더 영리한 농업

Conservation agriculture, a set of farming practices designed to reduce water use and improve soil fertility, is increasingly common on large commercial farms. The tricky part is making it work for small-scale farmers.

In Brazil, 75 percent of cropland is grown without tillage. © 2005 J. Banning/Panos

In a way, it was a tropical storm that blew conservation agriculture into South America. In October 1971, when heavy rains and wind hit Herbert Bartz’s farm in Rolândia, Brazil, they washed away not only his crop, but also the soil it was growing in. Bartz had heard about a more sustainable way of farming known as no-till—that is, farming without plowing—and he decided to travel to the United Kingdom and the United States to learn more.

In the late 19th and early 20th centuries, farmers plowed up the prairies of the US and Canadian plains, leaving little or no organic matter, not even crop residue, to hold the soil together and conserve moisture. As a result, when drought hit in the early 1930s, the soil was blown away in destructive dust storms. After the Dust Bowl, farmers returned to farming—but instead of plowing, some innovators dropped seeds into narrow slots cut into the soil, leaving the surrounding vegetation untouched. Their farms became both more productive and more sustainable, and the method became widespread.

This is the type of farming Bartz saw on his visit. He immediately put in an order for a no-till planter of his own and in 1972 began cultivating his land without tilling it. His neighbors called him crazy—until they saw the results. Gradually, they started to emulate him. Now, 40 years later, 75 percent of Brazil’s cropland is grown without tillage, benefiting farmers’ yields and profits and enhancing the health of the country’s soils and water.

Today no-till cultivation is a key element in conservation agriculture and is one of many practices designed by farmers, extension agents, and scientists to make agriculture more sustainable. While these practices are increasingly used by large-scale and commercial farmers in developed and developing countries, adapting them for small-scale and poor farmers has been a harder sell.

“These are great technologies. But how do you make them work for farmers where markets are thin— where the services, inputs, and technologies aren’t always available—and where farmers don’t know much about them?” says IFPRI Senior Research Fellow David Spielman.

Soils & Water Tapped Out

Globally, an estimated 15 percent of land—and 40 percent of agricultural land—is degraded. That is, the land suffers from a range of natural- and human-caused problems including soil erosion, loss of nutrients, desertification, salinization, and waterlogging. As soil quality declines, crop yields take a hit.

Water resources are also under strain. Excessive and unchecked water extraction for irrigation in many countries has depleted aquifers far faster than they can be naturally replenished. According to the World Water Assessment Programme, about 10 percent of the world’s irrigated land suffers from waterlogging and salinization owing to poor drainage and irrigation practices.

Much of the soil and water degradation comes from unsustainable farming practices. Farmers plow their land, for example, to prepare fields for planting, incorporate fertilizers into the soil, aerate soil, and control weeds and pests. But plowing reduces valuable organic matter in soil, disrupts the channels created by roots and worms, and increases the risk of wind erosion. on natural land where vegetation seals in soil and water, soil loss is normally very low: less than half a ton per hectare per year. In contrast, on each hectare of traditionally farmed agricultural land, farmers lose 45–450 tons of soil a year.

“Most scientists have been working to increase yields for the last 40 to 50 years,” says Spielman. “Only recently have we seen a real awakening around the need for sustainable yields.”

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Farewell, Plow

In some ways, conservation agriculture mimics a natural landscape. Because soil is not disturbed and the ground is always covered with plant matter, microorganisms and earthworms do the job of “tilling” the soil and balancing soil nutrients. The permanent plant cover prevents the soil from getting too hot in tropical climates. In fact, conservation agriculture has been likened to the floor of the rainforest.

And so, in addition to retiring the plow, conservation agriculture requires permanent ground cover—usually residues from the previous season’s crop—and regular crop rotation. The crop residues add organic material to the soil, help retain moisture, and protect against erosion from runoff. The rotation of crops—particularly legumes—improves soil fertility and prevents buildup of pests and diseases.

For small-scale farmers, conservation agriculture can be less expensive and time consuming than conventional tillage farming. In the areas of the Indo-Gangetic Plains of India where rice and wheat are grown in alternate seasons, a study shows that farmers using conservation agriculture spend an average of US$55 less in cultivation costs, save 50–60 liters of fuel and 15–50 percent of water, and raise crop yields by 247 kilograms per hectare.

Indeed, the practice is now used on an estimated 105 million hectares of farmland worldwide, though still mostly in North and South America and mostly by large-scale farmers cultivating soybeans, wheat, and maize.

