ºthe Principles of Rational Agricultureº by Albrecht Daniel Thaer (1752±1828)

J. Plant Nutr. Soil Sci. 2003, 166, 687±698 DOI: 10.1002/jpln.200321233 687 ºThe principles of rational agricultureº by Albrecht Daniel Thaer (1752±1828). An approach to the sustainability of cropping systems at the beginning of the 19th century

Christian L. Feller1*, Laurent J.-M. Thuris1,2, Raphal J. Manlay1, Paul Robin3, and Emmanuel Frossard4

1 Institut de Recherche pour le DØveloppement (IRD), Laboratory MOST (Organic Matter in Tropical Soils), BP 64501, F-34394 Montpellier Cedex 5, France 2 Phalippou-Frayssinet SA, Organic Fertilizers, La Mothe, F-81240 Rouairoux, France 3 Institut National de la Recherche Agronomique (INRA), UMR 1123-System, Cirad-Lavalette, TA 179/01, F-34395 Montpellier Cedex 5, France 4 Swiss Federal Institute of Technology (ETH Zurich), Institute of Plant Sciences, Group of plant nutrition, P.O. Box, Eschikon 33, CH-8315 Lindau, Switzerland

Accepted 13 October 2003

Summary ± Zusammenfassung The identification of quantitative fertility indicators for evaluatingthe sustainability of croppingand farmingsystems has become a major issue . This question has been extensively studied by the German agronomist Albrecht Daniel Thaer at the beginning of the 19h century. In this paper Thaer's work is set in its historical background, from the end of the 16th century (Palissy, 1580) to the middle of the 19th century (Liebig, 1840). Then the paper focuses on Thaer's quantitative and complex fertility scale (expressed in ªfertility degreesº), which was based on soil properties, on the requirement of nutrients by plants, and on the croppingsystem (includingcrop rotation). Thaer expressed soil fertility and economic results as a function of rye production in ªscheffel of rye per journalº (ca. 200 kgper hectare). He also proposed a scale to describe the intrinsic fertility of soil. Thaer used this approach to assess the effect of major German croppingsystems on soil fertility. He applied it to eighttheoretical systems and nine existingsystems in a true modelingapproach. Thaer completed the fertility evaluation for the nine existingsystems with a detailed economical analysis commentingthe limits and potentialities of each system. Thaer's approach was used with success duringhalf a century as it combined numerous empirical findings on soils and fertilization with organic substances in a sophisticated model. Unfortunately and despite effective practical applications, the scientific foundations of Thaer's ªHumus Theoryº proved definitively false as soon as 1840 when Sprengel and Liebig published on mineral nutrition of plants. Thaer's work deserves to be rediscovered since it approaches the modern issue of the sustainability of croppingand farmingsystems.

¹Grundsätze der rationalen Landwirtschaftª von Albrecht Daniel Thaer (1752±1828). Ein Ansatz zur Nachhaltigkeit von Anbausystemen zu Beginn des 19. Jahrhunderts Die Identifizierung von quantitativen Fruchtbarkeitsindikatoren, mit denen die Nachhaltigkeit von Anbau- und Bewirtschaftungssystemen evalu- iert werden kann, ist ein wichtiges Thema geworden. Diese Frage wurde zu Beginn des 19. Jahrhunderts von dem deutschen Agronomen Albrecht Daniel Thaer intensiv untersucht. In diesem Beitragwird die Arbeit von Thaer in ihren historischen Zusammenhanggestellt,d.h. vom Ende des 16. Jahrhunderts (Palissy (1580)) bis zur Mitte des 19. Jahrhunderts (Liebig (1840)). Anschlieûend wird Thaers komplexe quantitative Fruchtbarkeitsskala (ausgedrückt in ªFruchtbarkeitsgradenº) vorgestellt, die auf Bodeneigenschaften, dem Nährstoffbedarf der Pflanzen und dem Anbausystem (einschlieûlich der Fruchtfolge) basierte. Thaer formulierte die Bodenfruchtbarkeit und ökonomische Resultate einer Kultur oder einer Fruchtfolge in ªScheffel Roggen pro Morgenº (ca. 200 kg pro Hektar). Thaer schlug auch eine Skala vor, um den inhärenten Wert des Bodens zu beschreiben. Er benutzte diesen Ansatz, um die Auswirkungen von in Deutschland verbreiteten Anbausystemen auf die Bodenfruchtbarkeit zu bestimmen. Er wandte diesen Ansatz auf acht theoretische und neun reale Systeme an, d.h. mit einem echten Modellie- rungs-Ansatz. Er vervollständigte die Beurteilung der Fruchtbarkeit der neun existierenden Systeme mit einer detaillierten wirtschaftlichen Ana- lyse, wobei er die Grenzen und die Leistungsfähigkeit jedes Systems kommentierte. Thaers Ansatz wurde ein halbes Jahrhundert lang mit Erfolg benutzt, da er zahlreiche empirische Beobachtungen über Böden und Düngung mit organischen Substanzen in einem komplexen Modell vereinigt. Trotz erfolgreicher praktischer Anwendung erwiesen sich die wissenschaftlichen Grundlagen von Thaers ªHumustheorieº schon 1840 definitiv als falsch, als Sprengel und Liebig ihre Arbeiten über die mineralische Ernährung der Pflanzen veröffentlichten. Thaers Werk ver- dient es, neu entdeckt zu werden, da es die aktuelle Frage nach der Nachhaltigkeit von Anbau- und Bewirtschaftungssystemen behandelt.

Key words: cropping system / humus concepts and history / agricultural sciences history / soil organic matter / fertility indicators and scale / economical scale / sustainability PNSS P123/3B

1 Introduction agricultural sciences. The three components of sustainability (economic, ecological, and social) can be assessed from on- For more than a decade now designing sustainable cropping farm study cases and/or from experimental designs provided and farmingsystems has become a major research issue in that these studies are conducted over several decades. A major limitation of these studies is the strongdependence of * Correspondence: Christian L. Feller; the results on the local initial conditions. This makes it neces- E-mail: [email protected] sary to model the dynamics of croppingsystems using(gene-

