Since humankind invented agriculture tens of thousands of years ago, farmers have worked extensively to enhance crop yields. Traditional methods such as irrigation and improved plant varieties resulted in significant advances, as did the chemical fertilizers introduced after World War II. With a growing world population and rising concerns about the environment, agribusiness firms are pushing forward with genetically engineered seeds and matching pesticides, even as many small farmers suggest that organic farming is more sustainable.
A 2012 metastudy published in the journal Nature, “Comparing the Yields of Organic and Conventional Agriculture,” compared existing studies on crop yield to understand the differences in output between organic farming and conventional industrialized agriculture. The results are relevant to both the United States, which has a high penetration of genetically modified crops, and the developing world.
The findings include:
- Under the best conditions — with certain crops, appropriate environmental conditions, and effective management — organic systems can approach the yields of conventional agriculture. The organic yields are typically lower than conventional ones, but the degree of difference is highly dependent on the particulars, and can range from 5% to 34% lower.
- How crops are watered can make a significant difference: Organic crop performance can be 35% lower under irrigated conditions, but only 17% lower under rain-watered conditions.
- Under drought conditions, organic crop yields can surpass conventional ones: “Soils managed with organic methods have shown better water-holding capacity and water infiltration rates and have produced higher yields than conventional systems under drought conditions and excessive rainfall.”
- Organic yields are initially low after conversion but increase over time as soil fertility and management improve. “Organic performance improves in studies that lasted for more than two seasons or were conducted on plots that had been organic for at least three years.”
- With the best management practices in both systems, organic farming can show excellent performance. “Nutrient and pest management in organic systems rely on biological processes to deliver plant nutrients and to control weed and herbivore populations. Organic yields thus depend more on knowledge and good management practices than conventional yields.”
“To establish organic agriculture as an important tool in sustainable food production, the factors limiting organic yields need to be more fully understood, alongside assessments of the many social, environmental and economic benefits of organic farming systems,” the authors state. “In the end, to achieve sustainable food security we will probably need many different techniques — including organic, conventional, and possible ‘hybrid’ systems to produce more food at affordable prices, ensure livelihoods for farmers, and reduce the environmental costs of agriculture.”
Journalist’s Resource has a number of studies relating to agriculture, including the effect of biofuel targets on food supplies, the water footprint of humanity, and the effects of genetically modified corn on nearby crops.
Keywords: metastudy, science, nutrition