Tian Chang, Zhou Xuan, Liu Qiang, Xie Gui Xian, Rong Xiang Min, Zhang Yu Ping, Huang Si Yi, Peng Jian Wei
College of Resources and Environment, Hunan Agricultural University/National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources, Changsha 410128, China.
Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, Changsha 410128, China.
Ying Yong Sheng Tai Xue Bao. 2018 Oct;29(10):3267-3274. doi: 10.13287/j.1001-9332.201810.029.
Nitrogen (N) leaching is a major pathway of N losses in paddy fields. Here, an experiment was conducted to assess the effects of the reduction of controlled-release urea application on grain yield and N leaching in a double-cropping paddy field. Fertilization treatments included zero-N (CK, control, 0 kg N·hm), conventional urea (CU, 180 kg N·hm), and four polymer-coated urea fertilization levels, i.e., 1.0CRU, 0.9CRU, 0.8CRU, 0.7CRU, which represented 0, 10%, 20% and 30% reduction of fertilizer inputs relative to CU, respectively. Leachate was collected at the soil depth of 60 cm using field leakage pool method. Nitrogen leaching peaked shortly after fertilization, implying that measures should be taken to prevent N leaching in the early period. Nitrogen losses from leaching were 42.3 kg N·hm for 0.8CRU, and by 37.7 kg N·hm for 0.7CRU, significantly lower than the leaching in CU (53.9 kg N·hm). Nitrogen leaching in 0.7CRU was significantly lower than that in 1.0CRU (51.3 kg N·hm). 11.9%-13.5% of the fertilizer N was lost via leaching across the six treatments with comparable N loss rates. Rice yields, N utilization efficiency and N harvest index were significantly higher in 0.8CRU and 0.7CRU relative to CU. Our findings suggested that the use of CRU would permit a reduction in N application by 20%-30%, which could maintain the rice yield and obtain a reduction in N leaching.
氮素淋失是稻田氮素损失的主要途径。在此，进行了一项试验，以评估在双季稻田中减少控释尿素施用量对谷物产量和氮素淋失的影响。施肥处理包括不施氮（CK，对照，0 kg N·hm²）、常规尿素（CU，180 kg N·hm²）以及四个聚合物包膜尿素施肥水平，即1.0CRU、0.9CRU、0.8CRU、0.7CRU，分别表示相对于CU减少0%、10%、20%和30%的肥料投入。采用田间渗漏池法在60 cm土壤深度处收集渗滤液。施肥后不久氮素淋失达到峰值，这意味着应在早期采取措施防止氮素淋失。0.8CRU的淋失氮损失为42.3 kg N·hm²，0.7CRU为37.7 kg N·hm²，显著低于CU的淋失量（53.9 kg N·hm²）。0.7CRU的氮素淋失显著低于1.0CRU（51.3 kg N·hm²）。在六种处理中，11.9% - 13.5%的肥料氮通过淋失损失，且氮损失率相当。相对于CU，0.8CRU和0.7CRU的水稻产量、氮素利用效率和氮收获指数显著更高。我们的研究结果表明，使用控释尿素可减少20% - 30%的氮素施用量，这既能维持水稻产量，又能减少氮素淋失。
