Generating bio-CNG from paddy straw answer to residue disposal
Given the large quantity of paddy straw, its in-situ incorporation may neither be advisable nor sustainable. Mulching may release excess methane, causing air pollution besides burdening the soil with silicaUpdated: Nov 08, 2019 17:12 IST
Like every season, this time too, the burning of paddy straw has posed health and environment problems. The National Green Tribunal and the Supreme Court have expressed concern like never before. The central and state governments of Punjab and Haryana and Uttar Pradesh are trying, both by persuasion and coercion, to dissuade farmers from burning paddy straw but nothing substantial has come out.
The farmers think that a matchstick can save the entire additional cost. The short window between harvesting the paddy and sowing the next crop and non-affordability of costly machinery are the two arguments they give. It necessitates bringing farmers on board while exploring other options, which could be gamechangers, to manage not only paddy straw but also other crop residue.
Unfortunately, the options are not yet being explored and projected by governments as they may be under pressure of the machinery and fertiliser lobby for it involves a huge amount of subsidy. Nonetheless, the predominant solution being put forward so far is in-situ incorporation of paddy straw. The argument behind it is maintaining the soil productivity by ploughing back organic matter. Going by this argument, the central government had earmarked Rs 1,151 crore for subsidy on machinery for the 2018-19 and 2019-20 fiscals. Is it on the advice of agro-scientists or under pressure of subsidy-driven machinery and fertiliser lobbies that alternative options are being kept under wraps?
Crop diversification is not taking off despite paddy being a high water-guzzling crop and the water table falling in Punjab and Haryana.
Given the large quantity of paddy straw, its in-situ incorporation in the soil may neither be advisable nor sustainable in the long run. How long and how much organic matter in the form of paddy straw can be ploughed back? Is it really needed? Besides, in-situ mulching of paddy straw may also release excess methane, causing air pollution and burdening the soil with a high proportion of silica that is contained in the paddy straw.
There are multiple options of paddy straw management that can be tried along with taking care of the soil and human health and environment. The generation of bio-CNG from residue, including paddy straw, seems to be a viable alternative as it will manage the biomass without harming the environment besides producing organic manure for crops.
Punjab Agricultural University, Ludhiana, has approved the organic manure (a byproduct of bio-CNG) that will decrease the demand for chemical fertilisers and pesticides. Besides, it can generate a significant amount of revenue (in the form of GST), additional income for farmers and much-needed employment (between 5 lakh to 7 lakh) in the states of Punjab, Haryana and western UP. Private entrepreneurs are willing to pay farmers between Rs 1,500 and Rs 1,800 per tonne for delivering paddy straw at the plant head.
VICE TO VIRTUE
The recently announced comprehensive biomass management policy by the CII-NITI Aayog has worked out the potential of setting up of bio-CNG plants to the tune of 1,486 units in UP, 1,111 in Punjab, 307 in Haryana and 38 in Rajasthan with a total capital cost of Rs 47,004 crore for the four states. A couple of small-sized plants are already in operation and it is learnt that there is demand for such a gas as it is cheaper than natural CNG. There is, thus, a rationale for creating an environment to establish a sufficient number of bio-CNG plants so that the hitherto serious problem can be turned into virtue.
Instead of only subsidising the machinery for incorporating the crop residue in the soil, the government needs to think of handholding private entrepreneurs venturing into the production of bio-CNG, at least during the initial years. The options can also give additional income to farmers besides improving the air quality and environment. Financial resources can be mobilised through corporate social responsibility (CSR) as rural development and environment are included in CSR activities. The labour component for baling and transporting crop residue to the plant may be covered under MGNREGA. NABARD can also be roped in for financial resources and technical advice.
The writer is professor of eminence, Guru Nanak Dev University, Amritsar, and professor of economics, CRRID, Chandigarh.