Stubble Burning - Impact of practice and its alternatives to overcome the problems

 

Introduction:

Stubble is the base of the plant and the straw residue remaining on the surface of the soil following the harvest of particular crops. This includes material discharged from the harvester. For a range of reasons, this material is often burned so that the land is clear for reuse.

What is stubble burning?

Stubble burning is the act of removing paddy crop residue from the field to sow wheat. It’s usually required in areas that use the ‘combine harvesting’ method which leaves crop residue behind.

Combine harvesters are machines that harvest, thresh and also clean the separated grain, all at once. The problem is that the machine doesn’t cut close enough to the ground, leaving stubble behind that the farmer has no use for. There is pressure on the farmer to sow the next crop in time for it to achieve a full yield. So, the Stubble burning is the quickest and cheapest solution to clear the field.

It is mostly practised in Punjab, Haryana and Uttar Pradesh to clear the fields for the sowing of Rabi Crop from the last week of September to November. There is only a short time between the harvesting of paddy crop and the sowing of the next crop.

Burning crop residue is a crime under Section 188 of the IPC and under the Air and Pollution Control Act of 1981. On December 10, 2015, the National Green Tribunal (NGT) had banned crop residue burning in the states of Rajasthan, Uttar Pradesh, Haryana and Punjab where the practice is prevalent.

Soil and Air pollution:

Stubble burning may leads to both the soil and air pollution. Microorganisms present in the upper layer of the soil as well as its organic quality gets affected. Due to the loss of ‘friendly’ pests, the effect of ‘enemy’ pests has increased and as a result, crops are more prone to disease. 

The crop residue burning released 149.24 million tonnes of carbon dioxide (CO2), over 9 million tonnes of carbon monoxide (CO), 0.25 million tonnes of oxides of sulphur (SOX), 1.28 million tonnes of particulate matter and 0.07 million tonnes of black carbon. 

These directly involved in environmental pollution, and are also responsible for the haze in Delhi and melting of Himalayan glaciers.

Why is this only a problem in the Northern States?

Mostly this happens only in northern states of Punjab, Haryana, Western Uttar Pradesh and Uttarakhand for wheat.

The southern states also using the combine harvesting too. But the main difference is that they don't have the urgency to remove the stubble to make it ready for the next crop.

In the Punjab-Haryana-Uttar Pradesh belt, the farmers have to sow wheat crop next after the paddy. So, the field has to be harvested and readied for the next crop. For the wheat crop to reach full maturity and give maximum yield, the farmer has no option but to sow the crop latest by Mid- November. This is why the farmers of Northern States involved in the simplest and quickest method, Stubble burning.

Is Burning the only solution to take-over this crisis?

Not really, there are other options we can look at.

1. Happy Seeders

If farmers wish to remove stubble manually, they will need at least Rs. 6,000 - 7,000 per acre. To reduce these costs, as well as save labour and time, the tractor-mounted 'Happy seeders' to cut down the rice stubble and sow wheat seeds simultaneously. To use a 'Happy seeders' over one acre, farmers have to spend Rs. 1000 for rent and about Rs. 2000 on diesel. But farmers have complained about problems while sowing and low germination of wheat seeds, when sown with 'Happy seeders'.

2. Straw baler

A machine called a straw baler – to compress crop residue into compact bales – to bale rice stubbles and moving them out of the field. The state government may arrange to procure the stubble, along with paddy grain, by hiring balers to work for free for the farmers. The stubbles can then be sold to biomass-based power plants, paper mills and cardboard factories. But it failed because the machine takes an hour for every acre, typically producing 12-15 quintals of bales. 

3. Paddy straw chopper cum spreader

The machine to chop paddy straw left behind on mechanically harvested paddy fields. It chops the straw into pieces and spreads it around the field in a single operation, so wheat-sowing becomes easy. It is a mounted-type machine and can be operated by a tractor with 45-50 HP or more.

4. Pusa decomposer

Another alternative is the accelerated straw decomposition process. The Indian Agricultural Research Institute has developed a solution it has named ‘Pusa’, which can decompose crop residue into manure by accelerating the decomposition process. These agents act on the straw to make it soft and ploughable, break down its molecular components and release the nutrients into the field. As a result, Pusa may reduce the use and cost of fertilizers and could help increase the yield of the subsequent crop. It costs less than Rs 1,000 per acre.

5. Stubble Biochar

Another option is to convert stubble into biochar, which can be used as a fertilizer, by burning it in a kiln. For this purpose, a kiln has to be 10 ft wide and 14 ft high, and be able to accommodate 12 quintals of rice straw and convert it into 6.5 quintals of biochar in 10-12 hours.

6. Short duration varieties

Another way to reduce stubble burning is to replace long-duration paddy varieties with shorter duration varieties like Pusa Basmati-1509 and PR-126, which can be harvested in the third week of September itself. This will widen the gap between  end  of the rice season and start of the wheat season, allowing enough time for the paddy stubble to decompose, and eliminate the need for stubble-burning.

What would be the choice of farmers?

There are multiple alternatives to stubble burning, and farmers can choose between the technologies and machines most suited to their particular local conditions, with the objective of ‘no burning’.