Effects of nitrogen treatments on potato nitrogen accumulation and soil nitrate-nitrogen distribution under sprinkler fertigation system
PEI Shasha1,2, LI Yaojun1*, YAN Haijun1, GU Tao3
1. College of Water Resources & Civil Engineering, China Agricultural University, Beijing 100083, China;2. Hebei Institute of Water Science, Shijiazhuang, Hebei 050051, China; 3. China Irrigation and Drainage Development Center, Beijing 100054, China
Abstract：The integration of water and fertilizer for sprinkler irrigation is an important measure to improve the nutrient use efficiency of crops in the semi-humid region of Northeast China. In order to explore the effects of nitrogen fertilizer application on potato yield, nitrogen accumulation, and soil nitrate-nitrogen distribution under the condition of water and fertilizer integration of center pivot irrigation system. Three nitrogen topdressing levels were set in the experiment: 115 kg/hm2(F1), 165 kg/hm2(F2)and 215 kg/hm2(F3), respectively, and three frequency of nitrogen topdressing, i.e., C2, C4 and C6, representing 2, 4 and 6 times of nitrogen topdressing were conducted. One treatment of traditional ditching fertilization was selected as the control area in the experiment. The results showed that the tuber yield and commercial potato rate of F2C6 treatment were the highest. Under the same nitrogen application rate, the nitrogen accumulation of potato tubers increased with the increase of nitrogen application frequency. For the same frequency of nitrogen application, with the increase of nitrogen application rate, the nitrogen accumulation of tubers increased first and then decreased. At the stage of potato tuber expansion, the content of soil nitrate-nitrogen in 20-40 cm soil layer decreased with the increase of nitrogen application frequency under the same nitrogen application amount. It is suggested that the potato planting in the semi humid area of Heilongjiang Province should adopt the integrated scheme of sprinkler irrigation, and with medium fertilizer(165 kg/hm2)and high frequency(6 times of nitrogen topdressing).