ã 2003 WILEY-VCH VerlagGmbH & Co. KGaA, Weinheim 1436-8730/03/0612-687 688 Feller, Thuris, Manlay, Robin, and Frossard J. Plant Nutr. Soil Sci. 2003, 166, 687±698 rally) simple, robust, and preferably quantitative parameters. only one to be present in their composition (of the plants)º The parallel with economic sciences has lead to name these (1796, vol. 1, p. 627), parameters ªindicatorsº. or, this other definition (which is closer to the present mea- The history of agricultural sciences conceals various theories ning): aimingat identifyingquantifiable fertility indicators in order to model the functioningof croppingsystems. The German º... trees have imperceptibly prepared the earth we cultivate. agronomist Albrecht Daniel Thaer, the most important and This humus or mould that insures the abundance of harvests famous one in the first half of the 19th century (see annex), is is due to the tree remains, accumulated during several centu- an exceptional pioneer of this approach. ries, ... Destroy a forest ... continually sow on this soil, bit by bit crops will absorb the mould, rains will sweep away the rest In this article a brief reminder is given on the theories in plant ... This previously black and fertile soil will change in colora- nutrition and on the role of humus in soil fertility until the tion, it will just remain a dry earth grain, arid and granularº middle of the 19th century. We then show how the ªHumus (1781, vol. 1, pp. 390±401). Theoryº developed by Thaer allowed him to elaborate a remarkably quantified evaluation system of the sustainability This quotation illustrates one of the principles of plant nutri- of croppingsystems and, from then on, to model the functio- tion at these times, namely as plants ªabsorb the mould (or ningof farmingsystems. This paper refers solely to Thaer's humus)º for the elaboration of their dry matter ± thus announ- reference work ªThe principles of rational agricultureº in four cingthe later experimental justifications that will make a basis volumes, of which the original edition was published in 1809 of the work of Thaer. and which was published in French in 1811 (Thaer, 1811). Here, all excerpts are from the French edition. When neces- In 1823, the great chemist Chaptal (1823) still refers to ªmine- sary, the German edition published in 1837 (Thaer, 1837± ral humusº. Thaer (1811±1816) is the first to define precisely 1839) and the American edition published in 1856 were con- humus as a soil constituent: ªThe usual name of this sub- sulted. We use in this report the surface and production units stance is ªterreauº (mould). This designation has been widely given in the French edition. misunderstood as it referred to the layer of vegetable earth rather than the special part of the substances forming it. This mistake has been repeated even in the writings of eminent 2 Historical summary on the concepts agronomists which led to increasing misconception of this of humus and plant nutrition before 1809 part of science. This is the reason why I adopted the termof Humus which is unequivocal. Generally, the scientific design- 2.1 Meaning of the term ªhumusº ation of ªearthº is not appropriate; properly speaking, it is not earth; it was only designated so for its powdery form... Although humus bas been the focus of debates on plant nutri- Humus is the residue of animal and plant putrefaction, it is a tion and therefore on fertility since the antiquity, its definition black body.º (Thaer, 1811±1816, vol. 2, pp. 102±114). varied strongly over time, especially in the 18th century. There is a semantic confusion that has not been entirely ruled even A much detailed and ± at this time ± complete description of today, since the term ªhumusº keeps two meanings: organic humus composition, extractability, and properties follows in constituent of soil and soil horizon (Duchaufour, 1970). For Thaer's text that remains acceptable nowadays (Feller and the Latin agronomists (Virgile, Columnelle) humus means Boulaine, 1987). ªsoilº. The term ªhumusº is gradually abandoned after Cice- ron and replaced by ªterraº, which led to the French words ªterreº (earth), ªterreauº (compost), ªterre vØgØtaleº (vegeta- 2.2 Plant nutrition theories and agricultural ble earth or mould, the earth of the garden). Around 1400, doctrines before and after Thaer the Latin root reappears in the French verb ªinhumerº (to bury), and Wallerius (1753) uses ªhumusº in his earth classifi- Most historical studies on plant nutrition theories systemati- cation. The Latin word ªhumusº officially reappears in the cally refer to the followingtrilogy:(1) Palissy's ªSalts Theoryº Encyclopedia of Diderot and d'Alembert (1765, vol. 8), with (Palissy, 1580, original edition), (2) Thaer's ªHumus Theoryº the meaningof ªmouldº. In 1781, ªhumusº passed from Latin (1809; Thaer, 1811), and (3) Liebig's ªMineral Theoryº (Liebig, into French; it is cited several times in the l'AbbØ Rozier's 1840). ªCours complet d'agricultureº (1781±1805), a dictionary-like work that synthesized the agronomical knowledge at that Bernard Palissy, the man of the ceramics, is a major figure of time. However, this works contains very different definitions natural sciences. He is not just one of the pioneers of geology of ªhumusº such as: and palaeontology in their modern understanding but he is also one of the first soil scientists (Feller, 1987, 1989). He is ªcalcareous earth is thus the only vegetable mould, the per- generally considered as the brilliant precursor of the ªMineral fect humus soluble in water, and the only one establishing Theoryº of plant nutrition published by Liebig in 1840. Never- and constituting the frame' of the plants ... if plants are piled theless, the conceptual contribution of Palissy to this subject up ... undergoing decomposition ... we will end up with a pure has been overestimated as historians of soil science interpre- calcareous earth, the perfect humus. Farmers, keep on pro- ted the word ªsaltº as synonymous with ªmineral substanceº ducing this precious humus, which is real animal earth', the (in its modern sense), although Palissy himself had a far

ã 2003 WILEY-VCH VerlagGmbH & Co. KGaA, Weinheim J. Plant Nutr. Soil Sci. 2003, 166, 687±698 ºThe principles of rational agricultureº by Albrecht Daniel Thaer 689 vaguer conception of it (Feller, 1998). This is attested by the readingof this third memory, we see that this conclusion is following, seldom quoted, excerpts from his complete works not supported by any experimental fact. (Palissy, 1880, new edition): ª(the salt) is the frame of all things ... that forms scents and flavors ... the sugar is salt ... The debate on plant carbon nutrition between the defenders the tannin is salt ... the salt whitens all things ... it is a mastic of the photosynthesis and those of the ªHumus Theoryº that links mineral matters ... that delights the moods ... main- remains much contradictory at the end of the 18th century tains the affection between the male and the female because and beginning of 19th century. The ªHumus Theoryº is defen- of the strength given to the genital parts ... it helps with the gene- ded by Virey (1803), but it is firmly combated by Patrin ration ... and renders all things in diaphanous body ... it makes (1803): º... one knows that plants take their increase not from vegetate and grow all seeds ...º. By the end of 16th century, the soil but fromthe atmosphere.Thousand experiences Palissy's belief lies still far from the credible theory of have provided a direct proofº. Similarly, Saussure (1804) Sprengel and Liebig on the mineral nutrition of plants. demonstrates that if the plant can partially feed from ªterreauº (soil organic matter, mould), 95 % of its dry matter originates In the 17th century, ideas about waters and salts more or less from the atmosphere. This idea will be taken up again by similar to those of Palissy are developed by Van Helmont Sprengel (1826) and Liebig (1840). (Boulaine, 1989). In the beginning and middle of the 18th century, many authors such as Valmont de Bomare, Pluche, The ªHumus Theoryº prevailed almost until 1840. Martin's Home, Duhamel du Monceau, La Salle de l'Etang, Bonnet, work (Martin, 1829) announces the shift from the ªHumus and Rozier refer to the ªjuicesº, the ªoilsº, the ªbituminous Theoryº (largely spread after the publication of Thaer's work) substancesº as principles of vegetation (Feller and Boulaine, to the still nascent ªMineral Theoryº. Martin is a remarkable 1987; Feller, 1997a, b). Tull (1733, in Bourde 1967) suggests forerunner in several concepts. He admits that a large part of that the plant is fed by its roots from tiny soil particles, and plant material comes from water and the atmosphere. Howe- thus recommends repeated plowingto divide soil parti- ver he assigned humus a key role in plant nutrition through cles, and the abandonment of manure application. This the enrichment of atmosphere carbon dioxide content resul- theory was first defended by Duhamel du Monceau tingfrom humus decomposition, but not throughan enrich- (1750±1756, in Bourde, 1967), but criticized by Pattullo ment in soluble carbon, as suggested by Hassenfratz' theory. (1759) and by La Salle de l'Etang (1768). Duhamel du Mon- The practical consequence of this revised ªHumusº, yet ceau finally rallies to the necessity of manure application ªMineralº Theory is that soil fertility management principles (Bourde, 1967, pp. 311±386). must consider the management of organic inputs.

