Ever hear of farming systems research, training and visit, and participatory rural appraisal? If so, chances are you’re a veteran of the 1970s and 80s era war on food insecurity, then blitzing across the African continent. This war had no generals, shock troops, enfilades, pincer movements, or Maginot line to defend. No hearts and minds to spar over. As Henk J.W. Mutsaers recalls, the battle played out in the rarefied confines of elite international research centers, extension bunkers, and donor silos, edging into the tactical embrace of consultants and purveyors of development aid, armed with infectious goodwill and an appetite for money. Its Waterloo moment came in the late 1990s, when the patience of the World Bank, the IMF, and bilateral and philanthropic entities had been tested enough to cut the cord and move on. Now, as ever, Africa’s production of cereal grains is placed at the bottom of global rankings, and food deficits in many countries are still endemic. What went wrong?

If the name H.J.W. Mutsaers doesn’t ring a bell, he’s a Dutch agronomist, crop modeling enthusiast, and author of Peasants, Farmers and Scientists: A Chronicle of Tropical Agricultural Science in the Twentieth Century (Springer, 2007). Part history, autobiography, and technical monograph, Peasants, Farmers and Scientists tells the story of tropical agricultural science and agricultural development from the beginning of the 20th century, an era of colonial rubber, oil palm, and sugar plantations that beckoned cavalier European agronomists like Henk Mustaers. The book’s eleven chapters, nine appendices, and expansive bibliography dish up, on a non-trivial yet comprehensible level, the evolution of tropical agriculture science from colonial handmaiden to development agent, focusing primarily on the interplay of donors, scientists (local and foreign), research centers, and farmers in West and Central Africa in the second, post-colonial half of the century. On exhibit are field notes, disputations, and scientific gleanings from the author’s far-flung gigs as researcher in the Dutch East Indies (now Indonesia); lecturer at Wageningen Agricultural University in the Netherlands and at the Ecole Nationale Supérieure Agronomique (ENSA), near Yaoundé, Cameroon¹; researcher at the International Institute of Tropical Agriculture in Ibadan, Nigeria, West Africa; and lately, freelance consultant.

Figure 1. Native stone terraces in the Mandara Mountains, northern Cameroon. The terraces capture rainfall during the brief rainy season, improving water infiltration and conserving soil. Sorghum and millet are the principal crops in this semi-arid zone. (Image: Walters Collection)

For the uninitiated, you’ll learn the nitty-gritty of shifting cultivation (“the mother of all systems”), sugarcane breeding, clever indigenous farming practices, experimental smallholder technologies, crop modeling (of course), innovative methods for evaluating technology in farmers’ fields, and agro nutrient budgets. Astonishing practices like “écobuage”, described anecdotally in Chapter 5, “Forests, Fallows and Fields,” as a method of slowly burning grass residue in soil trenches under low-oxygen conditions in western Cameroon, anticipate the concept of pyrolysis for biochar production. In Nigeria, there’s an ingenious Yoruba maize-sorghum-yam rotation that modern agroecologists would have a hard time improving on; native soil- and moisture-conserving stone terraces in the Mandara Mountains of northern Cameroon (Figure 1); and the obscure “van der Meulen” method of speargrass (Imperata cylindrica) suppression and soil rejuvenation that exploited the peculiar habits of two legumes, velvet bean (Mucuna pruriens) and Centrosema, and a deep-rooted invasive Eupatorium species (Chromolaena odorata), to further whet your appetite. Since my blogging time is limited to after-hours and weekend punting, and the attention span of online readers is abridged, I’ll limit my comments to a couple of resonant themes in Peasants, Farmers and Scientists about African agriculture, to which I can add substance.

The first theme turns on this question: Can a modern market-centered African agriculture evolve from its peasant roots, or will this require a completely different mindset? At one time, Mutsaers believed that Africa’s peasant farmers could transition to a market-based system if alternatives to slash-and-burn were found. This view is embedded in the idea that the traditional subsistence farmer is a rational operator, or at least what we consider rational in a post-subsistence, modern agribusiness world. The idea is that improved genetics, fertilizers, lime, nitrogen-fixing legumes, and other inputs should increase returns to labor and land, fostering the transition to a market-centered enterprise.

Ah, but the picture has always been (and still is) much more complicated than that. Technologies like no-tillage planting failed to take root in sub-Saharan Africa, only to blossom in Southern Africa, North and South America. Promising non-mechanized “appropriate” technologies aimed squarely at resource-limited smallholders have also fallen flat. Take alley cropping, for example. Briefly, alley cropping is a method of planting annual crops between rows of perennial trees, especially fast-growing multipurpose nitrogen-fixing species such as white lead tree (Leucaena leucocephala), Erythrina (Erythrina poeppigiana), and Gliricidia (Gliricidia sepium) (Figures 2a and 2b).

Figure 2. (a) Alley cropping in the highlands of western Cameroon. Note the large unpruned perennial trees. Perennials furnish green manure, but they can also compete aggressively with food crops for moisture and nutrients. (b) Raised beds planted with maize, beans, and cocoyam. Intercropping is favored by peasant-farmers in Africa, but agronomists prefer monocropping because a single crop facilitates modern management practices. (Image: Walters Collection)

A typical alley cropping scenario involves intercropping maize with root crops (sweet potato, cassava, cocoyam) or cowpea, or a combination of these, in succession between trees planted about 4 meters apart. The trees are pruned to small hedges at the start of the growing season, and perhaps once or twice thereafter, with trimmings placed in the alleys as “green” manure. The concept of green manuring dates back to antiquity: Roman agricultural writer Varro (116 – 27 BC) advised plowing under legumes such as beans and lupines in their green, unripe state to improve the soil. Cato, Columella, and Pliny gave similar advice. Alley cropping updates the green manure concept to include woody perennial species.

