factors including climatic variability and human activities," will most likely become the greatest threat to humanity in the future because it diminishes the Earth's capacity to support human beings with the steady increase in global population [START_REF] Chen | Desertification in north China: background, anthropogenic impacts and failures in combating it[END_REF]. Desertification is one of the most serious environmental and socioeconomic problems [START_REF] Kassas | Desertification: a general review [J][END_REF][START_REF] Zhao Halin | Effects of desertification on temporal and spatial distribution of soil macro-arthropods in Horqin sandy grassland, Inner Mongolia[END_REF]. Thus, many anti-desertification efforts have been made, including determination of the underlying mechanisms of desertification [START_REF] Fullen | Desertification and reclamation in North-Central China[END_REF][START_REF] Runnström | Is northern China winning the battle against desertification? Satellite remote sensing as a tool to study biomass trends on the Ordos Plateau in semiarid China [J][END_REF][START_REF] Zhanjin | Evaluation of aeolian desertification from 1975 to 2010 and its causes in northwest Shanxi Province, China [J][END_REF][START_REF] Duanyang | The dynamics of desertification in the farmingpastoral region of North China over the past 10 years and their relationship to climate change and human activity[END_REF], risk assessment of desertification [START_REF] Santini | A multi-component GIS framework for desertification risk assessment by an intergrated index[END_REF][START_REF] Ladisa | A GIS-based approach for desertification risk assessment in Apulia region, SE Italy [J][END_REF], monitoring of desertification development [START_REF] Hill | Monitoring 20 years of increased grazing impact on the Greek island of Crete with earth observation satellites[END_REF][START_REF] Del Barrio | Assessment and monitoring of land condition in the Iberian Peninsula, 1989-2000[END_REF][START_REF] Dawelbait | Monitoring desertification in a Savannah region in Sudan using Landsat images and spectral mixture analysis[END_REF][START_REF] Jinya | Monitoring and analysis of grassland desertification dynamics using Landsat images in Ningxia, China [J][END_REF], and investigating the effectiveness of anti-desertification projects [START_REF] Yulin | Effectiveness of sand-fixing measures on desert land restoration in Kerqin Sandy Land, northern China[END_REF][START_REF] Geli | Effectiveness of ecological restoration projects in Horqin Sandy Land, China based on SPOT-VGT NDVI data[END_REF][START_REF] Miao Renhui | Effectiveness of shrub planting and grazing exclusion on degraded sandy grassland restoration in Horqin sandy land in Inner Mongolia[END_REF]. China is one of the world's most desertification countries [START_REF] Tao | Research progress on aeolian desertification process and controlling in North of China [J][END_REF][START_REF] Feng | Combating desertification in China: Past, present and future[END_REF][START_REF] Yang | Desertification assessment in China: An overview [J][END_REF]. The desertified land in China occupies approximately 13 % of the country's total surface area and is a major source of Asian dust [START_REF] Zhenxin | A numerical simulation of dust storms in China[END_REF]. To address this problem, the Chinese government has launched several projects to fight desertification, such as "Three-North Shelterbelt Project" in 1978, "Grain for Green Project" in 1999, and "Beijing and Tianjin Sandstorm Source Controlling Project" in 2000. Because of these projects, the desertified land has been diminished and environment has become better in China, as well as in Horqin Sandy Land [START_REF] Yulin | Effectiveness of sand-fixing measures on desert land restoration in Kerqin Sandy Land, northern China[END_REF].

For desertification mechanism, the following is the general consensus: natural characteristics and human activities were the driving factors of desertification. However, at different locations and different periods, the main driving force of desertification is diversity. For instance, some researchers have proposed that desertification was caused by climate change in the Mu Su Sandy Land and Otindag Sandy Land and their adjacent regions, and this hypothesis was supported by archaeological evidence [START_REF] Weilin | When Maowusu become a desert? -View through new archaeologocal finds[END_REF][START_REF] Zhaoqing | The evolution of the Maowusu Desert and the reclamation in the adjacent areas in the Ming Dynasty[END_REF][START_REF] Wang | Evolution of the southern Mu Us Desert in North China over the past 50 years: An analysis using proxies of human activity and climate parameters[END_REF], whereas others have argued that human activities were the causes [START_REF] Renzhi | Mu Us Desert evolution as indicated by the deserted ancient cities along the Sjara River[END_REF][START_REF] Wei | Study on process of desertification in Mu Us Sandy Land for last 50 years, China [J][END_REF]. Meanwhile, previous studies explored the effect of single or multiple factors of human activities on desertification [START_REF] Zhaoqing | The evolution of the Maowusu Desert and the reclamation in the adjacent areas in the Ming Dynasty[END_REF][START_REF] Wang | Evolution of the southern Mu Us Desert in North China over the past 50 years: An analysis using proxies of human activity and climate parameters[END_REF]. Otherwise, rural settlement is the place where all human activities occur. The patterns of vegetation coverage around rural settlements are also not clear. So, it is significant to study the relationship from the micro view of rural settlement and from the comprehensive view of taking rural settlement as the place of human activities gathering, between rural settlement and desertification. Vegetation coverage can indicate desertification risk and is an important indicator of the fixation of sand dunes and the restoration of soil fertility. So understanding the patterns of rural settlements and vegetation coverage can offer scientific support for anti-desertification efforts. The following can be determined: the critical potential desertification area, how desertification spreads in area, and what strategies can be adopted to enhance the effects of anti-desertification methods.

As mentioned above, the aims of this study are the following: (I) investigate vegetation coverage patterns (desertification risk degree) around one rural settlement and between 2 adjacent rural settlements, (II) analyze the driving forces of the difference of vegetation coverage in different regions, (III) put forward strategies to anti-desertification by increasing vegetation coverage.

