The food crisis of 2007–2008 and record food commodity prices in 2010 have brought questions about agricultural productivity back to the fore. The critical role of research in developing and sustaining productive and resilient agricultural systems is being acknowledged anew, as can be seen from the emergence of new funders like the Bill and Melinda Gates Foundation and high-profile initiatives such as the Alliance for a Green Revolution in Africa. Historical studies of agriculture are commonly written from an economic, social-historical or political perspective, whereas the role of science and technology in agriculture – with the possible exception of plant breeding – has so far not received the attention it undoubtedly warrants. Many everyday decisions of farmers are in fact closely tied to scientific and technical developments and, at the same time, are highly contingent on political, legal and economic factors. For instance, the choice of plant varieties links the science of plant breeding with seed legislation, intellectual property rights, corporate power and an increasingly vocal sector of civil society that fights for the preservation of plant genetic resources and fundamentally questions the existing legal and scientific framework. For classical agrarian history many of these processes remained marginal, but they are characteristic of what the environmental historian Frank Uekötter describes as the agrarian knowledge society. The classical agrarian knowledge society is, according to the author, a network of researchers, extension services, media and farmers. Such networks serve the purpose of translating scientific developments into practical agronomic advice and, finally, agricultural practice, but they are also responsive to farmers' experience. In his voluminous study, Uekötter describes the development of German agriculture from the middle of the nineteenth century to the 1980s as a knowledge history which is structured in time by generational change – innovative practices appear when farms are handed over to a new generation.

Uekötter identifies four generations in his study. After 1890, with the establishment of regional chambers of agriculture, with their extension services, and the development of new fertilizers, science began to make serious inroads into German agricultural practice. However, a holistic image of the farmer, with an intuitive feeling for the proper method to cultivate his land, remained dominant. After the First World War, synthetic fertilizers and the increased use of mechanized equipment – both promoted by industry and farmers' associations – continued the trend towards a more ‘scientific’ and technologically oriented agriculture. The author characterizes this phase as a time of experimentation and uncertainty. Uncontrolled use of fertilizers led to the acidification of soils, and agricultural machinery was so expensive, crude and unreliable that there was no obvious benefit. After the Second World War, massive intensification of agriculture and vast structural changes in the social and economic organization of rural areas took place. An enormous number of small farms disappeared; farmers became more professional; the European Community introduced the Common Agricultural Policy; mechanization increased immensely – an especially entertaining part of Uekötter's study deals with the unbridled enthusiasm many farmers display for their machines; and new, profitable, but fertilizer- and water-hungry species (especially maize) were cultivated. The so called Flurbereinigung (land consolidation) initially led to big losses in biodiversity. In the 1980s the organic countermovement gained in strength; this questioned previous development and promoted more sustainable ways of agriculture. Agriculture and the design of food systems have remained highly politically and scientifically charged issues.

Frank Uekötter frames this narrative using a deficit model. He describes an agrarian knowledge community that did not succeed in translating the breadth of scientific knowledge into robust agricultural practice – and nonetheless achieved astonishing productivity growth. Uekötter claims that this was achieved by reducing the complexity and opaqueness of distributed agrarian knowledge systems – simplistic solutions were propagated by powerful scientific and industrial interest groups as the only way forward. Agricultural chemistry promised increased productivity through increasing fertilizer input and chemical pest control. The long-term effects on soils and water – a concern voiced from early in the twentieth century – were simply disregarded. Such issues, however, remained of crucial importance in the always marginal but surprisingly robust and vigorous organic farming movement – a movement that kept knowledge and practices alive that presently are highly valued again, even in mainstream agricultural science and politics, where ‘sustainable intensification’ and ‘greening’ have become new buzzwords.

I have doubts, though, that a deficit model is the most appropriate framing narrative. Contestation might have been a more suitable analytical concept for Uekötter's project. Agronomical knowledge is characterized by approaches with incompatible epistemologies and ontologies that are allied with divergent political, corporate or civil-society backers. Presently, reductionist biotechnology-led approaches compete with more holistic agro-ecological methods – and bridges between these approaches are rarely built. The challenges that agriculture faces always were and continue to be – to use a fashionable term – ‘wicked problems’. This phrase is used to describe a problem that is difficult or impossible to solve because of incomplete, contradictory and changing knowledge and requirements that are often unclear. Simple solutions are not appropriate for such problems, but in agriculture this applies not only to reductionist approaches, but also to organic farming or agro-ecological approaches, which do not provide convincing answers to some pressing challenges, such as the need to raise yields.

Frank Uekötter in the end proves to be a bit too ambitious with his study. He raises many interesting questions, but his frame of analysis is not quite suited to offering wholly satisfying answers. Nevertheless, the author succeeds in showing that agriculture could become a very productive field of study, analysing the two-way traffic of knowledge and practices in the networks made up of research institutions, policy actors and the farm.