Jean-Marc Boussard

The Future of the European Common Agricultural Policy : Is a New Philosophy Possible?

Keywords: Common Agricultural policy, Price volatility, State intervention, market failure, supply management. _______________

On actual agricultural markets, price rarely equate marginal cost, as they should. Thus, agricultural policy should be focused on market failures, as was the 1960 CAP which, unfortunately, neglected supply management. Under certain conditions, a generalized "quota" system would in addition provide safer instruments for environmental policy.

rhythm the shift can be conducted, and how to make it working without too much complaints from entrenched habits.

Yet, pillar 1 shrinking rhythm is not what this article is intended to deal with. On the contrary, it develops the idea that pillar 1 is still the most important and reasonable aspect of the CAP. If the European Sate were to pursue the present dismantling policy, under the pressure of necessity, other institutions would probably fill up the gap left by the removal of market management instruments. It would probably not be the end of the CAP, because such an institution can very well survive its necessity. But it would certainly be the end of its power on the European and world agriculture. First the theoretical reasons which induce this thinking will be examined. Then, a few political sciences considerations will be developed.

I -WHY IS IT NECESSARY FOR POLITICAL AUTHORITIES TO CARE FOR AGRICULTURAL MARKETS?

The key consideration here is that agricultural markets are not working properly. This is the only and sufficient reason for State intervention in production decisions.

The most obvious market failure is precisely what Pillar 2 is supposed to bring correction to. As we have seen, is has been originally designed for, as far as possible, recreating markets where they are missing. Notice these "externality markets" are largely token ones: for, of course, the problem is not (or not primarily) to allocate pollution rights or amenity production quotas between producers, but to decide which pollution level is admissible, or which amenity is demanded in which quantity. For this, no market indications are available in any way. What the "externality markets" can only do is, assuming the Society's wishes are known (through electoral processes, enlightened despots, or any other mean), to enforce the decisions taken by political authorities at lower cost. This is important, but not essential.

The strange thing is doing that -in the pillar 2 framework -completely independently of pillar 1 considerations: for pollutions, amenities and commodities are obviously joint agricultural products, and jointness is notoriously a difficulty in production economics. Further researches should (and are) undertaken in order to grasp all the aspects of the problem. Yet we shall not pursue this discussion here, and just concentrate our attention on the strict pillar 1 issues -the commodity market failures.

Idly functioning markets : testimonials

Indeed, if markets were working properly (that is, marginal cost equating price, thus maximizing the joint consumer and producer surpluses), no pillar 1 type agricultural policy would have ever been necessary. If such policies were progressively set up during the course of history, it is because such situation only rarely occurs. Indeed, most of the time, on actual agricultural markets, prices do not equate marginal costs. This can be show on the most casual agricultural commodity time series. Figure 1 shows the price of corn in Chicago, in constant 2000 US $ since 1860. Nobody can seriously imagine the marginal cost of corn being 513 in 1910, reaching 764 in 1911, and coming back to 508 in 1912… This is but an example: similar jumps can be observed with almost any available agricultural commodity free market price in the world. This fact kills the key argument for letting markets operate freely. In the absence of relation between costs and price, markets lack all pretence to optimality. On the contrary, market interventions might very well lead to second best optimality, with price closer to "true" long run marginal costs. The advanced economic theory brings some support to this assumption1 .

Most of the time, farmers are risk averse2 . A risk averse producer does not equate marginal cost with the mean, but with the "certainty equivalent" price. The certainty equivalent is normally far below the mean price, the more as price volatility is larger and the farmer poorer (figure 2) . This means that with volatile prices, production is constantly below the optimum (in Pareto sense) level. Many models support this view. Let us only recall the famous article by [START_REF] Freund | Introducing risk into a programming model[END_REF] in Econometrica, 50 years ago. In Freund's experiment, a linear programming model of North Carolina farmers was built, first, "without" and then "with" risk considerations. In the first case, the average expected income was maximized, instead of a certainty equivalent in the "with risk" situation. While the former resulted in a quasi monoculture of the most risky crops, the latter's optimal solution was diversified and similar to actual crop patterns. Of course, in the second case, not only was the representative farmer's benefit smaller, but it was also made of a significant "risk premium", with, therefore, marginal costs far below expected prices.

Figure 2 : Non optimal equilibrium with risk

Observations also confirm this analysis. For instance, if we consider the US corn series on figure 1, a "break" is clearly visible3 in the 1940's : before that date, corn price is volatile and almost stationary (or slightly increasing). After, it is much less volatile, and decreasing. Indeed, most statistical time series breaks detectors indicate such an event in this series in the late 30's. Now, 1940 is also the date at which US price support policies begun taking effect. It is tempting to conclude that, far from standing as an outrageous rent paid to farmers at tax payer's expense, US price support policies rather benefited to consumer, through lower food cost. Of course, the fall of US corn price after production was disconnected from market can be only a mere coincidence. Yet, there exists evidences (Boussard and Gerard,1994) of positive links between price stability and production growth everywhere in the world.

Thus, both observation and theory suggest that price stability could lead to a more efficient agricultural system. That was the key motivation for the 1960 CAP setting, following earlier similar (especially, US) policies established in the late 30's. Now, in the late 80's, these policies (both US 1935 AAA policies and the CAP) has been deemed failures-the 1992 CAP reform being a mere consequence of this analysis. Where was the problem ?

What was wrong with the 1960 CAP ?

