Navindu Gupta

Groundwater NO3 and F Contamination Processes in Pushkar Valley, Rajasthan as Reflected from 18O Isotopic Signature and 3H Recharge Studies

Agricultural activity in the Pushkar Valley, Rajasthan is constrained due to limited availability of good quality water. In this context, occurrence of nitrate and fluoride in the groundwater was investigated and reported. Integration of stable isotope (δ18O) data with recharge characteristics (based on 3H-tracer studies) helps in clearly characterizing the processes controlling contamination by point and non-point sources. High nitrate and fluoride groundwaters are associated with high δ18O waters. This indicates that significant quantities of evaporated (isotopically enriched) surface run-off water and rain water infiltrate along with nitrate and fluoride salts in the soil. The applicability of this approach under different hydrometeorological conditions is also confirmed.

Impacts of Biogas Slurry Application on Soil Environment, Yield and Nutritional Quality of Baby Corn

Large amount of biogas slurry is pro-duced in India and their disposal is a major con-cern for the environment. So resource utilization of biogas slurry appears to be prospective and obligatory for now days. This study investigates the potential use of by-products of biogas pro-duction, i.e. biogas slurry (BGS) from agricultural waste treatment, as nutrient sources in agricul-ture. The BGS contain considerable amounts of plant nutrients, their use as soil amendment may improve crop production and physical properties of soil by preventing adverse environmental im-pacts of chemical fertilizers and waste disposal. Thus, field trials were conducted in 2013–2014 indicating that 50% BGS along with 50% chemi-cal fertilizer gave 20% more yield in terms of cob as well as biomass. Combination of BGS and N fertilizer increase protein and total sugar content of the baby corn cob up to almost 100% and 41% respectively over control. There was en-hancement in the organic matter, bulk density and porosity of soil matter in the soil after BGS application. It indicates that BGS in combination with fertilizers (1: 1) should be used as soil sup-plement for production increments and soil ame-lioration.

Status of Nitrate Contamination in Ground Water near Delhi: a Case Study

Abstract Intensive use of fertilizers for the ever increasing farming and agro-industry have revolutionized crop production. At the same time, contribution of the nutrients such as nitrates from applied fertilizers to surface and ground water is a major concern. 15N isotope studies have shown that for most crops less than 10 per cent of applied fertilizer is lost by leaching and the major source of leached nitrates can originate from the soil organic reserves and mineralized nitrogen. The present study has been undertaken to assess the level of nitrate and to explore the possible source of the same in some of the villages around Delhi since most of the inhabitants of these villages use this water for drinking and domestic purposes. The ground water samples collected in May-July (Summer) 1996 and October-November (Autumn) 1996 and analyzed for major halides and oxy-ions using Ion Chromatography (DX-300, Ion Chromatography, USA). Results revealed that levels of nitrate concentration in ground water are above the maximum permissible limit (45 mg/L nitrate). One of the sources of nitrate is arable agriculture where the intensification of agricultural practices in the last two to three decades has increased causing nitrate leaching in soil-water systems. The distribution of nitrate in ground water is controlled by some of the hydro-meteorological factors like precipitation, irrigation, vegetation up-take, redox reaction, denitrification. The excessive concentration of nitrate in drinking water can cause methaemoglobinaemia (blue baby syndrome) in infants and stomach cancer in adults. It is now established that nitrate itself is not that toxic but its reduced species; nitrites were found to be more active biologically and are sources of concern for human health. The study provides information to the planners for management of water resources as well as for judicious application of fertilizers with special reference to nitrogenous, in order to prevent further deterioration of soil and ground water.