2. My personal background is from a small farm in Ontario, Canada. The farm still maintains a rotation of 3 to 4 crops integrated with a complete but small swine production enterprise, supporting my father and my brother’s family. I also worked four years as agronomist in Bangladesh, and thus have a good appreciation for low-to-no-input agriculture, as well as its limitations.

3. I am employed by the Potash & Phosphate Institute (PPI), a not-for-profit science organization. It is funded by the fertilizer industry; by the primary producers of the two fertilizers. My role is director of research and educational programs in Eastern Canada and the Northeast US. PPI’s programs are directed to the impacts of phosphorus and potassium use: impacts on crop yields, on food quality, and on the environment.

4. The notion of organic agriculture is more important to the fertilizer industry than its small percentage of land area would imply. The word “organic” itself resonates pleasantly. Consumers value the concept for good reasons: a perception of safe, healthy food, produced naturally, without impairing the environment. The word organic is used in disciplines from chemistry through theology, and though its meaning varies, it rarely connotes anything negative.

5. While consumers may prefer and choose organic for good reasons and out of good motives, the practice of organic agriculture may not deliver all they perceive. Consumer preference is important to our industry. In the world of business, the customer is always right. Our industry strives to manage plant nutrients to produce the healthy food the consumer demands. But it is also important that the consumer be educated accurately on the merits of organic production.

6. Consumer interest in healthy foods is evident in several other emerging trends in the food industry. Functional foods and nutraceuticals already comprise a market estimated by some to be twice that of organic foods. These, like organic foods, are chosen for perceived health benefits. However, since they are based on identifiable components or phytochemicals in the end product, the health claims are testable by science.

7. Crop management can impact these phytochemicals. Recent science has shown, for example, that potassium is related to functional food properties of soybeans. Health-promoting isoflavones were shown to be boosted by soluble, inorganic potassium chloride. This discovery opens an exciting opportunity for research to elucidate the impacts of the 14 mineral nutrients and their interactions on such health-related qualities. The fertilizer industry supports such research.

8. Organic cropping systems clearly yield less than those that have all available technologies at their disposal. While individual crop comparisons may show no difference, analysis of the complete system – including the land area required to produce organic sources of nutrients – will show considerably reduced yields. Also, short-term yield differences may be smaller than those in the longer term. To evaluate the sustainability of the yield comparisons, the balance of nutrients applied to and removed from the field must be considered. Many fertile soils may produce good yields with a deficit in phosphorus and potassium inputs for ten years or more, but this will not be sustainable.

9. Across the United States and Canada, our most recent summary of soil tests shows that substantial areas of soil remain deficient in phosphorus and potassium. Of the 2.5 million soil samples submitted for field crops, 47 percent tested medium or lower in phosphorus and 43 percent tested in that category for potassium. These are soils on which a crop response to those nutrients is expected, whether applied as organic sources like animal manure or mineral sources like fertilizer.

10. The challenge facing agriculture today is to increase the quantity and quality of food produced, with less detrimental impact on the environment. For sufficient flexibility to meet that challenge, integrated cropping systems should have access to all necessary resources for efficient, bio-intensive production. If organic farming is defined only as that which is done with a restricted list of inputs, its ability to meet the challenge will be less than that of integrated farming systems.

11. The concept of organic farming must be defined in a manner that accurately communicates the practice, in a non-misleading way, to the public. Acceptance of separate standards must avoid implying that organic production delivers benefits that have not been established on the basis of sound science.

12. We don’t expect organic agriculture to take over, nor do we expect it to go away. We need to work together to communicate an accurate image of agriculture and its issues to the public.

Question: (abridged version)

Agriculture as practiced in the Corn Belt – the corn-soybean rotation – is unsustainable owing to erosion, nutrient losses impacting water quality, and subsidized inefficiency. What can we do about it?

Answer:

1. I agree that crop production in the Corn Belt is unsustainable, but for a reason that differs from those you have cited. Our current analysis of the nutrient balance of the Corn Belt States shows a deficit in both phosphorus and potassium. Currently producers are applying less in fertilizers and manures than the crops remove. The geographic decoupling of the livestock industry from feed production is largely responsible. To correct this problem, in the future we expect to see either adoption of technologies that make manure nutrients more transportable, or some geographic RE-coupling of livestock to feed, to re-establish balance between nutrient supply and removal.