A natural idea for dealing with (apparently) random events such as agricultural price fluctuations is insurance. But it is difficult to insure prices, because prices are high or low for everybody at the same time. Therefore, even assuming random "iid4 " prices, risk sharing must be done throughout time, "bad" years being compensated by "good" ones5 . This raises enormous financial problems which can hardly be left to private insurance firms, so affluent they might be. On the other hand, governments can very easily do it6 . If they decide that the domestic price will be once and for all set at the equilibrium level, this decision being enforced by an adequate system of variable levies and subsidies at the border, in the long run, the cost of the policy should be zero, while the production and consumption system should behave exactly as with a smooth and efficient free market. This was the rational behind the 1960 CAP -a perfect price insurance system.

Figure 3 : Absence of equilibrium with guaranteed price

Yet, there was a flaw in the reasoning (figure 3): prices fluctuations are not random, but they depend upon supply and demand. In the case of agriculture, supply in the long run is fairly elastic, because the production function is homogenous of degree one: if a technique is feasible and profitable over one hectare, it can be reproduced over millions of hectares. Elementary economic theory shows that, in this case, the marginal cost is constant and the supply curve is flat, parallel to the x axis. Of course, this is not completely true, because fixed factors, such as land, cannot be expanded without limits. But the share of land in agricultural production cost is too small for the slope of the supply curve to be large, so that, in practice, everything goes as if the supply curve was indeed nearly flat. Now, with a fixed price, the demand curve too is flat, parallel to the x axis… and two parallel lines cross over at infinity! Here is the explanation for the failure of the 1960 CAP (and all similar policies in the world, being wheat in EC, or cocoa in Ivory Coast): with fixed price for unlimited quantities, production always tends to supersede demand, whatever the price… And, of course, in such a setting, the policy cost becomes quickly insuperable7 .

What could have been done ?

We have just seen that, in this context, authorities are considering coming back to free market. Of course, this is absurd, since coming back to free market will not suppress the reasons which were at the very origin of its abandonment8 At the same time, it looks like the only feasible escape from overproduction, and there are hopes that new institutional innovations could at least alleviate the inconvenience. Indeed, futures markets give the possibility for a farmer to be absolutely sure, at planting time, of the price which is to be paid at harvest time, and to make plans in accordance. In many analysts' views, futures markets allow farmers equating marginal cost and future prices, thus bringing back market efficiency. This would be true if futures were determined over a time horizon long enough to match farmers planning horizons, if they were not too much volatile, and if the risk premiums requested by speculators (who "sell security against risk", but at a cost) were not too large. None of these conditions are met. This must be the reason for why few farmers actually make use of such devices, as noticed by William ( 2001)° Yet, a very natural idea to overcome the difficulty of overproduction is to put a bound on the government price guaranty: a relatively high price would be granted up to a certain quantity, while any quantity produced in excess of this "quota" could be sold at market price. Such a solution, supported by serious economists (such as [START_REF] Hazell | Farmers' expectation, risk aversion and market equilibrium under risk[END_REF] was proposed in the US at the end of the 80's, under the name of PEG (Payment entitlement guarantee). It is described at length elsewhere [START_REF] Boussard | Price risk management instruments in agricultural and other unstable markets[END_REF]. It can be interpreted as a kind of future market, with the government playing the role of a risk buyer speculator at virtually no cost. It is not distorting, since, ultimately, quantities sold on the "free international market" should be produced at marginal cost, provided the sum of nation wide allocated quotas be less than domestic consumption 9 .

II -POLITICAL ECONOMY CONSIDERATIONS

Why are policy makers so reluctant in face of market regulation?

Several reasons can explain the prudent attitude of economists and policy maker with respect to supply management. policies in the History. . 9 It would also be necessary that producing at world price beyond the quota limit be allowed, contrary to what exists with EC milk quotas. Notice the WTO dispute settlement body recently judged that US domestic cotton subsidies were not decoupled, because these subsidies were lowering US cotton marginal cost. This is at least discussible.

a) The bad repute of the rents associated with "quotas": since, in order for the production under quota to be secured, the "under quota" price must be fairly greater than cost (otherwise, the quantity under quota would not be certain to be produced), farmers get a profit from holding quotas. Most neoclassical economists are rightly severe against rents. Now, it remains to be ascertained if rents should be necessarily avoided. They can be recommended in certain cases: for instance, nobody, apparently, complains about rents derived from patents. This is because, (rightly or wrongly) the benefit of such patent rent are deemed necessary to encourage research and innovation, which, otherwise, would be deprived of any market. In the specific case of the rent associated with production quotas in agriculture, it could be justified by a similar argument: the difference between price and average cost is indeed a price paid by consumer for food security and technical progress, since, in the absence of such a device, farmers would be reluctant to invest and innovate. The price, in this situation, could rise at levels endangering food security, at least for the poor. Undistorting production quotas, as defined above, would avoid such a situation. Then, why complain about quota rents10 ? Moreover, the "quota rent" can very well reduced to a small value if the authorities are wise (and powerful) enough to revise quota price at regular intervals, tacking account of technical progress and changes in production costs. b) Most politicians are persuaded that the reason for setting an agricultural policy is to guarantee a minimum income to farmers. This is the rational for limiting the decoupled payments beyond a certain limit: "big" farmers need not income supports.

It is a strange vision: governments are not established to secure farmers income, no more than the income of any other citizen. Government cannot have any other objective than to provide minimum welfare -including food security -to all citizens, and not farmers only. Then, why is farmer income support so easily deemed necessary? Simply because it turns out that it would certainly be difficult to provide food security without farmers. Indeed, for achieving food security, farmers must not be swept out by the first crisis occurrence. This is the reason for why the 1958 Stresa Conference mentioned farm income as one of five objectives for the CAP. The term "objective" was surely misshapen, since it is not possible to optimize five objectives simultaneously. Yet, setting a minimal farm income level as a constraint for public policy might be very sound. But it is certainly not sound to maximize farm income at other citizen expenses. As a consequence, the right to get decoupled government payment whatever the circumstances is certainly much more abnormal than any kind of price support11 .

