Agricultural innovations for sustainable crop production

Abstract

Sustainable crop production intensification should be the primarystrategic objective of innovative agronomic research for the comingdecades. A range of often very location-specific options exists for farm-ing practices, approaches and technologies that can strengthen sus-tainability and at the same time intensify crop production in terms ofincreased output and productivity (efficiency). The main challenge isto encourage farmers in the use of ecologically-appropriate technolo-gies and practices and to ensure that knowledge about sustainable pro-duction practices is increasingly accepted, applied and innovated uponby farmers. There is a large but underutilized potential to integratefarmers’ local knowledge with science-based formal knowledge. Thisintegration aims at innovating improved practices and technologicaloptions through favourable institutional arrangements to foster aninnovation system. The same holds true for the design, implementa-tion and monitoring of improved natural resource management thatlinks community initiatives to new external expertise and knowledge.A comprehensive effort should also be undertaken to measure differ-ent stages of the innovation system, including technological adoption,adaptation and diffusion at the farm level, and to investigate theimpact of agricultural policies on technological change, technical effi-ciency and production intensification. This paper provides a review of agronomic management practices

supporting sustainable crop production systems and intensification,and testifying to developments in the selection of crops and cultivars.The paper also describes crop farming systems taking a predominant-ly ecosystem approach and it discusses the scientific application ofthis approach for the management of pest and weed populations. In

addition, it reviews the improvements in fertilizer and nutrient man-agement which are at the basis of productivity growth and it describesthe benefits and drawbacks of irrigation technologies. Finally, it sug-gests a way forward based on seven changes in agricultural develop-ment that heighten the need to examine how innovation occurs in theagricultural sector.

Introduction

Over the last 40 years, world population has increased by more than4 billion and in the next 40 years it is expected to increase from theestimated 7 billion in 2011 to around 9.1 billion in 2050 (Figure 1).Nearly all of this population increase will take place in the part of theworld comprising today’s developing countries, while the greatest rel-ative population increase (120%) is expected in today’s least-devel-oped countries. This ever-growing population will lead to an increasein the global demand for food for at least 40 years to come. In order tomeet the additional food demand – excluding additional demand foragricultural products used as feedstock in biofuel production – agricul-tural production must increase by 70% globally, and by almost 100% indeveloping countries. This increase is equivalent to an extra billiontonne of cereals and 200 million tonnes of meat to be produced annu-ally by 2050, compared with the production between 2005 and 2007(Bruinsma, 2009).In the past, the primary solution to food shortages was to bring more

land into agriculture and to exploit new fish stocks. In the future, ourability to produce food will be affected by growing competition for land,water, and energy , and by the urgent requirement to reduce theimpact of the food system on the environment. The effects of climatechange are a further threat to food security (Godfray et al., 2010;Government Office for Science, 2011). The relationship betweenresource demand and supply is unbalanced. Yet, in the last 5 decades,though grain production has more than doubled, the amount of landglobally devoted to arable agriculture has increased by only 9% (Pretty,2008). In the last 50 years there has been a marked growth in food pro-duction which dramatically decreased the proportion of people season-ally or chronically hungry, despite the doubling of the total population(Figure 2).Some new land could be brought into cultivation in Sub-Saharan

Africa and South America, but the demand for land from other humanactivities makes this an increasingly unlikely and costly solution, par-ticularly if protecting biodiversity and the public goods provided by nat-ural ecosystems (for example, carbon storage in rainforest) are givenhigher priority (Balmford et al., 2005). In recent decades, agriculturalland that was formerly productive has been taken away by urbanizationand other human uses, as well as by desertification, salinization, soilerosion, and other consequences of unsustainable land management.Further losses of agriculture’s natural resource base, especially waterloss which may be exacerbated by climate change, are likely to happen(IPCC, 2007). Recent policy decisions to produce first generation bio-

Correspondence: Prof. Michele Pisante, Agronomy and Crop SciencesResearch and Education Center, Department of Food Science, University ofTeramo, via Carlo R. Lerici 1, 64023 Mosciano S. Angelo (TE), Italy. Tel. +39.0861.266940 - Fax: +39.0861.266940. E-mail: [email protected]

Key words: agronomic practices, crop intensification, farming systems, sus-tainable agriculture.

Received for publication: 4 April 2012.Accepted for publication: 28 July 2012.

©Copyright M. Pisante et al., 2012Licensee PAGEPress, ItalyItalian Journal of Agronomy 2012; 7:e40doi:10.4081/ija.2012.e40

This article is distributed under the terms of the Creative CommonsAttribution Noncommercial License (by-nc 3.0) which permits any noncom-mercial use, distribution, and reproduction in any medium, provided the orig-inal author(s) and source are credited.

