MITIGATING NITROUS OXIDE (N2O) EMISSION AND INCREASING PRODUCTIVITY THROUGH UREASE AND NITRIFICATION INHIBITORS UNDER FIELD CONDITIONS.
Byline: Muhammad Kamil Sardar Ali and Khadim Dawar
Urease and nitrification inhibitors are proposed as these intend to lessen nitrogen losses, reducing environmental impacts associated with N fertilizer application, thereby enhancing crop nitrogen use efficiency (NUE) and productivity. A field experiment was established using silt loam soil (New Developmental Farm) to evaluate the effectiveness of urease (Agrotain) and nitrification (Nitropyrin) inhibitors coated urea on minimizing nitrous oxide (N2O) emission and plant growth hormone (Gibberellic Acid salt) on harvest growth and yield of Maize at research area, The University of Agriculture Peshawar, during summer 2015. N fertilizer (Urea) @ 200 kg N ha-1 with or without UI (Agrotain at 3 L t-1), NI (Nitropyrin 200 g ha-1) and plant growth hormone (GA-S at 60 g ha-1) were applied in 2 splits at different growth stages. Each treatment had 4 replicates laid out in Randomized Complete Block Design.
The results showed that N-Inhibitors and GA-S treated urea significantly (p<0.05) increased the yield and yielding traits of maize over granular urea and control. Combined application of both inhibitors and GA-S showed superiority over nitropyrin, agrotain and GA-S in terms of increased yield. The highest biological yield (15295 kg ha-1), grain yield (6067 kg ha-1), stover yield (9228 kg ha-1) and total N-uptake (161.2 kg ha-1) of maize (grand mean increased 36.8 %, 40 %, 25.5 % and 48.4 % respectively) were recorded in combination of all treatments compared with urea.
The results obtained on soil N mineralization of NH4-N and NO3-N concentration showed a significant variation over 28 days interval of fertilizer application with N inhibitors increasing the soil inorganic N availability and shifted the main form of soil inorganic N from NO3-N to NH4-N thus retaining more N in soil solution. N2O fluxes varied through time and between treatments; mean N2O flux was the highest in the urea alone, while the urea coated with nitropyrin, agrotain and combined nitropyrin + agrotain significantly lowered the mean N2O flux by 17.1 %, 13.5 %, and 32.4 %, respectively, over urea alone. Total N2O emission in the nitropyrin, agrotain and combined nitropyrin + agrotain and urea alone treatments during the 28 days experimental trial was 1.89, 1.97, 1.54, and 2.28 kg N2O-N ha-1, respectively.
These results indicate that reducing the rate of urea hydrolysis and inhibiting nitrification with combined use of agrotain, nitropyrin in an alkaline calcareous soil is important to reduce N losses and N2O emission, improve fertilizer use efficiency of applied urea with maximum bioavailability to plants thus increase the yield of Maize crop.
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|Publication:||Journal of Himalayan Earth Sciences|
|Date:||Dec 31, 2016|
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