Study area and study transect

Study area

Horqin Left Back Banner (HLBB) is a county covered 11481 km 2 in Inner Mongolia and located in northern China with a geo-location from 121°30′E-123°42′E and 42°40′N-43°42′N (Fig. 1). HLBB lies in the agro-pastoral fragile ecotone, being a part of Horqin Sandy Land which is the first sandy land in area in China. Being a typical temperate continental climate type, its average annual temperature is 5.3 °C-5.9 °C. Average annual precipitation is 415 mm and is concentrated in June to August, accounting for 70 % of average annual precipitation. The average annual rainfall reduces from east to west and from south to north. Average annual evaporation is 3.9-4.5 times the average annual rainfall. Average annual wind speed is between 3.5 m/s-4.5 m/s and high-speed windy days are concentrated in winter and spring. Generally, the average number of windy days with a speed of >5 m/s (causing sand blowing) reaches 40 in one year. The landform in HLBB includes undulating sand dune, flat sand land, dune slack, and plain. Geomorphic characteristics are connections of fixedsand dune, semi-fixed sand dune, and moving sand dune and the alternative distribution of undulating sand land and marshy land. Sand dunes are mainly distributed in the north, south, and west of HLBB. The plain is located in the east. Aeolian sandy soil is the main soil type which takes up 68.9 % in all area of HLBB.

In general, the physical features of HLBB create conditions for the formation and development of desertification.

Being an agro-pastoral ecotone, the main animals raised in HLBB are sheep and cattle. Maize is the staple planting crop, and the cropping system is one harvest a year. In 2013, the population was 4.05 × 10 5 , and population density was 35/km 2 . The numbers of sheep and cattle were 4.678 × 10 5 and 4.013 × 10 5 , respectively. The maize planting area was 1.61 × 10 5 hm 2 accounting for 86% in all sown area.

Study transect

A total of 262 villages are in HLBB, and analyzing the relationship between vegetation coverage and rural settlement for each village would be difficult. Belt transect method was employed. A belt from north to south, which contains 9 villages (Fig. 1), was chosen. In the belt transect, precipitation ranges from 280 mm in the north to 360 mm in the south. The study transect is located in the sand dune distribution zone, which is vulnerable to land desertification. Elevation drops from 280 m to 40 m. Elevation of HLBB changes from 304 m to 14 m. Agriculture and animal husbandry coexist in the transect area. Cropping system is one harvest a year, and the crop is mainly maize. Thus, the study transect can represent the whole study area in natural conditions and production mode. Villages in the belt transect include Bayantala Gacha (BYTLGC), Momai Gacha (MMGC), Bianjie Gacha (BJGC), Baixingtu Gacha (BXTGC), Genggei Gacha (GGGC), Wuguan Gacha (WGGC), Wudantala Gacha (WDTLGC), Hailasitai Gacha (HLSTGC), and Xinaili Gacha (XALGC) from north to south. Gacha as an administrative unit is equal to village.

Materials and methods

Materials

Vegetation grows well in August because rainfall is rich in June to August [START_REF] Shuhai | Extraction of desertification information based on decision tree in northern Liaoning province[END_REF]. Some questionnaires on the above mentioned aspects were created. In this paper, NDVI was chosen as the vegetation index to reflect vegetation coverage and was calculated with the software of ENVI. Before calculating NDVI, radiometric calibration and atmospheric correction were made by ENVI. Then, geometric registration was conducted between reflectance imagery and land use map, and the registration accuracy was 0.205 pixels. The polygon layer of 9 rural settlements for 9 villages was converted into gravity center point layer to analyze the spatially changing patterns between the vegetation coverage and rural settlements with the help of geographic information system software (ArcGIS 10.0).

Methods

Vegetation index

Desertification is closely related to vegetation coverage. Low level vegetation coverage indicates high risk of desertification, especially in sandy land areas. NDVI is a significant measure that reflects vegetation coverage [27-28] and was calculated as Formula 1 [START_REF] Myneni | The interpretation of spectral vegetation indexes[END_REF][START_REF] Myneni | Interannual varations in satellite-sensed vegetation index data from 1981 to 1991[END_REF]. The higher NDVI value, the better the vegetation coverage.

) ( ) ( NIR RED / NIR RED NDVI    (1)
RED represents reflectance of red band and NIR represents reflectance of nearinfrared band.

Vegetation coverage changing patterns around one rural settlement and between 2 adjacent rural settlements

To analyze vegetation coverage changing patterns around one rural settlement and between 2 adjacent rural settlements, four directional lines (east, west, south, and north) were made. These lines started from gravity center points of rural settlements and ended at village boundaries by ArcGIS 10.0. Then, buffering was made for two sides of each line, and the buffering distance was 300 m with the help of ArcGIS 10.0; 300 m is equal to the length of 10 grids. At last, starting from intersection point of the line and the boundary of rural settlement polygon to village boundary, a NDVI value was obtained by averaging NDVI values of 10 grids every 30 m. In this way, vegetation coverage changing condition was obtained in the 4 directions (Fig. 2). The vegetation coverage of 4 directions represents vegetation coverage condition around one rural settlement.

One line was made to connect 2 adjacent rural settlements, and the buffering distance for 2 sides of each line was 300 m (Fig. 2). Starting from the intersection point of connected line and the boundary of one rural settlement polygon and ending at the intersection point of connected line and the boundary of the other rural settlement polygon, the averaged NDVI was calculated every 30 m to determine vegetation coverage condition between 2 rural settlements. In terms of NDVI changing trend in each direction, 4 changing patterns of NDVI were obtained, as follows: high region-low region, high region-low region-high region, high region-low region-high region-low region, and high region.

