Prof. (Dr) R.D. Gupta
These days, environmental pollution is an emerging threat to living organisms belonging both to higher and lower categories, and as such there is great concern in today’s context pertaining to its effect on the overall ecosystem. The technological development in agriculture including horticulture and olericulture has resulted in unlimited exploitation of natural resources disturbing whole of the ecological balance between living and non living components of the biosphere. This disturbed ecological balance or imbalance in environment has affected not only the yield of various crops but has also caused lot of pollution in air, water and soil.
Air Pollution: Intensive agriculture sprawled by the green revolution led to air pollution. It is attributed to in appropriate use of fertilizers i.e; adding of more quantity of nitrogenous fertilizer (Urea) produced a number of pollutants. Major air pollutants are nitrogen oxide (NO), nitrogen dioxide (NO2), dinitrogen oxide (N2O), carbon monoxide (CO), gaseous halogens, peroxyacetyle nitrate, hydrocarbons, suspended particulate matter etc. When concentration of these pollutants becomes high, characteristic symptoms may appear on surfaces of leaves, even on flowers, seeds and fruits, thus decreasing the market value of the crop. Studies with a range of different pollutants indicate gradual increase yield loss with increasing concentration of pollutants as found in barley and soybean (Sarkar and Mishra, 2004). Air pollution also reduces rainfall in temperate region, according to a new study. It is an indication of how human activities are influencing global rainfall pattern.
Water Pollution: Now a days, water pollution is one of the greatest concern whose impact on agriculture is significant. There is an accumulation of heavy metals not only in soils but, also in soil moisture or water. Ground water has been contaminated with heavy metals such as Cadmium (Cd), Chromium (Cr), nickle (Ni), Lead (Pb). The ground water in most areas of Punjab, especially Bathinda carries uranium contents beyond the permissible limits (of 60 parts per billion) by the Bhabha Atomic Research Centre and WHO (15 parts per billion-ppb). The source of contamination is located at the ground level. The level of uranium in the groundwater is 50 per cent over the WHO norms. Although its sources of contamination is not yet known. However, environmentalists blame rampant use of fertilizers, pesticides and other chemicals to boost food grains production for the contaminated ground water. Arsenic contamination in ground water has been reported from West Bengal, India and countries like USA, Argentina, Chile, Finland, Nepal and Bangladesh. Out of 20 countries in different parts of the world, where from ground water arsenic contamination and human sufferings have been reported. Symptoms of arsenic poisoning include skin disorders, weakness, nausea and vomiting with diarrhoea or constipation. With the progress of poisoning the symptoms attain more characteristic features which consist of oedema, enlargement of liver, respiratory diseases and skin cancer. Arsenic contaminated irrigation water used in agriculture can inject the heavy metal into food web and, thereby, man. Indeed, arsenic uptake by crop plants grown in soils contaminated groundwater has been now noticed. The large scale of potential health impacts of arsenic is so high that it should be considered a public health emergency, deserving priority action.
As all nitrogenous fertilizers are soluble in water as such NO3 so formed after their application moves readily into the ground water. Heavy rains or irrigation can also carry NO3 into the ground water. High NO3 contaminated water causes “Methaemoglobinaemia” in infants after its drinking. In the agriculturally advanced states of Punjab and Haryana where fertilizer is used, had NO3 levels beyond safe limits in the wells as well as in many places of Varanasi and Jaunpur of UP, Gujarat and Karnatka.
Soil Pollution: Chemicals used in agriculture sometimes leaves considerable amount of residues depending upon persistency directly affect adversely beneficial soil organisms, especially nitrifying bacteria, azotobacters and rhizobia. Nitrifying bacteria (NItrosomons and Nitrococcus) are very essential for converting ammonical nitrogen to nitrate, which is taken up by the plants for their growth. Azotobacters and Rhizobia are responsible for fixing atmospheric nitrogen and, thereby, increasing the fertility of the soil. Accumulation of harmful gases such SO2, CO, NO etc, several organic and inorganic compounds in the soils in excessive quantities in long term use ultimately cause physiologically adverse effects on crop productivity. Not only this, chemicals used are widely associated with wide spread soil pollution, mainly depending upon the persistency of the chemicals.
Environment Management: Management of the environment requires a comprehensive and integrated approach in a sustainable manner. Although it is difficult task yet man made activities may satisfy to a considerable limit. Overall management approaches are as follows:
* Agriculture and food processing industries contribute significantly to environmental pollution. So, reduction in the emission from industry may help to stabilize, the present concentration of air pollutants.
* There is a need to spread awareness about the damage caused by the contamination of water resources. Cancer and water borne diseases are common among people consuming untreated ground water or water of rivers. People of Agra get water from the river Yamuna carrying poisonous water/runoff losses from fields of Haryana and Delhi.
* Now a days, scientists are concentrated on adoption of organic farming. It is because in organic farming there is use of biological alternatives in place of chemical fertlilzers and use of bio-pesticides or integration of chemicals and organics like treated municipal waste compost etc. Ecofriendly neem formulated chemicals, split fertilizer application deep placement are the means to restore our ecosystem from the pollution.
* Sensitive crops like barley, maize, bean, tobacco should not be cultivated in the areas having high concentration of air pollutants. But tolerant plants may produce satisfactory yield. Mustard, oat, can sustain to produce economic returns in soils having high content of heavy metals (Zn, Cu, Mn etc), and are very useful in the soil where reclamation is practically impossible.
* The None Government organizations associated with farmers can play a vital role in the production of medicinal plants/ adoption of organic farming by educating the farmers about the cultivation, productivity and use of medicinal plants and methods of organic farming.
* Always make balanced use of fertilizers. It would be much better if fertilizers are added on the basis of soil test report.
(The author is former Associate Dean-cum-cum Chief Scientist KVK, SKUAST-J)
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