Jérôme Blanc
email: jerome.blanc@univ-lyon2.fr

BEYOND THE COMPETITION APPROACH TO MONEY: A CONCEPTUAL FRAMEWORK APPLIED TO THE EARLY MODERN FRANCE

As other European countries of that time, Early modern France was characterized by its monetary plurality. The purpose of the text is to present this plurality and analyse the ways it was articulated. After a presentation of the intention of the paper, Section 2 presents the problem of monetary articulations, referring to existing literature: competition is too often the only articulation mode referred to by economists; however, an other one is increasingly analyzed, complementarity. We state that complementarity is too vague to be relevant enough and build a conceptual framework identifying four distinct articulation modes : competition, simultaneousness, supplementarity and autonomy. Section 3 presents a short overview of monetary plurality in the French early modern period and it applies the theoretical framework to it in order to stress the various possible combinations of articulation modes of money. It emphasizes the case of royal coins as being close to supplementarity, the case of gold coins as being close to competition, and the case of méreaux as being between supplementarity and autonomy. Section 4 addresses briefly the question as to whether the monetary complexity of that period means chaos. The role of social stratification and intermediates in reducing the complexity of monetary plurality is emphasized. Section 5 concludes.

Intention

The analysis of money has been considerably enhanced in social sciences over the last decades. By distinguishing between all purpose and special purpose money, [START_REF] Polanyi | The Economy as Instituted Process[END_REF] has successfully accounted for the existence of money in non-Western societies and helped discard the barter fable [START_REF] Servet | La monnaie contre l'État ou la fable du troc[END_REF]. Anthropological works published by Parry and Bloch (ed., 1989) have put Western conceptions of money into perspective by confronting them with the representations and the institution of money within non-Western societies. By working on the social earmarking of monies in the United States, [START_REF] Zelizer | The Social Meaning of Money[END_REF] has broken away from the myth of money viewed as a mere quantitative, interchangeable and impersonal instrument. By rehabilitating the ethical and hierarchical dimensions of public faith in money that economics, as well as too many non-economic studies, neglect in favor of its mere inter-individual dimension, Aglietta and Orléan (dir., 1998) have helped show how the pure economic approach is ill-suited to apprehend this object in its essentiality. The book edited by Theret (ed., 2007) extends these works by showing how monetary crises cannot be comprehended with the help of mere economic conceptual tools. A certain convergence of economic, sociological, anthropological and historical works has enabled such developments.

In this type of research on money, an important line of enquiry triggered a reflection on the plurality of monetary forms. Recent collective works on monetary crises with a comprehensive view, including a wide series of historical and geographical cases, show the importance of monetary plurality as a driver of crises and as a consequence of crises (Théret, ed., 2007). But, beyond crises, one result was to identify as possibly normal and sustainable the coexistence of such a plurality even within modern societies. An extensive research on money in the world on the period 1988-99 led to identify a great variety of units of account and means of payment, during crises as well as during economically and financially stable periods, in Northern as well as in Southern countries [START_REF] Blanc | Les monnaies parallèles. Unité et diversité du fait monétaire[END_REF]. Eventually, beyond the very forms taken by money and various units of account, sociological and anthropological works show the great diversity of uses of money, so that this is today an important axis of reflection in social studies and sociology.

Acknowledging monetary plurality led us to investigate two founding categories of the economic approach to money: competition (between money) and fungibility (of money) [START_REF] Blanc | Usages de l'argent et pratiques monétaires[END_REF][START_REF] Blanc | Counteracting counterfeiting? Bodin, Mariana and Locke on false money as a multidimensional issue[END_REF]. Fungibility requires the ability to convert freely and easily one money into another. The competition approach to money states that all monetary forms are substitutes, so that rational agents exert rational choices in order to decide on the means of payment they use. Hence, a perfect fungibility is a necessity to let competition develop between money. Letting aside a first doubt over the permanence of monetary plurality through the selection process of competition, the competition approach is obviously not relevant enough to understand how distinct money are articulated. This viewpoint converges with approaches to money that put forward the complementarity dimension in order to explain the coexistence of various sorts of money (see especially [START_REF] Fantacci | Complementary Currencies: A Prospect on Money from a Retrospect on Premodern Practices[END_REF]2008;Kuroda, 2008a and2008b). Yet this text develops the hypothesis that it is necessary to go beyond the idea of complementarity, trying to refine the ways money can be articulated. Complementarity may indeed refer to very different articulations. The present text aims at building a systematic view of those modes, starting with general categories of possible relations between distinct sorts of money, and thus deepening the institutionalist approach to money.

Under this respect, the purpose of this paper is to take a stylized view of monetary complexity of Early modern France, centring on the 16 th and 17 th centuries, and to apply a conceptual framework able to take into account a wide range of monetary articulations. It appears that this historical period of France, featuring a rich context of monetary schemes and practices, widely helps understand what is at stake with the problem of monetary competition. But, aside this major point that I want to emphasize, another point I would like to stress is the idea of complementarity split up into 3 distinct ideal types. The French case of Early modern period will lead to confront those ideal-types to a simplified view of the reality of that period.

Consequently, section 2 presents the basic framework able to discuss the articulations of this plurality. Four criteria are identified, whose combinations help define distinct articulation modes. This discussion puts in perspective the mainstream articulation mode, that is competition between currencies, as well as breaks up the complementarity hypothesis into a series of specific modes, which should be more relevant, for more precisely built. Section 3 presents a short overview of monetary plurality (or complexity) in the French early modern period (which shares its main features with other European places of that time), and it applies the theoretical framework to it in order to stress the various possible combinations of articulation modes of money. The articulation between royal coins is especially emphasized, ranging from large coins of high and fine metallic content to small coins of low metallic content; the case of gold coins from various origins; and the case of the méreaux, small local coins of no significant metallic content. Overall, competition appears to be a specific articulation mode, especially aside the case of "supplementarity". Then, section 4 addresses briefly the question as to whether the monetary complexity of that period means chaos. The role of social stratification and intermediates in reducing the complexity of monetary plurality is emphasized. Section 5 concludes with a short series of remarks.

Defining basic articulation modes

The present section is intended to build a basic logical framework for understanding articulation modes, discussing a set of binary relation between money, leading to identify four major articulation modes. This discussion puts in perspective the mainstream articulation mode, that is competition between currencies, as well as break up the complementarity hypothesis into a series of specific modes that should be more relevant, for more precisely built.

Monetary qualities

The conceptual framework to be mobilized in order to answer to those questions is firstly based on the assumption that money does not only refer to quantity: it refers to qualities as well. Those qualities are generally known and even acknowledged, but are barely integrated as such in an economic theory of money. Four qualities can be distinguished. As a general scheme of solving debts with the use of a unit of account, and made concrete and useable in payments through a variety of ways, money (i) takes on specific monetary forms, (ii) is inserted in symbolic universes, (iii) conveys socio-economic earmarking guiding its uses and (iv) is characterized by a certain authenticity1 .

(i) Money is made concrete and useable in payments through specific forms that can be of a large variety. "Monetary forms" refer to the different monetary instruments that can be used as means of payment by non-financial agents. The monetary forms of the Early modern period presented below were mostly metallic coins: gold, silver, billon or pure copper coins, plus a variety of méreaux made of lead, tin or copper. Paper currencies started to circulate in local areas outside France (especially in Sweden around the middle of the 17 th century, with the short experience of Palmstruch's bank), while the use of accounts existed already on a wide scale. Talking of monetary forms, it is to be considered not only the material (e.g. gold of a precise fineness and weight) but the way it is shaped and the symbols and information it conveys (e.g. a gold louis with the effigy of Louis XIII, a cross made of "L" and other features), since all those elements make this form a particular one, differentiated with others -should this make a difference in its value or not. Thus, the monetary form taken by money may produce a first orientation of uses. For example, gold coins were so costly that they could not be used by everyone. Or, degraded coins because of the action of clippers were not considered as good as the non-degraded ones.

(ii) Another quality is the symbolic universe in which money is inserted and in which it make sense. It refers to a homogeneous area of representations characterized by a hierarchy of values and moral norms. A kind of sovereignty is attached to each symbolic universe, and one can consider the area of monetary practices organized around a national currency as a particular symbolic universe. The introduction of an outside currency inside a given community provides a good illustration of the meaning of a symbolic universe. This was the case of Amerindian wampums introduced in the local monetary practices of the New Amsterdam (before becoming New York) in the 17 th century (Desmedt, 2008, pp. 278-280). Something that could have been used both in Indian communities and in New Amsterdam community changed radically its meanings when entering the New Amsterdam signification. For example, it would not be used as a ceremonial means of payment as this was the case in India communities! (iii) (iv) The two other qualities will not be considered in this text, because they are not directly related to the core of our argument: first, earmarking, which produces an informal orientation of monetary uses -especially because of moralities associated to specific origins of incomes [START_REF] Zelizer | The Social Meaning of Money[END_REF]; second, the way users perceive the authenticity of what they use as money -especially regarding the issuer: the quality of a currency that seems to be counterfeited is obviously worse than a true one. Suspicion, fear or even recognition of counterfeiting does not prevent in every case the use of the currency, especially when counterfeiting develops in periods of monetary shortage (Blanc and Desmedt, 2010, on 16 th to 18 th centuries).