Sixteen directions of 9 rural settlements had the NDVI changing pattern of high region-low region, as follows: BYTLGC-E, MMGC-S, MMGC-W, BJGC-S, BJGC-W, BXTGC-N, BXTGC-S, BXTGC-W, GGGC-N, WGGC-S, WGGC-E, WDTLGC-N, WDTLGC-E, HLSTGC-N, HLSTGC-E, and XALGC-E (Table 1). Mean NDVI values of 16 high regions changed from 0.58 to 0.81, and mean NDVI values of 16 low regions changed from 0.26 to 0.48. The maximum ratio of average NDVI value of high region to that of low region was 3.12 in XALGC-E, and the minimum ratio was 1.46 in BXTGC-N. In general, mean NDVI value of high regions was twice higher than that of low regions. Lengths of high regions varied from 330 m to 3510 m, and the average length was 1721.25 m. Lengths of low regions changed from 360 m to 3510 m. The average length was 1638.75 m (Table 5). Eleven directions of 8 rural settlements had the NDVI changing pattern of high region-low region-high region, as follows: BYTLGC-N, BYTLGC-S, BJGC-N, BXTGC-E, GGGC-S, WGGC-W, WDTLGC-S, WDTLGC-W, HLSTGC-S, XALGC-N, and XALGC-W (Table 2). NDVI values of the first high regions varied from 0.49 to 0.86, and average NDVI value of the first high regions was 0.68. NDVI values of the second high regions changed from 0.33 to 0.93, and average NDVI value of the second high regions was 0.64. NDVI values of low regions changed from 0.26 to 0.71, and average NDVI value of low regions was 0.44. The maximum, average, and minimum ratios of average NDVI value of the first high regions to that of low regions were 2.23, 1.55, and 1.11, respectively. The maximum, average, and minimum ratio of average NDVI value of the second high regions to that of low regions were 2.50, 1.45, and 1.10, respectively. Lengths of the first high regions varied from 480 m to 1590 m, and the average length was 913.64 m. Starting distances of low regions away from the boundary of rural settlement varied from 510 m to 1620 m. The average starting distance away from the boundary of rural settlement was 943.64 m. Ending distances of low regions away from the boundary of rural settlement ranged from 1110 m to 4350 m. The average distance away from the boundary of rural settlement was 3043.64 m. The average length of low regions was 2100 m. Starting distances of the second high regions away from the boundary of rural settlement varied from 1140 to 6490 m. The average length of the second high regions was 886.36 m (Table 5). Five directions of 5 rural settlements had the NDVI changing pattern of high region-low region-high region-low region, including BYTLGC-W, MMGC-N, BJGC-E, WGGC-N, and HLSTGC-W (Table 3). NDVI ranges of the first high regions, the first low regions, the second high regions, and the second low regions were 0.54 to 0.74, 0.30 to 0.43, 0.65 to 0.74, and 0.27 to 0.45, respectively. The average NDVI values of the first high regions, the first low regions, the second high regions, and the second low regions were 0.65, 0.37, 0.71, and 0.36, respectively. Average length of the first high regions was 648 m. The average starting distance and average ending distance away from the boundary of rural settlement of the first low regions were 678 and 2964 m. The average length of the first low regions was 2286 m. The average starting distance and average ending distance away from the boundary of rural settlement of the second high regions were 2994 and 4644 m. The average length of the second high regions was 1650 m. The average starting distance away from the boundary of rural settlement of the second low regions was 4674 m and the average length of the second low regions was 2220 m (Table 5). Another NDVI changing pattern for 3 directions of 3 rural settlements was high region, including MMGC-E, GGGC-E, and XALGC-S (Table 4). Average NDVI values of 3 directions were 0.68, 0.85, and 0.90 respectively. Lengths of 3 directions were 660, 2580, and 1440 m. Generally, the location selection of rural settlement give preference to the place that is rich in water and is fertile in soil resource. So, around one rural settlement, land is exploited into cultivated land and used for food supply and economic income. Furthermore, according to our field research, to keep the sustainable use of the relatively fertile cultivated land, farmers take conservation tillage (for example, crop straw stubble and no-tillage) to fertilize soil and reduce soil wind erosion under windy and less rainfall circumstance. Crops planted in the cultivated land around rural settlements grow well, and NDVI value is high. HLBB is a coexistence zone of farming and grazing and is a vast territory with sparse population. This zone had a population density of 35/km 2 in 2013. Outside cultivated land around rural settlements, the main land use type is grassland. Compared to the limited population, the area of grassland is vast. In case of drought years, the farmers adopt extensive cultivation to get grain. In this way, many grasslands are exploited and planted. However, the exploited land is abandoned in the next few years due to quick decrease in soil fertility after land use. According to the report of grassland resource survey in HLBB, all grassland may be exploited, planted, and abandoned within 8 years. This land use mode destroys land vegetation, and land becomes vulnerable to desertification. At the same time, grazing economy is a significant part of the family income for farmers, which can contribute >50 % of the total family income. Although banning grazing is conducted during 1 May to 1 June every year in HLBB, overgrazing still exists during other times in this zone according to our surveys. Overgrazing and extensive cultivation is devastating to the growth of vegetation. Thus, the NDVI changing pattern of high region-low region is formed, and the low region of NDVI is vulnerable to desertification.

On the basis of NDVI changing pattern of high region-low region, NDVI value increased with increasing distance from rural settlements, thereby indicating that vegetation coverage is improving. Average distance from the starting point of the second high region of high region-low region-high region to the boundary of rural settlement was 3073.64 m. According to our field survey, grazing distance is also about 3000 m. Furthermore, with increasing distance from rural settlement, farmers will not attempt cultivation. Thus, cultivation declines until no cultivation occurs. This finding demonstrated that vegetation coverage can improve in a manner similar to the vegetation coverage of cultivated land around rural settlements if vegetation could grow without disturbance from overgrazing and extensive cultivation in HLBB. The NDVI changing pattern of high region-low region-high region is formed. Relevant literatures and data showed that water consumption of grass is less than 300 mm, and some shrubs consume less than or about 300 mm of water; for example, Haloxylon ammodendron and Caragana microphylla [START_REF] Xuexiang | Water consumption characteristic of Haloxylon ammodendron for sand binding in desert area [J][END_REF][START_REF] Guangyang | Characteristics of Caragana microphylla sap flow and water consumption under different weather conditions on Horqin sandy land of northeast China [J][END_REF]. The average annual rainfall of HLBB was 328.5 mm during the vegetation growth period. Natural rainfall satisfies the water demands of grass and some shrubs in a large portion of HLBB. Thus, grass and shrub plants rather than trees should be chosen, and overgrazing and extensive cultivation should be forbidden in anti-desertification strategies in HLBB. Thus, shrub and grass can grow well, and vegetation coverage can be high.

Another changing pattern of NDVI was high region-low region-high region-low region. The average distance from starting point of the second low region to the boundary of rural settlement was 4674 m, which was the farthest away from rural settlement and was the other rural settlement. This changing pattern can be explained in the section on "vegetation coverage between rural settlements."

For MMGC-E, GGGC-E, and XALGC-S, NDVI changing patterns were high region only. Lengths of high regions were 660 and 1440 m for MMGC-E and XALGC-S, respectively. Lengths of the 2 high regions are short relatively, and land is used for cultivation. For GGGC-E, a river passes through from west to east. Water resource is relatively rich, and land is used for cultivation. So, NDVI values are high in the 3 directions. As to GGGC-W, several small scale rural settlements exist along the river, which can affect land use. Thus, no obvious change in trend of NDVI was observed (Fig. 3).