Popularized by B.T. Kang, G.F. Wilson, and colleagues at the International Institute of Tropical Agriculture (IITA) in Ibadan, Nigeria, alley cropping aimed to mimic elements of traditional slash-and-burn agriculture, in which trees are cut down while leaving the roots intact. After a period of cropping, the tree stumps resume their growth. Competition from sprouting trees and weeds, coupled with soil nutrient depletion, prompted the traditional slash-and-burn farmer to seek new ground every 2-3 years. Thus, the term “shifting cultivation” arose. Alley cropping short-circuited this endlessly itinerant slash-and-burn cycle by planting, purposefully, deep-rooted perennial trees to capture nutrients that leach down beneath shallow-rooted annual food crops. The dodgy nutrients are returned to the surface in the tree’s vegetative parts, fortified with minerals from the subsoil. Tree trimmings are mixed into the soil, where they decompose, releasing plant-essential nutrients and leaving behind a residue of humus. To facilitate farm operations, trees were planted in straight lines, leaving the spaces open for mechanized cultivation where feasible. Superficially, alley cropping appears to be the perfect, sustainable, and eco-friendly alternative to slash-and-burn.

As it turned out, alley cropping was not the perfect solution. Mutsaers parses the quantitative details in Appendix 4 “Nutrient Dynamics of Alley Cropping: A Simple Model”, for agronomists are also ruthless nit-picking scientists who are never satisfied until the numbers add up in the biophysical balance of accounts. If you steal from Peter to pay Paul, you eventually bump up against a form of biophysical entropy, aka diminishing returns. Crop and soil modeling is an excellent way to test this principle by predicting how the system will react to the ebb and flow of energy and nutrients. To my knowledge, this is the first attempt to simulate long-term productivity under alley cropping in the humid tropical forest zone. Indeed, even Musaers voiced surprise that it had never been done after so many years of alley cropping research.

If Mutsaers’s soil and plant nutrient allowances are taken as reasonable approximations, and the assumptions about system productivity are met, his simple model predicts that even on a favorable site with “good” soil, continuous maize-cassava and maize-cowpea alley cropping would be impossible in the long run without supplemental fertilizer. The demand for nutrients needed to sustain continuous cropping was predicted to outstrip available stocks even in the subsoil. As the soil’s nutrient stocks are siphoned off in food products, the production of tree trimmings eventually declines to a point where the system collapses under the strain of nutrient exhaustion. Mutsaers concludes, rightly, that alley cropping is a form of soil mining, especially the macronutrients phosphorus and potassium (calcium, magnesium, sulfur, and micronutrients were not included in the models). The model predictions were validated by measured crop yields from two 12-year alley cropping experiments in Nigeria, one with non-fertilized maize and cassava, reported by Tian et al. (2003; 2005), and a maize-cowpea system with fertilizer phosphorus and potassium, reported by Kang et al. (1999). Mutsaers admits taking some liberties in making assumptions about soil and plant processes in his alley cropping simulations, which may not extend to other soils and agroecological zones. One could quibble over his choice of 10 parts per million as a critical available soil phosphorus (P) level for maize production, which seems on the low side, but this depends on the type of extractant used to measure soil P and other factors like soil texture, nitrogen uptake, and capacity for P-immobilization.

Not coincidentally, a similar picture emerged from research by L.T. Szott, C.A. Palm, and P.A. Sanchez (1991) following a series of alley cropping trials in the Peruvian Amazon with upland rice and cowpea (Figures 3a and 3b).

Figure 3. (a) Alley cropping experiments in the Peruvian Amazon with upland rice flanked by perennial ice-cream bean (Inga edulis). Note the straight lines and uniform spacing of rice plants in the middle and the uniform distribution of Inga trimmings in (b). Controlled experiments like these were (and still are) the rule on agricultural research stations in the tropics, yet they failed to replicate the haphazard conditions of farmers' fields. (Image: NCSU Soil Science)

While it’s impossible to relate all of the details here, Szott and coworkers concluded that even with legumes pruned as hedges or as the principal crop, or both, continuous alley cropping was not sustainable on acid, infertile Amazonian soils without nutrient subsidies from outside the system. In other words, alley cropping failed to measure up in two distinct agroecological zones in Africa and South America. In the end, however, the promise of alley cropping did not fail due to nutrient exhaustion, as predicted by Mutsaers’ crop-soil models and borne out by multiple field trials in West Africa and Peru. The main problem was that farmers did not want to adopt alley cropping, a separate conundrum I’ll try to unpack.

