برهمکنش منبع نیتروژن و تنش خشکی در مرحله گلدهی ذرت بر جذب و کارایی نیتروژن و فسفر

Abstract

The effects of organic and inorganic N sources on nutrient (N and P) efficiency under the water-stressed conditions have not yet been determined. Thus, a field study was conducted to determine the influence of N from different sources along with drought stress on nutrient efficiencies of maize. Main plots consisted of two irrigation treatments (i.e., optimum irrigation and cut-off irrigation at silking stage for two weeks), and subplots comprised N fertilizers (cattle manure: 40.8 Mg ha-1, poultry manure: 13.3 Mg ha-1, urea fertilizer: 435 kg ha-1, cattle manure + urea fertilizer: 20.4 Mg ha-1and 20.4 Mg ha-1, respectively) and control (without fertilizer). Results indicated that the imposition of water deficit and fertilizer type had a significant effect on N uptake while P uptake was significantly affected only by fertilizer type. The highest N and P uptake were obtained with poultry manure. Similarly, significant differences in N and P use efficiency and N physiological efficiency were observed between the water deficit and fertilizer type (P<0.01). However, the effect of water deficit on N and P uptake efficiency was not statistically significant, althoughfertilizer type was remarkable. Nitrogen and P use efficiency and N physiological efficiency with poultry and cattle manures were significantly lower under water deficit than normal irrigation conditions. In conclusion, the highest N and P use and uptake efficiencies were obtained with poultry manure under normal irrigation conditions, but with cattle manure + urea fertilizer under water deficit conditions.