Soil degradation is defined as a change in the soil health status resulting in a diminished capacity of the ecosystem to provide goods and services for its beneficiaries. It includes loss of organic matter, decline in soil fertility/structural condition, erosion, adverse changes in salinity, acidity or alkalinity, and the effects of toxic chemicals, pollutants, excessive flooding/overgrazing/mining.
According to National Remote Sensing Centre (NRSC), out of 329 M ha total geographical area of India,120.4 M ha area is degraded through one or more degradation types, which in turn, is affecting the country’s productive resource base.
Socio-economic consequences of soil degradation include:
1.Loss of Productivity and arable land: It leads to reduced income for the farmers which have implication for the economy as a whole, threat to food security, higher production costs; it also hampers poverty reduction especially when agriculture is the dominant occupation.
2.Infrastructure damage: Degraded pastures may lead to floods and landslides thus imposing significant costs to land, property and human life, cost of treating siltation of reservoirs etc.
3.Rise in natural disasters: such as mud flows, floods, droughts and aridity.
4.Increased land reclamation costs: cost of afforestation, de-salinization etc.
5.Rise in inequalities: Reduced income in the absence of other alternatives to livelihood aggravate inequalities for families completely dependent on soil.
Soil provides various ecological services like nutrient cycling, carbon storage and habitat for living organisms.Soil degradation threatens these services and has other undesirable consequences like:
1.Sedimentation and eutrophication of waterways and reservoirs: leading to water pollution.
2.Soil compaction and surface sealing: It will affect the percolation capacity of soil, thus, affecting recharge of groundwater
3.Soil contamination (including effects of toxic chemicals and pollutants) :This affects nutrients in food crops.
4.Loss of biodiversity: Soil degradation may involve perturbation of microbial communities, disappearance of the climax vegetation and decrease in animal habitat.
Measures that can be taken to restore soil fertility and arrest soil degradation are:
1.Afforestation: it restores the carbon cycle, binds the soil and prevents soil erosion while facilitating soil formation.
2.Tackling salinization: by improving irrigation efficiency, using gypsum to reduce salinization.
3.Improved Agricultural practices: Conservation tillage (makes minimal changes to the soil‘s natural condition), strip farming, crop rotation, contour farming, rational use of fertilizers and pesticides, moving towards organic farming; preventing slash and burn agriculture, promoting soil testing to ascertain the nutrient requirement of the farm , agro-ecological farming etc.
4.Improved data management and coordination between various stakeholders.
5.Land use planning for agriculture, settlement and industry.
Soil degradation threatens world food security and various ecological services especially in the face of growing population and global climate change and needs to be tackled in earnest.This requires the systematic knowledge on the soils, their extent, distribution, characteristics, problems and potentials for optimizing land use. Innovations, in both science and farming practices, are urgently needed to achieve this goal, and efforts need to be taken by both policy makers and the public.