Soil resources are national treasure
Soil is a marvelous gift of nature to mankind. Without the presence of this thin layer on the top of earth, there would have been no life on the planet Earth. Hinduism pronounces ‘Man’s journey in the world begins with soil and ends with soil’. Soils and humans have evolved together- if soil get ruined, it takes humans and other lives along with it.
With the intent of raising level of awareness, appreciation and understanding on the role soils play in sustaining food security and securing essential ecosystem functions. We depend on soil for food, fiber and medicine. Soil acts as an engineering medium, a habitat for soil organisms, a recycling system for nutrients and organic wastes, a regulator of water quality, a modifier of atmospheric composition, and a medium for plant growth, making it a critically important provider of ecosystem services. Since soil has a tremendous range of available niches and habitats, it contains a prominent part of the Earth’s genetic diversity. A gram of soil can contain billions of organisms, belonging to thousands of species, mostly microbial, some worms, ants, termites etc.
Health of the soils a nation owns determines the quality of well-being of its people’. Humans for their own survival and for the sake of survival of their future generations, therefore, must not violate the quality of the soils inherited by them. Father of Green revolution Dr. MS Swaminathan once said ‘micronutrient malnutrition in soil breeds micronutient disorders in human- soil anemia breeds human anemia’.
Soil degradation & consequences
Unfortunately soil is subjected for rapid degradation, reducing its capacity to produce crops. Different types of soil degradation are loss of soil organic matter, soil erosion, soil acidification, soil pollution, soil salinisation, soil biodiversity loss, soil nutrient imbalance and nutrient deficiencies. As per UNO study, on an average it takes 30000 years to form 30 cm deep soil. Hence soil is precious for human survival.
Consequences of soil degradation are food and nutrient insecurity, water scarcity, climate change, mass migrations, reduction of ecosystem services.
In India about 32% of soils degraded (105 million hectares). In the world 40% soils (1035 Mha) degraded and 50% humans affected by soil degradation. Faulty agricultural practices like excessive and inappropriate tillage, excessive use of fertilisers & pesticides, excessive use of irrigation water, inappropriate cropping pattern, increased urbanisation caused soil degradation.
In the world 1035 million hectares (Mha) of degraded soils were reported, of which 33% (370 Mha) were found in Asia continent. In India of 142 Mha net cultivated area about 105 Mha of degraded farm land was reported. Among the factors contributing for soil degradation, soil erosion contributes for maximum damage (85.7 Mha - water erosion 73.3 Mha and wind erosion 12.4 Mha).
Soil fertility loss is another potential threat land degradation in India. National wide recent assessment based on lab analysis showed about 86% of are low in available N, 49% area are low in available P 20 % low in K, 25% low in S, 43 % low in Zn, 14% low in Fe, 7% low in Mn, 8% low in Cu and 21% low in B of Indian soils. This low fertility caused farmers to use excessive fertilizers. The fertiliser subsidy to Indian farmers causing increasing burden on the government’s exchequer (Rs.1,95,467 crores during 2023) in one end and their low use efficiency causing soil and environmental pollution in the other end. Excessive fertiliser use linked to pollution of groundwater with nitrates has become a serious health concern in soils receiving higher doses of fertiliser nitrogen. Nitrate pollution of ground water above the permissible levels in intensive cultivated areas of Punjab, Haryana, Gujarat, Maharashtra and Andhra Pradesh has been reported. Nitrous oxide (N2O), a potent greenhouse gas, has the global warming potential of 298 relative to 1 of CO2. Fertiliser N is the largest source contributing around 77% of the total direct N2O emissions from the agricultural soils. The disproportionate application of nitrogen fertilisers in relation to phosphorous and potassium fertilisers is cause of concern of soil degradation. The recent statistics showed the N:P:K use ratio of 8.0:2.9:1.0 in 2022-23 indicating imbalance use of P and K compared to recommended ratio of 4:2:1. This unhealthy trend needs to be reversed through development of appropriate strategies and policies to avert disastrous consequences.
Another form of soil degradation is Acidification of soils due to faulty use and excessive nitrogen fertilisers application. In our country about 26 Mha soils are moderate to strongly acidic. Soil Salinity is another soil health concern. In India, currently soil salinity influence productivity of 6.7 Mha. Soil pollution to an extent of 2.0 Mha due to mix of industrial effluents and urban solid wastes to soil.
Monitory losses of soil degradation
The deterioration in health of world soils, resultant economic and environmental consequences worldwide, not only loss of soil nutrients, eroded soils also get depleted of their native water storing capacity. In India it was reported annual soil loss of 5250 Mt which is equivalent to Rs.2,60,000 crores. Salinity is another global soil health concern. In India, currently excess salts influence productivity of 6.7 Mha, which is equivalent to about 5% of the net cultivated area. On the basis of conservative estimates (on 5% production loss basis), it sums up to about 12 Mt of food grains, valued at nearly Rs.9000 cores per annum.
Some of the solutions for control of soil degradation
(i) Strengthening of soil & water conservation schemes like integrated watershed development program (IWSDP), National Mission for Sustainable Agriculture (NMSA), NABARD etc for farmers participatory soil conservation. Contour cultivation, bench terracing, mixed cropping, intercropping methods reduce soil erosion.
(ii)Encourage organic/ natural farming to reduce fertilizer use and atmospheric pollution. Union government has approved a new Rs 2,481 crores National Mission on Natural Farming (NMNF), targeted at around 1 crore farmers by amalgamating all previous efforts made in this direction.
(iii) Soil site specific nutrient management (SSNM) and soil test crop response (STCR) based fertiliser recommendation methods will not only reduce fertiliser requirement but also improve crop yields besides reducing pollution. Needs adoption of advanced soil test methods like spectroscopic techniques for quick, easy and more accurate assessment.
(iv) Develop popular literature on aspects like importance of soil testing, balanced fertilizer use/integrated nutrient management etc. in local languages, and made available.
(v)Implement comprehensive land use planning to balance stakeholder needs while preserving soil health and quality.
(vi) Promote practices like terrace farming and rainwater harvesting for land restoration, increased crop yields, reduced emissions, and carbon sequestration.
vii) Promote zerotillage for improving soil health.
viii) Adopt more efficient irrigation methods like Drip and Sprinkler irrigation systems to reduce soil erosion, increase crop yield and economise irrigation water.
ix) Reclamation of acid soils by adding Lime fertilisers and reclamation of sodic soils by addition of Gypsum fertiliser will bring those degraded lands under cultivation.
Keeping the importance of valuable soil in to consideration United Nations Organisation and Food & Agricultural Organisation promoting celebrations of World Soil Day on 5th December every year with special theme. This year’s theme is “Care for Soil- Measure, Monitor and Manage” aiming to bring awareness among the governments and farmers to measure and quantify extent of soil degradation, monitor the soil degradation block wise/tahsil wise for initiating appropriate control measures and finally manage soil resources with utmost care and concern.
(The writer is Professor & Head, Agricultural College, Naira Acharya NG Ranga Agricultural University, Andhra Pradesh)