IMPACT OF FULVIC ACID AND NITRIFICATION INHIBITOR ON WHEAT PRODUCTIVITY AND NO3-N LOSSES IN CLAY SOIL.

Two field experiments were conducted at Sakha Agric. Res. Station, Kafr El-Sheikh Governorate, Egypt, during two successive seasons (2017/18 and 2018/19) to study the effect of fulvic acid and nitrification inhibitor on NO3 leaching and wheat yield and chemical constituents. A split plot design with three replicates were used with three fulvic acid applied i. e 0, 4.76 and 9.52 kg ha-1 as main plots as well as nitrogen fertilizers as ammonium sulphate (21% N) (with or without nitrification inhibitor (NI)) at rate of 90, 135 and 180 kg N ha-1, in sub-plots. Nitrification inhibitor 3, 4-dimethylpyrazole phosphate (DMPP) (EC 1.7 dS m-1and pH 4.4) was applied at 8%. Results indicated that the highest mean values of EC, OM and available NPK were obtained from soil in plots resaved 180 kg N ha-1 with DMPP + 9.52 kg fulvic acid ha-1. The highest mean values of plant height (110.34 and 111.42 cm); 1000-grain weight (55.60 and 61.00 g); grain yield (7.62 and 7.95 Mg ha-1); straw yield (13.64 and 14.02 Mg ha-1); N concentration in grain and straw were (2.09 and 0.84 %, respectively); N content of grain (152.97 and 149.56 kg N ha-1); N content of straw (99.51 and 95.58 kg N ha-1) and total N uptake by wheat (252.49 and 245.14 kg N ha-1) were recorded by 180 kg N ha-1 combined with 8% DMPP + 9.52 kg fulvic acid ha-1 in first and second seasons, respectively.