2. But are corn and soybeans inherently unsustainable? I would argue that although their production may not be sustainable on all the soils where it is now practiced, it is on many. Soils producing high yielding crops improve over time, even under continuous corn. Francis Childs’ farm in Iowa is an example – 30 years of continuous corn with high yields have made the soil healthy enough to sustain a corn yield on the order of 400 bushels per acre, with the same amount of nitrogen fertilizer per bushel of corn as the average in the industry!

3. When farmers harvest the North American corn crop, they currently remove an amount of nitrogen in the grain equivalent to 75 percent of the fertilizer applied to the crop. The loss of 25 percent is a concern. Its fate needs more research. Many in agriculture today are striving to make that loss smaller. Their efforts have already improved the situation: in the 1970’s, the loss figure averaged 40 percent.

4. High yield is important. Not only for profit, not only to feed the growing world, not only to save land for wildlife habitat, but for the benefit of the soil. No discussion of organic farming fails to mention the importance of organic matter for sustaining soil productivity. But the original and only primary source of organic matter is photosynthesis – plant productivity. Land areas deficient in mineral nutrients will not produce as much of this vital organic material. Integrated agriculture is making the progress demanded by the public, and the public needs to hear about it.

Comparing productivity

Comparing organic and conventional In this paper, the terms “conventional” and “integrated” are used interchangeably to describe cropping systems that do not fit the current definition of organic crop production. The term “integrated” is preferred, as it implies the use of all available and appropriate technologies that have been shown by science to benefit crop production. The use of term “conventional” reflects much of the literature cited, but should not be taken to imply a static system of production; rather, one that is continuing to evolve. cropping systems for productivity is difficult. Since crop production depends on many sources of inputs of a diverse nature (land, water, nutrients, genetic resources, labor, energy, technology, etc.) the definition of productivity depends on the particular input efficiency under consideration, and on the interactions among inputs. Fortunately in agriculture – in the short as well as the long term – yield per unit area of land is the most critical component of sustainable productivity. Even so, since the two systems often produce a different mix of crops, the ability to compare productivity is limited.

Yield per unit area of land is important not only economically, but also for environmental, ecological and social reasons. For agriculture to be both sustainable and compatible with biodiversity in non-agricultural areas, most stakeholders agree that yields on existing cropland must increase while nutrient losses from cropland to air and water must be reduced. “For agriculture to be ecologically, socially and economically viable it is more favorable to increase productivity on existing land rather than expanding cultivation into marginal areas or fragile ecosystems. Manufactured plant nutrients, crop protection products and enhanced plant varieties contribute to this extensively and therefore allow farmers to increase productivity per cultivated unit area. The use and application of these products has to be adapted to local conditions, markets, and consumer demands. Integrated farming systems, which include a standard of best agricultural practices, are increasingly demonstrating the most appropriate way of achieving the goals of sustainability.” (IAFN, 2000)

In the literature comparing yields of organic and conventional systems, productivity claims are often made based on yield per unit area of specific crops in a rotation without bringing time into the evaluation. If the organic rotation contains fallow years or years in which a crop with limited marketable value is included, specific crop yields can be very misleading. Comparisons must be based on yield of marketable product per unit area per unit time.

Crops produced organically will not always yield less, but often do. For example, a 21-year study in Switzerland found that yields were 20 percent less when a rotation including wheat, potato and forage was grown organically (Mäder et al., 2002). However, the economically most important crop, potato, suffered the greatest yield reduction (38 percent). These yield reductions occurred despite the better structure and quality of the soils of the organic system, achieved because of external organic material inputs not supplied to the conventional system. The rotation comprised 43 percent forage crops, which could imply greater emphasis on animal agriculture than would be justified by local or global demand. As stated by Per Pinstrup-Anderson (2002), “…yields per unit of total land used for organic farming including the land needed to produce green manure and animal waste are not at a level necessary to avoid encroachment on ecologically fragile soils and still meet future food demands.”

External inputs of organic nutrient sources often contain nutrients that were originally supplied in an inorganic form, such as commercial fertilizers. Or they contain nutrients mined from soils external to the farm. Were organic farming to be more broadly adopted, such practice would lead to extensive soil nutrient depletion. Currently, for example, crops across Canada and the United States remove approximately as much phosphorus as, and more potassium than, that contained in the sum of all recoverable manure plus all commercial fertilizers used (PPI, 2002).

Nutrient Input Restrictions

Because organic production has greater restrictions on inputs, it is more difficult to maintain the same yield levels sustainably. Organic standards minimize or eliminate use of synthetic or manufactured inputs and encourage maximum use of local natural resources. Organic food producers rarely use readily soluble mineral nutrients. They also exclude some organic sources, such as sewage sludge and composts derived from wastes. Thus, they must rely to a greater extent on green manures, crop rotation, and (preferably composted) animal manures.