The concept of technology transfer is deeply embedded in every implementation of agricultural development. Nowadays, it’s more avant-garde to speak of “value chains,” but this is just a purloined buzzword that alienates donor-side bureaucrats from the untidy prospect of intervening in agricultural production systems. In the loosely defined putative research-extension alliance, technology is generated by scientists. The products are then disseminated by specialists schooled in the donor “recipients’” repertoire, in this case, peasant farmers. In principle, the spread of improved technology to rural producers is facilitated by public agencies, acting alone or in concert with international organizations. It’s a simplistic approach with many pitfalls. Perhaps its biggest flaw was the assumption that the priorities of public agencies, international organizations, and rural producers were mutually aligned. This was rarely the case. Thus, agronomists could push out novelties like alley cropping even though labor demand, access to inputs, land tenure, and other fixtures of peasant-farmers’ lives made no sense for them to change what they were already doing, except perhaps in exchange for free donor-supplied goodies while they lasted. Mutsaers concedes that this was a major obstacle to disseminating improved practices from the research stations. There were other lurking pitfalls too, from unexpected quarters. Let me elaborate on the “lurking pitfalls” from my trench-level experiences with cassava and rice in Sierra Leone.

Figure 4. Mosaic-resistant cassava growing in the author's multiplication nursery. Locals were unenthused by it.

Cassava (Manihot esculenta) is a traditional root crop in Africa, though it is scarcely known outside its native tropical habitat. As Mutsaers points out, cassava is alien to Africa; the plant was, in fact, introduced there from Brazil by Portuguese traders in the 16th century. Cassava is a tough plant that tolerates uncertain rainfall and marginal soil, two complementary virtues that have earned it the nickname “bread of the tropics”. One of cassava’s weak spots is its susceptibility to the African cassava mosaic virus, first reported from East Africa in 1894. Viral epidemics have severely affected cassava production, resulting in significant economic losses and, in some cases, famine. In the 1970s, high priority was given to breeding mosaic-resistant cassava. Scientists at the IITA in Nigeria achieved this by drawing on parent varieties developed earlier, through crossing M. esculenta with virus-resistant tree cassava (Manihot glaziovii), believed to be a natural hybrid of Ceara rubber and cassava species at the Amani research station in East Africa (the breeding process is much more complex than simply crossing two species, but I leave out the exact details). Back then, I was given some virus-resistant cassava “sticks”, as the vegetative stem cuttings are known, and advised to propagate them and give the offspring to farmers (Figure 4).

In theory, this was a good idea. In practice, it proved less redeeming. While the virus-free cassava increased beautifully, it wasn’t a hit with the locals. Breeding resistance to the cassava mosaic virus, it seems, also thickened the cassava leaf epidermis. Perhaps this was by design because the leaf-feeding whitefly is the principal vector of cassava mosaic (other anatomical and/or phytochemical traits may also have been affected; the exact resistance mechanism is unknown to me). In the event, the culinary properties of the virus-resistant cassava leaf were noticeably altered. Farmers complained that it wasn’t “sweet” like the native varieties. I should point out that eating cassava leaves was almost a daily ritual in Sierra Leone, so local preference may have steered people’s reactions. Over time I, too, had acquired a taste for the native leaf, and even this puumui could tell the virus-free cassava was inferior!

Similar resistance was encountered trying to disseminate improved japonica rice varieties bred at the International Rice Research Institute (IRRI) in the Philippines, which were increased locally by the West African Rice Development Association (WARDA). The IRRI varieties grew beautifully with fertilizer and controlled irrigation but lacked the fluffy texture and sweet flavor of native Mende upland “red” rice (Oryza glabberima) produced under traditional slash-and-burn cultivation (Figure 5). Swamp rice was a tough sell to slash-and-burn farmers, as were environmental controls like irrigation, seedling nurseries, and line-planting with sticks and string. Of course, fertilizer was out of the question for most farmers, so it was natural for them to favor native rice varieties better adapted to Sierra Leone’s acid, infertile upland soils, despite their generally low grain yields. But why did agronomists ignore upland rice? Breeding programs for upland rice did not exist in Sierra Leone, nor were there initiatives to stabilize upland production systems². The answer lay in the swamps, and the battle cry was “Develop them!”

Figure 5. (a) Traditional slash-and-burn farm in Sierra Leone. The tall grass surrounding the farmhouse is upland rice. (b) Typical inland valley rice farm near Kenema, Sierra Leone. Hazards like schistosomiasis and river blindness were a constant risk to farmers working these swampy lands. (Image: Walters Collection)

What does this say about the African peasant farmer’s capacity for change? Henk Mutsaers confesses that he’s had second thoughts about the idea of re-wiring the traditional peasant farmer for the future. Commercial, market-centered farming in Africa may require a completely different mindset that can only be gestated de novo rather than inoculated through participatory rural appraisal, training, and visit conferences. Indeed, there are signs of a new entrepreneurial vanguard in the ascendant peri-urban farming movement, a global trend taking its lead from a sophisticated reading of urban markets and demographics. Curiously, Mutsaers is silent about the ever-expanding Chinese footprint in Africa, a phenomenon observed for over two decades and bound to alienate African agriculture and markets. Of course, the Chinese are certainly not the only players in the global land grab; perusal of the Oakland Institute’s Understanding Land Investment Deals in Africa indicates a diverse mix of public and private stakeholders. In the event, the verdict is still out on the transglobal farming model. If carefully implemented and managed, vertically integrated “international” farming may contribute to the long-awaited green revolution in Africa. On the other hand, I don’t see why farmers must conform to any particular mold. Why can’t African farmers be traditional and market-centered, or a mixture of both? After all, there are greater extremes coexisting in the industrialized West: artisan modes of production, such as organic and specialty farm-to-table operations, in the shadow of industrial mega-farms in the Midwestern USA. I think there’s room for everyone’s persuasion.