Agricultural innovations for sustainable crop production intensificationMichele Pisante,1 Fabio Stagnari,1 Cynthia A. Grant2

1Agronomy and Crop Sciences Research and Education Center, University of Teramo, Italy;2Agriculture and Agri-Food Canada Brandon Research Centre, Manitoba, Canada

[page 300] [Italian Journal of Agronomy 2012; 7:e40]

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fuels on good quality agricultural land have added to the competitivepressures (Fargione et al., 2008). Thus, the most likely scenario is thatmore food will need to be produced from the same amount of (or evenless) land (Godfray et al., 2010).The challenge of increasing food production, food security and

farmer income is, then, to increase productivity. Productivity growthrefers to the change in output/input ratios over time. Therefore, it is aresource efficiency indicator used per unit of output. However, over thelast forty years much of the increase in productivity has been related toimproved genetic resources, increased utilization of pesticides,increased input of agricultural mineral nutrients, increased use ofmechanised farm power and fossil fuel and greater irrigation intensity(Figure 3).To feed a growing world population, we have no option but to inten-

sify crop production sustainably (FAO, 2011). A renewed focus on defin-ing concrete actions to improve agricultural productivity growth on asustainable basis is needed now. Intertwining challenges of climatechange and competition for land, water, and energy require attention inthe following areas: bridging the gap between actual and potential pro-ductivity levels in the agriculture of developing countries; investing inagricultural innovation, broadly defined; and improving national andinternational research collaboration (OECD, 2011).The new paradigms of sustainable crop production intensification

recognize the need for a productive and remunerative agriculturewhich at the same time preserves and enhances the natural resourcebase and environment, and positively contributes to harnessing theenvironmental services. Sustainable crop production intensificationmust not only reduce the impact of climate change on crop productionbut also mitigate the factors that cause climate change by reducingemissions and by contributing to carbon sequestration in soils.Intensification should also enhance biodiversity – above and below theground level – in crop production systems so as to improve ecosystemservices for a better productivity and a healthier environment. A set of soil-crop-nutrient-water-landscape system management

practices known as Conservation Agriculture (CA) has the potential toachieve all of these goals (Derpsch and Friedrich, 2010; Friedrich et al.,2012). CA has the potential for managing decreasing soil productivityand for improving the resource-use efficiency and the naturalresources base. Hence, it adapts to and mitigates climate change andleads to a more efficient use of inputs to reduce production costs.Integrated farming systems based on CA, irrespective of the location,management and socioeconomic conditions, must produce more forless to improve profitability and livelihood security for farmers.In short, the globally-shared challenge is to ensure a more efficient

use of available land and water resources as well as purchased produc-tion inputs. Thus, improving agricultural productivity is essential toincrease global food supplies on a sustainable basis (OECD, 2011).Standard agronomic land, water and crop management practices sup-porting the intensification of sustainable crop production include:selection of crops and cultivars, efficient farming systems for cropestablishment, plant protection, fertilizer and nutrient management,and sustainable crop rotations. When applied together, these practicescollaborate to improve factor and overall productivity (FAO, 2011).

What is needed to support sustainable cropproduction systems?

Investments in knowledge – especially in the form of science andtechnology – have featured prominently and consistently in moststrategies to promote sustainable and equitable agricultural develop-ment at the national level. In the long run, productivity growth requiresinnovation, i.e. a process of transforming knowledge into money

[Italian Journal of Agronomy 2012; 7:e40] [page 301]

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Figure 1. World population 1965-2050. Source: Population divi-sion of the Department of Economic and Social Affairs of theUnited Nations Secretariat (2007).

Figure 2. Changes in the relative global production of crops since1961 (when relative production scaled to 1 in 1961). Source:FAOSTAT (2009). Available from: http://faostat.fao.org/default.aspx

Figure 3. Graphical illustration of productivity growth. Source:OECD (2011).

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(whereas research is to transform money into knowledge) (Figure 4). Agriculture should innovate to increase competiveness by providing

advantages in the market, but also to offer more cost-effective publicgoods. Innovation can be based on the result of scientific researchabout processes or the attributes of a product, the introduction ofnew or significantly improved goods or services, or the use of newinputs, processes, organizational or marketing methods (OECD andEurostat, 2005). Scientific and technological knowledge and informa-tion add value to existing resources, skills, knowledge, and processes,leading to innovative or novel products, processes and strategies.These innovations can be simple, like changing the crops that are pro-duced, or more complex, like developing a new business model withentirely different production technologies to satisfy different needs(e.g. from better production and productivity to more quality such asflavour, fragrance, or colour). Innovation produces better packagingthat protects the nutritional content and also a cost system of more forless that allows establishment of more attractive prices. Economies ofscale are also a component of productivity growth for individual firms(Latruffe, 2010). The ability to innovate and to become more productive is partly

affected by the farm itself and the farmer’s engagement, but it can alsobe affected by the economic and political environment where the farmis operating (Porter et al., 2007). Innovation is therefore central todevelopment, and effective innovation systems include all the relevantstakeholders who can contribute to the discovery of underlying process-es and principles, transforming the principles into technologies andpractices and further adapting these to improve efficiency and perform-ance. Governments have recognized that much of a firm’s ability toinnovate can be driven by public research, infrastructure, regulations,taxation, and other public policies that have both direct and indirecteffects on the operating environment of firms (OECD, 2011). An exam-ination of the agronomic innovations (crops and cultivars; farming sys-tems for crop which take a predominantly ecosystem approach; man-agement of pest and weed populations; fertilizer and nutrient manage-ment and irrigation technologies) over the past four decades and theimpacts that they have had on crop productivity and the environmentcan help identify those areas where sustainable intensification of agri-

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Figure 4. Raffler’s circle explaining the difference betweenresearch and innovation. Adapted from H. Raffler (VPInnovation of Siemens, unpublished).

