Abundance and variation of gaseous NH3 in relation with inorganic fertilizers and soil moisture during Kharif and Rabi season.

Abstract

In an agricultural country like India, inorganic fertilizers are the major contributors of atmospheric NH3 in rural areas affecting soil, vegetation and water bodies. In this study, day-night and seasonal variation of ammonia emissions were measured from July 2017 to June 2018 during Kharif and Rabi crop seasons at a rural agricultural site in Jhajjar district of Haryana. Also, NH3 emission inventory is prepared for the amount of fertilizers applied during its basal and top dressing. NH3 concentrations were noticed significantly lower after basal dressing of DAP fertilizers as compared to the concentrations after top dressing of urea. NH3 concentration in air increased with decrease in water saturation of the soil. NH3 emission was recorded as 1.4 to 45.2, 63.1 to 190.9, and 98.9 to 187.5μgm-3 during sowing, fertilizer addition, and grain filling stages, respectively, in Kharif season. Apart from these crop stages, NH3 was measured as 56.8 to 249.5μgm-3 during crop residue burning period. On the other hand, NH3 emissions ranged from 22.9 to 68.4, 59.4 to 104.71, 26.3 to 56.0, 48.2 to 147.2, and 21.5 to 80.4μgm-3 during sowing, crown root initiation (CRI), panicle initiation, grain filling, and maturity crop, respectively, in Rabi season. The average NH3 concentrations during Kharif season (125.3μgm-3) were significantly greater than the concentrations during Rabi season (51.8μgm-3). However, a reduction in the NH3 values was observed in the period between Kharif and Rabi seasons, which could be attributed to the wet deposition during monsoon and gas to particle conversion due to less temperature conditions during the periods.