Experts at a CSE webinar warn that soil biological health remains a critical blind spot in Indian agriculture.
Evidence shows degradation due to pesticides, monocropping, residue burning and excessive fertiliser use.
Integrating biological indicators into national soil monitoring, scaling affordable tests and promoting agro-ecological practices vital.
These can help restore productivity, cut emissions and improve nutritional security.
Earlier this week, the Centre for Science and Environment (CSE) organised a webinar on ‘Improving Soil Biological Health’ to discuss its latest report on the issue. The webinar brought together a panel of leading scientists, policy experts, and industry innovators to discuss the report’s findings.
The expert panel included Alok Kumar Srivastava, Director, ICAR-National Bureau of Agriculturally Important Microorganisms, Debashish Mandal, Head and Principal Scientist, Soil Science and Agricultural Chemistry Division, ICAR-Indian Agricultural Research Institute, Ramanjaneyulu GV, Executive Director, Centre for Sustainable Agriculture, Prafull Gadge, Founder and CEO, Biome Technologies Pvt Ltd, Amit Khurana, Director, and Rajeshwari Sinha, Senior Programme Manager from the Sustainable Food Systems Programme, CSE.
The findings of the report Improving Soil Biological Health: The Role of biological Components and Monitoring Approaches — were presented in the webinar. It emphasised the need to focus on biological health of the soil towards improving overall soil’s health and monitor it as part of routine national-level monitoring. This was followed by a panel discussion where experts shared their insights on this critical, yet often ignored, biological dimension of soil, the engine of agricultural productivity.
Experts recognised that degradation of Indian soil is a growing crisis, and that soil biological components play a vital role when it comes to improving the status of declining soil health.
Key drivers contributing to deteriorating soil health include indiscriminate pesticide and agrichemical use, crop-residue burning, monocropping, dependence on high-yielding varieties, poor organic matter recycling, and soil compaction due to mechanisation. This has led to a high imbalance in the natural soil community that helps in maintaining microclimate of soil and in nutrient cycling. There is therefore a selective negative pressure on soil as well as plant microbiome. Excessive fertiliser use also causes nitrate pollution and nitrous oxide emissions.
Microorganisms in soil (such as bacteria, fungi) serve as essential vehicles that solubilise bound nutrients, making them plant-available and suitable for uptake. Without healthy soil biology, fertiliser uptake efficiency also remains low — nitrogen use efficiency is only 30-40 per cent, while phosphorus efficiency is 15-20 per cent. A better soil biological health is also linked to better soil physical health, and overall soil function.
The importance of testing soil biological parameters was acknowledged, provided there is support available in terms of right infrastructure and expertise. At present, soil testing laboratories are focusing on nutrients and are not equipped to measure soil biological functions.
There was a broad consensus that it is possible for soil biological health monitoring to be integrated as part of national level monitoring schemes. Enzymes like dehydrogenase and urease (tests for which can cost upto Rs 100-200 per test) were suggested options for monitoring from point of view of feasibility, affordability.
Other enzymes like phosphatases and glucosidases, microbial biomass carbon, and total viable microbial counts could also be explored if simplified methods are available or developed. Concerns regarding feasibility of using high-end molecular tools such as 16S rRNA and metagenomic approaches for large-scale on-the-ground testing were noted.
In addition to the above, the need for tests at farmer level (simple, visual, easy-to-do, adoptable) to help them take a decision was highlighted. In line with this, point-of-care testing is a potential solution for monitoring soil biological health on-farm and on a real-time basis. However, challenges remain around validation, accuracy, low awareness and farmer adoption of such on-farm test models.
Experts agreed that while direction of change towards monitoring soil biological health is clear, the focus must now shift to speed and scale of implementation of measurement approaches.
For better soil biological health, there is need for parallel efforts to be made as microbes cannot be seen independently of soil, cropping system and agronomic practices. This involves practices such as reducing tillage, stopping puddling of rice, reducing fertiliser use, building more crop diversity and improving soil organic matter in farms.
Agro-ecological practices like cover crops, mulching and intercropping can also help to maintain living roots, essential for soil biological community’s survival and function. Farmers therefore need a plan and ecosystem for such transition backed by knowledge and financial support.
The deliberations also looked at the need to move away from centralised, lab-based bio-fertilisers towards production that is locally adapted, decentralised and fits regional soil conditions. This is so because India’s wide variety of soils and cropping systems harbor a different and diverse community of microbes.
The scientific community is in parallel working to map, isolate and characterise microbes specific to different regions of India. Research is also in progress to develop microbial formulations that can work for a specific crop for a particular set of conditions (smart bio-formulations) through synthetic community based strategies.
The limited impact on soil health improvement due to the current policy frameworks was also highlighted. Select national and state level policies for promoting non-chemical based farming approaches exist, but they do not seem to be moving on the ground. Centralised lab-based testing and data generation has not been able to positively impact fertiliser use, cropping pattern change, fertiliser subsidy patterns or farmer decisions.
There is need for government support to help farmers transition to better sustainable farming practices. For example, clear goals should be set for states to reduce chemical fertiliser use such as by 25-30 per cent over five years. Repurposing of subsidies and shifting financial support from chemical use to rewarding farmers who are transitioning to organic and natural farming can be considered. Alternative programmes to promote organic and natural farming should consider an area based approach rather than the current individual focus.
Declining soil health has been shown to be associated with growth of nutrient-poor crops — crops lacking in nutrients like zinc and iron. This is also contributing to the growing micronutrient deficiencies in population, as well as stunting and wasting in children.
Beyond productivity, experts argued that better soil biological health can also be linked to nutritional security and availability of chemical-free food. Improved nutrient uptake efficiency driven by better soil biology can reduce need for fertilisers, providing farmers with better livelihood and at the same time obtain better and increased yield.