Figure 5. Makeup of total food waste in developed and developing countries. Retail, food service, and home and municipal categoriesare grouped together for developing countries. Source: Godfray et al. (2010).

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cultural systems may be done in the future.The importance of innovations along the food chain and post-harvest

handling and processing is also growing to meet consumers’ demandfor food quality, storability and convenience. Although data are scarce(Figure 5), roughly 30% to 40% of food in both developed and develop-ing countries is doomed to be wasted mainly because of the lack offood-chain infrastructures and the lack of knowledge or investment instorage technologies in farms. In the developed countries, stricter foodquality regulations, consumer preferences and food processing andpackaging as well as modern urban life style are additional factors thatcontribute to food being wasted. Thus, there is a need for continuingresearch in post-harvest storage technologies (WRAP, 2008).

Crops and cultivars

Farmers will need a genetically diverse portfolio of improved crop vari-eties that are suited to a range of agro-ecosystems and farming practices,and are resilient to climate change. The Green Revolution succeeded inimproving productivity by using conventional breeding to develop F1hybrid varieties of maize and semi-dwarf, disease-resistant varieties ofwheat and rice. These varieties could be provided with more irrigationand fertilizer (Evenson and Gollin, 2003) without the risk of major croplosses due to lodging (falling over) or severe rust epidemics. Increasedyield is still a major goal, but the importance of greater water- and nutri-ent-use efficiency, as well as tolerance of abiotic stress, is also likely toincrease (Godfray et al., 2010). However, the heavy reliance on irrigationand intensive crop inputs, as well as the reduction in biodiversity associ-

ated with the replacement of local and varied landraces with cultivars thatare released and grown over a wide geographical area, may lead to areduction in the sustainability of crop production in the future. The high-yielding cultivars may also contain lower levels of trace elements thantraditional crops or than lower yielding cultivars, due to their high carbo-hydrate production. Currently, the major commercialized geneticallymodified (GMO) crops involve relatively simple manipulations, such asthe insertion of a gene for herbicide resistance or another for a pest-insect toxin. The next decade will see the development of combinationsof desirable traits and the introduction of new traits such as drought tol-erance. By mid-century, much more radical options involving highly poly-genic traits may be feasible. Production of cloned animals with engi-neered innate immunity to diseases that reduce production efficiencymay reduce substantial losses coming from mortality and sub clinicalinfections. Biotechnology could also produce plants for animal feed withmodified composition that increase the efficiency of meat production andlower methane emissions (Godfray et al., 2010). The issue of trust andpublic acceptance of biotechnology has been highlighted by the debateover the acceptance of GMO technologies. As genetic modificationinvolves germline modification of an organism and its introduction in theenvironment and food chain, a number of particular environmental andfood safety issues need to be assessed. Despite the introduction of rigor-ous science-based risk assessment, this discussion has become highlypoliticized and polarized in some countries, particularly in Europe. Ourview is that genetic modification is a potentially valuable technologywhose advantages and disadvantages need to be considered rigorously onan evidential, inclusive, case-by-case basis: Genetic modification shouldneither be privileged nor automatically dismissed (Godfray et al., 2010).


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Table 1. Effects on sustainability and ecosystem services of production system components applied simultaneously.

System component ► Mulch cover Minimum or Legumes Crop no-tillage (to supply rotation

plant nutrients)

Simulate optimum forest-floor conditions √ √

Reduce evaporative loss of moisture from soil surface √

Reduce evaporative loss from soil upper soil layers √ √

Minimize oxidation of soil organic matter, CO2 loss √

Minimize compactive impacts by intense rainfall, passage of feet, machinery √ √

Minimize temperature fluctuations at soil surface √

Provide regular supply of organic matter as substrate for soil organisms’ activity √

Increase, maintain N levels in root-zone √ √ √ √

Increase CEC of root-zone √ √ √ √

Maximize rain infiltration, minimize run-off √ √

Minimize soil loss in run-off, wind √ √

Permit, maintain natural layering of soil horizons by actions of soil biota √ √

Minimize weeds √ √ √

Increase rate of biomass production √ √ √ √

Speed the recuperation of soil-porosity by soil biota √ √ √ √

Reduce labour input √

Reduce fuel-energy input √ √ √

Recycle nutrients √ √ √ √

Reduce pest-pressure of pathogens √

Re-build damaged soil conditions and dynamics √ √ √ √

Pollination services √ √ √ √

N, nitrogen; CEC, cation exchange capacity. Source: Friedrich et al., 2009.

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Production systems for better productivity

Current crop production systems vary widely. There are many pro-duction systems which take a predominantly ecosystem approach andwhich are not only productive, but also more sustainable than tradition-al production practices in terms of environmental impacts.