Fabbroni (1780, cited by Bourde, 1967), whose work is rather As soon as 1826 and 1828, Sprengel, one of the first student unrecognized, writes ªWe can therefore conclude that the (during7 years) of Thaer and Einhof , disproved the Humus inflammable air (hydrogen) and the element of the light that Theory and postulated the theory of mineral nutrition of plants are absorbed by leaves, the water and the fixed air (carbon (Sprengel, 1826) and the law of the minimum (Sprengel, dioxide) pumped by roots and by the other external parts of 1828), 12 to 14 years before Liebig (1840), even if Liebig the plant, are the true nourishing principles of plantsº. He con- remained much more famous than Sprengel (van der Ploeg siders that organic restitutions provide the plant with nutrients et al., 1999). through their decomposition. At the same period, some pioneer studies on the photosynthesis have been published: that In his authoritative ªDie organische Chemie in ihrer Anwen- of Priestley (1777) on the release of oxygen by green plants, dung auf Agrikultur und Physiologieº (Liebig, 1840) Liebig that of Ingen-Housz (1780) on the role of the light in this phe- confirms, after Sprengel (1826), that the whole plant dry mat- nomenon, that of Senebier (1782) on carbon dioxide assimi- ter comes from minerals compounds: carbon from carbon lation by plants, and finally, in 1804, the famous book of de dioxide, hydrogen from water, and nitrogen, phosphorus, and Saussure ªRecherches chimiques sur la vØgØtationº (Chemi- the other mineral elements from soluble salts in soil or water. cal researches on vegetation) (Saussure, 1804). Thaer will The ªmineral theory of plant nutritionº brilliantly accounts for use (unfortunately not in an appropriate way) some of the the role of mineral inputs in soil fertility. ªMineralistsº gained a theoretical bases developed by Saussure to justify his victory, and this theory sounded the death knell of the ªHumus Theoryº (see below). ªHumus Theoryº. It opened the era of chemical fertilization, which has been largely documented elsewhere (Grandeau, In 1792, Hassenfratz publishes three memories in the Annals 1879; Boulaine, 1989). Most agronomists agreed about Lie- of Chemistry ªSur la nutrition des plantesº (About plant nutri- big's theoretical principles of plant mineral nutrition; however, tion) (Hassenfratz, 1792). In his two first memories, he strives some wondered about the impacts of the sole use of mineral to prove the falseness of recent theories especially that of fertilizers on soil quality management. Grandeau (1878) war- Ingen-Housz (1780, in Bourde 1967) on the role of the air in ned against Ville's ªexaggerationsº (Ville, 1853, 1867) who plant carbon nutrition. In his third memory Hassenfratz writes: was a passionate supporter of mineral fertilization: ªFrommy ªWe can conclude that, among all explanations given for the opinion, I will oppose to the dangerous assertions of M. G. increase in plant carbon by the action of vegetation, the one Ville concerning manure and the possibility of given up its use best connected with fertilizers, that better agrees with all, is in a standard farmº. Grandeau (1878) proposed a theory that the dissolution in water of coal, thus sucked up by the roots bridged the gap between the ªHumus Theoryº and the ªMine- and deposited into the plants; thus, coal dissolved in water is ral Theoryº by attributingan essential role to humus as a fac- one of the plant nutrientsº. Nevertheless, from a complete tor of solubilization, and thus of assimilation of mineral ele-

ã 2003 WILEY-VCH VerlagGmbH & Co. KGaA, Weinheim 690 Feller, Thuris, Manlay, Robin, and Frossard J. Plant Nutr. Soil Sci. 2003, 166, 687±698 ments with limited availability for the plant. He created the As a result of this second postulate, the plant demand in concept of ªbioavailabilityº that was fully supported by Liebig. ªnutrient juicesº is selective and varies with cultivated plants and the level of (soil) fertility which in turn also depends on It will be shown below how Thaer's work, built on partly false crop rotation. The experimental data on which this hypothesis theoretical foundations, was precursory in other ways. is based can be found in the work of Thaer's associate, Ein- hof (Thaer, 1811±1816, vol. 1, p. 214).

3 The scientific bases of Thaer's ªHumus These theoretical bases, implyingboth soil and plant, allowed Theoryº Thaer to elaborate a complex ± but global ± quantified system for the evaluation and prediction of soil fertility which was The ªHumus Theoryº is based on two postulates: a large part supported by brilliant agronomists, mostly practitioners like of plant dry matter is derived from humus, and the plant's Mathieu de Dombasle (1828, pp. 124, 145±146, 177±181, demand in ªnutrient juicesº is selective and varies with culti- 198±228, 329±361) and Martin (1829). vated plants. 4 Thaer: a quantified scale of the natural soil Thaer knew Saussure's work which he interpreted exaggera- fertility induced by practices and crop tedly accordingto his own hypothesis ( Thaer, 1811±1816, rotations vol. 2, p.105). Accordingto Saussure (1804), the plant has three sources of carbon: Thaer's great quality is his ability to define precisely his concepts and to aim for a quantitative approach to a ªrational the carbon dioxide from the air atmosphere. The gas is taken agricultureº as suggested by the title of his book. According up by the leaves and transformed in material rich in carbon; to Thaer ªrational agricultureº is the one that provides the best net income (Thaer, 1811±1816, vol. 1, p. 3). For this purpose, ªagriculture must therefore borrow from all these the carbon dioxide from the soil produced from the decompo- sciences some principles, used for the foundation of its own sition of fresh organic matter is taken up by the roots, then science, and, even if these sciences are not a significant part transported as it is in the leaves where it is turned into mate- of its teaching, agriculture nevertheless must have all of them rial rich in carbon; at its disposalº. Thaer therefore gathered a considerable amount of data, from bibliographical analysis, or from the ªterreauº (today, humus, mould or soil organic matter), a research of his own or of his associates. soluble part of which can be directly absorbed by roots. The productivity of the system is analyzed not only in terms From various experiments, Saussure concludes that the pro- issued from soil science (soil exhaustion) and agronomical portion of dry matter in a plant originating from mould only terms (plant and animal production) but also in economic represents 5 % of that supplied by the atmosphere. Moreover, terms, with the definition of a standard used both as an indi- Saussure is the first to identify the presence of mineral com- cator of fertility and as an economic calculation basis. The pounds (ashes) accumulated in non random proportions in approach is described hereafter. the plant (these proportions depending, among other things, of the soil type). However, he does not conclude about the need to balance the plant mineral balance budget with mine- 4.1 Choosing a quantified indicator of the fertility ral inputs to soil. At that time mineral fertilization was not a Thaer's fertility indicator is rye productivity. In the French edi- matter of discussion; only inputs providingcarbon for the syn- tion we used (Thaer, 1811±1816), the unit described is the thesis of material rich in carbon were considered, even ªscheffel of rye per journalº (sch jl±1), or approximately 200 kg though their nature remained a matter of debate. According grain ha±1. The volumetric unit ªscheffelº (ªboisseauº in to Saussure's theory, the atmosphere was an unlimited reser- French) is the same as used in the original German edition, voir of carbon that would not limit plant growth as soluble but ªjournalº is a French surface unit used by the translator organic matter originating from humus would. (E. V. B. Crud, see below his biography) instead of ªMorgenº the original German unit. In the 1856 English edition we con- A careful study of Thaer's book shows the author full support sulted, ªscheffelº was translated by ªbushelº and ªjournalº ± or to Saussure's ideas. Thaer admitted the existence of different Morgen ± by ªacreº. carbon sources for plants, but automatically referred to humus and fertilization with organic substances when spea- Thaer a priori states that a soil able to produce 2 sch of rye kingabout ªsoil fertilityº and its changes.For Thaer, humus jl±1 presents an intrinsic fertility value of 40 degrees. This and more specifically the humus fraction soluble in boiling value is given for a ªsandy clay, 2nd class soil for barleyº con- water (ªextractive matterº) constituted a potential source of taining28 % clay, 70 % sand, 2 % humus, and no limestone ªnutritive juicesº (or ªnutritive matterº or ªsucculent matterº, (Tab. 1). It should be kept in mind that at this time the average English translation in Thaer, 1856) for plants. Consequently, cereal yield ranged from 650 to 1000 kg grain ha±1 (Boulaine managing soil fertility would require the management of the and Feller, 1989; Boulaine, 1992). Thaer defines the intrinsic humus balance and the compensation of soil organic matter fertility value of soils or its ªnatural fecundity (or fertility)º. It is exportations by organic restitutions to soil. the productivity reached by a soil when it is so exhausted that