In addition, mixing equity and efficiency considerations is awkward, even in the eyes of the most orthodox economists. Efficiency requires factors being consistently priced and made use of, whatever the distribution of the incomes they generate. The distribution itself depends upon the nature of the rights peoples hold on factors. Thus, if more equity is required in farming, it would be wiser to change the nature of the rights (for instance, the property rights) rather than the (implicit) price of some of the factors through which subsidies are distributed (in the present case, the land and labour shadow prices of the large farm owner) 12 .

c) The very source of price fluctuations (and therefore, the strategies for bringing remedies) are not understood. Of course, everybody agrees that large agricultural price fluctuations are caused by small changes in supply which are magnified by the low demand elasticity for food. But few analysts recognize market failures behind supply changes, which are generally considered as "exogenous", engendered by climate or pests, out of any human control. Yet, if climatic or other circumstances can very well jeopardize local harvests, the question is open of the consequences of this sort of events for global markets: can a drought occur simultaneously in Australia, North America and Europe? This is not very likely.

On the contrary, since [START_REF] Ezekiel | The Cobweb Theorem[END_REF], the author of the "cobweb model", the local instability and "repelling" properties of agricultural markets equilibrium points is notorious. With a repelling equilibrium point, the way is paved for chaotic 13 behaviours in the agricultural commodity supply and demand dynamics [START_REF] Alligood | Chaos : An introduction to dynamical systems[END_REF]. Now, the global properties of a chaotic system are completely different from those of an exogenously perturbed equilibrium. In particular, while all "liberal" recipes are stabilizing the latter, they are counterproductive with the former, and vice-versa [START_REF] Boussard | Price risk management instruments in agricultural and other unstable markets[END_REF]. Since most economists (and probably, all the most influential of them) are persuaded fluctuations come from exogenous sources while they are endogenous, it is not surprising that policies are misdirected.

d) Especially, it has been contended that national quota were unfair at international level, because they were destabilizing the world residual market. This would be true if the international markets fluctuations were of exogenous origin, as it can be seen on Figure 4: Here, it has been assumed that a socialist minded government imposes a production quota on a domestic market, with a guaranteed price production equating the average domestic consumption level of 1000. But the annual production system of the country is submitted to random shocks, so that actual production is uniformly 14 distributed between 990 and 1010. Each year the deficit or oversupply is bought or sold on a residual foreign market defined by its demand curve : intercept 100, slope -0.5, and its autonomous supply uniformly distributed between 101 and 99. The residual market price is highly volatile, as shown by the continuous line on figure 4. If the quota is removed, and price freely determined by merging the supply and demand of the two markets (the intercept is still 100, but the slope of the demand curve is now 1/22), the resulting price is shown on the dotted line on figure 4 : clearly, the "without quota" curve is much more stable than the other one. 12 Let us be more precise: at present, subsidies are distributed on a per ha basis, on the ground that it is the only way of securing a decent reward to the family labours occupied on these hectares. Obviously, the Queen of England does not work on her land, so that it might seem useless to give her the same subsidy. However, if she does not work herself, she must hire workers to do the job. Most of the time, the cost of this hired manpower is the same as that of family workers in a small holding. Thus, if the subsidy is suppressed, the Queen will just have to stop farming, firing tenants and letting land going back to wilderness, or selling the land to present workers, the situation of whom will be unchanged. No gains will have be made, nor in efficiency nor in equity (since the Queen will still benefit of the price of the land sold). On the contrary, a progressive income tax will obviously strike the Queen's more than tenant incomes, which is what is sought for equity reasons. 13 Here, we refer to the mathematical theory of chaos -a special case of dynamic differential equations solutions, with no periodicity, and no ultimate fixed limit when time growth to infinity. 14 Of course, a uniform distribution is an heroic assumption, made here for simplicity. Many other distributions have been tried as well, with the same kind of results.

Price

The results displayed in the case "with endogenous fluctuations" (figure 5) are quite different. Here, although the supply and demand on the two markets are similar (the scale is different), the fluctuations are generated by a risk driven chaotic cobweb 15 [START_REF] Boussard | When risk generates chaos[END_REF]. In this case, the series "without quota" fluctuates much more than the series "with quota". Thus, in this context the imposition of a quota, far from increasing price volatility, is stabilising simply because it guarantees at least a minimal production, preventing low supply/high price situations 16 ,. Again, the above example is only illustrative. The source of agricultural price fluctuation is both endogenous and exogenous, which does not simplify the stabilisation 15 Specifically, the series "without quota" is engendered by a set of four recursive equations :

iance n Expectatio mean n Expectatio Supply b q t a q t A p t Demand q t p t p p p p t p t p var : ) ( ˆ: : 2 ^: 2 2 ~2 - = = + = - + = σ σ β α
here, p t and q t are actual price and quantity at time t. t p ˆand t 2 σ ^ are average and variance price expectations at time t. α, β, a, b are " technical " coefficients. p ~is a constant. A is a " risk aversion coefficient ". Thus, producers consider the average price as a constant. Only the expected variance of price is subject to change from period to period (modifying this expectation scheme, and replacing p ~ by some sort of moving average is easy, and do not change results significantly). Producers maximize the certainty equivalent of their incomes, which, after transformation, yields the supply equation. In the "with quota" case, the scheme is the same, except that the "under quota" quantity is produced for any t p ~ . 16 as a consequence, insofar as the world sugar market is driven by such a kind of fluctuations, it will be even more volatile in the next few years, when the EC sugar quotas will have completely been removed.

problem. Yet, the above discussion shows at least the importance of making a distinction between the two, and of designing policies in accordance. without with

PRICE TIME

Can pillar 1 be independent of pillar 2 ?

