Tackling the crisis of soil fertility

In his recent Mann Ki Baat, Prime Minister Narendra Modi talked about World Soil Day and emphasised on the destructive impact of excessive use of chemical inputs that has led to "damaging the health of Mother Earth" and called on farmers to cut the usage of urea by half to improve soil health and increase production. He talked about the importance of fertile soil to maintain a healthy food chain.  

The central government scheme of issuing Soil Health Card (SHC) to 14 crore farmers will enable them to understand their soil and help them grow suitable crops.

The NDA government hails its Rs 600 crore SHC project as one of the most ambitious programmes providing information on acidic levels, micronutrients and organic content of the soils. This is supposed to provide a scientific basis for improving soil fertility. Though the intention of providing SHC is noble, the way it is being implemented on the ground has raised doubts about its effectiveness in addressing the problem.  

Under the scheme, one sample is taken from a grid covering an area of 10 hectares in rain-fed land and from a grid covering 2.5 hectares of irrigated land. This kind of generalisation ignores the diverse soil characteristics within a small farm. For practical purposes, the SHC is of no use to an individual farmer as it does not represent the soil analysis of his individual farm.  

The organic matter present in the soil represents Soil Carbon (SC). The presence of SC is a definitive indicator of soil health. A high level of SC provides micro-nutrients to plants and improves water availability. Moreover, it improves soil structure, resulting in healthy plant growth.

Unfortunately, the availability of soil carbon in soils of India is abysmally low. The content of soil organic matter is 0.3% in the country; ideally, it should be 1-1.5%. This is due to extensive mining of soil fertility, soil degradation and indiscriminate use of fertilisers.  

The alarming rate of soil loss is 16.4 tons per hectare every year, according to a study conducted by Central Soil Water Conservation Research and Training Centre. About one millimetre of topsoil is being lost each year, resulting in a total loss of 5,334 million tons of fertile soil being eroded annually.  

The facts on the ground are more distressing. "In one acre of agricultural land, at least 200 tons of SC is required, whereas only two tons are present," says Narayan Reddy, who has been practicing organic farming for over four decades. His experience has shown that about 8-10 tonnes of SC is lost during the summer months, and the increasing temperatures due to climate change are accelerating the problem.  

The overall stagnation in agricultural production and low crop yields in the country is directly linked to loss of soil carbon. Ironically, instead of increasing the organic content in the soil, farmers are using more chemical inputs to increase the yields.

Poisoned soils

There is a close link between healthy soils and healthy food. With the indiscriminate use of artificial fertilisers and pesticides, the soils in our country have been heavily poisoned. Poisoned soils produce foods that cause health problems. We may produce more yields by applying more chemical inputs, but the final produce is devoid of micronutrients that are essential for building a healthy body.

The only solution to address the crisis of soil fertility is to grow biomass on the farm utilising available moisture and return this organic content back to soil.  

Instead of growing monoculture crops every year, crop rotation, fertilising with compost, increasing trees on the farm and covering the soil with live mulch during summer months are methods to increase SC. This helps to build humic substances, decomposing plant and animal matter that enrich the soil with micronutrients.

This requires a paradigm shift in the attitude of farmers from the deeply entrenched NPK (nitrogen-phosphorus-potash) mentality propagated by agricultural departments and research institutes.  

As farmers are already facing the impact of climate change, the crisis of soil fertility will exacerbate with rising temperatures. Conserving water and soil has to be the main objective to mitigate the impact of climate change. Obviously, increasing SC on the farm is one of the solutions to address the crisis.

Re-establishing harmony in the soil and regenerating the overworked soils is still feasible with the right interventions and policies. Organic farming provides an opportunity to enhance soil fertility and, at the same time, achieve sustainable crops that are wholesome.

With 17% of the world's population and just 2% of its geographical area, and high levels of malnutrition, it is essential for India to improve the condition of soil if it is to be able to provide food security and continued sustenance to the 55% of the population that is engaged in agriculture.

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