Soil is the next gold — this is as down-to-earth as it can be. This stepped-on material, which we take for granted, holds the key to so much we need to change in our world — from increased productivity, so we can grow more food, to sequestering carbon that is pushing temperatures to catastrophic levels. But this requires revisiting our understanding of what makes soil rich and what makes it tick.
Science is relearning this knowledge, bringing renewed focus to the wealth below, not just the plants above ground. The fact is, we are so much poorer because we do not accept that soil is a living being; that its health is measured by the millions of micro-organisms, bacteria and fungi living in it. This is the future.
Let’s join the dots. Today, we are learning that our health depends on the health of our gut microbiome. Emerging medical science is linking gut health to the diversity of living micro-organisms that must thrive in our bodies. These bacteria, fungi and virus number in the trillions and mostly reside in our large intestine and colon. It is estimated that one spoonful of stool contains more bacteria than all the people in the world. The key to the functioning of this “second brain” of our body lies in the diversity of these micro-organisms, which, in turn, is influenced by multiple factors, most importantly, what we eat.
Food science is learning about the mechanisms through which our diet interacts with the gut biome and impacts it. For instance, food high in sugar promotes the growth of certain opportunistic bacteria that can outgrow good bacteria and so on. The bottom line of this emerging science is that the more natural and diverse our food is, the more diverse will be the army of these micro-organisms in our gut.
But why am I digressing to food when we are discussing soil. Firstly, because it tells us how off-track science was for so long. We believed that we could push chemicals into our bodies and into our soils, and that all would be well. Instead, what we need is to build the foundations of health — whether of our soil or our body — and this requires us to invest in the diversity that makes bacteria and fungi to thrive. We need life for life.
For most conventional agriculture, soil needs inputs of nutrients, which are chemical fertilisers. India’s soil health card, for instance, focuses on chemical parameters of soil — nitrogen (N), potassium (P), phosphorus (K), organic carbon and minerals like zinc, magnesium and copper.
The focus is on npk, and the highest charge on public exchequer is the subsidy for chemical fertiliser, which has been increasing each year and stands at a whopping Rs 1.71 lakh crore, equivalent to 3 per cent of the country’s annual budget. India is the world’s biggest importer of these chemicals and given the blockades and disruptions of the war in the Gulf, this subsidy amount is expected to double in this financial year. This is a massive public investment to grow food.
The question is if this is really what the soil needs. My colleagues did an analysis of the 13 million soil health cards produced between 2023 and 2025, correlating fertiliser usage to the nutrient quality. We found that despite this heavy dosage and a 20 per cent increased usage of chemical fertilisers in the country, soils remained severely deficient in nitrogen and other macro- and micro-nutrients. This declining soil health is, in turn, adding to the crises of higher inputs, higher costs to farmers and lower returns.
This is where we need to understand the life below the soil. These soil organisms — micr-obiota like bacteria, fungi and algae; microfauna like protozoa and macrofauna like earthworms or beetles — are important as they work the soil, improving its ability to absorb nutrients, support plant growth and increase yields, much like our gut. Also, like our gut, the diversity of micro-organisms, depends on the diversity of crops grown. We need ways to monitor this biological health of soil so that we do not discount the wealth beneath our feet.
But this is not all. We know that soils are one of the world’s largest reservoirs of carbon. Given the fact that we have run out of time to mitigate greenhouse emissions, we need ways to enhance the ability of soils to sequester carbon — just as plants and trees, soil can take carbon out of the atmosphere. The question is how this will be mobilised, and this, again, brings us to the science of soils and the fact that this army of micro-organisms makes it all possible.
It is also emerging that while the measurement of soil organic carbon is important, it is only a proxy of soil’s biological health. This is because soil organic carbon measures both living (active) and dead (inert) carbon, but biological health is about active carbon. The analysis of India’s 13 million soil health cards also revealed that about 50 per cent of samples tested were low in organic soil carbon — and we do not even measure the life within.
All in all, this tells us how little we know and how we need to celebrate life’s little creatures that make it work.