There exist also large contradictions between pillar 1 and pillar 2. For instance, it is absurd to develop bio-fuels (which, for being produced in significant quantity, would require an enormous surface of land), while, at the same time, encouraging "bio" and extensive farming (which, also, require more land than normal farming to produce a given quantity of output) … This is one among many examples of such contradictions. Now, a prudent supply management policy would certainly provide the possibility of getting almost any wished environmental setting.

The example of milk quotas in France gives some clue in that respect. When it was established, many economists were critical of one of the French law provisions regarding quota mobility. According to this provision, quotas were mobile (they can be transferred from one farmer to another) only within certain geographical zones. In the eyes of a standard production economist, that was strange, because, for achieving the minimum cost, it would have been normal to let a quota market choose the best production location. Certainly, the reasoning was correct in terms of minimal milk cost. At the same time, it was justified for environmental reasons: without such a regulation, all milk production would have disappeared from mountainous areas, with large adverse effects on landscapes and erosion17 . Thus, the regional allocation of milk quotas was a simple and efficient way of securing environmental friendly production techniques, at the cost of a definite production cost increment.

An alternative would have been to pay an additional fee for mountain region farmers to raise milk cattle. Assuming an ideal fee level computation, just compensating mountain farmers for their natural disadvantages, the overall result would have been exactly the same: cattle would have been raised in the Alps, at a certain cost for taxpayers. But the computation of the fee would have caused sever problems. Sometime, it would have been too much, sometime too low. In addition, the fees would have to be adjusted each year to cope with changing input prices. With quota regulations, the problem is self solved.

Again, this is but an example. Many other could be found. The core of the thing is that it is not theoretically possible to completely dissociate commodity and environmental decisions. Then, why not taking notice of it, and acting accordingly?

Concluding remarks

Thus, despite the efforts to bring the CAP -especially pillar 1 -meeting the standards of economic rationality, one has to be afraid that it is heading right down in the opposite direction. There is no rationality in decoupled payments (the more as the reality of decoupling remains to be demonstrated, see [START_REF] Berthelot | Why are blue box subsidies coupled ?[END_REF][START_REF] Grey | Green box mythology : the decoupling fraud, Report to dairy farmers of Canada[END_REF], Donogue and Whitacker, 2006, and many others). Abandoning all ideas of market management is both strange and dangerous while the malfunctioning of markets is precisely the reason for installing any agricultural policy.

The recent evolution of the world markets, with depleted security stocks and soaring agricultural prices could very well make this judgement obviously relevant. Contrary to a common creed, the 2007 shortage of grains was not due to the Australian drought, and probably not (or not yet!) to the bio-fuel production. It was the consequence of many market transmitted messages, indicating for several years that agricultural production was too large. World farmers received these messages well, and acted accordingly by reducing supply, although probably too late, and too much…Now, markets will transmit a new message, along which production is too low. One may expect it will increase too much in the next few years, resulting in depleted prices, farmers bankruptcy, and call for farm income support. In the meantime, it is also to be expected that a number of poor peoples in the third world will die from hunger. Indeed, after all, a large famine induced death toll is the most natural way of equating supply and demand on food markets when supply is low (this is what happens with natural animal populations, and also what Robert Malthus considered as the normal course of the economic system). This is not a rejoicing perspective, no more for farmers than for ordinary consumers… A possible way out is a careful management of agricultural (as well as bio-fuel) markets, through price and supply control on both sides. It could be future of the CAP pillar 1 if the EC wants to keep control of events. If not, especially if EC continue its ideological retreat far from reality, it is to be expected that other institutions -perhaps nations, perhaps international bodies -will seize the relay.

In particular, nowadays, contrary to the situation which prevailed before the Second World War, the rise in urbanisation makes impossible any direct contacts between farmers and final consumers. Food industry stands as a necessary intermediate body. Through vertical integration contracts, it could very well play the role of a market regulator, thus privately replacing all forms of State intervention. Of course, such a new institutional setting would only be workable if food industry firms benefit from large monopoly rents. But in the absence of government intervention, these rents are the more easily obtained and kept as, because they require transportation, the corresponding processes stand (at least potentially) as natural monopolies. It is not sure the consumer (or even the tax payer) would really benefit from such a situation.

  Figure 1 : US corn price 1860-1998 Cent per bushel -1998 constant US $

  Figure 4Exogenous shocks : residual market price, with and without quotas

  Figure 5Chaotic cobweb: residual market price, with and without quotas

A considerable body of literature was devoted to this topic during the 50's and the 60's. It seems to have almost entirely forgotten recently. SeeWaught(1944), Massel(1969, 1970),Newbery and Stiglitz (1981),[START_REF] Schmitz | Commodity price stabilization : The theory and its application[END_REF], , and many others, including dissenting[START_REF] Oi | The desirability of price instability under perfect competition[END_REF]

The fact has been challenged.Serious papers, such as Binswanger (1980) provide evidence that even third world farmers might actually be risk lover. This is certainly formally true. In fact, this conclusion relies upon subtleties in the definition of risk aversion. For instance[START_REF] Kimball | Precautionary saving in the small and in the large[END_REF] shows the possibility of "risk lovers" being "prudent". In practice, everything goes "as if" they were really risk averse.

it is also detected by these statistical tests which serve to detect breakpoints in time series, as those described by[START_REF] Viviana | Detection of breakpoints in volatility[END_REF].

