Effects of Deep Percolation and Nitrogen Application on Rice Yields,Qualities and Water-fertilizer Use Efficiency under Controlled Irrigation and Drainage

In order to explore the water and nitrogen management mode of rice,pit rice planting experiments of combining deep percolation and nitrogen application are performed under controlled irrigation and drainage.The experiment is set up with two water treatments,low deep percolation L（3mm/d）and high deep percolation H（5 mm/d）,and five levels of nitrogen application at N0（0 kg/hm~2）,N1（150 kg/hm~2）,N2（225 kg/hm~2）,N3（300 kg/hm~2）,N4（375 kg/hm~2）for the whole growth period,a total of 10 treatments.The effects of different water and ni‐trogen treatments on rice yield,quality and water-fertilizer use efficiency are explored.The results show that rice yield increases and then de‐creases with the increase in N application under the same deep percolation treatment,and reaches the maximum of L-N2 treatments,exces‐sive nitrogen fertilizer input not only causes lower rice yield,but also decreases water-fertilizer use efficiency and eating quality.The low deep percolation treatment shows a trend of increasing yield compared with the high deep percolation treatment,while the low deep percola‐tion treatment can effectively improve water use efficiency.Overall,the water-nitrogen management mode for the N2 treatment under the low deep percolation conditions is closest to the goal of high-yield,high-quality and high-efficiency.This study is of great significance to strengthening the scientific management of water and nitrogen in agricultural fields,improving the water and nitrogen production efficiency and promoting the sustainable use of resources.