Returning to the subject of technology transfer, the failure of farming systems research (FSR) and other donor-inspired fads in Africa gives one pause to contemplate the legacy of foreign intervention in agricultural production systems. Africa is rife with monuments bearing witness to well-intentioned but ultimately botched attempts to reshape African agriculture along modern lines (Figure 6).

Figure 6. All your tractor are belong to us. Soviet-era Russian tractor stands sentinel near Ngaoundéré, Cameroon, evoking some long-ago combat scene. (Image: Walters Collection)

The Farm Settlement schemes in Anglophone countries mostly failed their objectives; the 1980s Unités Expérimentales research-extension alliance in Sénégal was hit and miss; the Tanganyika Groundnut Scheme, an epic failure; the Gezira-irrigated cotton scheme in Sudan, a marvel of engineering that failed to cash flow its infrastructure (now transitioning to rice?); and the infamous Office du Niger-irrigated rice scheme in Mali. The Office du Niger project is arguably the most enduring of the lot, but its fate since the 2012 insurgency remains unknown. In Africa, everything seems to hang by a gossamer. As Henk Mutsaers opines, for all the foreign aid directed at alleviating food insecurity in Africa over the past half-century, the continent still struggles. Why?

Unfortunately, Mutsaers does not offer a clear answer. Insofar as the FSR-inspired bandwagon was concerned, the author observed that “research stations in Africa were so different from a real farm that it made no sense at all to do detailed studies on crop management under conditions which only remotely resembled those of the farmer”. Moreover, too many field trials were designed “to rediscover things which had been found out countless times before or were in no great need of being found out”, and answering “evermore detailed questions which originated mainly in the scientists’ own minds, assisted by imaginary conversations with some phantom African farmers”. The author laments the devolution of FSR into a ritualized, self-serving professional cult where incantation of mumbo-jumbo like “linkages” and “capacity building” was valued above tangible outcomes that have a rational basis for measuring. In effect, the return to subsistence farmers after decades of research and development has been essentially nil. But not quite nil. Mutsaers points to some bright spots, like the testing and dissemination of Mucuna pruriens for speargrass control in the Bénin Republic by government extension services and the NGO Sasakawa Global 2000 Foundation. Impact studies from the late 1990s estimated that 14,000 farmers had used, or were still using, Mucuna.

Is Mucuna still planted by farmers in the Republic of Bénin today? What happened when extension workers stopped providing Mucuna seeds? What durable impact has Mucuna had on smallholder productivity in the Bénin Republic? We do not find these things out because the success of development projects “cycles” is measured by short-term impacts, which are quite apart from changing how people do things, in perpetuity. Generations of extensionists have relentlessly pitched legumes as cover crops and soil improvers. To paraphrase Henk Mutsaers, one cannot fail to be impressed by the magic of legumes. Legumes, however, are nothing new in agriculture. Nonetheless, each generation seems to rediscover legumes as something equivalent to finding the philosopher’s stone. Each time we’re told it’s a new approach, a new “understanding”. In reality, efforts to convince farmer-peasants in Africa to adopt legumes have not been successful. Legumes are fascinating plants valued for their ability to fix atmospheric nitrogen. But it’s unlikely that legumes, alone, or in combination, will herald a green revolution in African agriculture anytime soon.

Fast-forward: it’s 2014, and we’re still at it, conjuring the right technology ingredients. Lo and behold, a new paradigm is born to us: the Millennium Villages, a gem of the Earth Institute at Columbia University, United Nations Development Programme, and Millennium Promise (né 2006). This project delivers fertilizer and hybrid seed, among other offerings. The Soils, Food, and Healthy Communities project in Malawi aims to improve soil fertility, sustainability, and rural livelihoods with legumes (again!) and native open-pollinated crops. A multicolor Compact Technical Report for post-conflict Sierra Leone published by the Comprehensive Africa Agriculture Development Programme (CAADP) is larded with talk of “value chains” and “capacity building” across crops, livestock, and fisheries. And this announcement from AGRA, an anti-poverty project founded in 2006 with support from the Rockefeller Foundation and Bill and Melinda Gates Foundation: “Millions of smallholder farmers need to adopt promising ISFM (Integrated Soil Fertility Management; see Mutsaers, p. 373) options to generate sustainable yield increases and make farming more profitable.”

Will smallholders adopt ISFM practices this time around? Will these earnest projects succeed in creating a productive, sustainable template for African agriculture that eradicates poverty and food insecurity, as they promised but failed to deliver before? That, of course, is difficult to predict. But the odds aren’t tremendously good. Such projects may have a local impact, but I predict their long-term impression will scarcely register on the scale of development. Nonetheless, African agriculture is destined to change, driven by forces beyond NGOs’ control and operating outside their sphere. Tax and public policy incentives, education, patterns of global investment and trade, land tenure reform, mobile digital communication, GIS and deep learning³ technology, are most likely to stimulate private investment, mechanization, and growth in all sectors, including agriculture. For all the infectious goodwill, trampled warriors, and empty aid coffers, this may just be how poverty ends, worldwide.

