The Combined Effect of Urea and Organic Acid on Some Soil Properties, Yield and Nutrient Uptake by Wheat Crop

FIELD experiment was carried out during two successive seasons (2012-2013 and 2013-2014) to study the effect of organic acids and N-mineral fertilizers as well as their combination, on some soil properties, yield and nutrient uptake of wheat (Triticum aestivum L.) plants. In this study, eight treatments were used as follows: T1) Control (without addition); T2) 75 Kg N fed.-1; T3) 75 Kg N fed.-1 coated with humic acid; T4) 75 Kg N fed.-1 coated with fulvic acid; T5) 75 Kg N fed.-1 + 4 liter humic acid as a soil addition ; T6) 75 Kg N fed.-1 + 4 liter fulvic acid as a soil addition; T7) 75 Kg N fed.-1 + 4 liter humic acid as a foliar application and T8) 75Kg N fed.-1 + 4 liter fulvic acid as a foliar application. Results indicated that the soil organic matter (OM) and available N, P and K increased with the combined application of mineral N with organic acid over application of mineral N alone. The soil pH value decreased with organic acids applied as a soil addition compared with a foliar addition. The higher values of N uptake by grain yield and protein were 71.76 and 409.05 kg fed-1 in T3, respectively. The value of nitrogen used efficiency (NUE) ranged from 31.68 to 41.85 during the two seasons. The application of organic acid combined with N-mineral fertilizers gave better results in increasing the yield of wheat especially when nitrogen fertilizers coating with humic acid. Application of organic acid to the soil increased the yield by 2.56% and 10.21% in the first and second season, respectively as compare to urea alone. Based on the results of the current study, the combinations of N-mineral and organic acids can be considered as an integrated nutrient management to improve the soil fertility and wheat yield.