Feature Article

This paper investigates the potential use of composted cotton gin trash (CCGT) as a pesticide sorption medium in remediation of contaminated tailwater. CCGT was found to contain a large organic matter fraction (25.22%).

Nitrates enter human body through drinking water, food and air. Ingested nitrates converted to nitrite by microflora lead to methaemoglobinemia, increased free oxide radicals that predispose cells to irreversible damage and effects like cancer, increased infant mortality, abortions, birth defects, recurrent diarrhoea, recurrent stomatitis, histopathological changes in cardiac muscles, alveoli of lungs and adrenal glands, deterioration of immune system of the body.

During the past century through food and energy production, human activities have altered the world's nitrogen cycle by accelerating the rate of reactive nitrogen creation. India has made impressive strides in the agricultural front, in which N fertilizer plays a major role.

Anthropogenic activities are responsible for the enhanced emission of reactive nitrogenous species like nitrous oxide (N2O), oxides of nitrogen (NOx) and ammonia (NH3) into the atmosphere from the biosphere. This article reviews the available estimates of emissions of these reactive nitrogenous species for India.

The coastal and marine nitrogen cycle occupies a complex, central role within the biogeochemical cycles. Human interventions in the earth system have risen to unprecedented levels, strongly influencing the global nitrogen cycle. The nitrogen cycle in the open ocean compared to coastal ecosystems appears to have remained unharmed, although recent observations have shown increasing anthropogenic influence.

The South Asian rivers show a discharge weighted average NO3-N of 2 mg/l and average sediment-bound N, that is mostly organic, of 0.2%. The reported global average for the uncontaminated river system is of the order of about 0.028 mg/l (NO3-N). Hence, our freshwater aquatic systems can no longer be considered natural, at least with respect to nitrogen transport.

Nitrogen (N) is essential to the survival of all life forms and often limits productivity, decomposition and the long-term accumulation of carbon in terrestrial ecosystems. Soil and vegetation are the respective primary and secondary sinks for N in terrestrial ecosystems. Litter production determines the amount and quality of N returned to the forest floor and mineral soil. Decomposition of litter is crucial for N recycling and is influenced by a number of factors, including litter concentrations of N and lignin.

Nitrogen use efficiency (NUE) in plants is a complex phenomenon that depends on a number of internal and external factors, which include soil nitrogen availability, its uptake and assimilation, photosynthetic carbon and reductant supply, carbon

Safe and sufficient food production is an important issue in India. Development of improved varieties by modern plant breeding is crucial. Nowadays, GM (genetically modified) varieties are emerging as a strong tool and promise.