In closing, I submit that few people have witnessed, let alone examined, honestly, the troubled legacy of agricultural development in the last half of the 20th century as intimately as Henk Mutsaers (the late Norman Borlaug comes to mind). For this reason alone, Peasants, Farmers and Scientists stands as a landmark achievement. If you have ever hankered for the philanthropic life, or donated money for mosquito nets (rumor has it they make superb fishing nets), I urge you to read this book. If you’re not an agronomist, find one to explain the basics. You’re bound to learn something about food production in the process, which is a good thing. Sadly, the price of admission is a wallet-busting US$150+ per copy (Springer is an academic publisher catering mainly to institutional clients, no remainders). Even your faithful blogger and Acme Scientific Research Collaborative®CEO was reduced to borrowing a copy, fathom that.

Cheer up, though. At least you get to read this blog for free.

End Notes

¹ Coincidentally, the author and I worked at ENSA in Cameroon but at different times. I was there in the late 1980s during the construction of the new campus at Dschang, quite a distance from Yaoundé. The Dschang campus was a World Bank-funded project heralded as a new model for agricultural education and development across Africa. In turn, the project engaged leading academic talent from Europe, Asia, and the U.S. I was not in that rank. Nonetheless, it was a prized opportunity to hobnob with (and learn from) some big shots in the field of tropical agriculture.

² The interspecific upland hybrid sativa X glabberima a.k.a. NERICA rice was finally introduced in 1996 by the Africa Rice Center (né WARDA). NERICA’s creator, Monty Jones, won the 2004 World Food Prize for his efforts.

³ In 2014, when I wrote this piece, the term “deep learning” anticipated what is now called “Artificial Intelligence (AI),” exemplified by the iSDA Virtual Agronomist, developed with funding from the Bill and Melinda Gates Foundation. This tool holds great potential, but it’s unclear whether VA in Africa can walk on its own legs financially.

Disclaimer: I have no relations with the book author or publisher Springer. Links to digital content in this blog are for the reader’s information only, not an endorsement of that content.

Updated by the author 18 April 2019. Link check. Some links remain unresolved.

Second update by the author 27 November 2019.

Third update by the author 25 January 2022.

Fourth update by the author 02 November 2024.

Fifth update by the author 29 July 2026.

Further Diggings

Bingen, R. James and Jacques Faye. 1987. Agricultural Research and Extension in Francophone West Africa: The Senegal Experience. MSU International Development Papers. Reprint No. 13. Available at agricultural-research-and-extension-in-francophone-west-africa.pdf (verified 19 April 2014)

Kang, B. T., G. O. Kolawole, G. Tian, and F. E. Caveness. 1999. Long-term alley cropping with four hedgerow species on an Alfisol in southwestern Nigeria-effect on crop performance, soil chemical properties, and nematode population. Nutrient Cycling in Agroecosystems 54(2): 145–155.

Kleene, P., and H.J.W. Mutsaers. 2012. What is the matter with African agriculture?: Veterans’ visions between past and future. KIT Publishers, Amsterdam. In the same vein as PFS, conversations with those who were (and still are) on the front lines about accomplishments, failures, and what’s needed to meet Africa’s future challenges. Balanced with African, Anglo- and Francophone perspectives.

Salazar, A., L.T. Szott, and C.A. Palm. 1993. Crop-tree interactions in alley cropping systems on alluvial soils of the Upper Amazon Basin. Agroforestry Systems 22(1): 67–82.

Szott, L.T., C.A. Palm, and P.A. Sanchez. 1991. Agroforestry In Acid Soils Of The Humid Tropics. p. 275–301. In Nyle C. Brady (ed.), Advances in Agronomy. Academic Press.

Tian, G., B.T. Kang, and G.O. Kolawole. 2003. Effect of fallow on pruning biomass and nutrient accumulation in alley cropping on Alfisols of tropical Africa. Journal of Plant Nutrition 26(3): 475–486.

Tian, G., B.T. Kang, G.O. Kolawole, P. Idinoba, and F.K. Salako. 2005. Long-term effects of fallow systems and lengths on crop production and soil fertility maintenance in West Africa. Nutrient Cycling in Agroecosystems 71(2): 139–150.

Wallach, B. 1988. Irrigation In Sudan Since Independence. Geographical Review 78(4): 417. Available at irrigation-in-sudan-since-independence.pdf (verified 19 April 2014)

If I was starting a career in agriculture today, Australia is the place I would go to prepare for it.

Why?

One good reason is Richard Stirzaker, author of Out of the Scientist’s Garden: A Story of Water and Food (CSIRO Publishing, 2010, 193 pp.). Expert gardener, tinkerer, educator, raconteur and, Senior Research Fellow at the Commonwealth Scientific and Industrial Research Organization (CSIRO) in Canberra, Australia, Stirzaker melds the rigor of scientific thinking with a profound understanding of scale and problem solving as it affects how we feed ourselves. Stirzaker invites us to ponder the meaning of hard-to-pin-down words like “sustainable” that have ambushed the lexicon of agricultural scientists and emissaries of development (now pivoting to “climate smart®”). What does a template for sustainable agriculture look like in a world expected to reach a human population of 9+ billion by 2050?

