Effects of Water and Nitrogen Management on Water Productivity, Nitrogen Use Efficiency and Leaching Loss in Rice Paddies

Effective water and nitrogen (N) management strategies are critical for sustainable agricultural development. Lysimeter experiments with two deep percolation rates (low high percolation, i.e., LP HP: 3 mm d−1 5 d−1) five N application levels (N0~N4: 0, 60, 135, 210 285 kg ha−1) were conducted to investigate the effects of controlled drainage on productivity (WP) use efficiency (NUE) in water-saving irrigated paddy fields. The results demonstrated that NH4+-N NO3−-N major components total (TN) ponded leachate, accounting more than 77.1% 83.6% TN, respectively. risk leaching loss increased significantly under treatment or levels. High required greater irrigation input, thus reducing WP. In addition, uptake increasing application, but fertilization applied excess crop demand had a negative effect grain yield. NUE was affected by amount decreasing Water significant rice, their interaction not significant. For HP regimes, highest WP obtained ha−1 ha−1, Our overall suggested combination feasible mitigation strategy reduce losses through subdrainage provide nutrients available rice improve NUE, diffuse pollution. Long-term field trials necessary validate lysimeter results.