ã 2003 WILEY-VCH VerlagGmbH & Co. KGaA, Weinheim J. Plant Nutr. Soil Sci. 2003, 166, 687±698 ºThe principles of rational agricultureº by Albrecht Daniel Thaer 691 the economic balance of production is nil or negative. The For each class, an increase or a decrease in the humus con- soil must not be exhausted beyond its natural fecundity, tent of 0.5 % leads to a five units increase or decrease in intri- because ªit requires much more expenses to rebuild the nsic fertility. A 10 % increase in lime content increases soil fecundity neededº (Thaer, 1811±1816, vol. 1, p. 221). A table value by five to 10 units. The soil value is also modulated by (Thaer, 1811±1816, vol. 2 p. 136) summarizes the land ªintrinsic the thickness of the mould layer. Every additional inch of valueº (or natural fecundity) ranging on a relative scale mould increases soil value by four units, while every one-inch between 0 and 100 for 20 different soils (Tab. 1). The value decrease in mould thickness decrease the intrinsic soil ferti- 100 is set to the most fertile soil. This empirical scale yields a lity by eight units. relationship between the intrinsic soil fecundity and its content in clay, lime, sand and humus. However, Thaer restricts this scale to ªsoils with mild humus ... exempt of acid ... con- Numerous comments illustrate the part of the book devoted sequently soluble ... because the acidic humus destroys the to the ªVarious species of soils, their value, their use and their soil fecundityº and for an average six-inch thickness of mould. properties, in their relation with the soil constitutive partsº. In his comments, Thaer distinguishes six main land classes Thaer insists on the need to ªanalyze (soil) composition from accordingto a decreasingquality: ªsoil rich for wheatº, ªsoil its external characters onlyº (Thaer, 1811±1816, vol. 2, for wheatº, ªsoil rich for barleyº, ªsoil for barleyº, ªsoil for oatº, p. 138). He then makes an actual essay on soil survey ªsoil for ryeº. (Thaer, 1811±1816, vol. 2., pp. 164±166):

The intrinsic value of land is related to the soil texture, lime, l ªAfter the color ... the indices of the humus presence ... and humus content. For instance the ªintrinsic valueº of the are the soil lightness ... and a certain odor of mildew ... ªsoil rich for wheatº (a clayey soil), decreases by one unit for The clay reveals its presence by its tenacity and its each 1 % decrease in clay content. For the ªloamyº (lehm) or smoothness at touching; the sand by its roughness ... or sandy soils, the intrinsic value decreases by one unit for each again by examining with a magnifying glass ... The pre- increase of 1 % sand content. An evaluation of the texture sence of lime is revealed by the effervescence with effect is given in a table (Thaer, 1811±1816, vol. 2, p. 141). acidsº,

Table 1: Composition and intrinsic fertility value of some soils (Thaer, 1811±1816, vol. 2). Tabelle 1: Zusammensetzungund inhärenter Fruchtbarkeitswert verschiedener Böden ( Thaer, 1811±1816, vol. 2).

Earth mixtures listed here are in the followingproportions accordingto their intrinsic value Content (in %) Intrinsic Fertility Value

N Systematic denomination Vernacular denomination clay sand lime humus 1 Clay heavily impregnated by humus Rich soil for wheat 74 10 4.5 11.5 100 2 Very stiff and impregnated by humus idem 81 6 4 8.4 98 3 idem idem 79 10 4 6.5 96 4 Rich marly earth idem 40 22 36 4 90 5 Light soil impregnated by humus Pastures soil 14 49 10 27 ? 6 Sandy soil id. Rich soil for barley 20 67 3 10 78 7 Rich clayey soil Good soil for wheat 58 36 2 4 77 8 Marly soil Soil for wheat 56 30 12 2 75 9 Clayey soil idem 60 38 2 70 10 Clayey soil idem 48 50 2 65 11 Clay idem 68 30 2 60 12 Clayey soil 1st class soil for barley 38 60 2 60 13 idem 2nd class soil for barley 33 65 2 50 14 Sandy clay idem 28 70 2 40 15 idem Soil for oats 23.5 75 1.5 30 16 Clayey sand idem 18.5 80 1.5 20 17 idem Soil for rye 14 85 1 15 18 Sandy soil idem 9 90 1 10 19 idem 6 years soil for rye 4 95 0.75 5 20 idem 9 years soil for rye 2 97.5 0.5 2