Independently identically distributed

As noticed 4000 years ago by the Bible, with the story of Joseph, the Pharaoh prime minister. Notice that Joseph's policy ran into an international liquidity crisis, for, after a while, people in the Middle East had no more "gold nor silver" to pay for Egyptian stocks. cf Genesis, 41-42 and 47

This is the old argument by[START_REF] Arrow | Essays in the Theory of Risk Bearing[END_REF]

This outcome of the 1960 PAC had been predicted by Colin[START_REF] Clark | Agricultural Economics -The Further Horizon[END_REF]. Unfortunately, this caveat was not understood at the time.

Notice "free market" is rather natural an institution, the flaws of which, precisely gave rise to all agricultural

Indeed, assuming stabilisation could be achieved through futures markets, the risk premiums to be paid to speculators could very well exceed the rents paid to quota owners by a large amount… This point could be the subject of further studies.

This anomaly is particularly evident this year, where large payments will be made to farmers already benefiting from high prices.

As a matter of fact, this regulation resulted also in large transportations by trucks between excess and deficit production regions -certainly not an environmental blessing! But this is another story! .


Augustin Balontrade

Marie-Hélène Ropers

Christian Schwieger

A Scilingo

M C Anon

Marc Anton

Amaranth Protein Isolates at the Air-Water Interface

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

Amaranth is a grain mostly harvested in subtropical and some tropical regions of Asia Africa and America where it constituted traditional meals. The renewal of interest for its crop lies in its nutritional value: the seed contains a higher protein value than other cereals and its essential amino acid composition is close to the optimum required in the human diet. Its high nutritional value, coupled with interesting functional properties, led us to ask whether these proteins could be used as dispersing agents in food products to get a better balance in essential amino acid.

Amaranthus hypochondriacus isolate proteins were extracted from defatted seed flours. The surface activity of their soluble extracts was studied at pH 2 and 8 at the air-water interface.

The soluble extract at pH 2 exhibits a better surface activity and a significantly higher viscous modulus than the soluble extract at pH 8. The spectra obtained by Infrared Reflection Absorption Spectroscopy (IRRAS) revealed that the film thickness increases more weakly at pH 2 than at pH 8 during the compression of the film. The simulation of spectra obtained by angular variation indicates that the proteins re-organise more significantly at the interface at pH 2 than at pH 8. At pH 2, amaranth proteins suffer a significant denaturation and dissociation, whereas at pH 8 the native structure is preserved. This structural difference explains the different behaviors at the interface.

These results orient the single use of amaranth protein isolates to acidic pH while mixed films with other proteins must be considered at higher pH.

CIDCA, calle 47 y 116 -(1900) La Plata, Pcia. de Bs. As, Argentina

INRA, UR1268 Biopolymères Interactions Assemblages, F-44316 Nantes, France † Present address: Martin-Luther-University Halle-Wittenberg, 06120 Halle / Saale, Germany


In vivo studies planned in the european integrated project "Lycocard" (Role of lycopene for the prevention of cardiovascular diseases)

Version définitive du manuscrit publié dans / Final version of the manuscript published in : Annals of Nutrition and Metabolism, 2007, vol.51, no Epidemiologic studies suggest that lycopene-rich foods, i.e. tomatoes and tomato products, may provide protection against cardiovascular diseases. However, there are many details regarding bioavailability, metabolism, and molecular mechanisms involved in lycopene biological activities that are still unknown. Lycocard's in vivo studies consist of both animal and human trials aiming to answer the main following questions:

• do genetic polymorphisms in putative intestinal transporters of lycopene affect lycopene absorption efficiency ? In vivo effect of diets enriched with traditional and newly developed tomato products on obese and normal weight subjects (Dr A. Mordente, Nutriunit Roma, Italy ) The project started April 1, 2006 andwill end in march, 31, 2012. Results produced by the different WP will be available regularly during this period and will be added on the Lycocard website www.lycocard.com.

. 1

 1 Manuscrit d'auteur / Author manuscript Manuscrit d'auteur / Author manuscript Manuscrit d'auteur / Author manuscript In vivo studies planned in the European Integrated project "Lycocard" (Role of lycopene for the prevention of cardiovascular diseases) Patrick Borel INSERM, U476 « Nutrition Humaine et Lipides », Marseille, F-13385 France; INRA, UMR1260, Marseille, F-13385 France; Univ Méditerranée Aix-Marseille 2, Faculté de Médecine, IPHM-IFR 125, Marseille, F-13385 France.

  • does absorption efficiency depend on lycopene cis-trans isomerisation ?• what are the main lycopene metabolites produced in the body ?• what is the concentration of lycopene and its metabolites in tissues ?• what is the role of lycopene on gene activation ?• what is the effect of lycopene on redox status ? • does lycopene improve endothelial function ?

