Simple farming method improving sustainability of impoverished Asian nations

So-called “low-till” farming, which does away with intensive and repeated ploughing of farmers’ fields, is increasing harvests, reducing water use by as much as 30 to 50% in a region often scarred by drought, and requiring less fuel for running tractors on farms, and because there are a half to two-thirds fewer weeds, herbicide use is also reduced, scientists from the Mexico-based International Maize and Wheat Improvement Center (CIMMYT) say. Farmers in Bangladesh, India, Nepal, and Pakistan are taking up low-till agriculture in such numbers that the impact in the region could be as great as the so-called Green Revolution of the 1970s, the group says.

The success of the approach, which is largely the result of pioneering agricultural research and promotional work by CIMMYT in partnership with the national research programmes of South Asia, comes at an opportune time as water scarcity in Asia and, more specifically, a three-year drought in Pakistan, threaten the region’s rice and wheat yields. Traditionally in this rice-wheat cropping region, far more ploughing than in other agricultural systems is required as the soil is wet and muddy after growing rice. As ploughing significantly delays the planting of wheat, the crop often does not mature before the onset of the hot, dry season before the monsoon, resulting in shrivelled grain and reduced harvests and incomes. In addition, ploughing exposes the soil to air, which oxidises soil matter and roots, depleting organic matter and soil moisture over time, and increasing the need for irrigation.

Low-till agriculture, however, leaves much or all of the soil surface and existing ground cover undisturbed during the planting process, using a ‘planter’ or ‘seed drill’. In one pass across a field, the planter places seeds and fertiliser through the rice straw left standing from the previous harvest into the soil below, with these roots providing channels for wheat roots to grow; a habitat for beneficial insects to prey on invasive insects; and, as it decomposes, a natural fertiliser of organic matter for the wheat crop. The low-till technology is designed to be accessible to farmers with limited resources who have no equipment, little cash, and often very little land, for example some 74% of the farmers who used low-till last year in Haryana State, India, did not own tractors and are considered resource-poor farmers.

Other low-till practices are also being used in the region, such as raised soil beds, or ‘bed planting’ and direct seeding of pre-soaked wheat seeds into still-moist rice fields, or ‘surface seeding’. The benefits of the agriculture include:

• as much as 30 to 50% of water per year in the region, or up to five billion cubic metres of water, is saved by low-till increasing the amount of moisture retained by the soil when it is ploughed less by conserving more moisture at planting, the crop being ready for harvest before the hot season arrives, and irrigation water flowing faster over a field that has not been tilled, so less water is pumped;
• decreasing or eliminating tractor and water pump usage means up to 75% less fuel is used, as much as 800,000 tonnes of carbon dioxide per year;
• an earlier start to planting wheat means that the wheat crop more effectively shades out growth of weeds, such as the problem Phalaris weed, reducing the need for herbicides; and
• planting wheat immediately after harvesting rice means the crop is planted three or four weeks earlier than it can be with a ploughing system, enabling the crop to mature fully before the hot, dry weather sets in, increasing crop productivity and income.

According to CIMMYT, the area being planted to low-till agriculture is increasing ten-fold per year after initial problems with persuading locals to change their methods, with manufacturers unable to make planters fast enough to meet the demand from farmers. More than 150 million people depend solely upon the region’s rotational cropping of rice and wheat during the wet and dry seasons, which is the most important agricultural system for feeding South Asia. “To feed soaring populations, farmers must increasingly use more fertiliser, water, and herbicides to get the same or greater crop yields from their land,” said Professor Timothy Reeves, director general of CIMMYT. “Low-till agriculture enables them to increase their productivity while at the same time decreasing – not increasing – these inputs. This new agricultural revolution in South Asia is poised to be a greener revolution than the one that took place in the 1970s.”

“Low-till is one of the best examples in the world of technologies working for both people and the environment,” Reeves continued. “Currently, low-till practices are being used for sowing wheat after the harvesting of rice. An example of its rapid spread is found in India and Pakistan, where the area sown to low-till agriculture increased from a modest 3,000-plus hectares in 1998-99 to surpass 100,000 hectares in 2000-2001. It is anticipated that this area could surpass 300,000 hectares next year and soon reach one million hectares.”