The qualitative differentiation of currencies leads us to consider them in principle as different monies whose fungibility is not guaranteed. The analysis of the conditions of monetary articulation, which requires operations of conversion, comes in the matter precisely because of such uncertainty over monetary fungibility. The major point is that money is not considered as a mere quantity (in units of accounts). Yet, qualitative differences help take into account distinct ways of using money, as well as distinct concrete monetary forms. In this renewed framework, understanding how money are articulated requires an analysis of binary relations between two given qualities of money. Those relations cannot be understood as purely instrumental (that is, horizontal, between equivalences), since hierarchical criteria play they role through the symbolic universe as well as symbols conveyed by monetary forms.

Binary relations

Four relations may be identified, whose combinations seem to provide useful criteria for building basic articulation modes: commensurability, convertibility, co-use, coincidence. It is worth noting that the economic postulate of fungibility of money stems from the combination of the two first relations: a common evaluation of holdings, followed by conversion.

Commensurability

Commensurability is the very first fundamental criterion to be considered as to an analysis of monetary articulations. No contact between two different money is possible without their commensurability, ie an ability to obtain a common evaluation of them through a given rate. Let us consider a holding under a monetary form H i . Quantitatively, H i is defined by a given quantity (x i ) of a currency C i , so that H i =x i. .C i . Qualitatively, it is characterized by the monetary form F i it takes and the symbolic universe U i in which it is inserted -not considering here the two other qualities of earmarking and authenticity, so that H i =(F i , U i ). The commensurability of this monetary holding H i implies that it can be expressed in quantitative terms in relation to another holding H j , characterized by the same set of criteria, with the help of an equivalence rate (r) so that

€ r = x i / x j .
While it as the very basis of any monetary articulation, commensurability cannot be viewed as obvious. The qualitative characteristics of money to be converted, the general conversion rules that prevail in the symbolic universe under scrutiny, or technical constraints, may preclude all comparison. The lack of a rate (r) or the multiplicity thereof, help avoid or limit comparisons and conversions.

Convertibility

Conversion of one money into another obviously requires their commensurability. However, this condition is not sufficient. From an anthropological point of view, conversion means the transformation of the money's characteristics so that all its qualities (or part of them) are transformed: the symbolic universe in which it is inserted or / and the monetary form it takes -not considering other qualities as earmarking and authenticity [START_REF] Blanc | Counteracting counterfeiting? Bodin, Mariana and Locke on false money as a multidimensional issue[END_REF].

Foreign exchange, both in economic terms and in its common acceptation, consists of a conversion operated on the symbolic universe and the monetary form: for instance, the conversion of a sum of Euros in Canadian Dollars. But the withdrawal of cash from a bank account is also a conversion operation in the broader sense. A conversion can also be performed by the transition from a symbolic universe to another without the transformation of the monetary form: Colonial history offers examples of different uses of colonial cash by indigenous populations [START_REF] Servet | Démonétarisation et remonétarisation en Afrique. XIXe et XXe siècle[END_REF] or, conversely, different uses of indigenous money by the colonists [START_REF] Servet | Démonétarisation et remonétarisation en Afrique. XIXe et XXe siècle[END_REF][START_REF] Desmedt | Généalogie d'une monnaie mondiale : aux origines du dollar[END_REF].

Co-use

Different sorts of means of payment can be used simultaneously, which can be summed up by the relation of "co-use": for example, adding today a coin and a banknote in order to complete a payment means that there is a co-use, or simultaneous use, of those two sorts of money. This binary relation requires the first relation seen above, ie commensurability, so that the distinct money being used simultaneously are expressed in a unified unit of account. It requires too the mathematical property of reflexivity: a given money (more precisely, a given money holding characterized by a specific set of qualities) can be used with other identical money (other money holdings characterized by the same specific set of qualities). It is worth noting that co-use does not require the convertibility of the money holdings.

Coincidence of sphere of uses

A last relation can be identified, that will be useful for the forthcoming reflection: the coincidence of spheres of uses of distinct money holdings. The coincidence relation means that various money holdings are useable in the same socio-economic spheres: for the same set of operations or goods and services, with the same partners, by the same set of users, within the same territory, etc.

Articulation modes

Once briefly identified, it appears that each one of those pure binary relations can be considered as the key criterion (however combined with others) allowing to characterize an ideal type of articulation: respectively (given the order of the binary relations presented above), autonomy, competition, simultaneousness, supplementarity. As competition is the main articulation mode considered in monetary economics (if not the only one), we will start with this case.

Competition (focusing on convertibility)

Focusing on the binary relation of convertibility leads to identify competition as a first basic articulation mode between money. Actually, competition requires a combination of commensurability, convertibility and at least a degree of coincidence of spheres of uses. These are minimum requirements, that let substitutability emerge. Substitutability means that currencies are interchangeable, regarding their potential uses: either their qualities are identical, or those qualities are treated so as to become not relevant or meaningful, so that a comparison may be operated through the mere quantitative criterion. One can observe competition even when substitutability is incomplete -but anyway exists (Figure 1). In the largest view of it, competition can come from the combination of the four criteria. Through commensurability, currencies can be compared through a single rate (r). Moreover, substitutability requires a minimal degree of convertibility (and, thus, of commensurability) between currencies: there is a capacity to change a currency C 1 for a currency C 2 , through the single rate (r). This capacity is all the more immediate and unrestrained than convertibility is fully implemented. Money is thus fully fungible, as postulated by mainstream approaches to money. Figure 2 summarizes the case of competition regarding the four binary relations previously identified. Each binary relation is figured by an axis of a square graph, each axis featuring different degrees (from 0 to 4) of a given binary relation2 .

Figure 2 -Competition

Competition can emerge with a minimal combination of convertibility, commensurability and coincidence, but is all the more powerful than all three binary relations are fully implemented (black triangle). Eventually, competition can gather all the four criteria (arrow downwards).

What about non-competitive articulation modes?

Having identified four potential binary relations between money, it becomes possible to formalize other articulations than the competition model. Historically, theoretically and even doctrinally, in a quite small set of works and sometimes remote, what appears clearly besides competition is the idea of complementarity (on a historical and theoretical viewpoint, [START_REF] Fantacci | Complementary Currencies: A Prospect on Money from a Retrospect on Premodern Practices[END_REF]and 2008, Kuroda 2008aand 2008b; on a theoretical and doctrinal viewpoint, applied to the contemporary situation and promoting complementary currencies beside national currencies, [START_REF] Greco | New Money for Healthy Community[END_REF][START_REF] Lietaer | The Future of Money. Creating New Wealth, Work and a Wiser World[END_REF]). However, complementarity is highly ambiguous, since one can identify distinct meanings behind the various cases studied by scholars. This is why it seems more relevant to split complementarity into three distinct articulation modes: simultaneousness, supplementarity and autonomy.

Simultaneousness (focusing on co-use)

Simultaneousness means the ability to use simultaneously, i.e. to combine, different sorts of money in order to achieve a given payment operation. Today, for example, it is possible to achieve a payment by combining various coins and notes, but a payment cannot be operated, generally, by the combination of, say, bank money and coins. Under Early modern monetary system, it would have been possible to use simultaneously various billon coins, but probably not gold coins with the smallest of billon.

If the main binary relation here is co-use, it also requires a coincidence of spheres of uses (so as to let money be used simultaneously for one purpose), as well as the basic principle of commensurability; but nothing is required regarding convertibility. Of course, the latter can be present, as shows the possible extent of the model toward the right (Figure 3). In this case, simultaneousness may be associated with a degree of competition.

Supplementarity (focusing on partial coincidence)

Supplementarity is built on the basic idea of partial coincidence of spheres of uses of a given money, so that another one adds up something new. For example, today coins and even notes are generally legal tenders up to a certain amount, above which only bank money can be legally used. Such ceilings were implemented in France by the 1577 reform, a part of which was aimed at limiting the use of small coins (pure copper as well as billon) [START_REF] Boyer-Xambeu | Private Money and Public Currencies: The 16th Century Challenge[END_REF].

Supplementarity requires nothing regarding convertibility, commensurability and co-use. But of course one can have supplementarity with a positive combination of them, since coincidence is never total (their spheres of uses are not identical), which means that co-use is never total too (Figure 4). In those cases, supplementarity may be associated with a degree of competition and a degree of simultaneousness.

Such form of complementarity is what is at stake in Kuroda's works (2008aKuroda's works ( , 2008b)). This leads indeed to identify different "layers" or "currency circuits", where various sorts of currencies are complementary because they serve different spheres of uses.

Figure 4 -Supplementarity

Autonomy (focusing on the absence of commensurability)

Autonomy as a pure concept denies any sort of substitutability between money holdings. It relies on the absence of any commensurability (no rate r may help compare one holding with the other), which implies that monetary qualities are absolutely not reducible to quantities. As a consequence, no convertibility is possible at all and, of course, no simultaneous use is possible (Figure 5). Autonomy refers to no relation; it is as such a particular, and radical, case of supplementarity. Fungibility is totally out of consideration. The French méreaux presented below fall in this category, when they only circulate in closed networks.

Monetary plurality and articulations in the case of Early modern

France (16 th -17 th Centuries)

This section will present the main features of the monetary system and monetary practices of Early modern France, centred on the 16 th and 17 th centuries. What will be under examination are the internal monetary relationships, excluding foreign flows and exchanges. The complexity people had to cope with mainly came from the variety of means of payment throughout the kingdom. This variety can be presented by distinguishing two main sets of means of payment (royal and non-royal) adding to this presentation the complementary circulation of the so-called méreaux in several cases.

The theoretical framework that has been built will be applied to those cases. This requires to think articulations between currencies, not currencies by themselves. Our observations lead to consider the following possible articulations: between the three metallic sorts of royal coins, between large royal coins and large foreign coins ; between small royal coins and méreaux.