Conservation agricultureConservation agriculture (CA) is a method designed for resource-

saving agricultural crop production whose aim is to achieve acceptableprofits together with high and sustained production levels while simul-taneously preserving the environment. Interventions such as mechan-ical soil tillage are reduced to an absolute minimum and externalinputs, such as agrochemicals and nutrients of mineral or organic ori-gins, are applied at the optimum level and in a way and quantity thatdoes not interfere with, or disrupt, the biological processes (FAO,2012). Healthy soils underpin CA, which in turn is characterized bythree intertwined principles, namely: i) continuous minimum mechan-ical soil disturbance and no-till direct seeding; ii) permanent organicsoil cover with crop residues and cover crops; iii) crop diversificationwith crop rotations and associations in case of annual crops or plantassociations in case of perennial crops. CA facilitates good agronomy,such as timely operations, and improves overall land husbandry for rainfed and irrigated production and is complemented by other good prac-tices, such as the use of quality seeds and integrated pest manage-ment. Benefits of CA, shown in Table 1, include improved moisture con-servation and water infiltration, reduced run-off of pesticides and fer-tilizers, reduced consumption of fuel, improved organic matter contentwith associated carbon sequestration, improved diversity of soil, flora,and fauna, better wildlife habitat, better soil structure, reduced windand water erosion, less labour and less investment in equipment(Cook, 2006; Huggins and Reganold, 2008; Stagnari et al., 2009;Kassam et al., 2012). CA has also proved to contribute to significantincreases of crop production (40-100%) in many regions with decreas-ing needs for farm inputs, in particular power and energy (50-70%),time and labour (50%), fertilizer and agrochemicals (20-50%) andwater (30-50%). Furthermore, in many environments soil erosion isreduced to a level below the soil regeneration one or it is avoided alto-gether, and water resources are restored in quality and quantity to lev-els recorded before the land was put under intensive agriculture(Montgomery, 2007; FAO, 2011).A summary of numerous published studies comparing no-till to con-

ventional tillage under natural rainfall conditions showed that, on aver-age, no-till reduced soil erosion, water runoff and herbicide runoff by92%, 69% and 70%, respectively (Royal Society of London, 2009). Afteran intense rainfall of 100 mm in 24 h, Chaves (1997) found that directdrilling reduced the peak flow by 86% and the weight of sediment leav-ing the catchment by 98%, compared to conventional till (Table 2).Improved planters and better herbicides led to the widespread adoptionof CA in many parts of the world over the past 40 years. Conservation

agriculture is now practiced on some 125 million ha worldwide, orabout 10% of the total crop land. Highest adoption levels (more than50% of crop land) are found in Australia, Canada and the southern coneof South America. Its adoption is increasing in Africa, Central Asia andChina (Pisante et al., 2010; Friedrich et al., 2012).Such sustainable production systems are knowledge-intensive and

relatively complex to learn and implement. They are dynamic systems,offering farmers many possible combinations of practices to choosefrom and adapt according to their local production conditions and con-straints (Pretty, 2008; Kassam et al., 2009, 2010; Godfray et al., 2010;Pretty et al., 2011). Modernization and transformation based on CAprinciples and practices (as well as on existing, though in transition,practices) require affordable sources of adapted good-quality seeds,affordable mineral fertilizer, as well as farm power, equipment andmachinery, and pesticides (herbicides, insecticides, fungicides, etc.).Field operations required by each system are summarized in Table 3,

together with the outcome of calculations on fuel energy requirement.Fuel energy requirement includes an appropriate allowance for theoverhead energy used in equipment manufacture and maintenance.Policy planning and investment are required to establish/strengthen

the seed, fertilizer, pesticide, and farm equipment machinery sectors.In particular, national action plans for input supplies and services con-sistent with national crop sector strategies would be essential toensure the delivery of sector development strategy, projects and cam-paigns (FAO, 2010). Limitations associated with CA are elaborated in(Shaxson et al., 2008) and can include increased crop diseases andinsect pests (Cook, 2006), development of herbicide-tolerant weeds,reliance on agrichemicals, excess moisture, cooler soils, initialincrease in nutrient requirements, and requirement for specializednutrient management to avoid immobilization and volatilization(Malhi et al., 2001). Where livestock is part of the farming system,switching to CA from tillage agriculture requires a different way of

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Table 2. Parameters of the MUSLE model, values of run-off andsediment load from conventional tillage and no-tillage.

Parameter Description CT NT

CN Runoff-generation factor 70 45R (mm/24h) Rainfall amount 100 100K Soil erodibility 0.0013 0.013L Slope-length factor 4 4S Slope-steepness factor 0.5 0.5C Factor for use/management of soil 0.3 0.05P Factor for mechanical practices 0.5 0.5Q (m3) Runoff volume 326,000 45,000Q (m3/s ) Peak flow 36.3 5Y (t) Sediment load 3198 58CT, conventional tillage; NT, no-tillage. Adapted from Chaves (1997).

Table 3. Machinery operations and energy requirements for three tillage systems.

Operations Residue Tillage frequency, operations/crop Herbicide Planting Σ fuel energymanagement spraying MJ/ha

Representative systems Primary Secondary Seedbed

TA conventional tillage, no herbicide 1 2 2 0 1 1941CA reduced/zero, <1 tillage/crop 1 0.6 0 0 4 1 1116CA permanent bed, minimum tillage 0.25 0 0 3 1 397TA, tillage agriculture; CA, conservation agriculture. Source: Tullberg (2005).

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managing the available functional biomass. This different manage-ment implies that the needs of both soil health and livestock feedrequirement should be met, and that over time more residues shouldbe allocated to cover the soil. This can be a challenge in certain drylandsituations (Kassam et al., 2012), but not in others (Landers, 2007;Owenya et al., 2011).

