Soil degradation causes severe reduction in crop yield
27 Jan 2019
Dr Rattan Lal, Distinguished University Professor of Soil Science at The Ohio State University in Columbus, has been honoured with prestigious Japan Prize for 2019 for his outstanding contribution to sustainable soil management for evaluating recommended agricultural practices which reduce risks of soil degradation and of anthropogenic climate change.
Nirmesh Singh, Editor of AgriNation, in conversation with Dr Rattan Lal to understand why soil degradation is an important issue and what India should do.
What is soil degradation? What are the factors of soil degradation? Why is it an important issue? How does soil degradation affect the crop production?
Soil degradation refers to decline in soil health, and the attendant reduction in capacity of the soil to produce goods and services of interest to human and nature. Factors affecting soil degradation include erosion (by water and wind), depletion of soil organic matter content and plant nutrients, salinization, acidification, compaction and reduction in soil biodiversity. It affects at least one-third of the entire land area of India. It is important because of its adverse effects on health of human and the environment especially the quality of water, and air. Depending on the severity of soil degradation, it causes a severe reduction in crop yield. Yield of most crops in India are low because of soil degradation.
The problem of soil degradation is aggravated by land misuse and soil mismanagement such as burning of crop residues, removing soil for brick making, excessive irrigation with brackish water, lack of manuring and use of unbalanced fertilizer (applying nitrogen but not phosphorous, potassium or micronutrients such as zinc)
What is your research about and how is it going to reduce risks of soil degradation?
The research shows that risks of soil degradation are reduced by adoption of improved practices such as keeping the soil covered, retention of crop residues on the soil surface rather than in-field burning, controlled grazing, using compost and green manure, adopting integrated nutrient management based on combination of organic and inorganic fertilizers as guided by soil test, not removing soil for brick making, avoiding flood irrigation and using sprinkler or drip irrigation, and reducing ploughing on sloping land and instead using vegetative barriers planted on the contour, growing cover crops.
How does a farmer contribute to soil degradation and what are the best agriculture practices to prevent it?
Farmer contributes by using extractive farming. Soil is like a bank account. You cannot take out more than what is put in it. Thus, soil must be protected, restored and improved. All ancient scriptures in India emphasize the protection of “Dharti Mata” (Mother Earth) and existence of human beings in peace with the natural elements – air, earth, water, fire and ether. They also highlight the importance of soil for well-being of humans. Sustainable and efficient use of water and other natural resources is also highlighted in holy Quran. Agriculture practices as discussed above must be adopted by farmers for good soil health.
Does climate change also play a role in soil degradation?
Yes, soil degradation increases risks of climate change, and it in turn is aggravated by the changing climate. These two aggravate one another.
What is the level of damage that has been done till now in the world, including India?
In the world about 2 billion hectares of land are degraded. In India about 115 million hectares are degraded. It is a very serious problem in India, South Asia and globally.
Do you think there is a need for National Soil Policy in India?
Yes, there is an urgent need for India to have a national soil protection policy.