Plurality inside the royal monetary system

Royal units of account and coins

Sixteenth century French monetary system was built on the basis of the livre tournois unit of account. The hierarchy livre / sous / deniers (identical to other hierarchies in European countries at that time, and coming from the Carolingian empire) had been established in 794, with the fixed equivalences as follow: 1 livre = 20 sous = 240 deniers (with 1 sou = 12 deniers). The tournois definition of the livre, meaning a certain weight of silver, referred to a province of the kingdom, and was embodied by the royalty from 1205, whereas other local units of account were progressively rejected. However, the main other unit, which was the parisis definition of the livre, and which was 25% higher than the tournois definition, remained in use in specific parts of the kingdom and was concretized by specific small coins that were struck in several parts of the kingdom, especially at the end of the 16 th century. The use of the parisis was legally forbidden in 1667, but lasted several years more, since the Dictionnaire universel de commerce, written from the years 1690 by Jacques Savary des Bruslons, still testifies to its use as a unit of account3 . Anyway, this one had become very marginal.

The royal system of means of payment had been reformed in 1266 by the king Saint Louis. He had established a three-parts system, which, in the 16 th and 17 th centuries, was composed of gold coins (centred on the écu, then the louis), silver coins (centred on the teston, then during a short period of time, the franc, and eventually the ecu) and billon coins, made of an alloy of silver and base metal. From the reform of 1577, other coins were struck with pure copper4 . Regarding their legal value, their maximum bracket was 1:720 in 1578 and rose to 1:2400 in 1640 with the creation the gold louis, 10 livres worth.

Enhancements and debasements5 made the system more complex. Enhancements rose the legal tender (extrinsic value) of unchanged existing coins. This required the proper information of all subjects of the kingdom, so as to enforce the royal decision. Debasements introduced new coins of a lower metallic content (intrinsic value, either through the lowering of the metallic weight, or through the lowering of the metallic fineness) into the circulation. [START_REF] Fantacci | Complementary Currencies: A Prospect on Money from a Retrospect on Premodern Practices[END_REF] showed that those two possible monetary policies referred to the opposite nature of large and small coins. Enhancements were the most used manipulation regarding large coins, since, being used as a reserve of wealth and for big transactions, a stable metallic content was more important to the users than a stable legal value. For example, the gold ecu, which was the centre of the monetary system of France between 1488 and 1640, was debased three times (1519, 1552 and 1561) but was enhanced much more frequently. We should add to this analysis the fact that, during long periods of crises, voluntary prices, that is, prices at which coins were actually taken by merchants and the people, were higher than the legal tenders, sometimes bearing volatile movements6 . On the contrary, debasements were operated mostly on small coins, since, being used in daily transactions, a stable legal value was more important to the users than a stable metallic content. For example, the French sols coins experienced 12 debasements between the beginning of the 16 th and the end of the 17 th century, whereas their legal tender only changed once, when it rose from 12 to 15 deniers in 1692 (Spooner, 1972, p. 331).

As a result, the number and the variety of royal coins multiplied as the decades went by. For example, three new sorts of gold coins were introduced during the 16 th and 17 th centuries: the henri in 1549, the louis in 1640 and the lis in 1655, not to mention the existing écu, whose legal circulation ended in 1691 after a multitude of distinct subtypes, metallic contents and cry-ups (from 12 sous tournois in 1266 to 114 sous tournois in 1691)... Demonetizations ordered by the king only smoothly reduced the diversity of coins, because the demonetized coins often remained in circulation several years, decades and sometimes centuries after. They had different metallic contents than the new ones. For example, coins from Charles VI (king from 1380 to 1422) still circulated under Louis XVI (1643-1715), while coins minted under Henri II (1547-1559) were still in use in the beginning of the 18 th century. The last deniers to be minted were issued in 1649, but some still circulated in provinces eighty years after.

Overall, while Savary des Bruslons (1719, I, col. 1672and II, col. 772 and 1080-81) stated that 31 authorized royal coins were in circulation, the actual number of coins in use was notably higher -without taking counterfeit coins into account.

Articulations between royal coins : the role of supplementarity

When trying to understand how coins were used during that period, a first distinction arises between large coins (say, gold and silver coins) and small coins (billon and copper). This refers for example to the analytical distinction established by [START_REF] Sargent | The Big Problem of Small Change[END_REF], studying the conditions in which the issue of small coins can be operated by avoiding either the general want of that sort of coins, or inflationary effects due to their massive issue. The "dual currency system" analyzed by [START_REF] Fantacci | Complementary Currencies: A Prospect on Money from a Retrospect on Premodern Practices[END_REF] refers to the same sort of distinction between coins with an intrinsic value (gold and silver) and coins that do not have any.

Actually, historians and numismatists, although recognizing the lack of knowledge on this point, rather stress that the system, according to monetary uses (and not policies), was more stratified. According to Belaubre (1987, p. 501), regarding the first half of the 13 th century, "there is not unity in the composite society of money users". Braudel (1979, I, p. 404) states, for the period of early modern Europe, that "each metal, with the coins which correspond to it, undertakes a series of transactions": the use of silver, gold, and billon-copper were mainly separate circulation flows. Guerreau (1987, p. 529) acknowledges "the very weak permeability between the circulating networks of the three metals". They do not refer to the same social groups, so that their transaction networks may appear separate : "It seems to me that, without proof to the contrary, we should make the hypothesis of a quasi-separation between the circulation of gold and that of silver, of very inconvenient crossings controlled by a tiny part of the people, and of obviously distinct characteristics of the circulation on both sides of this borderline" (Guerreau, 1987, p. 531). Moreover, we know little about the flows between gold and silver and between silver and billon : "studies on the concrete conditions of use of the various coins are still notoriously scarce", and we do not have "any idea of the importance of exchange operations gold / silver and silver / gold with respect to the ordinary trade flows of those two metals", with the same problem with the relations silver / billon (Guerreau, 1987, p. 531). Thus, a major concern is about the ways contacts could be established between those coins and, thus, between the quite separate social spheres. Here appears the major role of moneychangers and different levels of merchants, ranging from the local level to the specific case of merchant-bankers of intra-European activity (those who managed fairs in Latin Christendom) and to the extra-European level7 .

Eventually, coins, as regards the metal they were made of, were mostly not in a competition relationship. Commensurability was obviously assured, because all those coins were subordinated to the same unit of account (the livre tournois, see Figure 9). However, convertibility required all the more the mediation of various levels of merchants and moneychangers than the difference of value and of metal between coins was large. This means that competition was all the more possible between coins than their legal value and metal was closer or identical. Given that distinct metals referred to specific uses, one can stress the major role of the coincidence binary relation. Consequently, co-use was scarce. Finally, it seems that royal coins of different metals were in a supplementarity relationship, because each sort of metal (under the form of coins) referred to specific spheres of uses (their coincidence was very partial) and led to specific sorts of transactions (Figure 6). This social stratification is a major factor reducing the actual monetary complexity experienced by the people.

Other coins : foreign coins, local coins

As extra-territorial systems of accounting transactions and financial operations, it will not be dealt with the merchant-banker's money of change developed inside Lyonese fairs during several decades of the 16 th century -called "écu de marc" (see especially [START_REF] Boyer-Xambeu | Private Money and Public Currencies: The 16th Century Challenge[END_REF]. These sorts of monetary schemes, intended to be autonomous from sovereign's debasements, were indeed in use between the only set of merchant banker's of the Latin Christendom, so that they served as network monetary schemes mostly autonomous from the other sorts of money of any kingdom. What will be under examination in this section are the case of foreign coins and local coins. Both induce specific articulation modes.

Foreign coins: the case of international competition between gold coins

In spite of recurrent edicts forbidding their circulation or trying to mastering their price in unit of account, foreign coins circulated easily. Borders were indeed highly porous, and foreign coins penetrated in the kingdom through trade with neighbouring countries, as well as through fairs. Some of those foreign coins were small ones (billon), and in several places a real flood of foreign billon entered the kingdom, as for example during the decades 1570-90. Others were silver or even gold coins, like the Spanish pistole. In 1577, Henri III published an edict demonetizing 180 sorts of foreign coins coming from nearly 20 spaces of sovereignty (Bayard and Guignet, 1991, p. 224). However, the edict did not forbid the use of the Spanish pistole, which had a major role in gold monetary circulation of the kingdom (for 10 livres tournois), and a few other Spanish and Portuguese coins [START_REF] Boyer-Xambeu | Private Money and Public Currencies: The 16th Century Challenge[END_REF]. The pistole circulated at least up to the end of the 17 th century. Overall, Braudel (1979, II, p. 167) states that, in 1614, 82 different sorts of metallic coins (including royal and foreign) were in use in the French kingdom.

The case of foreign coins leads to interesting remarks on the articulation of especially large coins, that is to say, gold coins. We have seen that the royal monetary system obviously included gold coins, but that, nevertheless, foreign gold coins would circulate easily and widely inside the kingdom.

There was a harsh competition especially between the French gold coins and the pistole. They were indeed highly interchangeable for the population, especially merchants and the nobility, who had an access to them. The pistole was so appreciated by the people (say, not all the people, since a few only could have them in hands and use them) that, in 1640, the first gold Louis imitated them. Moreover, it said that the marriage of Louis XIV with Maria-Theresa in 1660, a daughter of the Spanish king, contributed to the abundant circulation of those coins in the French kingdom (Sédillot, 1955, p. 416). In this case, the commensurability of coins was ensured by the common use of the unit of account, through legal tenders and, more accurately, voluntary prices that reflected the relative abundance of those coins, their relative metallic content and trust embodied in them. This commensurability was completed by an easy convertibility, especially treated by moneychangers and high levels of merchants. Moreover, the substitutability of those coins was all the more important than their spheres of uses coincided (Figure 7).