ã 2003 WILEY-VCH VerlagGmbH & Co. KGaA, Weinheim 692 Feller, Thuris, Manlay, Robin, and Frossard J. Plant Nutr. Soil Sci. 2003, 166, 687±698 l ªTo make an exact description of an extent of soil based same productivity a wheat will exhaust the soil by 13 degrees on the composition, as well as on the mix of the soil con- (more demandingcrop), a barley by 7 degreesand an oat by stitutive parts, and that could serve as a guide not only in 5 degrees (less demanding crop) (Thaer, 1811±1816, vol. 1, the estimation of the soil value but also in its cultivation p. 215). and in the choice of the rotation, it is absolutely necessary to follow a regular and well ordered approach ...º. 4.3 Quantifying improvement of fertility according Then follows a description of the soil grid, the working out of to cultivation practices and rotations a map with ªstationsº, ªThe depletion caused by grain harvests is compensated for in three ways ... (i) the contribution of farmyard manure, (ii) l º... the agronomist observes soil nature ... As soon as he conversion of the fields into pasture grounds, and (iii) a dead witnesses a change ... he reports this portion on the map; summer fallow attended with proper cultivationº. then he examines the soil in a more particular manner ... he removes some shovelfuls of earth with the spade ... Thaer values a priori the improvements as follow: and if needed he puts ... approximately a pound ... in a small bag on which he marks the number or the letter of the station ... one must not omit to indicate whether the (i) for manure: the soil gains 10 degrees of fertility by applying change is sharp or ... happens in a shaded wayº, a load of 2000 pounds of well fermented manure comingfrom straws and cows, horses or pigs excreta. l on the map one can also report ªthe various blend of which the soil is composed, by washed colors indicating (ii) for pasture: the soil gains from 4 to 14 degrees of fertility insensitive changes by nuances ... represent height and dependingon plant productivity as it determines the quantity sinking by lines ... characterize the more or less great of manure produced by the cattle. The improvement brought quantity of humus by black points ... and all deserving by the pasture can be quantified directly or indirectly. The sur- remarks ... If the lower layer of soil changes ... that can be face needed to feed a single animal is used to quantify very sensitively rendered in the profile of the leveling by directly the effect of the meadow. If four journals are needed colors that indicate the thickness of the various layers ... It to feed a cow, the improvement of fertility by the meadow will is necessary to use the auger or land-sound and to intro- be estimated at six degrees; but for a twice smaller area (two duce it as deeply and as often as necessaryº. All this ª... journals) the improvement will be 14 degrees. Thaer propo- will soon indicate which kinds (of soils) are homogeneous, ses a table of correspondence between different animals and which ones have a different nature; and this, most (Thaer, 1811±1816, vol. 3, p. 278). As an example, if three often without the recourse to the chemical analysisº, journals are needed to feed a cow of 450 pounds (live- weight), 4.5 journals are necessary for a horse, 1.5 for a goat, and 0.5 for a pig. These data are additionally modulated l and Thaer to conclude: ªNo operation will fully compen- by the quality (weight) of the cattle. The improvement brought sate an enlightened agriculturist for the trouble which it by the pasture can also be indirectly quantified ªaccording to costs himas this modeof proceeding; he will here find the the state of fecundity in which the soil is found when left in solution of all those phenomena which previously pastureº. Pasture productivity depends on the nature of pre- appeared inexplicable, and will thus be enabled to apply vious crop and on the previous fertility level: if a plot of 40 an efficacious remedy to the various impediments and degrees of fecundity gains 10 degrees, in the same condi- inconveniences which he may meet in the cultivation of tions of pasture management, a plot of 90 degrees will earn his propertyº. some 15 degrees (Thaer, 1811±1816, vol. 1, p. 219). For ley pasture with clover, applyingthe same type of calculation, 4.2 Quantifying plant demand in ªnutrient juicesº Thaer states that soil fertility will improve by 10 degrees for a soil of 60 degrees of fecundity and by 16 degrees for a soil of (and therefore soil exhaustion) 90 degrees. All these values are modulated by others factors Thaer built a comparative scale of demand in ªnutrient juicesº such as: ªthe number of cereal harvests that the soil has pro- for several crops, based on data collected by his friend and duced since the last manure applicationº, the number of associate H. Einhof, a pioneer agricultural chemist (Browne, years (2 to 5) since the pasture establishment, ªthe dispo- 1944, and see below annex A1). ªNutrient juicesº must be sition of the soil to produce herbages, good or weakº (Thaer, understood as ªthe glutinous principle, the starch and the 1811±1816, vol. 3, p. 281). sugared mucilageº. Accordingto Einhof's analyses values for ªnutrient juices are as follows: wheat: 78 %, rye: 70 %, barley (iii) A ªdead summer fallowº (a spontaneous vegetated fallow 65 to 70 % according to kind and its goodness, oat: 58 %, len- growing on a soil that has been ªcleaned and pulverizedº) will til: 74 %º. Therefore, one scheffel of wheat weighing 92 add 10 degrees of fertility in a soil of 40 degrees of fecundity, pounds will extract 7114/15 nutrient juices, one scheffel of rye 12 degrees for 60 degrees, etc. weighing 86 pounds will extract 601/5 nutrient juices, one scheffel of barley weighing 72 pounds will extract 464/5 These examples show the sophistication of Thaer's system, nutrient juices, and one scheffel of oat weighing 52 pounds which takes into account the multiple interactions existing will extract 301/4 nutrient juices. Consideringthat a rye har- within a croppingsystem and which controls the transfers of vest of 2 sch jl±1 will exhaust the soil by 10 degrees, for the fertility.

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5 Thaer: application of the soil fertility index fecundity is 17.24 degrees. That will be always the case for to various complex cropping systems six grain harvests and amendment of only five manure loads per journal. In order to prevent this important soil depletion, 5.1 Evaluation of the changes in soil fertility in the rotation should have been interrupted after the fifth crop; different theoretical cropping systems however, by means of a pen, the sixth crop had again been able to take place ... without a new fertilizationº. Then, he Two theoretical croppingsystems analyzed by Thaer are makes a comparison between the two systems: ªFor the given as example in Tab. 2: triennial rotation ... it will be absolutely necessary to obtain elsewhere a supplement of fertilizer or to demand only one l nine-year conventional triennial rotation with fallow, crop during three years, in order to give to the soil a year of rest and complete fallow. As for the improved alternate rota- l seven-year alternate rotation with ley farmingimproved tion, one will be obliged to modify it, by substituting to a part with housingthe livestock in the stable. of forages, some cash crops for sale, which by absorbing its fertilizer overabundance raise it to the highest level to which it These tables are reproduced (with slight modifications) from could reachº. This is a wonderful discourse on the durability Thaer, (1811±1816, vol. 1, pp. 226 and 230). of the different croppingsystems.

For the conventional triennial rotation, there is a 17 degrees fecundity loss while a 30 degrees gain occurs for the impro- Altogether Thaer applies his approach to eight models of ved alternate rotation. For the triennial rotation Thaer com- croppingsystems. The results are summarized in a table ments (Thaer, 1811±1816, vol. 1, p. 226): ªThe loss in soil (Thaer, 1811±18116, vol. 1, p. 230), here Tab. 3.

Table 2: Some calculations used by Thaer to evaluate changes in soil fertility under two theoretical cropping systems (Thaer, 1811±1816, vol. 1). Tabelle 2: Einige Berechnungen von Thaer zur ¾nderung der Bodenfruchtbarkeit in zwei theoretischen Anbausystemen (Thaer, 1811±1816, vol. 1).