Fig. 3. NDVI changing condition of GGGC-W

In all, a high region of NDVI existed near rural settlements, in which land does not easily undergo desertification. Desertification does not occur easily because land near rural settlements is used for cultivation and is tilled year after year. Outside of cultivated land near rural settlement was a low region of NDVI that comprises mainly grassland. Because overgrazing and extensive cultivation, both of which destroy vegetation growth, coexist in this region, vegetation coverage is poor, and the land is vulnerable to desertification. With increasing distance from rural settlement, a high region of NDVI appears which indicates that vegetation coverage is improving. This phenomenon is mainly due to the decline of effect of human disturbance on vegetation growth, and rainfall can meet the water demand of shrubs and grass. If human disturbance to vegetation growth can be stopped, restoration of vegetation can succeed. As to the second low region of high region-low region-high region-low region, an explanation is given in the section on "vegetation coverage between rural settlements." region-low region-high region-low region. For the rural settlements with NDVI changing pattern of high region-low region-high region-low region, the second low region does not result from the extensive cultivation and overgrazing itself, but rather from the overgrazing of the other rural settlement. This phenomenon can be demonstrated by distances from the juncture of village boundary and connected line of 2 adjacent rural settlements to 2 rural settlements. The distance from the juncture to BYTL, which had the NDVI changing pattern of high region-low region, was 4350 m. Distance from the juncture to MMGC, which had the NDVI changing pattern of high region-low region-high region-low region, was 5160 m. The distance from the juncture to BXTGC, which had the NDVI changing pattern of high region-low region, was 2340 m. The distance from the juncture to BJGC, which had NDVI changing pattern of high region-low region-high region-low region, was 4410 m. The distance from the juncture to GGGC, which had the NDVI changing pattern of high regionlow region, was 4590 m. The distance from the juncture to MMGC, which had NDVI changing pattern of high region-low region-high region-low region, was 4890 m. Human disturbance from rural settlements with the NDVI changing pattern of high region-low region is the reason for the formation of the second low region of high region-low region-high region-low region. According to our field surveys, junction area is closer to the rural settlements, which have NDVI changing pattern of high region-low region. Overgrazing at the second low region mainly comes from the closer rural settlements. At the same time, overgrazing from the farther rural settlements is vanished. In the second condition, vegetation coverage at junction area of 2 villages was at the intersection of high region of one rural settlement and high region of the other rural settlement. One rural settlement had the NDVI changing pattern of high regionlow region-high region, whereas the other had the pattern of high region. Distance from the juncture to MMGC, WGGC, and XALGC, which had NDVI changing pattern of high region, were 630, 1230, and 960 m. Distances from the juncture to BJGC, WDTLGC, and HLSTGC, which had NDVI changing pattern of high regionlow region-high region, were 2520, 3300, and 3390 m, respectively. Because distance from the juncture to rural settlements with NDVI changing pattern of high region-low region-high region is farther, human disturbances to the junction zone decreases. At the same time, distance from the juncture to rural settlements with NDVI changing pattern of high region is nearer, and land is used for cultivation. Thus, the vegetation coverage at the junction area improves.

In the third condition, vegetation coverage at junction area of 2 villages was at the intersection of low region of one rural settlement and low region of the other rural settlement. Both rural settlements had the NDVI changing pattern of high region-low region. NDVI at the junction area is much smaller than that of the high region. These results are due to the overgrazing and extensive cultivation from 2 rural settlements. Land in the junction area is more vulnerable to desertification.

Conclusions

Four NDVI changing patterns existed around rural settlements, as follows: high region-low region, high region-low region-high region, high region-low region-high region-low region, and high region. Due to natural conditions, for example water and soil, land is used as cultivated land around rural settlements, and vegetation coverage improves. Outside of high region around rural settlements is a low region of NDVI because of the overlapping effects of overgrazing and extensive cultivation; thus, the area is vulnerable to desertification. With the increase of distance far away from rural settlements, human disturbance decreases, vegetation coverage improves, and the high region of NDVI appears again. For the second low region of NDVI of high region-low region-high region-low region, it comes from the overgrazing of another rural settlement. There were 3 conditions of vegetation coverage at the border region of 2 adjacent villages. First, vegetation coverage at junction area of 2 adjacent villages was at the intersection of low region of one rural settlement and low region of the other rural settlement. One rural settlement had NDVI changing pattern of high region-low region, and the other rural settlement had NDVI changing pattern of high region-low region-high region-low region. The second low region of high region-low region-high region-low region for one rural settlement results from the other rural settlement's overgrazing. Second, vegetation coverage at junction area of 2 adjacent villages was at the intersection of high region of one rural settlement and high region of another rural settlement. One rural settlement had NDVI changing pattern of high region-low region-high region and the other rural settlement had NDVI changing pattern of high region. Third, vegetation coverage at junction area of 2 adjacent villages was at the intersection of low region of one rural settlement and low region of the other rural settlement. Both rural settlements had NDVI changing pattern of high region-low region. The overlap effect of overgrazing and extensive cultivation from 2 rural settlements makes the NDVI at junction area much smaller.

Strategies for anti-desertification

Vegetation coverage condition is closely related to land desertification. Outskirt of cultivated land around rural settlements is the emphasis area of anti-desertification because the vegetation coverage is poor and overgrazing and extensive cultivation are severe in this area. Banning grazing and stopping extensive cultivation should be done to protect vegetation growth and to further promote anti-desertification. At the same time, far away from rural settlements, another high region of NDVI appears again, indicating that vegetation can grow well in the study area when no human disturbance affects vegetation growth. Integrating with the natural condition of the study area, grasses and shrubs rather than trees should be chosen for antidesertification. Thus, vegetation can show improved growth, and anti-desertification efforts can succeed further.

The formation of the second low region of NDVI for high region-low region-high region-low region comes from overgrazing of another rural settlement. NDVI value at junction area of 2 adjacent villages, which had the NDVI changing pattern of high region-low region, is much lower. Unclear grassland poverty makes the misuse land resource at the junction area. So, clarification of land property right can affect the rational use of grassland and can help in anti-desertification.

