Environmental Studies(ES)

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ENVIRONMENTAL STUDIES

Lesson 5: Food resources

Water logging and salinity

Various water bodies like the rivers, streams, lakes and aquifers are in use for irrigation, is treated with millions of tons of chemical fertilizers and pesticides for improving yields resulting water quality degradation due to their residues. Irrigation activities associated with inefficient use of water in the arid and semi-arid zones served by dams is causing salinity. The addition of salts to the soil and its underlying strata by irrigation water contributes to salinity. Vast areas of land with deep-rooted natural vegetation have been cleared for farming which is resulted in the streams and enhance their salt content. Salinization reduces soil productivity. In advanced stages it kills all vegetation and transforms fertile and productive land into barren land, leading to loss of habitual and reduced biodiversity. Economically, salinization causes huge losses through reduced food production and other damages.

In many countries where populations are expanding rapidly, the production of food is unable to keep pace with the growing demand. There are great disparities in the availability of nutritious food. Intensive agriculture operations, fossil fuel combustion and widespread cultivation of leguminous crops have led to huge additional quantities of nitrogen, land degradation and fall in agriculture produce. Spraying of pesticides had lead to ecological damage like human toxic effects, cancer and respiratory diseases, soil erosion, water logging and salinity.