	In vivo studies have been organised into work packages listed in the table below
	WP 15 Determination of nuclear receptor activation by lycopene, lycopene (Z)-
	isomers/metabolites and tomato preparations in transgenic animals (Dr R. Rühl,
	Debrecen University, Hungary)
	WP 16 Analysis of the redox status of mononuclear cells isolated from chronic smokers
	and hypercholesterolemic patients before and after supplementation of a tomato-
	rich diet (Dr P. Palozza, Roma University, Italy)
	WP 17 Effect of polymorphisms in intestinal lycopene transporter(s) on lycopene
	bioavailability (Dr P. Borel, INRA/INSERM/Marseille University, France)
	WP 18 Evaluation of oxidative stress and lipid status in human plasma: influence of smoke
	exposure and lycopene supplementation (Dr G. Lowe, Liverpool University, UK)
	WP 19 Study of lycopene isomerization in human plasma by isotopically labelled lycopene
	(Dr V. Boëhm, Jena University, Germany)
	WP 20 Evaluation of atherosclerosis prevention by lycopene in animal models (Dr V.
	Stangl, Charité Berlin, Germany)
	WP 21 Effects of lycopene and different tomato products on endothelial function in
	humans (Dr V. Stangl, Charité Berlin, Germany)
	WP 22-
	23


Francois Guerrin

Jean-Marie Paillat

Collective animal manure management

published or not. The documents may come

Guerrin F., Paillat J.-M., 2010. Collective animal manure management simulation and environmental impact assessment. 24th European Conference on Operational Research (EURO XXIV), Lisbon (Portugal), July 11-14 2010, MD-44, #4, p. 86 and TD-4 #3, p. 189. Collective animal manure management simulation and environmental impact assessment F. Guerrin & J.-M. Paillat Cirad, UR 78 Recyclage & Risque Reunion Island This contribution deals with simulation modelling to help manage agricultural production systems. It describes the use of a Systems Dynamics complex model to simulating the functioning of pig slurry collective spreading plans in Brittany (Northwestern France), where intensive livestock farming has a well-known harmful environmental impact, namely on groundwater and coastal waters. The simulated plan involves 11 pig farms (encompassing both livestock and crops) located in a zone with excess slurry and 11 land owners located at about 40 km from the former. Individual pig farmers use part of their slurry to fertilise their own crops while they are regularly collected by collectively managed trucks to export their excess slurry to be applied on the remote crop farms. The model dynamically simulates the slurry stock evolutions at the pig farms and the spreading fluxes on crops, both at the pig farms and the remote crop farms. It simulates also several indicators likely to assess the environmental impact of this spreading organization's functioning: gas emissions (ammonia, methane) at slurry storage and application, time/distance spent in slurry transportation and application, excess Nitrogen with potential water pollution risk. It shows also the interaction between the individual farm and the collective organization levels.


Santiago Lopez-Ridaura

Hayo Van Der Werf

Jean Marie Paillat

François Guerrin

Environmental systems analysis of agricultural systems: Coupling dynamic simulation models with Life Cycle Assessment

Keywords: pig slurry, manure management, ammonia, methane, COMET

Life Cycle Assessment (LCA) is usually carried out using fixed coefficients for resource use and emissions as the basis for the calculation of the environmental impact of a product or a service. However, in agriculture, where the systems' functioning largely depends on the dynamic organisation of agricultural practices and on variable climatic conditions, coupling dynamic simulation models with LCA seems necessary. This paper presents the combination of a dynamic simulation model and LCA to assess the environmental impact of a collective pig slurry management system. The model simulates the production of slurry, its stock level in storage facilities, its transport and application to crop fields, as well as the gaseous emissions occurring in these stages, under different management strategies and climatic conditions. Results from the combination of these approaches show the great variability of the agronomic and environmental performance of the collective slurry management system in relation to different organisational schemes, agronomic decisions and climatic conditions.

OBJECTIVE

Life Cycle Assessment (LCA) has gained popularity in the last decade for the environmental evaluation of a product or service and it is used by scientist and professionals from a wide range of fields and disciplines. LCA is normally carried out as a steady state method where fixed coefficients of resource use and emissions are used for the inventory analysis and fixed characterization factors are used for the impact assessment.

In agriculture, however, the functioning of a system largely depends on (i) the dynamic organisation of agricultural practices and (ii) the variable climatic conditions. The combination of these determinants can strongly affect the agronomic and environmental performances of agricultural systems. For this reason, envisaging the coupling of dynamic models and LCA seems a promising way to better understand the intertwined technical and environmental performances of agricultural systems.

The aim of this paper is to show the combination of such modelling and assessment approaches. A specific example of a collective pig slurry management system is shown. The dynamic model simulates the production of slurry, its stock level in storage facilities, its transport and application to crop fields, as well as the gaseous emissions occurring in these stages, under different management strategies and climatic conditions. Results from the dynamic model serve as input for the inventory analysis of an LCA of collective slurry management scenarios.

METHOD The context of the study

In Brittany, Western France, nitrogen (N) in the form animal manure surpasses crop needs of the region. This represents an important environmental hazard as its mismanagement threatens the quality of water resources and contributes to the emissions of NH 3 , CH 4 and N 2 O. Under current French regulations, excess manure has to be treated or exported to other regions for its application to crop land [START_REF] Lopez-Ridaura | Environmental evaluation of transfer and treatment of excess pig slurry by life cycle assessment[END_REF].

In the Southeast of Brittany, a group of pig farmers has proposed a collective pig slurry transfer plan. In this plan, 57.6 Mg as N of pig slurry belonging to 11 pig farmers will be transferred to a group of 22 crop farmers, at a distance ranging from 33 to 55 km and applied to different crops (winter cereals -wheat and triticale-, grain and silage maize, oilseed rape and grassland).

System dynamics and the COMET model

The system under analysis includes only the excess slurry to be transferred and takes into account the production, storage, collection, transportation and application of slurry [START_REF] Lopez-Ridaura | Agronomic and environmental evaluation of collective manure management for a group of farms[END_REF]. The dynamic model (COMET -COllective management Model for environmental and logistic Evaluation of manure Transfer plans), simulates these stages of excess slurry management as well as the gaseous emissions (NH 3 and CH 4 ) during slurry storage and application. COMET, programmed in VENSIM ® , is the product of the integration of other stand-alone models [START_REF] Guerrin | Magma: A model to help manage animal wastes at the farm level[END_REF][START_REF] Guerrin | Simulation of stock control policies in a two-stage production system application to pig slurry management involving multiple farms[END_REF][START_REF] Morvan | Vers une prévision opérationnelle des flux de N résultant de l'épandage de lisier: paramétrage d'un modèle dynamique de simulation des transformations de l'azote des lisiers (STAL)[END_REF].