The méreaux: an ambiguous case

Small local coins were to circulate in several places, issued by local authorities, by local merchants (tavern tenants for example), by secular religious groups, etc. Some were remaining feudal coins, in a few parts of the kingdom. Others were the méreaux. Their English equivalence, tokens, are briefly presented by Grierson (1975). The French case is extensively analyzed by [START_REF] Labrot | Une histoire économique et populaire du Moyen Age : les jetons et méreaux[END_REF]. It appears that the English tokens and the French méreaux were not identical, especially because of a distinct monetary context (a worse and more recurrent shortage of small coins in England) and a distinct legal framework (in England, the circulation of tokens were not forbidden before 1817). As presented by [START_REF] Labrot | Une histoire économique et populaire du Moyen Age : les jetons et méreaux[END_REF], the French méreaux were mostly just coin-like objects, serving a series of non-monetary purposes as game tokens, tokens for accountancy calculus, medals, etc. They had the form of a coin and they bore the mention "Moneta", and sometimes symbols like animals (e.g. squirrels). They were generally made of lead, copper or tin. Yet, those méreaux sometimes went to circulate, either in a small and closed area, or, less frequently, in a widened and opened area.

If coins made of distinct metals are mainly articulated through supplementarity and gold coins through competition, what about the méreaux ? There can be two different cases when examining them.

Sometimes, the méreaux were used as a debt recognition and vouchers, issued especially by chapters toward the poor or toward people who came accomplish services. In this normal case, they were insulated in a very specific, and local social sphere, as the religious community of a chapter, a set of external professionals working for a chapter (like masons). People received a payment for their services under the form of méreaux, that were useable inside the chapter or toward external professionals also working with the chapter (like bakers or taverns). Thus, in this general case, they were insulated and autonomous schemes, not having any contact with the external (normal) monetary circulation. On this extreme situation of insulation, the major point is the absence of commensurability that prevents any external articulation. This is thus a case of quite pure autonomy.

However, in a series of cases, generally related to a harsh want of money in the local area as a city, be it during a severe monetary crisis or simply recurrent, the méreaux circulated in a broader space than an insulated network of persons. Ecclesiastic méreaux were the most numerous to be used in such a manner. This was the case in Mâcon during 3 or 4 centuries until 1557, when the lead méreaux, issued by the chapter to the priests and choristers, circulated for the value of 1, 2 and 6 deniers (see [START_REF] Labrot | Une histoire économique et populaire du Moyen Age : les jetons et méreaux[END_REF], p. 40-41, quoting Constans, 1658) This was the case too in Autun until 1557, in Luçon in 1772, etc. Other cases came from municipalities themselves, providing small coins to the local circulation and involving sometimes huge quantities of issues (in Béthune until 1521, in Amiens around 1660, etc.). In Amiens, some of the méreaux were worth 1/3 of a denier, while the smallest royal coin, the denier, was not minted any more since a few years. The bad quality and the easiness of their counterfeiting (as in Béthune) could limit the tolerance of royal authorities. However, even in this case, they could hardly be considered as competing the small royal coins: indeed, either those royal coins were lacking, or anyway the hierarchy of monetary quality led to consider the méreaux as a worse currency than the royal one -which had the good consequence of making them circulate… Eventually, the general lack of small coins could lead taverns and innkeepers to issue their own méreaux to the use of their customers, especially in the 15 th and 16 th centuries. Those méreaux were, as the others, of a small value: some circulated for the equivalence of 1/2 denier, ie one maille, which were no more minted since 1411. As a consequence, the situation ranged between that of supplementarity (when the méreaux provided a means for paying in a sphere that did not coincide with existing monetized spheres) to competition (when coins of similar value existed -but this was rare), even through simultaneousness (when using the méreaux aside with other coins, billon or copper). The major case seemed to be the supplemental one, because of the lack of small currencies under the value of a denier.

The role of social stratification and mediations in reducing the complexity of monetary plurality

Even shortly presented as done above, the monetary complexity of the period appears as obvious. At first glance, this complexity gives an impression of unintelligibility of the monetary system and appears close to chaos. However, it has been analysed recently as the result of a sort of voluntary construction [START_REF] Fantacci | The dual currency system of Renaissance Europe[END_REF]. More largely, it has never been considered chaotic by historians, even if it generally seemed complex and far less suited to the people's and merchant's needs than our contemporary monetary system. But a deepened and precise examination of the way money was issued, managed and used help identify regularities and features that show an overall underlying order [START_REF] Blanc | Les citoyens face à la complexité monétaire : le cas de la France sous l'Ancien Régime[END_REF]. Money must be observed as embedded in a social context. One basic, but major distinction that leads to understand the way complexity is dealt with by money users is the difference between money "viewed from the inside" and "money viewed from the outside" (an expression from Charles Rist). The first one provides a subjective view on monetary plurality, while the second one provides an objective view. From the inside, it appears that complexity is far lower than only observed from the outside. This difference comes from the fact that money instruments referred to specific uses, areas, social groups, etc. This idea can be summarized saying that money is socially bounded, so that everyone does not have an access to everything and does not use everything that is money. Social boundaries located socially the use of money, while operators like moneychangers made the link between the different social group. Thus, people from a given social group faced a much simpler set of currencies than could formerly appear when unravelling the overall monetary complexity. Moreover, people had techniques for treating and sidestepping (see [START_REF] Blanc | Les citoyens face à la complexité monétaire : le cas de la France sous l'Ancien Régime[END_REF]. As a result, money was not the same for everybody.

Figure 9 summarizes the elements of the complexity and the relationships that has been under examination. In the general space of accounts unified by the use of the livre tournois, means of payment were already highly plural: small currencies and larges coins composed the royal payment system, being a fiscal currency managed by the Mint, while external means of payment, like the méreaux, could develop according to local contexts. Aside those currencies, a wide range of large foreign coins circulated, coming from external spaces of account. Figure 10 shows an (over)simplified stratification of money uses, gathering the people in two groupings only and the currency in four sorts. It shows at least that each social grouping faced a reduced variety of coins. Figure 11 shows the role of sorts of intermediaries in managing monetary complexity. Central to this management are moneychangers, also generally developing sorts of banking services. Of course, inside this grouping it should be distinguished sub-groups regarding the sorts of operations they developed and what customers they had. Moreover, a series of distinct merchants can be identified that, each one, had specific monetary practices. Figure 12 summarizes the various monetary practices of the various groups of intermediaries.

All this means that intermediaries served as operators reducing and managing monetary complexity for their customers. As a consequence, the extent of possible competition between currencies depended both 1) on the criterion of convertibility, and coincidence of spheres of uses. 2) and on the extent of the operations of those intermediaries, because they were those who actually implemented the convertibility.

Concluding remarks

A first set of remarks relates to the historical case presented in the paper. "From the outside", early modern French monetary system was composed of a complex series of means of payment (royal coins, old and demonetized coins, foreign coins, méreaux…). Nevertheless, "from the inside", an important social stratification and the mediation of specific operators reduced sharply this complexity. The latter combined different sorts of articulations, ranging from a high competition degree (gold coins) to autonomy (méreaux inside communities), through degrees of supplementarity (royal coins). As regards the four ideal types of monetary articulations built in the paper, simultaneousness is the only one that has not been analyzed, although it refers for example to the co-use of distinct billon or copper coins. The following table summarizes this research.

A second set of remarks relates to the present theory of monetary articulations. Competition is not the only way money are articulated. Competition is limited by the coincidence criterion, but meantime it is made possible by the mediators like moneychangers that implement convertibility. In order to let competition develop between currencies, the less currencies have the same sphere of uses, the more moneychangers and other mediations are necessary (see Figure 1). Complementarity appears to be a composite view of distinct articulation modes (simultaneousness / supplementarity / autonomy). The most important in the case of early modern France is that of supplementarity, but insights in other contexts could show the importance of the two others. Of course, empirical cases do not fit exactly with the ideal types -but must be analysed as combining various criteria and able to evolve through social changes.

Figure 1 -

 1 Figure 1 -Competition and the requirement of a coincidence of spheres of uses

Figure

  Figure 3 -Simultaneousness

Figure

  Figure 5 -Autonomy

Figure

  Figure 6 -Royal coins

Figure

  Figure 7 -Gold coins

Figure

  Figure 8 -Méreaux

Figure 9 -

 9 Figure 9 -Monetary plurality of the Early modern France summarized, 16-17 th century

Figure 10 -Figure 12 -

 1012 Figure 10 -Social structure of money uses / 1

Table 1 -Summary

 1

	Relation between money	Ideal type when this relation is	Examples
	of different qualities	considered central
	Convertibility	Competition	Gold coins
	Commensurability	Autonomy	Isolated méreaux
		(absence of commensurability)
	Co-use	Simultaneousness	Various billon and copper
			coins
	Coincidence	Supplementarity	Small coins and large
	(of spheres of uses)	(partial coincidence)	coins around 1577

A deepened view on the qualities of money is developed in[START_REF] Blanc | Usages de l'argent et pratiques monétaires[END_REF].

0 -absolutely not, 1-difficult, 2-medium,

3-easy, not generalized anyway, 4-total.

Savary des Bruslons, vol. I, column 1672-73 and II, col. 986.

See Spooner (1972, p. 330-332) for a synthetic view on French coins.

Though this is of old use,[START_REF] Sargent | The Big Problem of Small Change[END_REF] prefer to use 'cry-ups' when referring to what we will call here 'enhancement'.