Crops in rotation Harvest product Absorbed juices Added fecundity Remainingfertility (Year N) (scheffels) (degrees) (degrees) (degrees)

Triennial rotation of 9years with fallow Natural fecundity: 40 40 Manure 5 loads: 50 90 Fallow (1) ± ± 10 100 Rye (2) 6 30 ± 70 Barley (3) 5 17.5 ± 52.5 Fallow (4) ± ± 11 63.5 Rye (5) 3.81 19.05 ± 44.45 Oat (6) 4.44 11.11 ± 33.34 Fallow (7) ± ± 10 43.34 Rye (8) 2.6 13.0 ± 30.34 Oat (9) 3.03 7.58 ± 22.76 Fecundity loss ±17.24 7 years alternate rotation, perfected with cattle feeding in the stable Natural fecundity: 40 40 Manure 8 loads: 80 120 Potatoes (1) 80 30 10 100 Barley (2) 7 25 ± 75 Clover (3) ± ± 13 88 Clover (4) ± ± 13 101 Rye (5) 6.06 30.03 ± 70.7 Pea + ± 20 50 100.7 4 manures (6) Rye (7) 6.04 30.21 ± 70.49 Fecundity gain +30.49

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Table 3: Variations of soil fertility in eight theoretical cropping sys- l gain of 15 to 30 degrees corresponding to rotations with tems (Thaer, 1811±1816, vol. 1). pasture systems 3 to 7; Tabelle 3: Unterschiede in der Bodenfruchtbarkeit in acht theoretischen Anbausystemen (Thaer, 1811±1816, vol. 1). l loss of 4 degrees for rotation 8 with stalling but for a farm Theoretical Crop rotations Fertility Fertility with limited manure inputs. This situation is therefore sel- system Gain Loss dom comparable to the equivalent theoretical models reference (degrees) (degrees) described above; A Triennial rotation with fallow and 17.24 5 wagons of manure in 9 years l gain of 39 degrees for system 9 with stalling. B The same ... with pea on the first 22.67 fallow Globally, the results computed from the theoretical cropping systems matched those observed in existingfarms except for C The same ... with potato 23.47 rotation 8. D Seven years triennial rotation, 17.67 with grazing E That of 9 years, idem ± 0.34 5.3 Economic assessment of various existing cropping systems F That of 11 years, idem 6.75 G 4 years alternate rotation, with 53.76 Here Thaer studies the economic results of the cropping feedingin the stable systems described in Section 5.2. He makes a very precise H That of 7 years, idem 43.55 economic evaluation based on the humus balance and production costs. For this purpose, he establishes relationships between animal and plant productions and organic inputs needed, and he quantifies humus inputs and outputs at the 5.2 Evaluation of the changes in soil fertility in plot and farm levels. He derives the amount of manure requi- various existing cropping systems red to reach a given cereal yield, as well as the acreage under pasture needed to maintain enough livestock for The results obtained with the theoretical croppingsystems manure production. Thaer records, for each season, working are compared to those obtained from 9 existingcropping times and their costs (includingthose spent on maintaining systems (Thaer, 1811±18116, vol. 1, pp. 232±237). These and supervisingcattle and farm in general).All data are are: expressed on a scheffels of rye value basis. Data are presen- ted in nine very large tables and one summary table (reprodu- N1. Nine-year triennial rotation with fallow (model A of ced here in Tab. 4) at the very end of Thaer (1811±1816, Tab. 3); vol. 4).

N2. New rotation (improved triennial rotation), from West- Usingthis approach, Thaer quantifies the net income genera- phalia (models B or C); ted by the 9 croppingsystems described above.

N3, 4, and 5. Various alternate rotations with grazing, from l System 1, with a net income of only 1514 scheffels of rye, Mecklenburg(models D, E or F); l Systems 2, 3, 4, 5, and 6 , with values varyingfrom 2200± N6. Alternate rotation with grazing, from the Holstein 3030 scheffels of rye, (models D, E or F); l Systems 7, 8, and 9 with values ranging from 4320±5940 scheffels of rye. N7. Alternate rotation with livestock kept overnight in the stable (models G or H); Thaer's comments (Thaer, 1811±18116, vol. 2, pp. 5±7) are summarized below: N8. Alternate rotation with large livestock kept in the stable (models G or H); l System 1. It is the ªtriennial rotation (fallow system) in all its purityº. Thaer emphasizes the absence of pastures, N9. System with large cattle and wool sheep kept in the sta- the weak production and poor quality of manure: ªmanure ble (not modeled in Tab. 3). is only strawy and thin, consequently much less active. The given cereal yield can even be overestimatedº. Systems 1±6 correspond to main farmingsystems adopted at that time in Germany. Systems 7±9 were rather improved l System 2. It is the ªimproved triennial rotation ... very alternatives implyinginvestments, especially in manure sup- common nowadays, it is established in the greatest part ply. Variations, in degrees of fertility, between the beginning of the current kingdomof Westphalia, a land blessed by and end of the rotation are the following: nature, and that one could have been called new rotation of Westphalia. The systemincludes a fallow receiving six l variations of ±2 to +2.5 degrees for systems 1 and 2; wagons of manure. It is satisfactory since it does not

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Table 4: Economical evaluation of nine existingcroppingsystems ( Thaer, 1811±1816, vol. 4, final pages). Tabelle 4: Wirtschaftliche Beurteilungvon neun existierenden Anbausystemen ( Thaer, 1811±1816, vol. 4, letzten Seiten).

Cropping Product Product Fertilizer** Cropping Cattle Product Grains Product Net Product system in straw in forages, Expenses (reduced in (reduced in (reduced in reference* (reduced in (reduced in scheffels of rye) scheffels of rye) scheffels of rye) quintals of hay) scheffels of rye) Quintals Quintals Quintals Scheffels Scheffels Scheffels Scheffels

1 5794 1800 15188 1451 558 2387 1514 2 9748 4020 27536 1853 1003 3755 2885 3 5961 4194 20310 1530 1417 2785 2670 4 6244 5480 19448 1520 1280 2786 2545 5 6002 5200 18404 1546 1039 2706 2199 6 6464 4650 22228 1582 1651 2958 3028 7 9895 11400 56590 2412 3037 3698 4323 8 13717 14850 51154 2803 3331 5414 5942 9 10973 12315 41791 2514 3178 4323 5188 * The studied croppingsystems are described in the text ** Fertilizer inputs expressed in quintals of manure