In COMET, the production of slurry is considered a continuous process, temporarily stored in the under slatted floor pits and emptied by batches every 36 days to external storage tanks. During storage, NH 3 and CH 4 are the main gaseous emissions and, in COMET, they are calculated on a daily time step. Emission factors from Loyon et al. [START_REF] Loyon | Gaseous emissions (NH 3 , N 2 O, CH 4 and CO 2 ) from the aerobic treatment of piggery slurry -Comparison with conventional storage system[END_REF] has been corrected by slurry nitrogen content (for NH 3 ) and by temperature (for the two gases) using equations from Pelletier et al. [START_REF] Pelletier | Ammonia emissions from swine manure storage tank. Technology for Recycling of Manure and Organic Residues in a Whole-Farm Perspective. Vol. II. 12^th Ramiran International conference[END_REF].

Each tank storing slurry is emptied by trucks that carry it from the pig farms to intermediate storage facilities in the spreading region. These storage facilities are covered and therefore no gaseous emissions occur. The supply from the pig farms to the intermediate storage is based on one of the policies described in Guerrin and Médoc [START_REF] Guerrin | A simulation approach to evaluate supply policies of a pig slurry treatment plant by multiple farms[END_REF]: (i) a delivery is tentatively triggered when the intermediate storage tank is below a lower level; (ii) the choice of the pig farm to be collected first is based on its slurry stock level, transportation distance and size (i.e. the fullest, furthest, biggest farm is collected first).

The calendar for slurry application to crops is defined by crop management and national regulations (slurry application is forbidden at various periods for different crops and during weekends). Surfaces and doses of slurry for the different crops are defined in an agreement between the pig and crop farmers according to fertilisation schemes provided by the crop farmer for each crop. In COMET, two priority rules are implemented to define the crop fields to spread: a priority based on crop type: winter cereal > oilseed rape > maize > grassland and, among fields with same crop, a priority on the degree of fulfilment of the N to be applied (i.e. the largest deficit first).

The feasibility of entering fields to spread is driven by climatic conditions and scenarios are built with different rules based on present and previous rainfall (RR) and potential evapo-transpiration (PET) (Table 1). Based on technical advisers' experience, two criteria are defined: the RR-PET of the current day (called RPd) and the ten days moving average of RR-PET (called RPa). Two rules to enter the fields are defined: when it rains (i.e. RPd > 0), it is not possible to spread and the slurry can be applied after a delay defined according to the advisors' knowledge of crop and soil types (Table 1). The delay depends on the value of RPa relative to two thresholds (0 and 2 mm in our simulations) and on the spreading capacities according to the soil types (hydromorphic vs well drained soil) and soil cover (cereals vs grassland). Spreading is performed by a Terragator® before soil tillage for maize and oilseed rape and just after tillering for winter crops and grassland.

NH 3 emission after spreading is simulated with STAL parameterised for Brittany [START_REF] Morvan | Vers une prévision opérationnelle des flux de N résultant de l'épandage de lisier: paramétrage d'un modèle dynamique de simulation des transformations de l'azote des lisiers (STAL)[END_REF], with a 80% emission reduction due to slurry injection into the soil [START_REF]Control Options/Techniques for Preventing and Abating Emissions of Reduced Nitrogen Compounds[END_REF].

The Life Cycle Assessment model

An LCA model for the transfer of excess slurry has been developed which is fully described in Lopez-Ridaura et al [START_REF] Lopez-Ridaura | Environmental evaluation of transfer and treatment of excess pig slurry by life cycle assessment[END_REF]. The functional unit of analysis is one m 3 of slurry transferred and the phases included in the model are the on-farm storage of slurry, its transport and intermediate storage and its application to crop land. The inventory analysis includes resource use, such as concrete for the storage tanks, steel for making transport and spreading units and diesel used for slurry transport and application. Also, as slurry is used as organic fertilizer for crops, chemical fertiliser saved by slurry application is subtracted from the environmental impact of the slurry transfer scenarios.

Instead of using fixed coefficients for CH 4 emissions during slurry storage, and NH 3 emissions during slurry storage and application, the results of COMET simulations are used. Also, the amount of chemical fertiliser saved by slurry application is calculated by COMET after discounting all N losses. N 2 O emissions after slurry application is considered to be 2% of the total N applied to crop land [START_REF] Ipcc | IPCC Guidelines for National Greenhouse Gas Inventories[END_REF].

Total (direct, indirect and avoided) emissions and resource use are aggregated and expressed in terms of four impact categories: Eutrophication (in kg PO 4 -eq.), Acidification (in kg SO 2 -eq.), Climate Change (in kg CO 2 -eq.) and Non-Renewable Energy Use (in MJ of Lower Heating Value (LHV)-eq.). For the quantification of indirect resource use and emissions, the BUWAL 250 [START_REF] Buwal | Okoinventare f¨ur Verpackungen[END_REF] , ETH-ESU [START_REF] Frischknecht | SimaPro 6 -Database Manual -The ETH-ESU 96 libraries[END_REF] and IDEMAT [START_REF] Tudelft | IdeMAT Database for materials[END_REF] databases were used as implemented in SimaPro 6 [START_REF]SimaPro 6 Method. Database Manual[END_REF].

