Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, People's Republic of China.
University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China.
Sci Rep. 2020 Dec 9;10(1):21582. doi: 10.1038/s41598-020-78648-w.
A pot experiment was used to explore the distribution of fertilizer N and agronomic effects in a paddy soil-rice (Oryza sativa L.) system. Five treatments were set: without nitrogen, straw and inhibitor (C), urea (U), urea + straw (US), urea + urease + nitrification inhibitor (UI) and urea + urease + nitrification inhibitor + straw (UIS). Soil and urea-derived microbial biomass N increased significantly in US and UIS compared with straw-free treatments at seedling and tillering, indicating that biotic process play an important role in the retention of fertilizer N with straw addition. About 10% urea-N was recovered as fixed ammonium (FA) at seedling stage, subsequently released at tillering and maturation regardless of treatments, which emphasizes the importance of FA in the retention and supply of fertilizer N in paddy soils. Compared with U, rice yield and N uptake in US decreased by 7.8% and 25.2% respectively, while inhibitors (UIS) alleviated the reduction by 16.4% and 31.6%. The current research indicated UIS is recommended as the most appropriate management strategy in paddy soils of Northeast China based on N dynamics. But the economic effect as well as the field-scale validation need to be further evaluated.
采用盆栽试验研究了氮肥在稻田土壤-水稻（Oryza sativa L.）系统中的分布和农学效应。共设置 5 个处理：不施氮肥、秸秆和抑制剂（C）、尿素（U）、尿素+秸秆（US）、尿素+脲酶+硝化抑制剂（UI）和尿素+脲酶+硝化抑制剂+秸秆（UIS）。与无秸秆处理相比，US 和 UIS 处理在苗期和分蘖期的土壤和尿素衍生微生物生物量 N 显著增加，表明生物过程在秸秆添加条件下对氮肥的保持起着重要作用。在苗期约有 10%的尿素氮被固定为铵态氮（FA），随后在分蘖期和成熟期释放，无论处理与否，这强调了 FA 在水稻土中保持和供应氮肥的重要性。与 U 处理相比，US 处理的水稻产量和氮吸收量分别降低了 7.8%和 25.2%，而抑制剂（UIS）处理则缓解了 16.4%和 31.6%的降低。本研究表明，基于氮素动态，UIS 是中国东北稻田土壤的最佳管理策略。但需要进一步评估其经济效益和田间规模验证。