FLAT, FLATTER . . .

Leveling with farmers about water conservation

Punjab, India. This farmer used laser land leveling to conserve water and reduce fuel costs on his wheat and rice fields. © 2010 D. Spielman/IFPRI

IFPRI’s David Spielman and Nicholas Magnan are studying how small-scale farmers can be incited to adopt laser land leveling—a precursor technology for a more holistic conservation agriculture system—to make their fields really, really flat. Their work among small-scale rice and wheat farmers in the eastern reaches of the Indian state of Uttar Pradesh is part of a larger CGIAR program called CSISA—the Cereal Systems Initiative for South Asia.To get the most out of conservation agriculture, it helps to have level fields where irrigation water can flow evenly, preventing waterlogging in some places or drying out in others. Laser land leveling is also a resource-conserving technology on its own: it can reduce farmers’ use of water, and diesel fuel for pumping the water, by 20–30 percent.

Yet adopting laser land leveling is not simple for the small-scale farmer. Operators of leveling services find it more profitable to serve large-scale farmers—they can spend less time on the road between clients and more time earning money in the field. Many farmers know little about the virtues of laser land leveling because few extension agents or local agricultural departments promote it. Moreover, the farmers in eastern Uttar Pradesh, like those in many countries, don’t actually pay for their water—water is available at no charge beyond the small cost for fuel to pump it. “Where groundwater is free, farmers don’t pay the full price of water so they don’t have the incentive to save,” says Magnan.

In cases where the benefits to society from laser land leveling—in terms of reduced water and fuel use and lowered greenhouse gas emissions—could be greater than the benefits to some individual farmers, or where some farmers are unsure how laser land leveling will benefit them, how do you persuade them to adopt the technology?

One solution is to offer a discount system that makes the service available at an affordable price, at least initially. Spielman and Magnan set up an experimental auction in India to find out how the government and the private sector could work together to create a pricing mechanism that would be affordable for both the government and the farmers. They found that at the market price of 500 rupees per hour, only 5 percent of small-scale farmers’ land would be leveled, whereas cutting the price by half would bring the amount of land to be leveled up to 50 percent.

If this mechanism were targeted to specific types of farmers—for example, farmers who were members of vulnerable social groups or castes—then more farmers could enjoy the benefits of leveling. The challenge is designing a pricing mechanism that serves everyone’s interest.

“Ultimately, we wanted to find out how the public sector and the private sector might work together to promote the technology in a cost-effective manner that’s both profitable for service providers and beneficial for small farmers,” says Spielman, “without being overly costly for the government.” It’s a tough balance to strike, but it helps to have a level field. And once the farmers learn about the benefits by using the technology and watching others use it, they may be willing to pay more for it.

Never Heard of It

Sustainable farming approaches look like win-win solutions, but small-scale farmers have not adopted these practices in large numbers. “Each technology faces barriers to adoption that are very context specific. You need to understand the particular market failures or other barriers in each situation,” says Magnan.

One important barrier for conservation agriculture is lack of awareness and understanding. “The barriers to adoption include lack of technical know-how both by farmers and extension staff,” says Kufasi Shela, chief land resources conservation officer in Malawi’s Ministry of Agriculture, Irrigation and Water Development. “Some extension staff are yet to understand what conservation agriculture is and what it is not, and this ultimately affects the way they relate to their farmers.”

Work by IFPRI Senior Research Fellow Ephraim Nkonya confirms this. When extension agents in Nigeria and Uganda were asked what advice they give to farmers about improving yields, about 70 percent advised using better seeds as a first response, followed closely by chemical fertilizers, then pesticides. only 1 percent of the respondents talked about organic practices such as intercropping with trees, an element in the wider suite of conservation agriculture practices.

The problem is similar in Morocco, where two-thirds of cereal farmers depend on rainfall and the frequency of drought has risen from an average of one in eight years in the mid-20th century to a more recent average of one in two years. Conservation agriculture has been shown effective in improving soils, sustaining yields, and lowering farmers’ costs in the region. But Rachid Mrabet, director of research for Morocco’s Institut National de la Recherche Agronomique, says because extension staff are unfamiliar with conservation agriculture practices they aren’t strong promoters.

A New Mindset

Abandoning the plow requires a different vision of what farming entails. “You need a mindset from farmers and researchers to go from plowing a field to not doing anything,” says Bruno Gerard, who leads the Conservation Agriculture Program of the International Maize and Wheat Improvement Center (CIMMYT).