Differences exist among rural settlements in terms of population and number of livestock. Length is different for the same region in the different NDVI changing patterns. So, the determination of emphasis zone range for anti-desertification should be combined with the specific situation of rural settlements.

Fig. 1 .

 1 Fig. 1. The location of HLBB and the selected rural settlements

Fig. 2 .

 2 Fig. 2. Directional line of each rural settlement and connected line of 2 adjacent rural settlements

  Note: Dot in the curve means the juncture of village boundary and connected line of 2 adjacent rural settlements; a represents the first condition and b represnts the second conditon.

Fig. 4 .

 4 Fig. 4. NDVI changing trend between 2 adjacent rural settlements for the first condition and the second condition

Fig. 5 .

 5 Fig. 5. NDVI changing trend between 2 adjacent rural settlements for the third condition

Table 1 .

 1 NDVI changing pattern of high region-low region Village name and direction Starting distance/m Ending distance/m Average NDVI

	BYTLGC-E	0 1080	1050 2250	0.70 0.41
	MMGC-S	0 1860	1830 2730	0.73 0.30
	MMGC-W	0 2220	2190 3450	0.79 0.47
	BJGC-S	0 2910	2880 4890	0.58 0.29
	BJGC-W	0 780	750 2190	0.70 0.36
	BXTGC-N	0 780	750 2100	0.70 0.48
	BXTGC-S	0 360	330 4200	0.68 0.38
	BXTGC-W	0 1170	1140 5880	0.69 0.34
	GGGC-N	0 840	810 1740	0.59 0.32
	WGGC-S	0 3240	3210 5070	0.78 0.35
	WGGC-E	0 3060	3030 3360	0.76 0.45
	WDTLGC-N	0 3540	3510 5130	0.63 0.33
	WDTLGC-E	0 630	600 2130	0.73 0.35

Table 2 .

 2 NDVI changing pattern of high region-low region-high region

	Village name and direction Starting distance/m	Ending distance/m	Average NDVI
		0	630	0.59
	BYTLGC-N	660	3510	0.40
		3540	5400	0.60
		0	870	0.49
	BYTLGC-S	900	4290	0.30
		4320	6600	0.33
		0	1380	0.54
	BJGC-N	1410	3630	0.27
		3660	4080	0.47
		0	480	0.66
	BXTGC-E	510	3270	0.36
		3300	3390	0.47
		0	990	0.83
	GGGC-S	1020	2940	0.42
		2970	5070	0.57
	WGGC-W	0	690	0.79

Table 3 .

 3 NDVI changing pattern of high region-low region-high region-low region

	Village name and direction Starting distance/m Ending distance/m Average NDVI
		0	330	0.54
	BYTLGC-W	360 3510	3480 4800	0.38 0.74
		4830	7920	0.42
		0	510	0.74
	MMGC-N	540 4020	3990 4500	0.43 0.73
		4530	8100	0.35
		0	870	0.59
	BJGC-E	900 2010	1980 2430	0.30 0.70
		2460	2700	0.32
	WGGC-N	0	870	0.68

Table 4 .

 4 NDVI changing pattern of high region

	Village name and direction Starting distance/m Ending distance/m Average NDVI
	MMGC-E	0	660	0.68
	GGGC-E	0	2580	0.85
	XALGC-S	0	1440	0.90

Acknowledgment

We would like to recognize the National Science Foundation of China (grant 4127111) and the Special Scientific Research of the Ministry of Land and Resource (grant 201411009) for the support of related data and yield survey. We are grateful to the Inner Mongolia Land Surveying and Planning Institute and Inner Mongolia Land Consolidation Institute for support.

Vegetation coverage between rural settlements

For vegetation coverage at the border region of 2 adjacent villages, 3 conditions for 8 connected lines existed according to NDVI changing trend along each connected line. First, vegetation coverage at junction area of 2 adjacent villages was at the intersection of low region of one rural settlement and low region of the other rural settlement, including: BYTLGC-MMGC, BJGC-BXTGC, and GGGC-WGGC (Fig. 4a). Second, vegetation coverage at junction area of 2 adjacent villages was at the intersection of high region of one rural settlement and high region of the other rural settlement, including MMGC-BJGC, WGGC-WDTLGC, and HLSTGC-XALGC (Fig. 4b). Third, vegetation coverage at junction area of 2 adjacent villages was at the intersection of low region of one rural settlement and low region of the other rural settlement, including BXTGC-GGGC and WDTLGC-HLSTGC (Fig. 5). The difference between the first and third conditions was the NDVI changing pattern of rural settlement.

In the first condition, NDVI changing pattern of one rural settlement was high region-low region, and NDVI changing pattern of the other rural settlement was high


Shasha Li

Research on Coordinated Development between Animal Husbandry and Ecological Environment Protection in Australia

Keywords: Australia, animal husbandry, ecological environment, Intensive management

Australia is one of the countries whose scientific level of usipng grassland resources and animal husbandry development level is very high and the way to coordinate Australia's animal husbandry and ecological environment protection is worth using for reference. This study focuses on facilities about the Australian government's controlling and protecting of ecological environment in the process of development of animal husbandry, and combines with the current problems in the process of China's animal husbandry development, in order to explore a suitable path for implementing the animal husbandry sustainable development in China.

Introduction

The animal husbandry in Australia is rather developed where sheep and cattle are the main livestock. In addition, the number of sheep in Australia is the top in the world, and Australia is known as "riding on the sheep's back country". In the early, the development model of Australia's animal husbandry tended to rough grazing.Since the early 19th century, European settlers' increasing investment in science and technology, introducing high quality forage grass and implementing policies and measures are conducive to the development of animal husbandry. Especially after the Second World War, the number of Australia's livestock breeding stock and livestock production increased significantly. In 1972, compared with 1950, the number of cattle and sheep breeding stock increased by 87% and 44% respectively and wool production grew by 89% in comparison to the average output from 1947 to 1949.

In addition, compared with 1955, the beef and egg production increased by 86% and 95% respectively [START_REF] Wu | Advanced animal husbandry of Australia [J][END_REF] . During this period,there are mainly three points about the cause of the rapid development of animal husbandry in Australia. The first point is that during the post-war, world economy began to recover andthe demand for animal products increased at home and abroad. Developing animal husbandry can not only meet the domestic demand, can increase income through export animal products. So animal husbandry industry had more obvious competitive advantage than other industry. The second point is that the Australia government ordered the Italian prisoners of war to engage in livestock production, which increased the required labor input during the process of livestock production from 1941 to 1947.