require deep tillage that is so detrimental to marly soils. Thaer's recommendation holds a remarkable quality: It is an Elsewhere the local circumstances do not allow its substi- holistic judgment which takes into account both agricultural or tution by a better oneº. environmental local constraints and variations that any farmer is likely to meet and some future prospects in some cases for the development of new alternatives. Thaer took into consi- l Systems 3, 4, and 5. They º... are alternate rotations of deration the durability of both plant and animal productivities various kinds with pastures such as those encountered in and economical balance. In that sense, he is an important the Mecklenburgº. Beyond their productivity, their interest forerunner of the concept of sustainability in agriculture. lies in the fact that ªthese systems are the less demanding in work and farmexpenses ... which makesthemespe- cially commendable in a country that lacks labor and capi- 6 Conclusions talº. Thaer's approach is exceptional from several points of view (see also annex A1). For his contemporaries he was very l Systems 6, 7, 8, and 9. All these systems include ªalter- famous, and his work had a strongimpact duringthe first half nate rotations with pasturesº and improvements of cattle of the 19th century. Royer (1847) in his book on German agri- management (stabling). They imply intensification of the culture wrote about Thaer: ªfounder (to who) we have vowed, croppingand livestock systems. In System 6 (named Hol- since 20 years, a sort of cultº. And Montyon and Franklin stein), the improvement consists in ªa better preparation (1836) in their ªPortraits des Hommes Utilesº (Portraits of of soil than that achieved in the Holsteinº. In System 7, Useful Men, published between 1833 and 1840) ranked ªstabling at night and in the morning associated with day Thaer amongthe best, between Humphry Davy (the English grazing on pasture has been added ... High cattle produc- inventor of the safety lamp for miners) and Guttenberg. tion here originates fromforage abundance and pasture Amongst his famous supporters we find Mathieu de Dom- availabilityº. System 8 ªis an alternate, rotation applied on basle (1829) as already mentioned and Sprengel and von the feeding of large cattle in the stable, and calculated on Thünen the economist who were his first students. Thaer's this kind of economy. The great quantity of fertilizer it direct follower in his modelingtask was Van Wulffen gives, authorizes to recover at least this product in grains. (1823,1830, 1847, cited by Wit, 1974). Although Sprengel, There, the works and expenses are the highest; however, the agronomist, was a student of Thaer, he disproved the it is again here that the net income is the most consider- Humus Theory and was a forerunner of the theory of mineral ableº. As for System 9, ªit gathers to the feeding of large nutrition of plants. cattle in the stable, the maintenance of a wool sheep herd. One conceives that only sheep of selected breed Thaer's mistake was to base his remarkable work of data col- are considered ...º this farm thus ªhas necessarily to get a lection and reflection on croppingsystems managementon a remarkable prosperity stateº. wronghypothesis, namely that the principal source of carbon for the plant is the soil humus. Had Thaer applied his reaso- ningto mineral balances, he would have been considered as Thaer concludes: ªany of my readers will be able to easily one of the greatest agronomists of all times. Thaer's period compute the proportional product that each of these exploita- probably did not favor the mineral aspects of plant nutrition, tions gets fromevery journal of its soil º. because fertilization was mostly based on organic inputs.

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This point put aside, Thaer's work is of astonishingactuality, The four volumes of Thaer's ªGrundsätze der rationellen and can be read as a contemporary treaty of agronomy. Landwirtschaftº (ªPrinciples for Rational Agricultureº) were Thaer was also one of the first ªsoil scientistsº. His approach published in Berlin between 1809 and 1812 and made him was global and quantified, considering all the components of famous throughout Europe. The book was translated in soil fertility (soil supply, plant demand, and cultivation practi- French by the Swiss baron and agronomist E. V. B. Crud (see ces) and complexity (all interactions drivingthe functioningof below) under the title ªPrincipes raisonnØs d'Agricultureº and croppingsystems). Issues raised and answers givenby was published in four volumes from 1811 to 1816. Two other Thaer remain modern since they encompass the search of French editions were released in 1830 and 1831; further editi- quantified and robust fertility indicators and the evaluation of ons were released in German (Thaer, 1837±1839), and Eng- the bio-physical and economic sustainability of croppingand lish, Danish, Italian, Dutch, Polish, Russian, and Swedish. even farmingsystems. Finally, Thaer adopted a true modelingapproach by confrontingresults of rather theoretical Thaer also devoted himself to the promotion of practical agri- systems to existingones. culture. He was the propagator of the potato. He adopted a rotation with clover and root plants and thereby suppressed the fallow while considerably improvingcattle feedingon Annex: Biographical elements about A. D. Thaer those light and dry soils on which pastures failed to settle. He and his translator in French E. V. B. Crud popularized, created, and manufactured some agricultural equipment. A.1 Albrecht Daniel Thaer (1752±1828)

Main written sources for Thaer's biography are Browne Thaer's influence on Prussian agriculture was considerable. (1944), Ritter (1956), Klemm and Meyer (1968), de Wit He demonstrated the potential improvements of cropping (1974), Böhm (1997, pp. 346±349), and Boulaine and Legros techniques on sandy soils of this country, promoted sugar (1998). Mathieu de Dombasle (1829, vol. 5, pp. 381±385) beet and potato croppingand involved himself in sheep bree- wrote an obituary paper on Thaer. Information is also availa- dingand wool production. Appointed a highoffice by the ble from electronic sources: http://www.Albrecht-daniel-thaer. government of his country, Thaer promoted the privatization organd http://www.Albrecht-thaer-gesellschaft.de. and improvement of communal land. Until his death, his publications contributed to codify and spread the best agronomical techniques of his time. Thaer was born in Celle on 14 May 1752. As son of a physi- cian, he studied medicine in Göttingen and defended his dis- sertation in 1774. In 1780 he became counselor of the He was a member of several scientific societies such as the Prince-Elector of Hanover, and was appointed as personal Braunschweig-Lüneburg Society of Agriculture and the Royal doctor of the Prince-Elector (George III, King of England) in Society of Great Britain (1784). He was a corresponding 1796. In 1786 he got married, and bought 30 ha of land at member of the French Academy of Sciences and was Celle gates, on which he settled an experimental farm. From appointed foreign member of the (French) Royal Society of 1798 to 1804 he published an ªIntroduction to English agricul- Agriculture in 1804. Thaer died in Möglin on 16 October tureº (three volumes) which made him famous. In 1799 he 1828. founded the Lower-Saxony Annals of Agriculture, with six volumes published till 1804. Thaer founded the first agricultural education establishment with his friend and collaborator A.2 Elie-Benjamin Crud Einhof in Celle in 1802. Accordingto Browne (1944, pp.179, 182) much of Einhof's work and data appear not only in that The French edition of the four volumes makingThaer's Thaer's work, but also in the pages of Hermbstädt's ªArchiv masterpiece suggests that the translator was a man of remar- der Agrikulturchemieº (Hermbstädt, 1803±1818) and were kable experience in agriculture, able of solid agronomical extensively quoted by Davy (1813) and others writers. Some reflection and aware of scientific advances of that time. Crud, of Thaer's and Einhof's students (K. Sprengel and J. H. van in the course of his translation, verified all the calculations Thünen) became as famous as him. In 1804, the Kingof made by Thaer, and when necessary gave corrected values. Prussia Fredrick William III had Thaer settled near Berlin on He did not hesitate to give his point of view, concordant or cri- 300 ha of arable land in Möglin, on which an Institute was tical, on many questions and sometimes to better specify the created in 1806 to educate and train agronomists. It was the field of application of Thaer's hypotheses. He wisely kept his first in Germany and one of the very first in Europe beside the comments as footnotes to avoid any confusion with those of Hungarian Georgicon. The Möglin Institute became the Royal Thaer. In his preface he wrote: ªwhen I had to make some Prussian Academy of Agriculture in 1819. This Institute ser- observation or modification originating from the difference in ved as a model to many agricultural teaching establishments our soil and our climate, or expressed opinions I had contrac- in Western (e.g. Grignon in France) and Central Europe. One ted through meditation or experience, I joined them in notes, year after the foundation of the University of Berlin (Humboldt and did not insert themin the textº . He further adds: ªI have Universität zu Berlin), Thaer gave a series of lectures on agri- allowed no cutting offº. It is laudable and worth recording, culture and rural economy from 1810 to 1819. Accordingto since it was unusual in that time (J. P. Legros, pers. comm.). the testimony in 1844 of Royer (1847), French inspector of Although Crud's translation ªis not fully satisfactoryº accor- agriculture in 1844, the school of Möglin badly survived its dingto Royer (1847), it was considered ªexcellentº by Mon- founder's death. tyon and Franklin (1836) (J. P. Legros, pers. comm.).

