The Hindu Business Line : Zero tilling can help increase crop yield significantly: Study

ZERO till or no-till farming, which has caught the fancy among farmers going for more than one crop in a year, can lead to increased yield if it is done correctly.

Zero till system is planting of crops with minimum soil disturbance.

In this system, seeds are directly placed into deep slits made with a specially designed seed-cum-fertiliser drill machine without prior land preparation.

In India, for example, farmers directly sow wheat after harvesting paddy without undertaking any ploughing operations.

All they do is irrigate the standing paddy crop a few days before harvesting. The rice is harvested near to the ground so that the leftover stubble is not more than 6 inches in height.

Wheat is then directly sown after 2-3 days by deploying the zero-till machine, utilising the residual moisture. The machine basically has knife-type tines that cut open slits in the soil to place seeds at appropriate depths.

Unlike conventional tillage, which involves digging up to 6-7 inches, the zero-till machine does not call for any opening up of the soil. Instead, it simply slits the field by about half an inch, while simultaneously drilling in the fertiliser and seeds. This helps the land retain adequate surface residues to prevent soil erosion.

The findings of the scientists of the Agricultural Research Service (ARS), an arm of the US Department of Agriculture, also dispels the view that the switch from conventional to zero till farming will take several years to reap benefits.

The ARS and Alabama Agricultural Experiment Station scientists began their research in 2000 on a 20-acre field, with conventional tillage on one half of the field and conservation tillage on the other half.

In a rotation of cotton and corn crops, cotton grown with conservation tillage resulted in 12 to 24 per cent higher yields each year of the study's first three years, compared to the conventionally tilled cotton.

The project discovered that as long as there is an adequate amount of residue from a cover crop, transitioning to conservation tillage provides immediate benefits.

As per the study, farmers should not terminate the cover crop too early. Instead, they should plant the crops within the recommended planting windows and let them grow until they are three to five feet tall and the next planting should be three to four weeks away. This will ensure that there is sufficient residue on the soil surface to reduce soil erosion and tap rain to maintain adequate soil moisture through the planting season.

The project has found that non-inversion ploughs— which will not disturb the crop residue— can be used to address soil problems. But the farmer should stick to conservation tillage with high production of cover crop residue as much as possible to reap the financial— and environmental— rewards.

In India, zero till farming has been found to save field preparation expenses by a minimum of Rs 2,000 per hectare. Moreover, it has also been found to save at least three weeks time required to clear the weeds from the field.

Buoyed by the success during the last three years, the Centre has said it would extend zero till farming to 1.5 million hectares of land under wheat this year.