Development of precision agricultureConventional crop management presumes uniformity. In order to

manage spatial variability, it is necessary to adopt management prac-tices that allow for the precise management of soils, crops, pestsaccording to localized differences within a field. Innovative agricultur-al techniques, known as Precision Agriculture, Site-SpecificManagement, Precision Farming, refer to innovative agricultural tech-niques aiming at improving production and reducing environmentalpollution through a more accurate management related to field vari-ability (Basso et al., 2005).The site-specificity of precision agriculture is intuitively appealing

and represents a means of improving the economic and environmentalperformance of the cropping system. Precision agriculture encompass-es a broad array of topics ranging from variability of the soil resourcebase, weather, plant genetics, crop diversity, machinery performance,most physical, chemical, biological inputs used in crop production, andsocio-economic aspects. A successful precision agriculture systemdepends on how well it can be applied to manage spatial and temporalvariability in crop production and on what benefits it could bring.Before this system can be adopted effectively, it is fundamental to havea clear understanding of the in-field variability, which is not an easytask. For example, rather than nitrogen (N) applications based on yieldgoals and an estimation of N supply using soil tests and a uniform ratewithin a field unit, precision management applies variable rates acrossthe field, according to the projected difference between N supply fromthe soil and N demand by the crop. The rate calculations were initiallybased on intensive soil sampling and analysis, using grids, soil types,landscape position, or some other method to divide the field into appli-cation units (Schlegel et al., 2005). The development of continuousyield-sensor and differential GPS (DGPS) has been perhaps the mostimportant and influential development in precision agriculture datacollection. Yield rates vary spatially and maps produced by the yieldmonitors systems demonstrate the degree of within-field variability(Batchelor et al., 2002; Basso et al., 2007, 2011). The magnitude of thisvariability is a good indicator of how suitable it is to implement a spa-tially variable management plan. Technological improvements will fol-low an evolutionary process and new developments will continue to beadapted for making agricultural decisions. It is anticipated that invest-ments in the development and diffusion of precision agriculture by theprivate sector will continue at a fast pace.

Organic farmingWhen practised in combination with CA, organic farming can lead to

improved soil health and productivity, increased efficiency in the use oforganic matter and energy savings. However, tillage-based organic pro-duction restricts the management options available to producers, oftenresulting in lower crop productivity due to excessive mechanical soil dis-turbance, nutrient deficiencies and weed, insect or disease problemswhere the cropping system is not adequately diversified and soil mulchcover is inadequate. Organic CA farming serves mainly niche marketsand it is practised in parts of Brazil, Germany and the USA, and by somesmall-holder farmers in Sub-Saharan Africa (Badgley et al., 2007).

Improvements in plant protection

Insect pest and disease controlImprovements in agro-ecosystem management can help avoid

indigenous insect pest outbreaks, respond better to pest invasions andreduce risks posed from pesticides to both human health and the envi-ronment.Integrated pest management (IPM) is an example of an ecosystem-

based production practice involving the scientific application of ecosys-tem principles for the management of pest populations and aiming atavoiding their build up to damaging levels. IPM is based on understand-ing the way local agro-ecosystem works, the relationship betweeninsect pests and their natural enemies, and the mechanisms regulatingthe balance between pest and predators (FAO, 2011).

Weed controlBefore World War II, weed control relied primarily on non-chemical

control mechanisms such as mechanical tillage, crop rotation, mowing,use of clean seed, field sanitation, delayed seeding, and the growth ofhighly competitive crops. Some selective broad-leaf herbicides weredeveloped from the 1930s to the beginning of World War II, but thedevelopment and the widespread adoption of 2,4-Dichloro -phenoxyacetic acid (2,4-D) in the mid- to late-1940s represented thebeginning of the modern era of chemical weed control. Use of herbi-cides became a significant factor in crop production in the 1950s, withintense activity in herbicide development during the 1960s and 1970s.In Canada, herbicides account for approximately 80% of total pesticidesales (Holm and Johnson, 2009). Development of effective herbicideswas one of the driving factors which guaranteed the development ofreduced tillage and no-till production systems and contributed to thedramatic increase in agricultural productivity over the past 40 years.The requirements of herbicide manufacturing energy set out in Table4 for herbicides commonly used in fallow situations are based on datafrom Zentner and colleagues’ (2004) and Green’s (1987) studies.


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Table 4. Energy requirements of herbicide manufacture.

Commercial product Herbicide/s Manufacturing energy Application rate Manufacturing energyMJ/kg kg/ha (label) MJ/l/ha

2,4-D Amine 2,4-D 98 0.500 49Atrazine Atrazine 190 0.500 95Spray Seed 250 Diquat 400 0.115 108.1

Paraquat 460 0.135Round-up CT Glyphosate 511 0.450 229.952,4-D, 2,4-Dichlorophenoxyacetic acid; CT, conventional tillage. Adapted from Zentner et al. (2004) and Green (1987).