Today, irrigation accounts for more than 70% of groundwater diversions annually, and for more than 90% of total consumptive water use including surface water (FAO 2010; Siebert et al. 2010). As Stirzaker notes, there is plenty of water on planet Earth, but 97% is salt-laden ocean water. However, if we try irrigating with saltwater, plants will wilt and eventually die. Less than 3% of water is fresh enough for watering plants, and two-thirds of this is locked up in icy blocks. The sustainability of our global food system is inextricably linked to the remaining 1% supply of freshwater. We can argue the merits of fertilizing with organic nutrients in compost over that of soluble inorganic fertilizer, i.e. the insufferable and counter-productive “natural” vs. “synthetic” debate. In all cases, essential nutrients must be dissolved in water and available at the plant root; and, there must be enough water in the soil to sweep nutrients to the exchange sites on roots if we are to sustain, let alone increase, the food supply. The problem of water supply is the most urgent one facing the global food system, and Stirzaker is acutely aware of this. Throughout, the author emphasizes the fundamental soil-plant-water relationships underpinning the agronomic sciences with a minimum of jargon and, explains how intervention in the food system can flounder despite the scientific merit of an idea.

The book is divided into three parts. Each part has seven chapters in essay form, loosely turning on a theme. Part 1 “The View From Our Garden” traces Stirzaker’s professional roots back to the family garden of his youth. He opens with this simple premise: “This is not a book about gardening. Yet the story of feeding the world begins in a garden”. The massive, unending streams of global energy, water, and fertilizer needed to keep the world fed are difficult for anyone to comprehend. But the garden, Stirzaker contends, is a scale we can comprehend. As a food production system, the home garden is relatively simple. The consequences of crop failure are usually not catastrophic for the gardener. One can tinker infinitely without the fear of going hungry or losing one’s shirt. The garden is also an excellent place to learn how plants interact with their environment. Plants respond to temperature, frost, day length, humidity, and moisture in different ways. Once we understand, for example, how onion varieties respond to day length or cabbage and broccoli to temperature, we can take advantage of this knowledge to maximize the variety, quality, and supply of food produced from the garden. The commercial grower exploits the same fundamental knowledge, only on a larger scale.

Part 1 also delivers the mea culpa agricola “The Lapsed Organic Gardener”. Early on, Stirzaker was an avid reader of gardening books. A particular favorite was The Complete Book of Self-Sufficiency by John Seymour. I never read Seymour’s epistle, but there were many books like this published in the 1970s mostly written with urban exiles and suburban homesteaders in mind. I, too, had teenage dirt hog idols like Louis Bromfield, author of Pleasant Valley (1943), Malabar Farm (1945), and Out of the Earth (1948). Bromfield’s literary star had long since faded by the 1970s and with it, his prolific writings, mainly surviving as obsolete, forgotten tomes moldering on the shelves of the public library where I first discovered them. Bromfield was not a practitioner of organic agriculture but adapted some concepts to his Ohio farm operation. Early on, he abandoned the idea of the generalized self-sufficient farm, to specializing in livestock and dairy. The pattern of the specialist farm has intensified in the post-WW II era, with little hint of changing direction. This is one of the irresistible forces driving contemporary food systems, Stirzaker concedes. The eco-friendly gardening methods described in books like Seymour’s are ill-suited to commercial-scale production. Still, one idea from the Malabar Farm sagas that continues to resonate with me is the potent but generally neglected influence of the subsoil in agriculture. Despite poor topsoil inherited from years of bad plowing, Bromfield was convinced that his glacial Ohio soils were fertile, advocating “farming from three to twenty feet down”. There, locked away in the rich subterranean fabric are stocks of water, nutrients, and trace minerals awaiting discovery by plant roots. His recipe for restoring worn-out land emphasized deep-rooted legumes like alfalfa.

Image 1. Louis Bromfield (1896-1956), Ohio-born American novelist and pioneer of conservation farming in the 1940s. Bromfield's recipe for restoring worn-out land emphasized deep-rooted legumes and grasses. Largely forgotten by the 1970s, the chronicles of Malabar Farm and Malabar-do-Brasil aroused my interest in food and energy systems, soil, and tillage.

Stirzaker built on the same idea decades later, mixing shallow-rooted vegetable crops with strips of alfalfa (aka “lucerne” in Australia). In this system, the deep-rooted alfalfa picks up nutrients that filter past the vegetables, pulling them back to the surface. Cuttings of alfalfa are then placed in the vegetable rows where they decompose, releasing the dodgy nutrients. The difference is, Bromfield’s alfalfa monoculture scaled commercially, whereas Stirzaker’s vegetable-alfalfa system did not.

This brings us to the subject of “agroecology”. Nowadays there is a great deal of buzz about agroecology, at least within academic circles. Agroecology emphasizes biological complexity like Stirzaker’s vegetable-alfalfa system. On a non-mechanized artisan level, mixed cropping systems may be successful but it is difficult to implement them on a commercial scale. Agricultural mechanization requires a degree of simplification to implement. In reality, a sustainable food system has many interlocking facets that impart buoyancy to the whole. Foremost is creating a soil environment where roots are unhindered by compaction, pH, and the supply of mineral salts and water. This depends on direct human intervention, not biological complexity.

Sustainable soil and water management should invoke a modus operandi that is adaptive and free of taboos provided it builds productivity, quality, and income following proven methods of land husbandry. The idea that there is one path leading to sustainability, whether fixed in the organic canon, biodynamics, net zero, permaculture, or what have you, is a conceit advanced mainly by those who do not comprehend the complex, interlocking infrastructure that has evolved to feed an urban, industrialized world. Agriculture isn’t natural, and leaving things for nature to balance out ensures that a large part of what we produce will be devoured by hungry competitors. This doesn’t mean, Stirzaker stresses, that we shouldn’t strive for better ecological outcomes to buttress the global food system. The challenge ahead is reducing agriculture’s ecological footprint as it becomes more productive, which it must. On the other hand, we must accept that there are stark efficiency constraints in commercial farming operations. As spectators, we’re not free to foist our cherished ideas on those who produce the food we eat.

