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Effects of nitrogen fertilizer and water management practices on nitrogen leaching from a typical open field used for vegetable planting in northern China

Wang, Dongyan, Guo, Liping, Zheng, Lei, Zhang, Yigong, Yang, Rongquan, Li, Ming, Ma, Fen, Zhang, Xinyue, Li, Yingchun
Agricultural water management 2019 v.213 pp. 913-921
biochar, cabbage, cucumbers, fallow, fertilizer rates, field experimentation, irrigation rates, leaching, lysimeters, nitrification inhibitors, nitrogen, nitrogen fertilizers, planting, pollution, rain, straw, synergists, temperature, urease inhibitors, vegetable growing, vegetable yield, China
Agriculture has contributed greatly to nitrogen (N) pollution globally. It is essential to study the causes and characteristics of N leaching to develop better N management strategies. A field experiment with cucumber–Chinese cabbage rotation was conducted in a typical open field for vegetable planting in northern China. The characteristics of N leaching were studied using the lysimeter method. The total N leaching (TNL) value under the conventional N application rate (780 kg ha−1 season−1) was 585.3 kg ha−1 for the entire vegetable year and it had a significantly positive correlation with the N application rate. Reduction of the N rate by 20% and 50% could decrease the TNL by 18.3% and 43.0% during the entire cucumber and cabbage season (including the fallow period), respectively. A 20% reduction in the N rate had no obvious impact on vegetable yields. The TNL was decreased by 2.6% throughout the year under a combined application of manure and chemical fertilizers. An amendment with a urease-inhibitor plus a nitrification-inhibitor, biochar, and straw could decrease TNL by 23.5%, 15.3%, and 7.1%, respectively, compared to that without amendments. A combined reduction of N and the irrigation rate by 20% showed a decrease of the TNL by 38.4%. The results showed that N leaching substantially contributed to the loss of fertilizer N in a typical vegetable field in northern China, where both the temperature and the rainfall were synchronized. Appropriate management practices can effectively reduce the TNL at different degrees without the negative impact on vegetable yields. These practices include the addition of synergists (urease inhibitors and nitrification inhibitors), the amendment with biochar or straw, and the reduction in both N rate and irrigation volume by 20%. Different measures can be adopted in the actual vegetable production according to the specific conditions.