The inputs allowed as fertilizers in organic production are generally lower and more variable in nutrient content and plant-availability than commercial fertilizers. To meet all the crop’s need using these inputs, they have to be applied at high rates. There is greater likelihood of supplying some nutrients at excess rates, which may lead to increased risk of loss and negative environmental impact. A commentary published in Nature recently by Trewavas (2001) points out the hazards of relying solely on organic sources for nutrients. He reported, “Manure breakdown cannot be synchronized with crop canopy growth, as is desirable, but continues throughout the growing season. Ploughing in of legume crops (a necessary part of the organic method to build soil fertility) and continued manure breakdown leads to nitrate leaching into aquifers and waterways at identical rates to conventional farms.”

Organic systems rely on tillage to incorporate organic materials and control weeds. Tillage increases mineralization (breakdown) of soil organic matter. Today’s integrated cropping systems are reducing or eliminating tillage, allowing crop residues to contribute more to increasing soil organic matter content.

Organic systems also vary more widely in nutrient availability because of reliance on indigenous soil fertility which exhibits strong spatial variability (Brandt and Molgaard, 2001). Nutrient input levels in organic farming systems tend to be lower than in conventional systems because the philosophy is aimed at growing crops under more natural conditions. Deficiencies of nitrogen, phosphorus, and potassium are natural conditions. These deficiencies reduce productivity.

Importance of Soil Quality

Productivity depends on soil quality. Soil quality – its structure and its capacity to retain water and nutrients – depends on inputs of organic material to maintain appropriate levels of humus. Nutrient inputs have large impacts on the total quantity of organic material produced and available to build soil humus. When nutrient deficiency limits crop yields it also limits their contribution of organic material (crop residue) to the soil. Nitrogen has particular importance, since soil humus maintains a carbon to nitrogen ratio of 10, and nitrogen inputs have been shown to stabilize soil carbon in the long term (Paustian et al., 1997).

The nutrient inputs critical to photosynthetic productivity (the original source of all organic matter) should be supplied by a combination of organic and mineral sources, as defined by integrated plant nutrition. “Integrated plant nutrition implies a combined use of various nutrient sources with special emphasis on those which can be mobilized locally by the farmers themselves. The benefit of organic inputs extends beyond their nutritional value, for example, by contributing to improved soil physical conditions. But organic materials are not sufficient to replenish nutrients removed by crop harvests. The complementary use of mineral fertilizers is essential to sustain soil fertility and to achieve increased production.” (IFA, 1996). “The use of inputs external to the farm and the community should complement the use of available organic materials, crop rotation, and other improvements in production systems.” (Pinstrup-Andersen, 2002).

The danger of nutrient deficiency limiting the primary production of organic materials for soil improvement is highlighted in the following statement: “…in most developing countries too little intensification [of agricultural production] is a major cause of natural resource degradation, as desperately poor farmers mine soil fertility and climb the hillsides in an effort to survive. …Low soil fertility and lack of access to reasonably priced fertilizers constrain farmers in many countries. Policies should encourage farmers to make appropriate use of organic and inorganic fertilizers and improved soil management.” (IFPRI, 2002)

Distinction of Natural versus Synthetic

It is often implied that nutrients used in organic cropping systems are “natural” as opposed to the “synthetic” or “chemical” sources used in conventional systems. Actually, any effort to differentiate foods from a nutrient source standpoint is of limited use because whether the source of nutrients is organic or inorganic, all nutrients are “chemical”…all are “natural” and exist in nature…and all nutrients are absorbed by the plant in the soluble inorganic form. The “natural” versus “synthetic” distinctions are not defensible on the basis of science.

Environmental Impact and Sustainability

Crop production uses the natural resources of soil, water and air, as well as genetic resources. Producing high-yield crops saves space for natural habitat. Managing inputs for profitable high-yield production minimizes losses of nutrients that could potentially adversely affect the quality of the surface waters that surround crop land and the groundwater below it. Crop production impacts on the atmosphere are also important. Increased crop growth will help to store more carbon in the soil to mitigate the increase in greenhouse gases.

Integrated farming systems face productivity challenges by managing site specifically, meeting the landscape-specific needs of the soils and crops. Prudent, scientifically sound use of technology in a systematic management program is essential to long-term sustainability. Improved and adapted genetic materials are a key component. Integrated pest management must be included, using best practices from cultural, biological, and chemical approaches. Conservation tillage and other practices to control erosion, maintain water quality, and reduce herbicide use are often critical components.