There are other practical considerations as well. Like other agricultural technologies, conservation agriculture works only if it is adapted to the needs of the local ecology, the farming system, and the farmer’s own plot.

This demands a lot from farmers, who need to make complicated and informed decisions about how to allocate labor, fertilizer, seed, and equipment, as well as time and effort. If immediate yield gains are not assured, they can be reluctant to adopt the practice. Still, Gerard says, their savings in fuel and water and the possibility of lengthening the growing period—by eliminating the time required for plowing—can raise profits, even if yields don’t rise in the first year.

HELLO, TREES

Persuading farmers to adopt more sustainable practices

Intercropping of cabbage, sugarcane, and poplar trees in Punjab, India. © 2010 D. Spielman/IFPRI

For millions of poor farmers cultivating small plots in Sub-Saharan Africa, agroforestry should make sense. Traditional farming methods and the constant search for fuelwood have stripped landscapes of trees. Planting leguminous trees alongside a field of, say, maize adds nutrients to soil and has been shown to double yields. “You can reduce fertilizer use by more than half,” says IFPRI Senior Research Fellow Ephraim Nkonya.The benefits of agroforestry are especially striking when rains fail. Farmers using agroforestry in years of poor rainfall can match the yields achieved by farmers using traditional farming practices in years of good rainfall. And when agroforestry is combined with fertilizer use, yields are even higher. Plus, the trees help prevent erosion and can provide fodder, fuelwood, and fruit. Yet poor farmers in most African countries typically don’t adopt agroforestry.

IFPRI researchers Ephraim Nkonya and Paswel Marenya decided to find out what it would take to get farmers to practice agroforestry and use fertilizer. They conducted an experiment with 271 randomly selected maize farmers in central Malawi to try to understand which policy solutions would be the most effective incentives. Farmers could choose to receive fertilizer subsidies, cash payments, or crop insurance on the condition that they practiced agroforestry.

A big part of the researchers’ project involved using games to educate farmers on the workings of insurance, with which they were completely unfamiliar. Some farmers who played the games did express an interest in insurance. Most, however, preferred fertilizer subsidies, which promised to increase their yields.

These results suggest that better information could help farmers make better decisions and that despite its shortcomings, returns to the current fertilizer subsidy program could be greatly enhanced if the coupons are given on the condition that the beneficiaries adopt conservation agriculture, agroforestry, and other improved land management practices.

Small-scale farmers are often reluctant to leave crop residues in the field because they normally feed the residues to their livestock or sell them to others as fodder. IFPRI’s Magnan points out that for some farmers, the benefits of using these residues for livestock feed outweigh the benefits of conservation agriculture, in terms of their immediate income.

“You have trade-offs between a relatively short-term return on feeding crop residues to livestock and a more long-term return on protecting the soil and maintaining good nutrient balances,” says Gerard.

To achieve the large-scale public environmental benefits of conservation agriculture, says Mrabet, governments should support farmers willing to try the technique.

And it’s important to look beyond yields. Without effective markets, increased yields can, in fact, depress prices. Without infrastructure, there can be no effective markets. Conservation agriculture produces concrete benefits in the field, but like all development efforts, it needs markets, roads, value chains, and more to sustain its impact.

In the face of dramatic land and water degradation, the main obstacle to advancing sustainable agricultural practices, says Spielman, is not a lack of potential solutions. “Many methods have been proven effective both for farmers and for the greater good,” he says. “What we need is more knowledge dissemination, more coordination among researchers, extension agents, governments, and wholesalers. We need better infrastructure and reliable markets.”

We also need to think differently. “The immediate need for poor farmers is just to produce in a given year,” says Gerard. “They don’t think about productivity in five or ten years.” So it could be that the fastest route to sustainability is to boost farmers’ productivity and then push them toward more environmentally friendly practices. “The pathway to sustainable systems may not be a straight one. You might have to go through transient unsustainability,” he says.

Of course, as IFPRI’s Paswel Marenya points out, governments could decide to promote these sustainable practices, through policies and extension services, just as they currently promote more conventional practices. “Just imagine if every smallholder farmer used conservation agriculture practices like these just a little,” he says. “Not only could they potentially improve their own productivity and livelihoods, but they could help reduce or repair harmful environmental consequences of unsustainable land management practices that affect us all.”