Soils: Blowing in the wind

As the International Year of Soils (2015) draws to an end it may be pertinent to ask, how clean is our soil. Soil and clean Sounds like an oxymoron. Perhaps that is why, while we speak of clean water or clean air, there has been very little talk about soil contamination. Like air and water, soil too has a direct bearing on the health of the people as 99 per cent of the food we eat grows on soil. Along with the food, we are also ingesting pollutants from the soil. Yes some of the pesticides and chemicals from the soil have entered our food chain. Before we go into more details, some facts about soil.

Soils are not inert. They are dynamic living systems. In fact, nowhere in nature are living species so densely packed as in some soil communities. Many insect species are soil dwellers for at least some stage of their life-cycle. A typical healthy soil is home to several species of vertebrates, earthworms, 20-30 species of mites, 50-100 species of insects, tens of species of nematodes, hundreds of species of fungi, bacteria and other organisms. Soil biota are central to decomposition processes and nutrient cycling. Soil is one of nature’s most complex ecosystems and one of the most diverse habitats on earth. Organisms inhabiting soils form a complex web of ecological activity called the soil food web that makes all life possible.

Take the humble earthworm, for instance. They ensure good, healthy soils, tirelessly digesting leaf litter and other biomass along with soil. In so doing, every 24 hours they produce one and a half times their weight of rich compost, high in all plant nutrients. The earthworm’s night soil has bacterial population that is nearly a hundred times more than in the surrounding soil. While burrowing they till the land, making it porous and easy to breath for the roots. By increasing the soil’s capacity to hold air, moisture and aggregates it helps to resist erosion. Like earthworms, other organisms living in the soil also nourish it. On good soils depends our world’s food security: let us not mindlessly trample upon them.

Ironically, actions we took, or are still taking, to make land more productive in order to meet the food requirements of our growing population have caused immense damage to our soil. The harm caused by excessive use of pesticides and chemical fertilisers has been so extensive that it could pose a real threat to our food security. And by 2050 the earth’s population will bulge to 9.6 billion. Unfortunately, much of this “bulge” will come from India, besides China and neighbouring South Asia. The world will need 60 per cent more food. India, for sure, will need to arrest the bulge and reverse land degradation. A third of India’s land is already degraded, putting a question mark on the sustainability of its food production.

According to (2010) estimates of the Indian Council of Agricultural Research, of India’s total area of 328.73 mha, about 120.40 mha is affected by various levels of land degradation. Nearly a quarter of India’s land is affected by desertification. As water and wind erosion is widespread across India, some 5.3 billion tonnes of soil gets eroded every year. Of this, 29 per cent is permanently lost to the sea, 10 per cent is deposited in reservoirs reducing their storage capacity, and the rest 61 per cent gets shifted from one place to another. Desertification or soil erosion, mainly caused by wind and rain, are natural phenomena we can mitigate by providing forest or other vegetation cover.

Where we need to bring about a major change is in the judicious use of pesticides and chemical fertilisers. Currently, many of the pesticides that India produces and uses extensively have been banned in other parts of the world. For instance, Monocrotophos, banned in the US because it killed birds and a wide variety of non-target insects, is still being used in India without any supervision. Excessive use of chemical fertilisers and pesticides is particularly high in the north-western part of the country and is one of the major reasons for soil degradation. A fallout is that the pollinator population — bees, butterflies, insects and even birds — has dropped drastically, a fact borne out by the Global Pollinator Project that was implemented by FAO, GEF and UNEP in 12 countries including India.

Reviving soils or pollinators will require an ecosystem approach to farming. It’s time we realised that farming is part of the eco-system and that soils have to remain sustainable for future generations, also keeping in view its important role in carbon sequestration. For now, the responsibility for soil health lies somewhere between the MoA, MoRD, and the MoEFCC. Their energies need to be synergised and the ministry of chemicals and fertilisers, responsible for all the pesticides and chemical inputs, needs to be brought into the discourse of soil health. It has to be an integrated approach.

The country’s recently launched Soil Card programme may, to a certain extent, solve the problem, provided it is backed by extension services to farmers. While a wealth of knowledge and research on soils exists in the country these need to be communicated to farmers. Unfortunately, simple measures like using leguminous plants in nitrogen fixing through crop rotation or mixed cropping are not being practised extensively. The results are there for all of us to see. Perhaps it is still not too late to make interventions that prevent or even reverse land degradation. We need to remind ourselves, it takes a thousand years for 1 cm of soil to be formed. Let’s prevent our soils from being blown away in the wind.

Shyam Khadka is the India representative of the UN Food and Agriculture Organisation