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Nitrogen (N) is an essential plant nutrient, therefore, N-deficient soils affect plant growth and development. The excessive and unwise application of N fertilizers result in nutrient losses and lower nutrient use efficiency that leads to the low crop productivity. Ammonia volatilization causes a major loss after N fertilization that causes environmental pollution. This experiment was conducted to evaluate the effectiveness of coating and uncoating N fertilizer in enhancing yield and nutrient-use efficiency with reduced ammonia emissions. The recommended rate of nitrogen and phosphorus, urea and di-ammonium phosphate (DAP) fertilizers were coated manually with 1% polymer solution. DAP (coated/uncoated) and potassium were applied at the time of sowing as subsurface application. While urea (coated/uncoated) was applied as surface and subsurface application. Results showed that nutrient use efficiencies of wheat were found to be maximum with the subsurface application of coated N fertilizer which increased nutrient-use efficiency by 44.57 (N), 44.56 (P) and 44.53% (K) higher than the surface application of uncoated N fertilizer. Ammonia emissions were found the lowest with subsurface-applied coated N fertilizer. Thus, coated fertilizer applied via subsurface was found the best technique to overcome the ammonia volatilization with an improvement in the yield and nutrient-use efficiency of wheat.

Rhizobium besides its nodule formation characteristic with members of Fabaceae family has been recognized for its great root colonizing ability and growth hormone production potential. In addition to nitrogen fixation in legume plants, rhizobia considered as beneficial tools and act as plant growth promoting rhizobacteria (PGPR) with many non-legumes. Present study was elucidated to determine the comparative role of Rhizbium sp for growth promotion of sunflower. Rhizobia were isolated from five different legumes (mungbean, barseem, lentil, chickpea, and vegetable pea) and checked for their auxin production efficiency. Rhizobial isolates Cp-4 showed maximum auxin potential (5.37 µg mL-1 IAA equivalents).Results showed that inoculation of all rhizobial isolates caused significant increase in growth and physiological parameters of sunflower plants. While prominent results were found with inoculation of mungbean rhizobial isolate Mb-2 which increases the chlorophyll a, N, P, fresh and dry matter of sunflower significantly by 8.34, 4.9, 36, 31, and 34%, respectively in comparison to uninoculated control plants. Hence, present study concluded that Rhizobium sp can be successfully used as PGPR in non-legumes after thorough investigations.