[START_REF] Spooner | The International Economy and Monetary Movements in France, 1493-1725[END_REF] especially reviews the movement in voluntary and legal prices of the ecu during the 16 th and 17 th centuries.

On categories of merchants, see[START_REF] Jeannin | Les marchands au XVIe siècle[END_REF]; on the specific case of merchant-bankers during the 16 th century and the central role of Lyon Fairs, see[START_REF] Boyer-Xambeu | Private Money and Public Currencies: The 16th Century Challenge[END_REF].


Lee R Dehaan
email: dehaan@landinstitute.org

James A Anderson

Prabin Bajgain

Andrea Basche

Douglas J Cattani

Jared Crain

Timothy E Crews

Christophe David

Olivier Duchene

Jessica Gutknecht

Richard C Hayes

Fengyi Hu

Jacob M Jungers

Søren Knudsen

Wenqian Kong

Per-Olof Steve Larson

Guangbin Lundquist

Allison J Luo

Pheonah Miller

Matthew T Nabukalu

Lennart Newell

Michael Olsson

Andrew H Palmgren

Valentin D Paterson

Jesse A Picasso

Erik J Poland

Shuwen Sacks

Anna Wang

Westerbergh

Per-Olof Lundquist

Guangbin Luo

Allison J Miller

Pheonah Nabukalu

Matthew T Newell

Lennart Olsson

Michael Palmgren

Andrew H Paterson

Valentin D Picasso

Jesse A Poland

Erik J Sacks

Shuwen Wang

Anna Westerbergh

Discussion: Prioritize perennial grain development for sustainable food production and environmental benefits

Keywords: soil quality, climate change, carbon sequestration, genome editing, intermediate wheatgrass, genomic selection

published or not. The documents may come

Introduction

The abundant potential of perennial grains, if developed, to address a wide array of global sustainability challenges to agricultural production has long been recognized. In 1990, the first extensive review of past efforts to develop perennial grains using species in the grass family was published [START_REF] Wagoner | Perennial grain development: past efforts and potential for the future[END_REF]. The review listed numerous reasons for perennial grain development, including reducing soil erosion, reducing inputs, conserving soil nutrients, building soil health, and improving farmer profits by reducing costs of inputs and field operations while preserving grain productivity. Although humans have consumed the seeds of perennial grasses for millennia, domestic perennial grains were not developed. As Wagoner described, efforts to develop perennial wheat through wide hybridization between annual cereals and perennial relatives were conducted in the Soviet Union beginning in the 1920s. Efforts later spread to other J o u r n a l P r e -p r o o f Journal Pre-proof regions and attempts were made to create perennial versions of other crops by cross-pollination with perennial relatives. These programs generally produced short-lived perennials with yields inferior to annual grains, and there was never a clear commercial opportunity.

In 2002, an exhaustive review of past and potential efforts to breed successful perennial grains was published [START_REF] Cox | Breeding perennial grain crops[END_REF]. Again, the authors concluded that decades of work had failed to produce yields on par with comparable annual grains. However, they also asserted that important avenues to high grain yield from perennials may have been overlooked. For instance, perennials can often use resources such as water, nutrients and sunlight that are unavailable to many annual crops due to their brief summer lifespans. The authors also described the potential of ongoing efforts to develop perennial rice and perennial sorghum by hybridizing the annual crops with their perennial relatives and suggested that repeated rounds of selection over many generations would enable simultaneous improvement in longevity and seed production traits by combining favorable alleles in new high-yielding perennial grains.

In the 20 years following the 2002 review by [START_REF] Cox | Breeding perennial grain crops[END_REF], perennial grain development efforts have grown in number and have attracted expanding attention as an approach to address urgent issues in agriculture. Reports are continuing to show the effectiveness of perennial crops in stabilizing production [START_REF] Sanford | Perenniality and diversity drive output stability and resilience in a 26-year cropping systems experiment[END_REF], improving soil quality [START_REF] Daigh | Bioenergy cropping systems effects on soil quality[END_REF][START_REF] Dehaan | Gourmet grasslands: Harvesting a perennial future[END_REF][START_REF] J O U R N A L P R E -P R O O F Emmerling | Impact of newly introduced perennial bioenergy crops on soil quality parameters at three different locations in W-Germany[END_REF][START_REF] Mcgowan | Soil organic carbon, aggregation, and microbial community structure in annual and perennial biofuel crops[END_REF], mitigating climate change [START_REF] Crews | What agriculture can learn from native ecosystems in building soil organic matter: A review[END_REF][START_REF] Jacot | Biofuel benefit or bummer? A review comparing environmental effects, economics, and feasibility of North American native perennial grass and traditional annual row crops when used for biofuel[END_REF], improving wildlife habitat [START_REF] Graham | Assessing wild bees in perennial bioenergy landscapes: effects of bioenergy crop composition, landscape configuration, and bioenergy crop area[END_REF][START_REF] Helms | Ant biodiversity and ecosystem services in bioenergy landscapes[END_REF][START_REF] Robertson | Perennial biomass feedstocks enhance avian diversity[END_REF] and protecting water quality [START_REF] Cacho | Introducing perennial biomass crops into agricultural landscapes to address water quality challenges and provide other environmental services[END_REF][START_REF] Culman | Soil and water quality rapidly responds to the perennial grain Kernza wheatgrass[END_REF][START_REF] Jungers | Reduced nitrate leaching in a perennial grain crop compared to maize in the Upper Midwest, USA. Agriculture[END_REF][START_REF] Moore | Regenerating agricultural landscapes with perennial groundcover for intensive crop production[END_REF]. Evidence of rapid expansion in perennial grain research is seen in a Google Scholar search, where only 5 articles containing the search term "perennial wheat" are returned from the year 2001, compared to 463 articles from 2021. Although the increase is substantial, perennial grain efforts remain insignificant compared with annual crops, as a search for "winter wheat" from 2021 provides more than 24,000 results.

Although efforts to develop new perennial grains remain relatively slight, they have been sufficient to attract critique from authors who regard the vision as being unlikely to succeed and unworthy of expanded investment [START_REF] Cassman | Progress Towards Perennial Grains for Prairies and Plains[END_REF][START_REF] Loomis | Perils of production with perennial polycultures[END_REF][START_REF] Smaje | The strong perennial vision: A critical review[END_REF]. These critiques are helpful, to some extent, as they allow a careful examination of the available evidence for and against greater investment in J o u r n a l P r e -p r o o f Journal Pre-proof programs that will require sustained effort over longer time frames than might typically be embraced by funders. Herein we will support our thesis that recent research progress, theoretical considerations, and advances in breeding and genetic technologies have combined to provide justification for an aggressive expansion in perennial grain research in the current and future decades.

Recent progress in perennial rice

Perennial rice currently provides the clearest example of what can be achieved through sustained investment in a perennial grain breeding program. An initial successful cross between annual rice (Oryza sativa) and the perennial relative Oryza longistaminata was obtained in 1996, and work was invigorated when the first promising F 2 progeny with good seed set and moderately strong rhizome production was identified in 2007 (Zhang et al., 2022). What followed were generations of selfing and selection for plants with increased pollen viability and short rhizomes. As generations advanced, plants were identified that had traits similar to annual rice (height, seed size, and grain set). However, the selected lines retained the ability to regrow vigorously after harvest. Subsequent rounds of backcrossing to various elite rice types have demonstrated the potential to introduce the perennial trait into different genetic backgrounds (Zhang et al., 2022).

In 2018, the first perennial rice variety, PR23, was released to farmers in China. While other rice varieties may have weak "ratooning" (regrowth after harvest), allowing a small second crop, PR23 has capacity for strong regrowth and sustained yield. Evaluated over eight consecutive harvests across four years, the perennial rice produced an average of 6.8 Mg ha -1 harvest -1 , similar to the yield of replanted annual rice, which is also harvested twice per year (Zhang et al., 2022). After the first season, perennial rice resulted in substantial savings on labor and other inputs, which boosted net farmer incomes (Zhang et al., 2022), consistent with earlier predictions made by advocates for perennial grain development [START_REF] Wagoner | Perennial grain development: past efforts and potential for the future[END_REF][START_REF] Cox | Breeding perennial grain crops[END_REF]. Additionally, reduced soil disturbance in perennial rice production provided measurable improvements in soil, as expected. For example, in four years of paddy perennial rice production, soil organic carbon content increased by a substantial 0.95 Mg ha -1 (Zhang et al., 2022).

J o u r n a l P r e -p r o o f

Since its release to farmers in 2018, farmer acceptance has been strong, and perennial rice cultivation is increasing rapidly. Although still less than 0.1% of the area of total rice production in China, in 2021 the area planted to perennial rice increased fourfold to 15, 522 ha on 44,752 smallholder farms (Zhang et al., 2022). Perennial rice is a clear example of how readily a new perennial grain can be developed, requiring an investment of less than US$20 million over 15 years [START_REF] Glover | Newer roots for agriculture[END_REF]. As the authors reporting the progress concluded, "perennial rice is a step change with potential to improve livelihoods, enhance soil quality and inspire research on other perennial grains" (Zhang et al., 2022).