The third point is that combined with the domestic and international market demand, the Australia government guided the livestock farmers to adopt the latest Science and Technology and farming equipment, what is more, the government implemented financial support and policy inclination to development the animal husbandry. Considering the scarcity of resources and the protection of ecological environment and basing on the conditions of natural resources and markets all over the world, the Australian government continuously adjusted the animal husbandry development policy in order to realize the coordinated development of animal husbandry and ecological environment protection.

Since the reform and opening, with the aid of the push of market economy, government policy support and irregular factors, China's animal husbandry were integrated and were in the transition period from extensive to intensivelittle by little. Extensive development pattern makes natural environment deterioratingsurrounding China's pastoral areas, which make the protection of natural resourcesface great challenge. This study summarizes the current development situation, the characteristics of the development of animal husbandry in Australia and the policy support and emphasis on the measures to protect the ecological environment in the process of sustainable development of animal husbandry. Analysis of Australian animal husbandry development can guide to seek a suitable way for China to coordinate animal husbandry development and ecological environment protection.

Current development situation of graziery industry in Australia

Australia's land area is about 7.68 million Km 2 , and the number of populationis about 23.71 million people of which 80% distribute in the eastern coastal areas. Most area of Australia is plain region, the climate is relatively dry and seasonal temperature difference is inconspicuous.The unique climate conditions in Australia forms a perennial natural pasture grazing. 55% of the land area is used to develop animal husbandry whose output value accounted for about 80% of the agricultural output in 2014. Animal husbandry in Australiaoccupies an irreplaceable position in the agricultural and even the entire national economy. In Australia,over average, everyone owned 5.00 sheep and 5.00 cowsin 2011. However, compared with the Australia,the Chineseperson just has the number of sheep and cattle less than a quarter [START_REF] Xuwen | Introduction of animal husbandry in Australia and its implication for China[END_REF] .

Data source:FAO statistical database(http://faostat.fao.org/)

Fig.1 Main livestock number of Australia from 1993 to 2013

Australia's sheep and goat breeding stock is the largest, followed by chicken and beef. From 1993 to 2013, Australia mainly livestock breeding stock is on the decline on the whole. From From 2006 to 2011, the number of beef, muttonand red meat production decline year by year (table 1).Combined with figure 1, it can be seen that the Australian animal husbandry is in the transition to a new development model. There are two possible reasons: the first one is that animal products exports accounts for a large proportion of total outputin Australian [START_REF] Xingwen | The characteristic of animal husbandry economy in Australia [J][END_REF] .With the rapid development of animal husbandry in emerging countries, the international market for Australia's livestock reliance declines, resulting in the decrease of breeding stock. The second one is that with the all-round development of economy, the international market increases demand for some of the agricultural economic crops, such as soybeanandrapeseed, so planting economic crops has more competitive advantage than raising livestock, which makes laborer to increase the crop planting area in parts of Australia animal husbandry area.

Note: Excludes Northern Territory, Tasmania and the Australian Capital Territory

According to above analysis, the Australian animal husbandry is transforming from a single animal husbandry toplanting-culture combined animal husbandry development model gradually.

The characteristics of harmonious development between graziery and ecology environment in Australia

Since the idiographic climate in Australia, natural pasture is the main food of animal composite feed. After more than 200 years of development, animal husbandry in Australia has completed transformation and upgrading and the ecological environment is protectedsimultaneously in the process of animal husbandry industry in Australia.In extensive development phase, the utilization of grassland resource in Australia also experienced overgrazing, pasture degradation and desertification process. In the early 20th century, the grassland in Australia has reached the ceiling of the bearing capacity and the deterioration of ecological environment has endangered the healthy development of animal husbandry. The stockholderstookpositive and effective cooperation to prohibitovergrazing behavior and improved ecological environmentfinally.

Seeding to revive ranch, formulating appropriate grazing capacity

According to soil conditions and climatic environment, planning different varieties of forage can not only balance the year's yield, but also helps to improve the quality of soil and increase the yield and to optimize the quality. Grassland yield of forage planting is five times as much as natural grassland [START_REF] Lizhong | Experience in the development of grassland animal husbandry in Australia and New Zealand[END_REF] . Grassland yield and regeneration ability determine the grassland grazing capacity.The Australian government boosted grassland ecological construction and decided appropriate grazing capacityaccording to the production capacity of grassland and grassland recovery ability to prevent the grassland desertification caused by overgrazing grassland. Each family determines reasonable scale of breeding according to suitable grazing capacity to avoid the behavior of grassland overgrazing.

Rotation grazing on an area basis and grazing off season

According to the different growth stages of herds, combining with the carrying capacity of grassland, the herdsmanadjusts grazing stages scientifically and managesgrassland pasture to guarantee the sustainable utilization of grassland resources. In addition, Australian governmentdivided grazing area all over the country into four different types of the grassland animal husbandryaccording tothe precipitation, temperature, and soil conditions such as low density livestock grazingdistrict, natural grassland grazing area, mixed farming zone and high density grazing area [START_REF] Baiming | Agriculture resources and their regional distribution in Australia[END_REF] . In the same zone, livestock farmers dividedfamily farm into several small areas of which 20% of the pastoral areas of grazing to protect other pasture grass growing in order to maximize the biomass.

Grazingin accordance with the law and utilizing the water resource rationally

The Australian government had strict rules on grassland construction, the development of environmental protection, water conservancy etc. The government would imposesevere penalties on violators, which ensured the coordinated development between animal husbandry and ecological environment protection and cultivated the ecological environment protection consciousness of farmers and herdsmen at the same time. The weather of Australian outback is drought where the average annual rainfall is less than 200 mm. In order to protect the grassland yield, it is indispensable to exploit and utilize water resources. In Australia, livestock farmers built small water storage low dam, reservoir and other water engineering projectgenerally.Storage of water resources ensures livestock drinking water and grassland irrigation.

