Study of Effects of Different Fertigation Modes on Soil Profile Nitrogen Distribution and Rice Yield

Field experiments were conducted for controlled and mid-gathering irrigation mode in Nanjing, Jiangsu Province, focusing on the effect analysis of this mode with different fertilizations on profile soil total nitrogen and alkali-hydrolyzale nitrogen distributions and rice yield compared with the conventional irrigation mode. Results obtained showed that both total nitrogen and alkali-hydrolyzale nitrogen in soil profile were decreased with the increase of soil depth. Fast decrement of total nitrogen was found from surface 0-20 cm of soil layer and it reached the plateau below 40 cm of soil layer. Under the same fertilizer application, both total nitrogen and alkali-hydrolyzale nitrogen in surface soil layer were lower under controlled and mid-gathering irrigation mode which reduced the loss risks of runoff and leaching of soil and fertilizer nitrogen. Controlled and mid-gathering irrigation reduced water comsumption and N pollutant discharge without significant changes in rice yield compared with conventional irrigation. Conjunction of organic and inorganic fertilizers significantly improved the rice yield and utilization rate of nitrogen.