Responses to concerns about perennial grain feasibility

Perennial grain crops have been proposed as a strategy to achieve expanded ecosystem services such as reduced erosion, greater resource use efficiency, reduced nutrient leaching, reduced watershed contamination, improved soil carbon content, and reduced dependence on fertilizer, herbicide, and tillage [START_REF] Broussard | A century of changing land-use and water-quality relationships in the continental US[END_REF][START_REF] Glover | Increased food and ecosystem security via perennial grains[END_REF]. Although various perennial crops and cropping systems are expected to have a range of impacts on these ecosystem services, there has been little disagreement that perennial grains producing yields as large as their annual counterparts would have environmental and sustainability benefits. Divergent viewpoints have more frequently arisen concerning whether breeding perennial crops with yields similar to annual crops is a feasible goal. If clear evidence exists that perennial grain crops would be impossible to breed or that the cost of their development would exceed the benefits, then we would agree that research would be better focused elsewhere. Instead, we find compelling recent results that provide multiple lines of support for prioritizing perennial grain breeding.

Alleviating concerns about the yield potential of perennials

The feasibility of breeding herbaceous perennial plants with high grain yield has been understandably questioned, since on average both wild and domestic herbaceous perennial plants tend to have lower seed production than their annual relatives [START_REF] Vico | Trade-offs between seed output and life span-a quantitative comparison of traits between annual and perennial congeneric species[END_REF]. In Wagoner's 1990 review, forage crops that had been selected for good seed production were found to have yields that might, in ideal circumstances, approach those of annual grains grown in the same region [START_REF] Wagoner | Perennial grain development: past efforts and potential for the future[END_REF], but the general trend is clear that herbaceous perennials tend to be lower seed producers than annuals.

J o u r n a l P r e -p r o o f

Journal Pre-proof However, it would be unscientific conjecture to say that just because something does not currently exist, it can never exist in the future. For instance, maize yields in the USA have increased more than five-fold since the 1920s [START_REF] Duvick | Genetic progress in yield of United States maize (Zea mays L.)[END_REF]. How was it possible to dramatically increase the grain production of maize when human-driven selection should have been favoring the highest seed producers for millennia?

The answer likely lies in a multi-pronged approach including transitioning from open-pollinated populations to F 1 hybrids, modifying the agricultural environment for optimal growth, and enhancing selection methodology to favor plants that are less competitive while being more stress tolerant, thereby avoiding wasteful competitive responses while growing in high population densities [START_REF] Dehaan | Perennial grain crops: A synthesis of ecology and plant breeding[END_REF][START_REF] Denison | Evolutionary tradeoffs as opportunities to improve yield potential[END_REF][START_REF] Duvick | Genetic progress in yield of United States maize (Zea mays L.)[END_REF]. Perennial grain breeders have argued that modern selective breeding, which has reduced competitive waste in annual grain fields, should similarly enable yield increases in perennials [START_REF] Dehaan | Perennial grain crops: A synthesis of ecology and plant breeding[END_REF]. While critics have suggested that the competitive nature of perennials means that they will inherently have lower seed yield [START_REF] Smaje | The strong perennial vision: A critical review[END_REF], the large competitive structures (e.g., large roots, tall stems) of wild perennials may simply provide a larger pool of resources from which to reallocate competitive tissues into harvestable grain [START_REF] Dehaan | Perennial grain crops: A synthesis of ecology and plant breeding[END_REF]. Just because wild perennials allocate more resources on average to competition than seed production, there is no reason to believe that the same must hold true for domesticated perennials [START_REF] Crews | The strong perennial vision: A response[END_REF]. The important unanswered question is to what extent can the benefits of perennial cropping be retained while selecting for increased yield, but evidence of increased soil carbon and improved soil quality under perennial crops selected for maximum aboveground yield is promising [START_REF] J O U R N A L P R E -P R O O F Emmerling | Impact of newly introduced perennial bioenergy crops on soil quality parameters at three different locations in W-Germany[END_REF][START_REF] Mcgowan | Soil organic carbon, aggregation, and microbial community structure in annual and perennial biofuel crops[END_REF].

The clearest arguments against investment in perennial grain breeding have focused on theories of resource allocation. One critic has summarized the position, stating, "For seed yields to approach those of annuals, however, plants would have to pull all available resources into seed production at the end of the growing season, as annuals do, making death almost certain" [START_REF] Denison | Darwinian Agriculture: How Understanding Evolution Can Improve Agriculture[END_REF]. We would suggest that this argument is only valid if "all things are equal" in comparing annuals to perennials. However, all things are not equal.

Perennials often have more rapid spring growth and a longer growing season, allowing access to more sunlight [START_REF] Dohleman | More productive than maize in the Midwest: how does Miscanthus do it?[END_REF]; they may also have longer roots, allowing access to more water and nutrients [START_REF] Duchene | Introducing perennial grain in grain crops rotation: the role of rooting pattern in soil quality management[END_REF]. Indeed, the success described above with perennial rice illustrates that perennial survival with high grain yield has now been achieved, clearly contradicting the claim that high J o u r n a l P r e -p r o o f Journal Pre-proof yielding perennials would be faced with "almost certain" death [START_REF] Denison | Darwinian Agriculture: How Understanding Evolution Can Improve Agriculture[END_REF] due to a strict trade-off between survival and yield. Further evidence is seen in the perennial grass crop Miscanthus, which can yield more aboveground biomass than maize in the Midwest US corn belt [START_REF] Dohleman | More productive than maize in the Midwest: how does Miscanthus do it?[END_REF][START_REF] Heaton | Meeting US biofuel goals with less land: the potential of Miscanthus[END_REF], showing that winter survival need not come at the cost of aboveground production.

3.2 Other perennial grains are being developed to follow the success of perennial rice [START_REF] Smaje | The strong perennial vision: A critical review[END_REF] argued that the lack of any successful perennial grain crops arising over the 10,000 years of agriculture suggests that such crops may be impossible. But he then goes on to state that "Nevertheless if sophisticated modern plant breeding techniques can overcome the obstacles hitherto obstructing a perennial grain agriculture, past impediments may lack future relevance" [START_REF] Smaje | The strong perennial vision: A critical review[END_REF]. We agree with this assessment and observe that concerns about the feasibility of high-yielding perennial grains is quickly becoming a historical artifact rather than a contestable hypothesis, as evidenced by the breeding technologies that produced high yielding perennial rice (Zhang et al., 2022) and are now advancing other perennial grains in development.

While perennial rice provides a recent example of a high-yielding perennial, advocates of perennial grains have previously argued that trees with higher reproductive allocation than modern annual grains are evidence that perenniality need not preclude high yields [START_REF] Van Tassel | Missing domesticated plant forms: can artificial selection fill the gap?[END_REF]. However, past critics discounted the high productivity of woody perennials as a "special case" where the yield of trees is irrelevant to high-yield perennial herbs because trees have unique "ecological and biogeographical characteristics" [START_REF] Smaje | The strong perennial vision: A critical review[END_REF]. Since all individual species have unique ecological and biogeographical characteristics, a similar statement could be applied to dismiss the relevance of perennial rice. Indeed, Kenneth Cassman stated in an interview that perennial rice is a special case, since annual rice already ratoons, and rice production has a high labor requirement [START_REF] Charles | Could this Cheaper, More Climate-friendly Perennial Rice Transform Farming? NPR[END_REF]. We would respond by pointing out that there are other perennial grain candidates, such as perennial sorghum, where the annual progenitor also ratoons. All perennial crops in development have unique advantages that may make them special cases in various ways, such as current use as forage crops or valuable by-products such as honey or fiber.

With every candidate crop having unique advantages, we cannot confidently predict which will be easiest to achieve, and we contend that the best way to determine which crops are feasible to develop is to attempt J o u r n a l P r e -p r o o f Journal Pre-proof many projects at once [START_REF] Dehaan | A pipeline strategy for grain crop domestication[END_REF]. Although critics may continue attempting to dismiss the existence of high-yielding fruit trees or perennial rice as irrelevant to the debate, we maintain that these achievements demonstrate that artificial selection can generate perennial crops with high reproductive outputs and are justification for expanding efforts to develop additional highly productive perennial crops [START_REF] Van Tassel | Missing domesticated plant forms: can artificial selection fill the gap?[END_REF].

Just as all annual grain crops have unique advantages and disadvantages in terms of growing environment and end uses, there is an array of perennial grain crops currently under various stages of development for a variety of initial target environments and uses. Every crop in the making faces a unique set of challenges and presents distinct advantages. As mentioned above, perennial grain sorghum has the same advantage as perennial rice, where the annual parent (Sorghum bicolor) was able to ratoon, but the hybrids with perennial Sorghum halepense have thus far lacked strong winterhardiness in the temperate environment [START_REF] Cox | High proportion of diploid hybrids produced by interspecific diploid× tetraploid Sorghum hybridization[END_REF]. Following the model of perennial rice, perennial sorghum lines are now being introduced to tropical environments, but years of work remain to integrate the perennial habit with locally adapted germplasm. Perennial silflower (Silphium integrifolium) is being developed by domesticating a forb native to the USA. While this species has large seeds and high yield for a wild plant, insect pests and diseases present in its native range have presented a unique challenge for the breeding program (Price et al., 2022). Sainfoin (Onobrychus vicifolia) is a forage legume that is just beginning domestication at The Land Institute. Its seeds are quite large, and yields are already substantial in dry regions, but thorough testing of the grain must be completed to determine if it is safe for human consumption. Perennial flax domestication is starting with perennial species of Linum. Although the perennial species grow vigorously in the target environment, improvement through breeding must be made for a wide array of traits, including growth form, seed size, germination, and early maturity (Tork et al., 2019). Perennial barley development is a possibility either through wide hybridization between annual barley (Hordeum vulgare) and the perennial Hordeum bulbosum or through direct domestication of the perennial. While the wide hybridization approach has been difficult due to low recombination between the annual and perennial chromosomes, direct domestication of H. bulbosum is now a real possibility due to the detailed genomic information which is available for barley [START_REF] Chapman | Perennials as future grain crops: opportunities and challenges[END_REF]. With knowledge of the genetic control of J o u r n a l P r e -p r o o f Journal Pre-proof the critical domestication traits of barley, analogous changes in the wild perennial might be rapidly induced by mutagenesis or genome editing.