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In the past 15 years there has been the rapid emergence of the useof GMO crops engineered to be resistant to specific herbicide modes ofaction. Although this use has provided huge benefits to producers interms of the ease and effectiveness of weed control in specific crops, ithas also caused consumer concerns as well as repeated applications ofspecific herbicide modes of action, particularly glyphosate in reducedtillage systems. Over-reliance on specific herbicide modes of action andfailure to follow effective herbicide rotations has resulted in the devel-opment of herbicide-resistant weed populations. This, coupled with alower rate of discovery of new herbicide modes of action since the1970s and the increasing public perception that herbicides and/orGMOs may carry environmental or health risks, has increased thedesire for reduced reliance on herbicides and increased adoption ofintegrated weed management.Integrated weed management relies on understanding weed-crop

interactions within the agro-ecosystem to improve crop competitionthrough practices such as effective fertilization, manipulation of seed-ing timing, placement and density, diversified crop rotations and soilmulch cover, selection of vigorous crop cultivars, use of certified seed,and other traditional methods of field sanitation. Improved weed man-agement and an improved understanding of weed ecology have playedan important role in the adoption of no-till management (Derksen etal., 1996, 2002). Further research and adaptation of diversified weedmanagement practices will be important in the future to attain optimalcrop production in a sustainable manner.

Improvements in fertilizer and nutrient managementDeclining soil organic carbon status along with deficiency of macro-

and micronutrients are major soil health problems, which limit produc-tivity. Soils rich in biota and organic matter are the foundation ofincreased crop productivity. The best yields are achieved when nutri-ents come from a mix of mineral fertilizers and natural sources, suchas manure and nitrogen-fixing crops and trees. Judicious use of min-eral fertilizers saves money and ensures that nutrients reach the plantand do not pollute air, soil and waterways. Policies to promote soilhealth should encourage conservation agriculture and mixed crop-live-stock and agro-forestry systems enhancing soil fertility. These policies

should remove incentives that encourage mechanical tillage and thewasteful use of fertilizers, and should inform producers about precisionapproaches, such as urea deep placement and site-specific nutrientmanagement (FAO, 2011). It is estimated that nearly 40% of the world’s population is currently

alive because of the discovery of the Haber-Bosch process for conver-sion of atmospheric N2 to ammonia (Smil, 2002). In particular, theincreases in crop production over the last 40 years have been driven byincreasing inputs of fertilizers, especially N fertilizer (Tilman et al.,2001, 2002). Though N fertilization is a crucial tool to produce crop andto avoid depletion of soil fertility, excess or poorly managed N can leadto environmental problems including soil and water acidification,eutrophication, formation of ground-level ozone and particulate matter,and loss of biodiversity. Direct nitrous oxide emissions for N applica-tions as well as CO2 emissions from the large amount of fossil fuel usedin fertilizer production and transport can also contribute to climatechange. The understanding and adoption of improved N managementpractices matching the rate, The understanding and adoption ofimproved N management practices matching the rate, source, timingand placement of fertilizer application to the crop demand and the envi-ronmental conditions in the field, will reduce the risk of a negativeenvironmental impact of fertilizers, and simultaneously it will improvethe system productivity, the nutrient use efficiency and production eco-nomics (Snyder et al., 2009). The use of soil testing to predict nutrientavailability from the soil and select suitable nutrient application ratesis an important starting point to reduce nutrient losses. However, soilanalysis is not always as accurate as desirable in predicting the nutri-ent supply (Dinnes et al., 2002). Further improvements in soil testingto predict N supply more effectively are needed. In particular, the poten-tial mineralization in the growing season is needed to fine-tune N rec-ommendation. The development of improved seeding and fertilizingsystems that will place N in sub-surface bands to reduce losses byvolatilization, immobilization, denitrification and leaching has playedan important role in improving N use efficiency, particularly underreduced tillage systems (Grant et al., 2001; Malhi et al., 2001; Grant etal., 2002a, 2002b). Adoption of CA management can be used to reducenutrients loss by erosion. Montoya (1984) economically quantified thecost of nutrients lost by erosion, for crops of maize and wheat under CA

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Table 6. Economy of irrigation water through soil covers.

Percentage Water requirement Reduction in water Number of times irrigated Number of days of soil cover (m3 /ha–1) requirement (%) during season between irrigations

0 2660 0 14 650 2470 7 13 675 2090 21 11 8100 1900 29 10 9Adapted from Pereira (2001).

Table 5. Costs of nutrients lost by erosion from conventional tillage and direct drilling, for soybean, maize and wheat.

Systems/crops Cost US$/ha Calcium TotalUrea Super phosphate Potassium chloride dolomite

(20% P2O5) (60% K2O)

Conventional soybean 5.98 0.03 3.11 0.23 9.35Conventional maize 6.02 0.01 0.74 0.05 2.23Conventional wheat 3.76 0.02 1.95 0.14 5.87CA soybean 1.69 0.01 0.87 0.06 2.63CA maize 0.34 0.00 0.17 0.01 0.53CA wheat 2.62 0.01 1.38 0.10 4.11CA, conservation agriculture. Adapted from Montoya (1984).

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and conventional tillage (Table 5). The losses under CA systems forsoybean, maize and wheat were 28%, 24% and 72%, respectively, com-pared with the conventional system.The recent development of a range of enhanced-efficiency fertilizers,

such as nitrification inhibitors, urease inhibitors and polymer coatedfertilizers, has provided producers with more options to improve nutri-ent use efficiency. These products work by controlling the release of thefertilizer into the soil solution to match the supply of N to crop demandor by slowing the chemical conversions of N to minimize N losses(Schlegel et al., 1987; Hendrickson, 1992; Grant et al., 1996; Rawluk etal., 2001; Karamanos et al., 2004; Frye, 2005; Watson, 2005; Grant andWu, 2008; Grant et al., 2010). Similarly, improved GPS tractor guidancesystems, use of remote sensing or ground-based sensors that canassess the N status of the growing crop can be used to apply in-crop Napplications, where required, more effectively (Schlegel et al., 2005).A key practice to avoid nutrient losses and improve nutrient use effi-

ciency from the soil- plant system is to ensure that other crop-growthrestricting factors are corrected to ensure optimal productivity, so thecrop efficiently utilizes the nutrients that have been applied (Cassmanet al., 2003). Water supply, pH, nutrient, soil condition, diseases,insects, and weeds should all be managed effectively to ensure rapidcrop emergence and avoid growth restrictions.