The assessed scenarios

Eight scenarios of collective slurry transfer were evaluated by coupling the use of COMET and the LCA model. These scenarios are built as a combination of two soil types determining access to fields for spreading (Well Drained -WD--and Hydromorphic -H-), two levels of spreader availability (3 or 5 days per week) and two climatic years in relation to rainfall (2001 with a wet late winter and 2002 with a dry one) (Table 1). A reference scenario is also evaluated in which fixed coefficients for gaseous emission during storage and application of slurry and an average storage time of 82 days is used as reported in Lopez-Ridaura et al. [START_REF] Lopez-Ridaura | Environmental evaluation of transfer and treatment of excess pig slurry by life cycle assessment[END_REF].

RESULTS

Figure 1 shows results obtained with the COMET model. It shows, for two scenarios, the storage level of excess slurry for the group of pig farmers and the emissions of CH 4 during storage. The difference between the two scenarios is due to rainfall conditions; in wet years like 2001, access to fields for slurry spreading is limited and therefore a larger volume of slurry is stored longer, thus increasing overall CH 4 emissions. Table 2 shows the NH 3 , N 2 O and CH 4 emissions and the N from fertilisers substituted by the slurry for eight scenarios and Figure 2 shows the results of these scenarios for the four impact categories with respect to the reference scenario (normalised at 1).

DISCUSSION AND CONCLUSIONS

The results for the eight scenarios show the diversity of the environmental performances of the slurry transfer plan in relation to agronomic and logistic decisions and climatic conditions. When slurry is spread on well drained soils and the spreader is available for 5 days a week, there are no important differences between climatic years as spreading is not limited. However, in comparison to the reference scenario, where fixed storage time and emissions are assumed, these scenarios show more impact on eutrophication and acidification and less on climate change implying that, in the reference scenario, CH 4 emissions during storage were overestimated and NH 3 emissions underestimated, especially at spreading.

When slurry application is limited by either the availability of spreader or soil conditions, climatic conditions strongly affect the environmental performance of the collective plan for excess slurry transfer. Thus, scenarios for wet years like 2001 have a poorer environmental performance than their dry year (2002) counterparts (i.e. over 20% impact increase for some categories). Scenarios where spreading is limited by either soil conditions or spreader availability, have up to twice the environmental impact of the reference scenario for some categories.

It has been shown that slurry transfer represents a net saving of energy due to the substitution of chemical fertilisers [START_REF] Lopez-Ridaura | Environmental evaluation of transfer and treatment of excess pig slurry by life cycle assessment[END_REF]. Between the scenarios simulated with COMET there are no mayor differences in energy use as differences in N substituted from chemical fertilizer are only between 3 and 8% and the energy used for transport and application of slurry, applicable equally to all scenarios, levels off the energy use. The scenario analysis presented here shows the importance of coupling dynamic modeling approaches and LCA for the environmental analysis of agricultural systems where agronomic and logistic decisions, as well as climatic conditions, represent the mayor determinants for their performance. The system evaluated here, limited to manure management, is only a small part of an agricultural production system. Expanding the boundaries of such a system to, for example, livestock and crop productions might increase the variability of its environmental performance related to changes in many more agronomic and climatic aspects.

Using average fixed coefficients for the inventory analysis in the LCA of agricultural systems may result in erroneous assessments of the environmental performance of specific practices. Also, climatic conditions and agricultural practices may affect the fate of pollutants in the environment. Therefore, characterization factors for impact assessment should also be simulated to improve our understanding of the variability of the environmental performance of agricultural systems [START_REF] Basset-Mens | Spatialised fate factors for nitrate in catchments: modelling approach and implication for LCA results[END_REF].

Coupling dynamic simulation models and LCA is a promising approach to assess the impact of organisational schemes, agronomic decisions and climatic conditions on the agronomic and environmental performance of agricultural systems.

Figure 1 .

 1 Figure 1. Daily slurry stock levels (A) and methane emissions (B) for two scenarios of collective slurry management as simulated by COMET

Figure 2 .

 2 Figure 2. Results from the LCA for eight scenarios of collective slurry management in relation to a reference scenario

Table 1

 1

	. Scenarios evaluated and delay imposed for
	accessing the fields in relation to rainfall
		Delay before spreading (days) in
			relation to RR-ETP (mm)
			Cereals		Grassland
	Scenarios	<0 0-2 >2 <0 0-2 >2
	WD -5 -2001	0	2.5	5	0	1	2.5
	WD -5 -2002	0	2.5	5	0	1	2.5
	WD -3 -2001	0	2.5	5	0	1	2.5
	WD -3 -2002	0	2.5	5	0	1	2.5
	H -5 -2001	1	4	7	0.5	2	4
	H -5 -2002	1	4	7	0.5	2	4
	H -3 -2001	1	4	7	0.5	2	4
	H -3 -2001	1	4	7	0.5	2	4

Table 2

 2

	. Emissions and N substituted from chemical
	fertilisers for eight scenarios simulated by COMET
		Emissions (kg m -3 )	substituted N from
	Scenarios	NH 3 N 2 O CH 4	fertiliser (kg m -3 )
	WD -5 -2001 1.15 0.16 4.17	3.28
	WD -5 -2002 1.13 0.16 3.70	3.29
	WD -3 -2001 1.41 0.15 6.76	3.14
	WD -3 -2002 1.17 0.16 6.19	3.27
	H -5 -2001	1.35 0.15 4.79	3.17
	H -5 -2002	1.14 0.16 3.77	3.29
	H -3 -2001	1.57 0.15 9.27	3.05
	H -3 -2001	1.44 0.15 7.15	3.13