A Way of Agriculture To Manage Both Land Degradation, Groundwater Depletion
Paddy farmers in the field, in Gingee, Tamil Nadu, December 2018. Photo: rajeevrajagopalan/Flickr, CC BY 2.0.
I have two pots of snake plants of similar age on my balcony, both planted on the same day but with different soil fills. One has cocopeat – coconut shell powder mixed with soil – and the other has regular, local soil, which has lower soil carbon content. This is why the plant growing from cocopeat is taller, has broader and more colourful leaves. Most productive Indian soils have less than 0.6% soil organic carbon; healthy soil should have at least 0.75%. The more the soil’s carbon stock, the healthier the plant, the people and the planet.
On October 2, Rattan Lal, who received the World Food Prize this year, delivered a virtual lecture in which he discussed how gradual soil degradation and loss of soil carbon contributed to the collapse of grand civilisations through history – from the Inca in the Andean region to the Indus Valley civilisation. His point was that a similar fate may await us if we don’t pay more attention to our soils.
According to the recently published Desertification and Land Degradation Atlas of India, 96.4 million hectares – making up 29% of the country’s total geographic area – became degraded from 2011 to 2013. The most important process of degradation was water erosion, which contributed to 11% of the total degradation.
Why is water, which should be enriching our aquifers, degrading land? Agriculture accounts for 90% of India’s freshwater consumption, and gets this water mostly from the ground. It’s also true that, according to the Central Groundwater Board, some 40% of our groundwater units are not in the ‘safe’ category. Both the Centre and state governments have been attempting different institutional, economic and technological ways to address the problem of groundwater depletion (if they are).
So as such, we are facing a potential crisis on two fronts: groundwater depletion and land degradation led by water erosion. In the longer term, both these forces will also accentuate the effects of climate change. To keep feeding our huge population, as well as export food, one place we need to look is right beneath our feet: the soil.
In this regard, consider the concept called conservation agriculture (CA). It consists of three agro-ecological practices: no ploughing, maintaining a permanent soil mulch or cover, and diversification in the cropping system. CA addresses both water management and checking soil degradation. This system increases water supply by capturing and releasing water in aquifers, with zero-tilled soil acting as a catchment. It also downsizes the crop demand for water by reducing evaporation and transpiration losses.
The 2020 World Water Development Report has endorsed CA for water management. Other alternative sustainable agriculture practices, including zero-budget natural farming, permaculture and direct-seeded rice, also adopt some principles of CA, although not all.
The agro-ecological literature includes many other benefits for farmers, including gradual reduction in fertiliser need, cost-savings and increased yield. According to one well-known paper, authored by Rattan Lal and published in 2004, a gain in carbon stock by one tonne per hectare of degraded land could translate to crop yields of wheat, maize and cowpea increasing by 20-40, 10-20 and 0.5-1 kg, respectively.
Bio-sequestration of carbon, using practices like CA, has the potential to offset 5-15% of the world’s fossil fuel emissions, by reducing 0.4-1.2 gigatonnes of carbon per year. Covering the soil with residue could also reduce the soil’s temperature by 4-5º C.
But for all these benefits, a continuous, zero-till CA system has yet to find widespread adoption within India.
In my experience working with farmers, as part of the Aga Khan Rural Support Programme, I have noticed a few barriers. First, the CA system is site-specific; it is not a “one size fits all” approach. It requires farmer-led testing plots at each new site, and which can then be scaled up gradually. Second, many farmers believe that tillage or ploughing is necessary for crop cultivation, and ploughing requires both farmers and extension workers to be trained.
Third, it is difficult to manage weeds. In June this year, for example, The Tribune reported that paddy farmers in Punjab rejected direct-seeding because “they require more seeds and have to spray weedicides twice, so the input cost doesn’t reduce” as was “being advertised” by the state agriculture department. In this regard, the support of the government and civil society is vital. Fourth, it’s important to have enough mulch or residue to keep the soil covered – but farmers typically burn this material.
Finally, farmers need the right kind of mechanisation to practice zero-tillage. Some solutions already exist, such as the multi-crop ‘Happy Seeder’ and jab-planter for smaller plots. Adopting CA could also provide opportunities to introduce small mechanised zero-till implements; mechanised, tractor-based tillage accounts for about 22% of mechanisation in Indian agriculture.
India’s precarious groundwater situation, land degradation and the threat of climate change all together make CA a desirable proposition – at least if we intend to tackle these challenges without comprising our agricultural productivity.
First published by The Wire on 12 Oct. 2020