Australian animal husbandry development model for China's enlightenment

As people living standard rising, for Chinese people, demand for animal products is on the rise. What's more,the price of domestic beef and mutton market is higher, which causespart of the pastoral areas overgrazing phenomenon, resulting in bearing pressure increasing and grassland ecological environment destructed [START_REF] Liu | Current status and main tasks of pratacultural development in China[END_REF] . In recent years, in order to maintain sustainable use of grassland, the Chinese government is strengthening the construction of grassland ecology and intensifying the efforts on ecological protection, such as returning farmland to grassland project and ecological compensation mechanism. However, support on the investment of pastoral animal husbandry development still has a lot of space [START_REF] Tao | Debate between grassland ecological protection and herdsmen's income[END_REF] .At the same time, livestock farmers list livestock production as the first goal at the current stage and lack the protectionenvironment consciousnessabout grassland ecological [START_REF] Yunhang | Animal husbandry in Australia[J][END_REF] . Although there are some difference about the basis of existing on the animal husbandry between Australia and China, China can combine their own development period of animal husbandry and existing problems to explore asustainable development way to coordinate animal husbandry development and ecological environment protection.

4.1 Planning and constructing regional and special pastoral areas to the climatic conditions all over China and the annual average precipitation, China shoulddivide and construct pastoral area and set up the appropriate grazing way to achieve balanced development in breedingaccording to the localterritory characteristicsto protect grassland resources and ecological environmenteventually.Referring to ecological grassland division from RenJizhou [START_REF] Renjizhou | Assumed plan on grassland ecological reconstruction in the source region of Yangtse River, Yellow River and LantsangRiver[END_REF] , we can divideChinese grassland animal husbandry into the following areas, such as north desert scrub area, qinghai-tibetalpine region, onobrychisuiciaefolia, the northeast forestdistrict, southwest karst mountain thickets grassland ecological economic zone and southeastevergreen broad leaved forest area.Planning and constructing regional and special pastoral areas is beneficial to promote the development of animal husbandry and ecological environment protection.

Planting grass and improving pastures

To alleviate the prairie excessive load problem, Australia government promoted to cultivate grass artificially. This move can not only guarantee the supply of grass feed and improve the soil butaccelerates the sustainable development. One of the methods to improve pasture construction is cultivating artificial grassland in the pastoral areas of China. In different area, herdsman shouldcultivate and plant suitable grassaccording to local climate and soil conditions. At the same time, the aid of soil testing and fertilizer technology on the shortage of trace elements in soilcan promote the growth of grass. In addition, the same pastoral areas should be divided into different farming area and the shepherd also should delimit the pasture use ratio to ensure the rest of the time grazing plot of grass growing.

Conducting water conservancy facilitiesconstruction

Water resources is the necessary means of production in the process of herbage growth, in pastoral areas with less precipitation, effective supply of water resources is a necessary condition for the sustainable development of animal husbandry. According to pasture areaand grazing capacity, the farm family can select suitable water conservancy project, such as the construction of reservoirs, small reservoirs, deep well and so on.If the condition is appropriate, the government can also construct large water conservancy facilities.

Strengthening the grassland ecological protection ability andpassing relevant laws and regulations for the protection of grassland ecological environment

The protection of the ecological environment is dependent on the government's support and guidance. The Chinese government should be on the basis of the existing ecological construction projects, strengthen ecological environmental protection, return grazing land to grassland continually, moderate grazing capacity and implement the effective governance of desertification and sandstorm. In recent years, the Chinese government issued some laws and regulationsabout ecological environment protection and the construction of grassland, which has obtained the good effect. These measures played a significant role in promotingtransformation of animal husbandry and ecological breeding. However, under the comprehensive effect of the inherent mode of production and the external economic environment, ecological protection consciousness of farmers still need to be further improved. The Chinese government should draw lessons from the Australian government's relevant measures, such as strengthening the professional training of herdsmen, intensifying the communication and collaboration between different pastoral areas, etc.

Conclusions

This study argues that theanimal husbandry of China should be based on the long-term view, pay attention to ecological environment protection in the process of animal husbandry and implement sustainable development strategy. Through summarizing the measures to coordinate the animal husbandry and ecological environment protection in Australian, combining with the current problems in the development of animal husbandry in China,this paperputs forward the planning and construction of regionalization and specialization, the construction of cultivated grassland in pastoral area and improvement of grassland,promoting water conservancy facilitiesconstruction, strengthening the protection of grassland ecologyand introducing relevant laws and regulations for the protection of grassland ecological environment policy suggestions, meanwhile, shoulddevelop modern animal husbandry and improve the ecological environment to promote the sustainable development of animal husbandry in Chinaultimately.

Acknowledgment

Funds for this research was provided by the Modern Agricultural Industry Technology System of China(CARS-41-K26)and China's Livestock and Poultry Industry Research Project during the 13th Five-Year Plan

figure 1 ,

 1 figure1, we can see that the sheep and goats breeding stock decline relatively obvious, down from 1.40 million in 1993 to 2013 in 0.71 million, dropping about 49.28%. The number change of beef cattle and pig breeding stock is not obvious, of which the former increased but pig breeding stock has a downward trend.From 2006 to 2011, the number of beef, muttonand red meat production decline year by year (table1).Combined with figure1, it can be seen that the Australian animal husbandry is in the transition to a new development model. There are two possible reasons: the first one is that animal products exports accounts for a large proportion of total outputin Australian[START_REF] Xingwen | The characteristic of animal husbandry economy in Australia [J][END_REF] .With the rapid development of animal husbandry in emerging countries, the international market for Australia's livestock reliance declines, resulting in the decrease of breeding stock. The second one is that with the all-round development of economy, the international market increases demand for some of the agricultural economic crops, such as soybeanandrapeseed, so planting economic crops has more competitive advantage than raising livestock, which makes laborer to increase the crop planting area in parts of Australia animal husbandry area.

Table 1 Main livestock products of Australia from 2006-2010 t

 1

	Year	Beef	Veal	Mutton	Lamb	Pig	Total red meat	Chicken(a)
	2006-07	2 195 714	30 578	270 988	412 584	381 866	3 291 730	811 591
	2007-08	2 105 706	26 417	243 119	428 388	374 409	3 178 038	797 280
	2008-09	2 098 615	26 489	219 820	415 867	321 005	3 081 798	832 456
	2009-10	2 056 514	52 262	161 774	412 537	331 261	3 014 347	834 409
	2010-11	2 089 233	44 133	123 245	391 340	342 101	2 990 052	1 014 978

Data sources: Bureau of Statistics of Australia(2012).