Several researchers have acknowledged that the environmental impact of organic farming systems is unknown and requires more research (Condron et al., 2000; Hansen, et al., 2001). While risk per unit area of farm may be lower, when practised as a small percentage of agricultural land, the overall environmental risks of organic production may increase dramatically as organic farming expands. Few studies have compared organic and conventional systems for risk per unit of production.

Sustainable crop production requires the efforts of all the world’s farmers. Both large-scale enterprises and smallholder agriculture have a role to play in the increasingly intensive business of producing crops. To sustain both the large and the small, the public must continue to provide the infrastructure to deliver agricultural inputs and outputs, the educational resources for knowledge generation and transfer, and the regulatory framework to assure a rational business climate. This includes development of mechanisms to assure consumers of the quality and safety of foods and other crop products.

Conclusions

The challenge facing agriculture today is to increase the quantity and quality of food produced, with less detrimental impact on the environment. For sufficient flexibility to meet that challenge, integrated cropping systems should have access to the necessary resources for efficient, bio-intensive production. If organic farming is defined only as that which is done with a restricted list of inputs, its ability to meet the challenge will be less than that of integrated farming systems. Lower input use equates to lower quantity and quality of food produced, with greater detrimental impact on the environment.

Public perception of the term “organic” connotes concern for product safety, healthfulness, and environmentally sustainable production. Policy development for organic agriculture must recognize that simple avoidance of specific inputs cannot assure that these concerns are addressed. Organic production must also include accountability for these concerns.

The concept of organic farming must be defined in a manner that accurately communicates the practice, in a non-misleading way, to the public. Acceptance of separate standards must avoid implying that organic crop production delivers benefits that have not been established on the basis of sound science. Such acceptance must recognize that integrated farming systems also produce safe, healthy food in an environmentally sustainable manner.

Bibliography

Brandt, K., and J.P. Molgaard. 2001. Organic agriculture: Does it enhance or reduce the nutritional value of plant foods? Journal of the Science of Food and Agriculture. 81:924-931.

Condron, L. M., K. C. Cameron, et al. 2000. A comparison of soil and environmental quality under organic and conventional farming systems in New Zealand. New Zealand Journal of Agricultural Research 43(4): 443-466.

Hansen, B., H. F. Alroe, et al. 2001. Approaches to assess the environmental impact of organic farming with particular regard to Denmark. Agriculture Ecosystems & Environment 83(1-2): 11-26.

IAFN. 2000. Statement of Industry, Topic 1. Choices in agricultural production techniques, consumption patterns and safety regulations: potentials and threats to sustainable agriculture. International Agri-Food Network. Discussion paper, 24 April 2000. United Nations Commission for Sustainable Development 8 Multi-stakeholder dialog segment on sustainable agriculture. New York, NY.

IFA. 1996. Plant Nutrients for Food Security. International Fertilizer Industry Association, FAO World Food Summit, November 1996.

IFPRI, 2002. Achieving Sustainable Food Security for All by 2020: Priorities and Responsibilities. May 2002. International Food Policy Research Institute. Washington, D.C.

Mäder, Paul, Andreas Fließbach, David Dubois, Lucie Gunst, Padruot Fried, and Urs Niggli. 2002. Soil Fertility and Biodiversity in Organic Farming. Science 296:1694-1697.

Paustian, K., H.P. Collins, and E.A. Paul. 1997. Management controls on soil carbon. p. 39-41, Chpt. 2 in: E.A. Paul, K. Paustian, E.T. Elliot, C.V. Cole (eds.) Soil Organic Matter in Temperate Agroecosystems, CRC Press, Inc.

Pinstrup-Andersen, Per. 2002. Towards a Sustainable Global Food System: What Will It Take? Keynote presentation for the annual John Pesek Colloquium in Sustainable Agriculture, Iowa State University, March 26–27, 2002. International Food Policy Research Institute (IFPRI), Washington, DC.

PPI. 2002. Plant Nutrient Use in North American Agriculture. PPI/PPIC/FAR Technical Bulletin 2002-1. Published by Potash & Phosphate Institute, 655 Engineering Drive, Suite 110, Norcross, GA, USA 30092-2837. ISBN # 0-9629598-4-7.

Trewavas, A. 2001. Urban myths of organic farming – Organic agriculture began as an ideology, but can it meet today’s needs? Nature 410:409-410.

See also: IFA position paper on the use of fertilizers in organic farming.