施氮水平对宁夏引黄灌区玉米氮素损失和土壤肥力的影响OA

To optimize the fertilization techniques for maize in the Yellow River diversion irrigation area and promote the effective transformation and rational utilization suggestions of nitrogen fertilizer,field plot experiments were conducted to study the effects of nitrogen application levels on soil nitrogen leaching loss and soil fertility of corn soils in Ningxia with the no-nitrogen treatment as the control,4 nitrogen fertilizer treatments were set up,including conventional nitrogen application(applying 420 kg/ha of nitrogen),optimized nitrogen application(applying 360 kg/ha of nitrogen),optimized nitrogen reduction(applying 270 kg/ha of nitrogen),and the combination of controlled-release nitrogen fertilizer and urea(applying 135 kg/ha of controlled-release nitrogen fertilizer and 135 kg/ha of nitrogen).Results showed that the combined application of controlled-release nitrogen fertilizer and urea achieved the highest grain and straw yields,which increased by 102.40%and 30.29%compared to the non-nitrogen control,respectively,and by 7.60%and 6.68%compared to the conventional farmer nitrogen treatment,respectively.The combined application also resulted in the highest grain nitrogen uptake(155.97 kg/ha),nitrogen use efficiency(32.25%),and nitrogen partial factor productivity(51.79 kg/kg),suggesting that its nitrogen supply mode better matches the requirements of the grain formation stage and reduces nitrogen consumption for straw vegetative growth.Nitrogen application significantly reduced total nitrogen leaching loss,specifically,the combined application reached the lowest leaching loss,significantly decreasing by 56.16%compared to conventional nitrogen application,which demonstrates that regulating nitrogen release rates to match crop demand can reduce loss,improve efficiency,and stabilize yield.The combined application treatment yielded the highest contents of total nitrogen,alkali-hydrolyzable nitrogen,available potassium,available phosphorus,and organic matter,indicating that appropriately increasing nitrogen application can enhance soil fertility,though excessive application may lead to soil salinization and nutrient imbalance.In summary,the combined application of controlled-release nitrogen fertilizer and urea maintains high yield and soil fertility at lower nitrogen input levels,demonstrating effective nitrogen management.