Precision farming yields many gains

The Chinese government's No 1 central document released in February attached great importance to high-tech agriculture, and it is a hot topic during this year's annual sessions of the National People's Congress and the Chinese People's Political Consultative Conference.

Everyone thinks high-tech farming means biotechnology, but it actually goes far beyond that. Biotech seeds are now being upstaged in the United States by a variety of "precision farming" technologies, such as drip irrigation and GPS guidance systems, that offer savings in the use of water and chemical inputs.

On big farms in the US four out of five tractors are now equipped with GPS systems that "auto-steer" the equipment in perfectly straight lines. With differential correction signals, these systems can tell a machine exactly where it is in a field, down to 1 square meter. This in turn allows on-board computers to access GIS mapping data and instruct the machine to apply fertilizer or lime at differential rates, location by location. This eliminates both under-application that can hold down yields and over-application that wastes money and pollutes the environment.

GPS positioning and sensing technologies also allow farmers to save on water, by instructing machines to deliver water only where the seeds have been or will be planted, and in response to actual soil moisture conditions at the depth of the plant roots. Computerized drip irrigation systems are even more precise, and lasers are now used to level fields so as to eliminate irrigation water runoff.

An earlier innovation in precision farming was no-till or reduced-till planting. In the 1970s, farmers learned how to seed unplowed fields, to minimize soil disturbance. This helped conserve moisture and sequester carbon, while saving on diesel fuel. A second dimension of precision arrived in the 1990s, when seeds were engineered to resist a chemical herbicide named glyphosate. Farmers who planted these seeds could control weeds without multiple pre-emergence chemical sprays and without energy-intensive mechanical cultivation. As a parallel development, seeds were also engineered to contain a protein that the larvae of insects could not digest. Farmers who planted these Bt seeds could reduce insecticide sprays and control pests with far greater precision. In fields planted with Bt maize or Bt cotton, only the insects actually eating the plant suffer any harm.

This kind of high-tech precision farming has multiple benefits. Since the 1990s when many of these techniques were first introduced, the annual rate of growth of total factor productivity in US agriculture has accelerated from 1.49 percent to 1.91 percent, reducing food costs while bringing more profits to farmers. Much of this new productivity has come from less wasteful input use. Total fertilizer use and total pesticide use have both declined in American agriculture since the 1980s, even as total production volume increased by roughly 45 percent. In the Organization for Economic Cooperation and Development world as a whole, excess nitrogen fertilizer use in farming has declined by 17 percent since 1990. This has also been good for the environment.

Chinese farmers who face water scarcity and who often damage the environment with too much nitrogen use might take an interest in these new precision-farming techniques, which do not have to be capital intensive.

In some cases China's farms will have no problem adopting these high-tech solutions. For example, China has been planting genetically engineered Bt cotton seeds since 1997. These genetically engineered varieties of cotton have given even small farmers in China a 10 percent increase in yield per hectare, along with a 60 percent reduction in the spraying of insecticides on cotton. China is now the largest producer of cotton in the world, with 69 percent of its cotton acres now planted with high-tech Bt varieties. In 2009, China also approved the planting of genetically engineered Bt rice, and in June 2008, Chinese Premier Wen Jiabao told the Chinese Academy of Science, to solve the food problem, we have to rely on big science and technology measures, rely on biotechnology, rely on GM (Genetic Modification)."

In other cases, China might want to consider low-tech solutions. The machinery used in the US to apply fertilizer will be too expensive for China's much smaller farms, but other new methods for applying fertilizer with greater precision and less waste are easily affordable. For example in rice cultivation, a new method called fertilizer deep placement replaces spraying urea on flooded paddy fields, which leads to runoff, with the placement of solid "briquettes" of fertilizer directly into the soil close to the root zone of the rice plant. This technique, currently being scaled up in Bangladesh, can reduce fertilizer use by 40 percent while increasing crop yields by 15 percent.

Greater precision in modern farming raises a farm's income, brings down food prices, and is good for the environment. China will want to move toward precision farming using its own unique mix of solutions, based on both high-tech and low-tech methods, including both conventional and biotech seeds. The new Chinese farming model that emerges can lead agriculture in all of Asia toward a more prosperous, environmentally sustainable future.

The author is B. F. Johnson professor of political science, Wellesley College, and adjunct professor of public policy, Harvard Kennedy School.

(China Daily 03/08/2012 page10)