Improved irrigation technologyUse of management practices that collect and save water is the driv-

ing factor to avoid water losses and improve water use efficiency fromthe soil-plant system. The use of improved, drought-tolerant crop vari-eties and of conservation agriculture – which holds water better – willincrease the water use efficiency in rain fed conditions. Maintaininghigh residue and adding organic matter while minimizing or eliminat-ing tillage promotes maximum water conservation. In the BrazilianCerrados less water was needed to irrigate the same crop when cropresidue was left on the surface (Pereira, 2001; Table 6). The total areaequipped for irrigation is now in excess of 300 million ha (AQUASTAT,2011). Irrigation is a platform commonly used to identify where to con-centrate inputs. However, making this sustainable intensificationdepends upon the location of water withdrawal and the adoption ofecosystem-based approaches, such as conservation agriculture, togeth-er with the other key inputs, healthy soils, improved genetic material,nutrient management and IPM, that are the basis of sustainable cropproduction. Surface irrigation by border strip, basin or furrow is oftenless efficient and less uniform than overhead irrigation (e.g. sprinkler,drip, drip tape). Micro-irrigation has been seen as a technological solu-tion for the poor performance of field irrigation and as a means of sav-ing water (FAO, 2011). There is also emerging research and develop-ment on precision irrigation. Automated systems have been testedusing both solid set sprinklers and micro-irrigation. They used soilmoisture sensing, and/or crop canopy temperature to define the irriga-tion depths to be applied in different parts of the field. Precision irriga-tion and precision fertilizer application through irrigation water areboth future possibilities for field crops and horticulture, but salt man-agement would be a critical factor in the sustainability of such produc-tion systems. The economics of irrigated agriculture still plays a majorrole in the use of sprinkler and micro-irrigation technologies, as well asin the automation of surface irrigation layouts. Rain guns provide oneof the cheapest capital options for large area overhead irrigation cover-age, but tend to incur high operating costs. Other overhead irrigationsystems have high capital costs and are marginal in smallholder com-mercial cropping systems, without the support of production subsidies.The service delivery of many public irrigation systems is poor owing

to deficiencies in design, maintenance and management. There ismuch to do to modernize systems and their management: both institu-tional reforms and separation of irrigation service provision frombroader supervision and regulation of water resources are required.

Drainage is an essential counterpart of irrigation, especially wherewater tables are high and soil salinity is a constraint. Investment willbe required in drainage to enhance the productivity and sustainabilityof irrigation systems and to ensure good management of farm inputs.However, enhanced drainage increases the risks of pollutants beingexported, causing degradation in waterways and connected aquaticeco-systems. Water management is a key factor in minimizing N loss-es and export from farms. In freely drained soils, nitrification is partial-ly interrupted, resulting in the emission of N2O, whereas in saturated(anoxic) conditions, ammonium compounds and urea are partially con-verted to ammonia, typically in rice cultivation. Atmospheric lossesfrom urea, therefore, can occur as both ammonia and N2O release overwetting and drying cycles in irrigation. Nitrogen is required in nitrateform for uptake at the root, but nitrate can easily move elsewhere insolution. The dynamics of phosphate mobilization and movement indrains and waterways are complex. Phosphate export from agriculturecan occur in irrigated systems if erosive flow rates are used in furrowirrigation, or if sodic soils disperse. Phosphate, and to a lesser extentnitrate, can be trapped by buffer strips located at the ends of fields andalong rivers, which prevent them from reaching waterways. Hence, acombination of good irrigation management, recycling of tailwater, and


Review

Figure 6. Developments in the intensity of public research expen-diture on agriculture in selected OECD countries (1992, 2000,and 2006). Public research expenditures are expressed as percent-ages of agricultural GDP. Source: OECD (2011).

Figure 7. Intensity of public research expenditure on agriculture(2006) expressed as a percentage of agricultural GDP (Agricultureincludes crop, livestock, hunting, forestry and fishing). Source:OECD research database and IFPRI/ASTI database.

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soil incorporation of phosphate can reduce phosphate export from irri-gated lands close to zero.The sustainability of intensified irrigated agriculture depends on

minimizing off-farm externalities, such as salinization and export ofpollutants, and maintenance of soil health and growing conditions.This should be the primary focus of farm level practice, technologyand decision-making. Sustainable agriculture across a range of rainfed, improved rain fed and irrigated lands involves trade-offs in landuse, water sharing in the broadest sense and the maintenance of sup-porting ecosystem services. These trades-offs are becoming morecomplex and have significant social, economic and political impor-tance (FAO, 2011).