Breeding is increasing yields of intermediate wheatgrass

Efforts to improve the grain yield of perennial intermediate wheatgrass (Thinopyrum intermedium) have been ongoing since the 1980s [START_REF] Dehaan | Development and evolution of an intermediate wheatgrass domestication program[END_REF], although until 2010, the project had a small investment, with less than half the effort of a single plant breeder provided each year. Since this is likely the longest-running project to directly domesticate a wild perennial herbaceous species for use as a grain crop, it is worth asking whether progress is being made. [START_REF] Cassman | Progress Towards Perennial Grains for Prairies and Plains[END_REF] claim to answer this question in the negative. [START_REF] Cassman | Progress Towards Perennial Grains for Prairies and Plains[END_REF] compiled a summary in table form of yields obtained in six agronomic trials of intermediate wheatgrass conducted between 2009 and 2018. The trials were performed in four different northern USA states using seed from four different breeding cycles from a program in Kansas. Never was the seed from more than one breeding cycle planted in a given trial. From this assembled data, they concluded, "Based on analysis of these results, there is no evidence of progress towards higher grain yields" [START_REF] Cassman | Progress Towards Perennial Grains for Prairies and Plains[END_REF]. No details regarding the methods of their analysis are presented, and the data which they analyzed was irrelevant to the question of yield progress, leaving their conclusions without merit.

There are three primary reasons that the data used by [START_REF] Cassman | Progress Towards Perennial Grains for Prairies and Plains[END_REF] were insufficient to quantify genetic progress. First, the concept of randomization, which is fundamental to statistical analysis, was ignored. Fisher, a founder of the field of statistics, stressed that "as is the randomization, so is the analysis" [START_REF] Street | Fisher's contributions to agricultural statistics[END_REF]. In this case, because breeding cycles were not randomized across locations, years, or management approaches, there would be no way of evaluating breeding progress without accounting for a host of unknown confounding variables. Secondly, one cannot hope to draw meaningful conclusions about breeding progress from such a small sample size. Before concluding that no evidence of an effect exists in an experiment, the scientist must be cognizant of the risk of Type II error (wrongfully failing to reject the null hypothesis). Failing to account for the sample size necessary to obtain relevant statistical power has been described as a "fatal" error in statistical analysis [START_REF] Kuzon | The seven deadly sins of statistical analysis[END_REF]. Third, the reality of genotype X environment interactions (GXE) has been neglected. The agronomic trials cited were situated J o u r n a l P r e -p r o o f between 800 and 1700 km distant from the location of the breeding program that developed the genetic materials used. Complex traits such as grain yield usually have high GXE, so meaningful evaluation of progress for this trait requires experimentation within the target environment. Testing for progress in a non-target environment ignores what is known about the substantial magnitude of GXE in related crops such as wheat [START_REF] Peterson | Similarities among test sites based on cultivar performance in the hard red winter wheat region[END_REF]. High GXE for traits such as grain yield across distances of 1000 km is expected, but fortunately not an insurmountable barrier for breeding. The clear solution is to, as in annual crops, have regional breeding programs which develop locally adapted varieties. Indeed, in the case of intermediate wheatgrass, three geographically diverse breeding programs are now in operation.

Intermediate wheatgrass has a history of remarkably rapid response to selection. Although Cassman and Connor stated that "there is no evidence of progress toward higher [intermediate wheatgrass] grain yields," one of the papers they cited contains strong evidence of breeding progress in intermediate wheatgrass [START_REF] Bajgain | MN-Clearwater', the first food-grade intermediate wheatgrass (Kernza perennial grain) cultivar[END_REF][START_REF] Cassman | Progress Towards Perennial Grains for Prairies and Plains[END_REF]. The intermediate wheatgrass variety MN-Clearwater was developed in Minnesota, USA for improved grain production by selecting out of the third breeding cycle from The Land Institute. Evaluated across five locations and two years, this single round of selection in the Minnesota environment increased yield by 230 kg ha -1 , or 49% [START_REF] Bajgain | MN-Clearwater', the first food-grade intermediate wheatgrass (Kernza perennial grain) cultivar[END_REF]. Other studies of breeding progress conducted in Kansas as part of The Land Institute's breeding program have shown increases of 150 kg ha -1 over two cycles [START_REF] Dehaan | Current efforts to develop perennial wheat and domesticate Thinopyrum intermedium as a perennial grain[END_REF] and 68 kg ha -1 cycle -1 over five cycles [START_REF] Tyl | Emerging crops with enhanced ecosystem services: progress in breeding and processing for food use[END_REF]. In Canada, breeding produced a steady yield increase of 79 kg ha -1 cycle -1 over five cycles [START_REF] Knowles | Recurrent mass selection for improved seed yields in intermediate wheatgrass[END_REF]. On a percentage basis, the yield gains have been roughly 20 to 30% per cycle, with cycle length varying from 2 to 4 years, for an average progress of about 10% per year.

While a young breeding program for a crop with initially low yields is expected to make large percentage gains, yield increases from selection are often linear. Thus, future gains should only be roughly extrapolated from past gains in terms of yield per area, rather than as percentage increases. Yield on an area basis in the trials mentioned above was increasing about 23 kg ha -1 year -1 . For wheat varieties released in the USA Southern Plains between 1992 and 2014, yield increase was 1.1% year -1 , or 17 kg -1 ha -1 year -1 [START_REF] Rife | A field-based analysis of genetic improvement for grain yield in winter wheat cultivars developed in the US Central Plains from 1992 to 2014[END_REF]. Thus, we see that when evaluated with a proper statistical design, even the earliest intermediate wheatgrass selection programs with meager resources were exceeding wheat breeding J o u r n a l P r e -p r o o f progress on a percentage basis and at least matching it in terms of absolute yield increase per year. Using modern genomic selection to perform one cycle per year could increase yield progress to 58 kg ha -1 year -1 , if current trends continue (Bajgain et al. 2022).

While traditional breeding produced substantial yield increases in intermediate wheatgrass, new techniques and knowledge of genes controlling domestication traits paired with genome editing are opening doors to breakthroughs in rapid domestication [START_REF] Lemmon | Rapid improvement of domestication traits in an orphan crop by genome editing[END_REF][START_REF] Li | Towards understanding the biological foundations of perenniality[END_REF][START_REF] Yu | Breeding future crops to feed the world through de novo domestication[END_REF]Zhu and Zhu, 2021). In recent years, development of genetic resources has made genome editing for rapid domestication of intermediate wheatgrass feasible [START_REF] Chapman | Perennials as future grain crops: opportunities and challenges[END_REF][START_REF] Dehaan | Development and evolution of an intermediate wheatgrass domestication program[END_REF]. Genomic selection can accelerate breeding in perennials by accurately predicting performance of plants using DNA collected at the seedling stage [START_REF] Mcclure | Genomics: a potential panacea for the perennial problem[END_REF][START_REF] Seyum | Genomic selection in tropical perennial crops and plantation trees: a review[END_REF]. This technique is being used to accelerate progress in the domestication of intermediate wheatgrass [START_REF] Crain | Genomic prediction enables rapid selection of high-performing genets in an intermediate wheatgrass breeding program[END_REF] and holds promise for many perennial species. These new methods have potential to accelerate domestication and produce viable new crops in just a decade or two, opening fresh doors of opportunity for developing transformative new crops [START_REF] Runck | The reflective plant breeding paradigm: A robust system of germplasm development to support strategic diversification of agroecosystems[END_REF].

New approaches to perennial wheat

As efforts to develop perennial wheat by hybridizing annual wheat (Triticum aestivum) with perennial relatives have been attempted on and off for nearly a century, it is worth asking whether this approach to perennial grain development still has merit. [START_REF] Cassman | Progress Towards Perennial Grains for Prairies and Plains[END_REF] summarized work on perennial wheat in Australia, and correctly concluded that "Progress in conducting agronomic research with perennial wheat derivatives in Australia is hindered because no commercial cultivars are yet available…" What was left unmentioned was that virtually no breeding efforts have been undertaken in Australia to develop adapted cultivars [START_REF] Hayes | Prospects for perennial grains in Australian farming systems[END_REF]. This is consistent with a fundamental conclusion of Cassman and Connor: perennial grains have yet to succeed due to "inadequate investment in R&D relative to the magnitude of the challenge" [START_REF] Cassman | Progress Towards Perennial Grains for Prairies and Plains[END_REF].

As a wide hybridization effort in an allopolyploid crop, perennial wheat is expected to have a different development trajectory in comparison to simpler introgression projects with diploids such as rice or J o u r n a l P r e -p r o o f domestication projects such as intermediate wheatgrass. While breeding is producing steady increases in yield of intermediate wheatgrass, wide hybridization may not produce similar stepwise improvements if the wide hybrids require breakthrough solutions to make them viable.

Perennial rice and now perennial sorghum breeding programs [START_REF] Cox | High proportion of diploid hybrids produced by interspecific diploid× tetraploid Sorghum hybridization[END_REF] have the benefit of recombination between corresponding chromosomes originating from the annual and perennial parents. In wheat, the annual and perennial parents have diverged to the point where chromosomes do not readily pair [START_REF] Banks | Varying chromosome composition of 56-chromosome wheat × Thinopyrum intermedium partial amphiploids[END_REF]. Presumably, chromosomes originating from wheat carry genes that are detrimental to perenniality, while chromosomes from the perennial parent harbor genes limiting critical traits such as seed size [START_REF] Cox | Breeding perennial grain crops[END_REF][START_REF] Cox | Progress in breeding perennial grains[END_REF]. Thus, past programs may have been able to obtain plants with moderate perenniality and moderate yield, but without recombination, they have been unable to make much additional progress.

