Next time you step on soil; look down and think. Soil is the next gold -- this is as down to earth as it can be. But it is not about the ground we step on; it is about the treasures below. If we understand this we can find solutions to our food; we can find answers to climate change.
Why do I say so? I am Sunita Narain, this is my show and thank you for watching me; thank you for all your support. Once again, my appeal to you is that please do like, please do share and please subscribe to our channel, Down To Earth.
Soil, earth, mud (mitti), is the most stepped on material. We take it for granted; we do not even think when we step on it; But it holds the key to so much we need to change in our world – from increased productivity so we can grow more food to sequestering or capturing carbon that is tipping temperatures to catastrophic levels.
But this will mean revisiting our understanding of what makes soil rich and what makes it tick. Science is relearning this knowledge so that there is a renewed focus on the wealth below, not just the plant above ground. The fact is we are so much poorer, because we do not accept that soil is a living being. If we do this, we will understand that soil health is measured by the millions of micro-organisms, bacteria and fungi. This is the future.
Just consider, how we must join the dots. Today, we are learning that our own health depends on the health of our gut biome. Emerging medical science is now linking our gut health to the diversity of living micro-organisms that must thrive in our bodies. These bacteria, fungi, virus are in the trillions; mostly in our large intestine, colon. It is estimated that one spoon of our stool contains more bacteria than all the people in the world.
The key to the functioning of this second brain of our body is how diverse is this body of living micro-organisms and this in turn depends on what multiple factors, including most importantly what we eat. Food science is learning about the mechanisms of interactions between what we eat and how it impacts the gut biome. So, for instance, food in high sugar breeds opportunistic bacteria, which can use fast fuel to outgrow good bacteria and so on. But the bottom-line of this new science is that the more natural and diverse our food is; the more will be the army of these living micro-organisms in our gut.
But why am I digressing to food, when we are discussing soil. Firstly, because it tells us how little and off-track science was for so long. We believed we could push chemicals into our body and into our soils, and all would be well. Instead, what we need is to build the foundations of health – our soil or our body – and this requires us to invest in the diversity that makes bacterial and fungi bloom. We need life for life.
For us soil is mud; for most agricultural scientists what soil needs is inputs of nutrients, which are chemical fertilizers that plants can use for their growth. India’s soil health card, for instances, focusses on chemical parameters of soil – nitrogen (N), potassium (P), phosphorus (K), organic carbon and minerals like zinc, magnesium and copper.
The key focus is on NPK – and the highest charge on public exchequer is the subsidy for chemical fertilizer, which has been increasing each year and stands at a whopping Rs 1.71 lakh crore, equivalent to roughly 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, it is expected that this subsidy amount will double in this financial year. This is a massive public investment and all to grow food that we need.
But 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 2023-2025; correlating the fertilizer usage to the nutrient quality. We found that despite this heavy dosage and a 20 per cent increased usage of chemical fertilizers in the country, soils remained severely nitrogen and other macro and micro-nutrient deficient. This declining soil health is in turn adding to the crisis of higher inputs, higher costs to farmers and lower returns.
This is where we need to understand living life below the soil. The reason these soil organisms – microbiota like bacteria, fungi, algae to microfauna like protozoa and macrofauna like earthworms or beetles are important is because they work the soil to improve its ability to absorb nutrients; for plants to grow and increase yield – pretty much like our gut. Also, like our gut, the diversity of micro-organisms, depends on the diversity of crops that are grown. We need ways to monitor the biological health of soil so that we do not discount the wealth below our feet.
But this is not all. We know that soils are one of the world’s largest reservoirs of carbon and given the fact that we have run out of time to mitigate greenhouse emissions, we need ways to enhance this ability of soils to sequester carbon – like plants and trees take it out of the atmosphere to make food. The question is how this will be mobilized and this again, brings us to the science of soils and the fact that this army of living micro-organisms makes this work.
What is also emerging is that while the measurement of soil organic carbon is important, but 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. India’s 13 million soil health cards also revealed that roughly 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. We need new science for new life.