Delhi Would Breathe Easy If Punjab Farmers Don’t Burn Paddy Straw

Burning of paddy straw by Punjab’s farmers is increasing air pollution in Delhi: A special report by Vivian Fernandes

Punjab’s farmers would not be burning paddy straw as they prepare fields for wheat sowing in winter if they followed conservation agriculture (CA) practices propagated by the Borlaug Institute for South Asia (BISA). BISA is a joint effort of the Indian Council of Agricultural Research and Mexico’s International Maize and Wheat Improvement Centre, which supplied the dwarf varieties of wheat that created India’s Green Revolution.

The Earth Observatory website of NASA, the space agency of the United States, shows hundreds of red dots like scattered confetti on a 30 October satellite grab of Punjab. “Red outlines indicate hot spots where the sensor detected unusually warm surface temperature generally associated with fires,” it said. “Thick plumes of smoke drifted from the hot spots.”

Burning of Straw Causes Air Pollution

The air quality index has dropped by 60 to 80 points in Delhi since Thursday, October 29, the Times of India reported. “It is inching towards the ‘very poor’ zone when children are advised not to spend time outdoors,” it said.

Soot from the burning fields adds to the load of carbon particles emitted by thousands of trucks transiting through Delhi. The Supreme Court has imposed a toll from 1 November to discourage them. Cold and moisture thicken the atmospheric soup and make the capital’s asthmatic air even more unbreathable.

Since paddy straw is rich in silica, it is not fed to cattle in north India. Baling the straw and transporting it to the state’s six plants producing electricity from crop waste is not economical.

Alternative to Burning

For the Indo-Gangetic Plains of northwest India, BISA’s research station at Rajowal in Ludhiana recommends that paddy straw be spread on fields and not burnt. An upward facing fan attached to combine harvesters helps them do this as they spew the straw after retaining grain. The straw acts like mulch and prevents weeds from growing. It also retains moisture in the soil.

A ‘Happy’ seeder, which follows the combine, parts the straw in neat rows and sows wheat seeds. Moisture present in the rice fields is enough for the wheat to germinate.

“An acre of rice straw adds 30 kg of nitrogen, 6 kg of phosphorus and 11 kg of sulphur”, says Pankaj Singh, agronomist and manager of the Rajowal farm. The rotting straw enriches the soil by enhancing its organic carbon content.

Saying ‘No’ to Tillage Cultivation

No tillage cultivation is another tenet of conservation agriculture. This might sound like heresy in Punjab, the land of the tractor. About six lakh tractors are said to be deployed in Punjab. They sweat an average of 350 hours a year against about one thousand hours required to justify the cost.

Tillage leads to the loss of soil moisture and the destruction of capillaries formed by the roots of the previous crop, which keep the soil soft. The state’s economic survey says zero-tillage cultivation saves Rs 3,600 in diesel costs (when prices were much higher than now).

“Farmers save time by not tilling. Earlier sowing allows wheat to make the best of the peak growth period in summer and adds about half a tonne of grain per hectare by avoiding the days of terminal heat,” says Harminder Singh Sidhu, BISA’s station-in-charge.

The Alternative

After the wheat crop, BISA recommends the sowing of moong, a short duration crop, which matures in about sixty days. Adding a leguminous crop like pulses to the rice-wheat cycle enriches the soil with atmospheric nitrogen and permits ‘sustainable intensification’ of agriculture.

Punjab’s economic survey says just 750 hectares of wheat area was under zero-tillage in 2001. This had gone up to 7.49 lakh hectares in 2011-12. Subsequent surveys do not state the progress since then.

Since wheat straw is used as fodder, Punjab farmers tend to plough the stubble under. BISA disapproves of this practice. It says moong or rice can be sown directly in the stubble covered fields. The seeders have been configured to just scratch the surface for paddy to be sown. Surface sowing raises yield by allowing more secondary shoots to emerge.

In direct-seeded rice (DSR), there is no puddling or transplanting. This not only saves diesel and wage cost but also reduces the environmental cost of paddy cultivation. In transplanted rice, stagnant water is used to kill weeds. The availability of minimally invasive new age herbicide molecules has made DSR possible.

The burning of straw is banned in Punjab. There is also a high court stay. But the law is not enforced, though collectors of some districts have threatened action.

Punjab’s farmers need to rethink practices to make their agriculture not only climate resilient but also environment-friendly. Conservation agriculture makes both goals attainable.

(Vivian Fernandes is consulting editor with www.smartindianagriculture.in)