Towards an innovation systems approach

Future solutions will require a revolution in the social and naturalsciences concerned with food production, as well as a breaking down ofbarriers between fields. The goal is no longer simply to maximize pro-ductivity, but to optimize across a far more complex landscape of pro-duction, environmental, and social justice outcomes.Agriculture could be a major beneficiary of research undertaken in

other areas of science or industries. The estimated benefits of agricul-tural research generally far exceed its costs, with the literature report-ing annual internal rates of return that range between 20% and 80%(Alston, 2010). Figure 6 presents the evolution of public agriculturalresearch expenditure as a percentage share of agricultural GDP in1992, 2000 and 2006. In these countries (with the exception ofAustralia), the intensity of public research for agriculture hasincreased over time. To generate innovative solutions that are relevant,acceptable and attractive for local populations, research on sustainablecrop production intensification practices must start at the local andnational levels, with support from the global level. A wide diversityexists in the intensity of public research expenditure among OECDcountries (Figure 7). Public agricultural research expenditure in theUSA, Ireland, Iceland and Japan accounted for more than 3% of theagricultural GDP in 2006, whereas it accounted for less than 1% inAustria, the Slovak Republic, Slovenia and Turkey. Although formalresearch is central to innovation, it is increasingly recognized that it isnot the only source of discovering new technologies for farmers andothers. Many new technologies are created without basic scienceunderpinning. More recently, the interactive relationships among basicscience, applied science and technology development have beenemphasized (OECD, 2009). The first and earlier view is that scientificresearch is the main driver of innovation, creating new knowledge andtechnology that can be transferred and adapted to different situations.This view is usually described as the linear or transfer of technologymodel. The second view (Figure 8), though not denying the importanceof research and technology transfer, recognizes innovation as an inter-active process. Innovation involves the interaction of individuals andorganizations possessing different types of knowledge within a partic-ular social, political, economic, and institutional context.In the contemporary agricultural sector, competitiveness depends on

collaboration for innovation. Innovation systems are increasinglyviewed as networks of knowledge flows with important two-way flows ofinformation (upstream and downstream) and spillovers of knowledgeamong the participants who are connected in formal and informalways. This more systemic approach suggests that innovation policygoes far beyond research expenditures and involves a wide range ofinstitutions that can affect incentives, knowledge sharing and theprocesses used for commercialization. The process of innovation and productivity growth includes not only

knowledge creation, but also the whole system of technological diffu-

Article

Figure 8. Innovation systems in agriculture model: the role ofmarket forces. Source: Arnold and Bell (2001).

Figure 9. Elements of an agricultural innovation system. Source:adapted from Arnold and Bell (2001:279).

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sion, adoption processes, interactions and market adjustments. Themarket itself is not sufficient to promote interaction and the public sec-tor has a central role to play. The evidence of linkages betweenresearch, productivity growth and competitiveness also stresses theneed to adopt an approach more innovation systems-like in agriculture.A conceptual framework containing elements of an agricultural innova-tion system, as shown in Figure 9, could be developed as well as multi-ple indicators that would help assess the performance of each aspect ofthe innovation systems in agriculture across countries.Knowledge, information, and technology are increasingly generated,

diffused, and applied through the private sector. Exponential growth ininformation and communications technology (ICT), especially theInternet, has transformed the ability to take advantage of knowledgedeveloped in other places or for other purposes. Following this trend,the knowledge structure of the agricultural sector in many countries ischanging markedly (OECD, 2011). In light of the above, seven changesin agricultural development heighten the need to examine how innova-tion occurs in the agricultural sector:Research is an important component – but not always the centralcomponent – of innovation.Markets, not production, increasingly drive agricultural develop-ment.The production, trade, and consumption environment for agricul-ture and agricultural products is growing more dynamic and evolv-ing in unpredictable ways.Knowledge, information, and technology are increasingly generat-ed, diffused, and applied through the private sector.has transformed the ability to take advantage of knowledge devel-oped in other places or for other purposes.The knowledge structure of the agricultural sector in many coun-tries is changing markedly.Agricultural development increasingly takes place in a globalizedsetting.

Concluding remarks

There is a huge, but underutilized potential to link farmers’ localknowledge with science-based innovations, through favourable multi-stakeholder institutional arrangements that can foster innovation sys-tems. The same holds true for the design, implementation and moni-toring of improved natural resource management that links communi-ty initiatives to external expertise. Agricultural development increas-ingly takes place in a globalised setting. Hence, future work should takea closer look at institutional arrangements in agricultural innovationand knowledge systems, and it should examine the respective roles ofgovernments and the private sector in strengthening innovation sys-tems and facilitating technological adoption. In this respect, somemeasures to take are: presence of research collaboration across sec-tors, protection of intellectual property rights, and knowledge flow. Acomprehensive effort should be undertaken to measure the differentstages of the innovation system, for example by testing its technologi-cal adoption and diffusion at the farm level, and to investigate theimpact of agricultural policies on technological change and technicalefficiency. The nature of production systems has been transformingfrom high-disturbance production systems with a high environmentalimpact to low-disturbance agro-ecological systems where productiontechnologies and practices are more in harmony with the ecosystemprocess and where both productivity and environmental services can beharnessed. Multi-stakeholder innovation systems have an importantrole to play in generating relevant technologies that can be adopted andadapted by farmers who must be an integral part of any effective inno-vation system.

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