砒砂岩与沙复配土水氮利用效率定量评估

he objective of this study was to quantify water and nitrogen use efficiencies (WUE and NUE) and their environmental impact for different ratio of soft rock and sand compound soil, and to provide some suggestion on optimizing water and nitrogen management practice. In this study, three ratios of soft rock and sand compound soil were conducted in Dajihan county, Yulin city. After a Water and Nitrogen Management Model (WNMM) was calibrated and validated, the yields, amounts of drainage, N leaching, WUE and NUE for different ratio of soft rock and sand compound soil were all calculated. The results showed that, for 1:1, 1:2 and 1:5 compound soil, With decreasing soft rock content in compound soil, the evapotranspiration was no significant change, and water drainage was increased significantly. Water use efficiencie could up to 1.30 kg m-3. N leaching and Ammonia volatilization were the main pathway of nitrogen loss, and crop uptake was the main sink of N. N use efficiency and fertilizer use efficiency could reach 33.13 and 24.93 kg kg-1 N-1, respectively. Water drainage and N leaching occurred mainly in the period of heavy rainfall or irrigation. Through scenario analysis of different rainfall year type, water and fertilizer management systems were formulated for different rainfall year type. This study showed that soft rock had a significant role in improving water, nitrogen and fertilizer use efficiency.