In their 2002 review, Cox et al. suggested that the task of developing perennial wheat could be nearly impossible until new molecular techniques were available [START_REF] Cox | Breeding perennial grain crops[END_REF]. This idea is proving prophetic, as the necessary tools may now be available for the first time. For example, tracking individual chromosomes and chromosome fragments by cytology was once cost-and time-prohibitive for use in breeding. Now, sequence-based methods can track chromosome presence and absence in wide hybrids at low cost [START_REF] Adhikari | A high-throughput skim-sequencing approach for genotyping, dosage estimation and identifying translocations[END_REF]. A reference genome is now available for the perennial parent currently used in perennial wheat hybrids, and with this resource, genome editing could be used to knock out or otherwise edit genes impacting important traits in the hybrids, eliminating the need for genetic recombination [START_REF] Dehaan | Development and evolution of an intermediate wheatgrass domestication program[END_REF][START_REF] Soto-Gómez | Sustainable agriculture through perennial grains: Wheat, rice, maize, and other species. A review. Agriculture[END_REF]. Alternatively, mutagenesis followed by genotyping to search for mutations in critical target genes could be effective [START_REF] Knudsen | FIND-IT: Accelerated trait development for a green evolution[END_REF]. With aggressive application of these tools, a breakthrough in perennial wheat may be imminent.

Opportunities and Risks

While new perennial grain crops could aid in addressing the greatest environmental challenge of our time, climate change, the protracted nature of the work required to breed the crops, formulate productive cropping systems, and study the potential risks and benefits inherent in the production of perennial grain J o u r n a l P r e -p r o o f crops means that sustained upfront investment will be required before positive outcomes are achieved.

Therefore, concurrent with the breeding of new perennial grain crops, experimental testing of the potential benefits of perennial grain cropping systems is underway, producing promising results thus far, while some uncertainties remain.

Research results currently support the capacity for perennial grains to substantially increase soil carbon, which would reduce atmospheric carbon dioxide while simultaneously enhancing soil quality [START_REF] Crews | What agriculture can learn from native ecosystems in building soil organic matter: A review[END_REF]. Increases in soil carbon storage under perennial cropping is driven by two mechanisms: reducing the regular disturbances, which exacerbate mineralization losses, that are associated with annual crop establishment [START_REF] Crews | Going where no grains have gone before: From early to mid-succession[END_REF] while simultaneously increasing carbon input through the potentially larger biomass production of perennial crops [START_REF] Newell | An initial investigation of forage production and feed quality of perennial wheat derivatives[END_REF] and increased belowground allocation [START_REF] Sprunger | Perennial grain crop roots and nitrogen management shape soil food webs and soil carbon dynamics[END_REF]. Soil carbon accumulation under perennial cropping has been found to improve soil health parameters, including greater microbial biomass and respiration [START_REF] Means | Annual and perennial crop composition impacts on soil carbon and nitrogen dynamics at two different depths[END_REF], greater microbial abundance and mycorrhizae indicators [START_REF] Duchene | Introducing perennial grain in grain crops rotation: the role of rooting pattern in soil quality management[END_REF]), N mineralization (McKenna et al., 2020), and increased particulate carbon accumulation [START_REF] Van Der Pol | Perennial grain Kernza® fields have higher particulate organic carbon at depth than annual grain fields[END_REF]. Furthermore, perennial cover will generally result in reduced soil erosion and greater climate resilience through increased water infiltration and storage [START_REF] Asbjornsen | Targeting perennial vegetation in agricultural landscapes for enhancing ecosystem services[END_REF]. However, many properties are expected to be sensitive to management and may vary according to crop species. Transitions between various perennial crops, which may involve soil disturbance, may be particularly critical points where the benefits of perennial cropping could be compromised [START_REF] Ryan | Managing for multifunctionality in perennial grain crops[END_REF].

Perennial grain cropping has significant potential to reduce emissions of nitrous oxide from production fields. The perennial grain intermediate wheatgrass has been shown to consistently reduce both soil moisture and nitrate pools [START_REF] Culman | Soil and water quality rapidly responds to the perennial grain Kernza wheatgrass[END_REF][START_REF] Jungers | Reduced nitrate leaching in a perennial grain crop compared to maize in the Upper Midwest, USA. Agriculture[END_REF][START_REF] Reilly | Reductions in soil water nitrate beneath a perennial grain crop compared to an annual crop rotation on sandy soil[END_REF], which are two primary drivers of nitrous oxide emissions. While there are theoretical reasons to anticipate reduced emissions of nitrous oxide from perennial crop fields, variation is expected and optimal crop management schemes will be necessary to maximize the benefits, as has been observed in the more extensively studied perennial biofuel crops [START_REF] Bai | Effects of biofuel crop switchgrass (Panicum virgatum) cultivation on soil carbon sequestration and greenhouse gas emissions: A review[END_REF].

J o u r n a l P r e -p r o o f

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The potential impact of perennial grains on the potent greenhouse gas methane is uncertain, although there have been some intriguing results. Because unsaturated upland soils have capacity to remove methane from the atmosphere, deeply rooted perennial grain crops which can dry the soil at depth have been observed to increase the methane sink capacity of fields in comparison to annual grains [START_REF] Kim | Perennial grain cropping enhances the soil methane sink in temperate agroecosystems[END_REF].

Perennial rice makes possible a range of no-till and flooding management regimes, (Zhang et al., 2022) so the crop could potentially reduce methane emissions. However, some intermittent flooding techniques have led to dramatic increases in nitrous oxide emissions [START_REF] Kritee | High nitrous oxide fluxes from rice indicate the need to manage water for both long-and short-term climate impacts[END_REF]. Clearly, more research is needed to develop management approaches for diverse perennial grain cropping systems to enable consistent greenhouse gas reductions.

New crops inherently come with new risks. While perennial rice can be sold directly into conventional markets, many perennial grain crops in development will be treated as novel foodstuffs, requiring development of new supply chains and unique consumer products. The commercial success of a new crop often requires the coordination of dozens of factors, including items such as quality seed, weed control methods, appropriate field equipment, access to processing facilities, and expertise for every step from seed handling to harvest and recipe formulation [START_REF] Jolliff | New crop development: Opportunity and challenges[END_REF]. Failure in any critical factor will jeopardize the success of the new crop. Perennial grain crops may carry some unique risks, such as the challenge of managing pests and disease without the simple techniques of annual tillage and crop rotation [START_REF] Cox | High proportion of diploid hybrids produced by interspecific diploid× tetraploid Sorghum hybridization[END_REF]. However, these risks may be offset by unique advantages, such as greater inherent pest and disease resistance [START_REF] Glover | Increased food and ecosystem security via perennial grains[END_REF], savings on costs to manage a crop that that does not require annual planting, and reduced risk of establishment failure when the crop is regenerating from overwintering structures.

For a new crop to succeed, a substantial societal investment in breeding, agronomic research, and early supply chain coordination is essential. A primary risk is that critical components for the success of the new crop will not be available. To achieve success, commercialization and plant breeding efforts must be coordinated to develop strategically diversified production systems and supply chains [START_REF] Runck | The reflective plant breeding paradigm: A robust system of germplasm development to support strategic diversification of agroecosystems[END_REF].

Thus, the greatest threat to the effort is the ebb and flow of funding cycles and market interest in diverse J o u r n a l P r e -p r o o f products with ecological benefits. The antidote to this risk will be sustained commitment from funders to strategically support the multifaceted effort to develop new crops over a timeframe of more than a decade.

Conclusions

Recent successes in breeding and genetics have now demonstrated the feasibility of perennial grain development. Perennial rice, which has produced yields equivalent to annual rice over eight harvests while improving ecosystem services and producer livelihoods, has shown how a perennial grain can create the triple win of food production, profitability, and sustainability. Theoretical concerns about the for perennials to produce competitive yields have begun to fade in the face of this clear achievement.

Similarly, the application of modern genetic tools such as genome sequencing, genomic selection, and genome editing to the development of perennial crops is demonstrating the ability to rapidly develop and introduce new perennial crops, [START_REF] Runck | The reflective plant breeding paradigm: A robust system of germplasm development to support strategic diversification of agroecosystems[END_REF] often waiting only on funding to accelerate the work.

If these and other revolutionary technologies are applied aggressively to the basic biology of perenniality [START_REF] Chapman | Perennials as future grain crops: opportunities and challenges[END_REF][START_REF] Li | Towards understanding the biological foundations of perenniality[END_REF] and the creation of new crops, they will be available in time to provide meaningful benefits to such grand challenges as soil quality and carbon sequestration to combat climate change and its impacts on food production [START_REF] Crews | What agriculture can learn from native ecosystems in building soil organic matter: A review[END_REF]. The critical need for the ecosystem services of new perennial crops grown in multifunctional landscapes [START_REF] Jordan | Sustainable development of the agricultural bio-economy[END_REF] has converged with the technological capacity to develop these crops, so now is the ideal moment to aggressively expand perennial grain research.

Declaration of interests

☐ The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

☒ The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:

Although this work received no direct financial support, the ideas presented in this Discussion are supportive of sustained funding of research directions currently engaged in by the authors.