Jinheng Zhang

Yonghong Sun

Lusheng Zeng

Hui Wang

Qingzeng Guo

Fangli Sun

Jianmei Chen

Chaoyu Song

Distinguish Effect of Cu, Zn and Cd on Wheat's Growth Using Nondestructive and Rapid Minolta SPAD-502

Keywords: Cu, Zn, Cd, SPAD-502, Wheat

des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

1.Introduction

Heavy metals (HM) means that some elements which have specific weights of more than 5 g/cm 3 (M. M. [START_REF] Lasat | Phytoextraction of metals from contaminated soil: a review of plant/soil/metal interaction and assessment of pertinent agronomic issues[END_REF]. Industrial revolution causes high anthropogenic emission of heavy metals into soil and water [START_REF] Ayres | Toxic heavy metals: materials cycle optimization[END_REF].Plants' rootsare the primary contact site for the metal ions (Eisenreich W,1996). As for plant metabolism, HMs such as Cu and Zn are essential microelement. But when present in excess, Cu and Zn also can become extremely toxic just like low levels of Cd, Hg, and Pb, (Dharmendra K. Gupta,2013). Incorporated various techniques of analysis have been used to quantify the effects of HMs on plant including leaf injury with visual assessment, biochemical assessment and spectral measurements.

The SPAD-502 meter uses two light-emitting diodes (650nm and 940nm) and a photodiode detector. The light-emitting diodes and photodiode detector measure transmission sequentiallythrough leaves (John [START_REF] Markwell | Calibration of the Minolta SPAD-502 leaf chlorophyll meter[END_REF]. SPAD-502 has been utilized for determining the nitrogen status, chlorophyll content, thickness of leaf , succulence of leaf , specific leaf area, leaf mass, leaf water content, photosynthesis, and so on. [START_REF] Campbell | Growing conditions alter the relationship between SPAD-501 values and apple leaf chlorophyll[END_REF]Castelli F, 1996;Azia ,2005). SPAD readings come from the leaves' transmitted spectra at 650nm and 940nm. It has been recognized as a simple and portable diagnostic tool to measure the greenness or chlorophyll content of leaves, thus it may become useful tool being used to assess the stress effects on plant growth.

The plant leaves had very strong enrichment ability for some elements and plant trace elements had a strong influence growth status of leaves, which can response to transmitted spectra of leaves at red and infrared bands used by SPAD. Few publications reported on SPAD as a tool to detect heavy metal stress of wheat. This research was undertaken to quantify the responses of SPAD readings of wheat among different heavy metal treatments. The objective of this present study was to find the potential of SPAD -502 assessing heavy metal Cu, Zn and Cd stress on wheat.

2.Materials and methods

The field plots (genotype of wheat is called Jimai 22) was treated with heavy metal Cu

4.Conclusion

Minolta SPAD-502 can be utilized to distinguish the effects of Cd, Cu, Zn on wheat as a nondestructive and rapid tool. The key findings from this research as follow:

(1) Different SPAD values appeared different growth stages of wheat under normal growing status. The highest SPAD values appeared at elongation and heading stages, which indicated the most vigorous growth stages of wheat are elongation and heading stages.

(2)The SPAD readings different and their standard deviations between CK and heavy metal treatment level i (CK and L1, CK and L2, CK and L3, CK and L4) showed that with the increased heavy metal treatment levels, the dispersion degree and standard deviations increased gradually, which indicated that the higher heavy metal concentration treatment, the more influence over wheat's growth.

(

(CuSO 4 •

 4 5H 2 O), Zn (ZnSO 4 • 7H 2 O) and Cd (3CdSO 4 .8H 2 O) at five-level treatments (see table1) and three repeated trials. Seed on 17 th October 2014. Plots with area of 2×3m 2 had been arranged in a randomized block consisting of same fertilizer applications (figure1). In-situ nondestructive SPAD values were measured by Minolta SPAD-502 on December 8 th 2014 (seedling stage), December 13 th 2014 (seedling stage), January 8 th 2015(tillering stage), April 18 th 2015 (elongation stage), April 30 th 2015 (booting stage), May 12 th 2015 (heading stage) and June 3 rd 2015 (filling stage) respectively. Middle of the upper full expanded leaves had been chosen to measure the SPAD values. In-situ Minolta SPAD-502 was taken 20-30 values per block. Table1. The concentration treatment levels of Cd

Figure1.

  Figure1. Distribution diagram of field plots (PVC sheets and earthen rows had been put among different blocks in order to block heavy metals diffuse among adjacent blocks)3.Results and discussion

Figure 3 .

 3 Figure 3. The dispersion degree increase gradually according to the sequence between CK and L1, CK and L2, CK and L3, CK and L4Compare the different between SPAD readings measured from check plot (CK) and heavy metal treatment level (L1), level2 (L2), level 3 (L3) and level 4 (L4) respectively at the whole growth stages. As the heavy metal treatment levels increased from L1 through L4, the dispersion degree increase gradually according to the sequence between CK and L1, CK and L2, CK and L3, CK and L4 (figure3 a,b,c,d). The dispersion degree also could be indicated by standard deviations of SPAD readings between CK and Level i (i =1,2,3,4 respectively). With the increase of heavy metal treatment levels, standard deviations of SPAD values increased step by step followed by the sequence between CK and L1 < CK and L2 < CK and L3 < CK and L4(figure4), which also can be proved by the SPAD value ratio of different level to CK (figure5).

Figure 4 .

 4 Figure 4. Compare standard deviation of SPAD values between CK and Level i (i =1,2,3,4 respectively)

Figure 5 .Figure 6 .

 56 Figure 5. SPAD value ratio of different level to CK

  3) Higher heavy metal level had lower Normalized SPAD values. Minimum difference of Normalized SPAD and standard deviation between CK and level i appeared at booting stage and heading stage. And Normalized SPAD among Cd, Cu and Zn treatments had lowest and similar variance at booting and heading stage. These results indicated that heavy metals have the least influence over wheat's growth at booting stage and heading stage. (4) Variance coefficients of Normalized SPAD of Cd treatments at seedling stage and tillering stage lower than Zn and Cu treatments, which indicated the influence of Cd over wheat's growth is less than heavy metal CU and Zn.

Acknowledgement

This paper was supported by the National Natural Science Foundation of China [41471279].