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A seven-page article was published on Crud by Martini Boulaine, J., and C. Feller (1989): Etablissement du premier record (1964). We give below a short summary: de France de productivitØ du blØ par le sieur Charlemagne ± Bobigny, 8 aoßt 1766. C.R. Acad. Agric. Fr., 75 (4), 31±38. Boulaine, J., and J. P. Legros (1998): D'Olivier de Serres à RenØ Elie-Benjamin Crud was born in Lausanne on 24 February Dumont. Portraits d'agronomes. TEDOC Ed., Paris, p. 317. 1772 and deceased on 15 May 1845 in the same city. Bourde, A. (1967): Agronomies et agronomes en France au XVIIIme sicle. S.E.V.P.E.N. Ed., vol. 3, Paris, p. 1740. Son of a notary, he did classical studies and settled as a Browne, C. A. (1944): Thaer, in: A source book of agricultural chem- notary in Lausanne from 1796 to 1801. He hold various politi- istry, Vol. 8. Chronica Botanica Company, Waltham Muss, USA, cal and administrative positions such as ªPrØsident de la p. 178±183. Chambre Administrative du Canton de Genveº and member Chaptal, J. A. Cte de (1823): Chimie appliquØe à l'agriculture (T.1, of the ªGrand Conseilº. In 1805, he became the Representa- p. 43). Huzard Ed., Paris, p. 298. tive of Switzerland in ChambØry to welcome the Emperor Davy, H. (1813) : Elements of Agricultural Chemistry. 1st edition, NapolØon as Kingof Italy. In 1808±1809, he was commissi- London. oned to make a report on agricultural establishments of the Diderot, D., and J. L. R. d'Alembert (1765): EncyclopØdie ou Diction- domain of Hofwyl directed by the agronomist E. v. Fellenberg naire RaisonnØ des Sciences, des Arts et des MØtiers. T. 8. Chez (1771±1844), what led to the initiation of strongrelationship Briasson, David l'AinØ, Le Breton, Durand, Libr., Paris. between these two scientists. From 1812 to 1836, he lived in Duchaufour, Ph. (1970): Article Humus, in: l'EncyclopØdie Universalis Italy in Massa Lombarda (Raven) where he had acquired a Ed., Vol. 8, Paris, p. 610. property. In 1838, he returned to Lausanne where he occu- Duhamel du Monceau, H. L. (1750±1756): TraitØ de la culture des pied various functions: member of the Municipal Council until terres suivant les principes de M. Tull, Anglais. Vol. 6, Paris. (Ref. his death, vice-president of the municipal court, president of from Bourde, 1967). the Institute of Blinds. Fabbroni, J. V. (1780): RØflexions sur l'Øtat actuel de l'agriculture ou exposition du vØritable plan pour cultiver ses terres avec le plus He is considered as a promoter of scientific agriculture in grand avantage et pour se procurer des engrais. Paris. (Ref. from France, Italy, and Switzerland, thanks to his French transla- Bourde, 1967). tion of Thaer's ªPrincipes raisonnØs d'agricultureº and to his Feller, C. (1987, 1989): Bernard Palissy a-t-il maniØ la tarire? Lettres own publication ªEconomie d'agricultureº (Paris, 1820; 2nd de l'AFES 11, 2±3 and 14, 8. edition in 1839). For this work, he received the Golden Medal Feller, C. (1997a): The concept of soil humus in the past three of the ªSociØtØ Royale d'Agriculture de Franceº in 1833. centuries. Advances in GeoEcology 29, 15±46. From his agricultural activity in Massa Lombarda, he wrote a Feller, C. (1997b): La matire organique des sols: aspects histor- book entitled ªEconomia teorica e pratica dell'agricolturaº iques et Øtat des conceptions actuelles. C. R. Acad. Agric. Fr. 83 (Venezia, 1842, 1844, 1845). In Switzerland, his reports on (6), 85±98. the agricultural establishments of E. v. Fellenberg in Hofwyl Feller, C. (1998): Petites histoires d'Humus. Une histoire d'eau ... had a great influence on the state of agriculture in Switzer- bien salØe, de Bernard Palissy. Lettre de l'AFES 46, 6±7. land (Geneva, 1808 and 1816; Zurich, 1808; Basel, 1809), Feller, C., and J. Boulaine (1987): La rØapparition du mot Humus au and his ªMØmoire sur l'assainissement de Villeneuve et de la XVIIe sicle et sa signification agronomique. Revue Forestire plaine du Rhôneº (Lausanne, 1840) testifies Crud's great Française 29 (6), 487±495. reputation concerningland-use planningand management. Grandeau, L. (1878): Recherches expØrimentales sur le rôle des matires organiques du sol dans la nutrition des plantes, in: Annales Station Agronomique de l'Est, Berger-Levrault et Cie Ed., Acknowledgments Nancy, p.225±352. Grandeau, L. (1879): Chimie et physiologie appliquØe à l'agriculture We thank Dr. J. P. Legros (INRA/ENSAM, Montpellier, et à la sylviculture. 1. La nutrition de la plante. Berger-Levrault et France), Dr. J. Balesdent (CEA, France), Dr. F. Penning de Cie Ed., Paris, p. 624. Vries (IWMI, Bangkok, Thailand), Dr. T. Gaiser (University of Hassenfratz, J. U. (1792): Sur la nutrition des vØgØtaux. Ann. Chim. Hohenheim, Germany), and Prof. Dr. W. Ehlers (Univ. Göttin- 13, 178±192 and 318±330, and Ann. Chim. 14, 55±64. gen) for their suggestions and bibliographical complements, Hermbstädt, S. F. (1803±1818): Archiv der Agrikulturchemie, für and Christiane Gujan and Else Bünemann for the German denkende Landwirthe, oder, Sammlungder wichtigsten Entde- translations. ckungen, Erfahrungen, und Beobachtungen aus dem Reiche der Physik und Chemie für rationelle Landwirthe, Güterbesitzer und Freunde der oekonomischen Gewerbe. 7 vols., Berlin. References Ingen-Housz, J. (1780): ExpØriences sur les vØgØtaux. Paris. (Ref. from Bourde, 1967). Böhm, W. (1997): Thaer, Albrecht Daniel, in: Biographisches Handbuch zur Geschichte des Pflanzenbaus. K. G. Saur, Klemm, V., and G. Meyer (1968): Albrecht Daniel Thaer, Pionier der München, p. 346±349. Landwirtschaftswissenschaften in Deutschland. VEB Max Niemeyer Verlag, Halle, Saale, p. 270. Boulaine, J. (1989): Histoire des pØdologues et de la science des La Salle de l'Etang, S. P. 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