Part 2, “A Journey Through Soil” gets down to the business of soil water, water supply, and irrigation; why, as Stirzaker asserts, it is so difficult to know how much water there is in the soil, and, why irrigation is often so inefficient or damaging to plants. As a veteran of the irrigation business, much of what Stirzaker says rings true. Chapter 10, “The Machingalana is Talking to Me” relates the author’s approach to solving a particularly thorny problem for the irrigator: measuring how much water is in the soil in a simple, straightforward way. Stirzaker’s answer is the FullStop wetting front detector, a simple mechanical device designed to detect the depth that water infiltrates in the soil. For now, I pass on the wetting front detector and related chapters because they deserve a separate blog which I must postpone for later.

Here, I want to focus attention on chapter 8, “The Tale of Clever Clover”. The clover in this tale is subterranean clover (Trifolium subterraneum), or sub clover for short. Clovers are legume plants. This means that they can self-produce nitrogen fertilizer, literally out of “thin air” (Earth’s atmosphere consists of about 78% nitrogen). A soil-dwelling bacterium called Rhizobium colonizes the roots of legumes, forming small nodules where they live. The bacteria come equipped with special enzymes needed to convert atmospheric nitrogen, which plants can’t use, to ammonium nitrogen which plants can use for protein synthesis. The bacteria fix the nitrogen and pass it on to the clover plant. In exchange, the bacteria get energy in the form of sugars from the clover (clover still needs potash, phosphorus, and lime so it’s no free lunch). The name “clever” clover presumably derives from this clever act of nature, or so it appeared to the science journalist who interviewed Stirzaker. The tale begins with an extra garden bed Stirzaker had seeded with sub clover. After blooming, the annual clover dies off naturally, leaving behind a nitrogen-rich organic mulch. Beneath this decaying mulch, Stirzaker found revitilized soil: soft, crumbly, aromatic. Eureka! At last, the Rosetta stone of no-tillage organic crop production was revealed, springing from beneath the remains of a humble clover plant. What followed is an avalanche of media attention directed at the Clever Clover plots and the man behind their discovery. Clever Clover kits were quickly assembled and sold like hotcakes. It must have been a classic light-bulb-goes-off moment like announcing you’ve just discovered DNA or something equally game-changing!

It was not to be. While Clever Clover was a big hit with home gardeners, it did not influence commercial vegetable production in Australia or elsewhere. As Stirzaker explains, innovations that solve one set of problems often create new ones, and scale matters. Planting systems designed for the garden may be eco-friendly innovations, but it is difficult to implement them on a commercial scale. New risks are introduced to the system, and farmers do not like taking risks with their livelihoods. Problems like: What happens if the clover gets infested with weeds or slugs? (Cutworms, wireworms, and rootworms are the under-mulch nemesis in North America). How do you plant and irrigate through the mulch, and what happens to the mulch after harvest? All were unknowns, and Clever Clover did not supply the answers.

The Clever Clover tale parallels a similar epiphany when I thought I had discovered, by accident, something game-changing, only to find that it, too, didn’t prove up under testing. This tale involves rye, a grass, but could apply equally to legumes like sub clover. Between 1999 and 2003 we were running subsoil nitrogen recovery studies on small grains. The aboveground plant biomass: grain, leaves, and stems, were cut in April and May, except for the “check” plots (these are control plots in agricultural field experiments). The checks were left alone: harvest, no clean cutting. In turn, the rye and other small grains went to seed. The rye, in particular, had grown very tall because we had planted corn on that land the previous year, and some of the nitrogen fertilizer that was applied to the corn crop carried over to the rye. The unharvested, uncut rye slumped over from the weight of its top-heavy growth (known as “lodging”), forming a perched canopy. Beneath this canopy, no weeds had germinated. In contrast, the plots that had been clean cut were covered with them.

Image 2. Small grain plots on the Thompson Farm, site of my Clever Clover epiphany. The green strip in middle is where grain was cut earlier, now flush with weeds. Compare to the weed-free under-canopy (inset) photo taken in mid-June in the unharvested plots (the greenish crust is moss growing on the soil surface). I thought we could duplicate the same weed-free effect in row crops with the mechanical roller-crimper, reducing the need for costly herbicides while advancing broader environmental goals such as reduced soil erosion and improved water quality. It didn't work out that way.

It is well known that rye releases toxic phytochemicals during decomposition that inhibit the germination of small seeds, a phenomenon known as allelopathy. What happens to those chemicals after the rye has been terminated is not well understood, but it is presumed they leach into the soil where they are broken down by microorganisms. Given the right conditions, I reasoned that duplicating this weed-free effect might be possible in annual row crops. Eventually, the mulch would decompose into a soft, spongy, organic mold, earthworms would improve aeration and recycle nutrients with their castings, and the soil would be conserved, all in one nifty package. This was my Clever Clover moment. I thought the conundrum of herbicide-free no-tillage could be solved with enough mulch. At the same time, reports of mechanical roller-crimper tools began to circulate in the agricultural world. Brazilian farmers were using the roller-crimper to non-destructively terminate standing cover crops, and prototypes soon appeared in North America. It wasn’t long before I got my hands on one of these tools. Field trials were initiated in soybean and cotton comparing high-density rye cover crop mulch with and without herbicide treatment. Turns out, as herbicide applications were reduced, weed populations increased in spite of the pressed mulch, and soybean and cotton yields declined in lockstep. Not unsurprisingly, the worst plots were the no-herbicide plots, some of which looked like triple-canopy jungle by the end of the season (summaries of this pioneering work are available here and here).

