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|Title:||AMMONIA VOLATILIZATION IN WHEAT UNDER DIFFERENT TEMPERATURE REGIMES|
|Publisher:||CENTRE FOR ENVIRONMENT SCIENCE AND CLIMATE RESILIENT AGRICULTURE INDIAN AGRICULTURAL RESEARCH INSTITUTE NEW DELHI|
|Keywords:||Ammonia volatilization, wheat, temperature, nitrogen loss, yield|
|Abstract:||Volatilization is the loss of nitrogen in the form of ammonia (NH3) and it takes place by the conversion of nitrogenous fertilizer into ammonium gas through hydrolysis. Ammonia volatilization is the major process through which nitrogen losses from soil takes place under increasing temperature scenarios. Large amount of NH3 emission not only causes environmental problems but also the nutrient losses which lead to economic losses by increasing the cost of production. Wheat is the most extensively grown cereal crop in India but excessive use of N fertilizer in the agriculture leads to low nitrogen use efficiency and lower net returns to the farmers. Thus this study was conducted to evaluate the effect of high temperature on ammonia volatilization and yield under different N levels in wheat crop. The four different temperature viz. Ambient temperature (T1), Temperature Gradient Tunnel (TGT) Control (T2), plus 3° C (T3) and plus 5° C (T4) and four different levels of nitrogen viz. 0, 90, 120 and 150 kg ha-1 in combinations were taken as the experimental treatments. Results showed that phenological length was decreased whereas plant height and leaf area significantly increased in TGT as compared to the ambient temperature. As the nitrogen levels increases, photosynthetic rate was also increases during all the growth stages and highest photosynthetic rate (25%) was observed at N150 as compared to N120 at anthesis. Stomatal conductance was found maximum during anthesis stage (0.53 dsm-1 at N120) followed by grain filling (0.58 dsm-1 at N120 and N150) and tillering (0.51 dsm-1 at N90) respectively and maximum photosynthetic rate was recorded during the anthesis (28.3 µ mole m-2 s-1 at N150) followed by grain filling stage (25.6 µ mole m-2 s-1 at N150). Grain weight plant-1, total grain weight, total biomass, number of tiller and number of spike were found maximum in T4 with harvest index up to 0.45. In all the treatments, nitrogen levels enhanced the N content in leaves, stem and gain. Chlorophyll content was found highest (60% increase) at anthesis in N150 as compared to N120. Nitrate reductase activity was found maximum at tillering followed by grain filling whereas glutamine synthetase was highest in N120 at T4 (28.5 µmol glutamylhydroxymate formed mg-1 protein h-1) during anthesis. The NH3 volatilization directly depends on the fertilizer application and was emitted effectively upto the 6th day from the date of fertilizer application. The rate of NH3 volatilization enhanced with the increase dose of N application and it was observed maximum (72.9%) at N150 as compared to without N level. The ammonia volatilization ranged from 4.2-20.4 kg ha-1 season-1 and it was highest (20.4 kg ha-1 season-1) in 150 kg ha-1 N application at T4 having 13.6 % applied N loss. Keywords: Ammonia volatilization, wheat, temperature, nitrogen loss, yield|
|Theme:||AMMONIA VOLATILIZATION IN WHEAT UNDER DIFFERENT TEMPERATURE REGIMES|
|Appears in Collections:||Theses|
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