Soil conservation and soil degradation

Dr HH Mate
Contd from prev issue
Conservation measures and technology: Measures of soil management designed to reduce the effects of accelerated erosion have been known in both the Western world and in the Far East since long before the beginning of the Christian Era. The value of forest for watershed protection was known in China at least ten centuries ago. The most important of the ancient measures on agricultural lands was terrace construction, although actual physical restoration of soil to original sites also has been practiced. Terrace construction in the Mediterranean countries, China, Japan and the Philippines represent the most impressive remarking of the face of the Earth before the days of modern earth- moving equipment. Certain land management practices that were soil-conserving have been a part of Western European agriculture for centuries, principally those centering on livestock husbandry and crop rotation. Conservational management of the soil was known in colonial Virginia and by Thomas Jefferson and others during the early years of the United States. However, it is principally since 1920 that techniques for soil conservation have been developed for many types of environment in terms of an integrated approach. The measures include farm, range, and forest management practices, and the building of engineered structures on land and in stream channels.
Soil Degradation: Loss in the quality or productivity of soil as a result of human activities is called soil degradation. Degradation is attributed to changes in soil nutrient status, loss of soil. Organic matter deterioration of soil structure, and toxicity due to accumulation of naturally occurring or anthropogenic materials. The effects of soil degradation include los of agricultural productivity, negative impacts on the environment and economic stability, and increased clearing of virgin forest and exploitation of marginally suitable land. Soil degradation has occurred over a large scale, over 2 billion hectares or, 5 million acres, and continues at a rate of perhaps 5  million hectares or 12 million acres per year.
    Soil consists of both solid space and pore space, the process being filled with water and air in various proportional soils vary widely in the extent and nature of organization of the solid phase or structure. Soil structure in part determines the stability of land for crop production or the vulnerability of land to erosion. Misuse of soil often results in compaction or densification, that is, loss of pore space. Compaction affects  the flow of water through soil and impedes growth of plant roots. Compacted soils generate greater runoff during storms and tend to be sensitive to soil erosion. Erosion results not only in lost soil productivity but also in contamination of lakes and streams with sediment and associated agrochemical. Wind erosion of unprotected soil can induce the development of desert like conditions or desertification. Soil degradation may impair the function of soil organism and thus natural conditions, soil offers a diverse habitat for many kinds of macro and microorganisms. The microbial community consists largely of bacteria, fungi, algae, and protozoa. Bacteria are the most numerous, whereas fungi represent the largest fraction of the microbial biomass or living mass. The soil microbial community is essential to cycling of nutrients and decomposition of wastes; thus hindrance of microbial activities may have serious ecological results. Microbial communities in arable land are usually resistance and able to recover from most environmental insults, such as deposition of toxic chemicals. Some soil ecosystems, such as a tundra, are more fragile than others and thus recover more slowly from perturbations. Though microorganisms tend to withstand transient chemical insults, soil microbial activity is generally closed related to the level of soil organic matter, thus degradative forces such as erosion that result in loss of organic matter may also result in long-term losses of microbial activity.
    Soil degradation often affects productivity through depletion of plant nutrients. Excessive leaching of cations involved in buffering soil pH may result in soil acidification, changing the solubility, and thus availability of certain nutrients to plants. It is also possible for misuse to result in concentrations of chemicals that are toxic to plants. Extreme land management practices, such as clear cutting of forests may result in long-term changes in nutrient cycling. Re-establishment of a forest floor after clear cutting may take as long as 500 years.   
* The writer/author is the eminent educationist sociologist and researcher/scientist. He visited/toured 30 capital cities and important cities of foreign countries during 1989-2020.He was awarded/conferred 8 doctorate degrees in different fields and knighthood degree by Indian universities & foreign universities. The author/writer of this paper can be reached at [email protected]