Image 3. Cover crop roller machine. Cover cropping adds a layer of complexity to the food system. For example, if termination of cover crop growth isn't timely, critical supplies of soil moisture can be rapidly exhausted, increasing the risk of drought stress for the subsequent summer cash crop. Richard Stirzaker underlined the necessity of understanding the consequences of our interventions in the food system. Sustainability has many facets, and future events may change the way we interpret it.

What happened? We were not able to deliberately reproduce the same effect observed in the small grain plots. The physical barrier created by the flattened rye residue, coupled with leaching phytochemicals, ultimately proved insufficient to keep weeds from germinating. The slightest gap in the mulch was enough to give tiny weed seedlings purchase. Worse yet, some of the weeds that gained a foothold were noxious perennials like horseweed, dog fennel, and pokeweed that would return year after year, with no reliable means of mechanical control. This was my Clever Clover moment. I understand just how Richard Stirzaker must have felt after realizing that it was all much more complicated; there’s no easy recipe for eco-friendly agriculture. In the following months we pitched the idea of rolling cover crops to the corn, soybean, and cotton commodity groups of North Carolina because we needed money to continue evaluating the roller-crimper tool. There were no takers. Producers were well aware of the cover crop roller and made it clear they had no interest in it. The project ended, and we moved on. I beleive there are still a few cover crop rollers in operation in North Carolina. But overall, mechanical roller-crimper has not influenced row cropping in North Carolina, or anywhere else in North America, for the same reasons that Clever Clover was unsuccessful.

The Clever Clover tale points up two enduring lessons as Richard Stirzaker tells it: (1) it is not easy to intervene in the food production system; and (2) there’s a big difference between having an impact and having an influence. “Impact” is something that rivets attention over a short period, i.e. the proverbial “flash in the pan” or “fifteen minutes of fame” syndrome all too common nowadays, especially for projects with short investment turnabouts. Having an influence takes a lot of persistent, painstaking effort over a long time horizon because it involves fundamental changes in the way people do things. When we tinker with agricultural systems, the full effect of our intervention is often obscured by short-term objectives. I suspected that establishment effects were hindering the efficacy of the cover crop roller. Longer-term studies would be needed to calibrate the system, including a transitional phase where the surficial weed seed bank could be exhausted through a combination of cover cropping and prescription herbicide treatment. This work never materialized.

To Stirzaker’s list, I would add a third lesson: It is not easy to discover something new. Farmers have been tinkering with clover and cover cropping for many decades. Few of these experiments have garnered the media attention of Clever Clover, but their stories nonetheless have been circulated in newspapers, agriculture journals, and magazines. In fact, the Clever Clover idea had been tested before Richard Stirzaker’s shadow graced the land down under. But who knows? Maybe someday, in a world very different from that of today, we’ll revisit the Clever Clover innovators like Stirzaker and others for guidance.

Image 4. Fall cabbages planted in pearl millet (Pennisetum glaucum) mulch after flattening with the cover crop roller. Cool-season crops like cabbage and broccoli were a better fit for no-till cover crop systems because the cooler temperatures in fall curbed warm-season weeds, leaving emergent winter annuals the only competition.

Part 3, “Feeding Ourselves” examines the global food production system, paying attention to the balance of productivity and ecological footprint. Tillage is a big part of that picture, and Stirzaker devotes a chapter to how our concept of land husbandry has changed over time. Should one double-dig the garden beds or no-till them? How does tillage affect the infiltration of water into the soil? Does soil structure matter? Is permaculture the answer? How are we to educate the next generation of agricultural scientists? Stirzaker explores these and other topics, each arising from questions about what we eat, how we use water, and how to think about agricultural efficiency in a realm of competing interests.

Out of the Scientist’s Garden is not a “how-to” manual. It will not teach you to make compost or become self-sufficient. There are no recipes for sustainable agriculture; no answers to humanity’s pressing need for ever more food, housing, and energy. It’s about “how to think about things”, using water as a didactic prop. Stirzaker’s hope is that readers will bear witness to their own experiences, perhaps reaching different conclusions.

I strongly recommend this book to anyone interested in agriculture, water, sustainability, and the natural resources. If you’ve been around the block a few times like me, eaten dust, indulged the worldly oracles, and taken the measure of all the moods of human wisdom and folly, there’s bound to be something here that parallels your turn in the arena.

Further Diggings

FAO, 2010. AQUASTAT-FAO’s Global Information System on Water and Agriculture. Available at https://www.fao.org/aquastat/en/. FAO, Rome, Italy.

Siebert, S., J. Burke, J.M. Faures, K. Frenken, J. Hoogeveen, P. Döll, and F.T. Portmann. 2010. Groundwater use for irrigation-a global inventory. Hydrol. Earth Syst. Sci. 14(10): 1863-1880. Available at https://hess.copernicus.org/articles/14/1863/2010/ (last access: 16 March 2013).

Text slightly edited from the original for clarity and links re-verified by the author 01 August 2026.