农艺深施及配施缓控释氮肥对水稻产量及氮素损失的影响

为探讨基肥"干施湿混"（施基肥-泡田-旋耙整田）结合追肥"以水带氮"（先施追肥再灌水）的农艺深施技术及其配施缓控释氮肥对氮素损失及水稻氮素吸收利用的影响，采用田间小区试验，设置不施氮肥（N0）、常规施肥（Nc）、农艺深施（Nd）、农艺深施配施缓控释氮肥再减氮10%（Ns）4个处理，研究了农艺深施及其配施缓控释氮肥对稻田田面水中氮素形态和浓度、稻田氮素流失量、水稻氮素吸收与产量、氮盈余量、土壤有效氮含量的影响。结果表明：与Nc处理相比，Nd和Ns处理均能降低氮素损失高风险期（基肥后7 d内，分蘖肥后5 d内，穗肥后4 d内）稻田田面水中总氮（TN）浓度，降幅分别为18.5%和49.8%，且主要降低了可溶性总氮（DTN），尤其是铵态氮（NH₄⁺-N）的浓度；Nd和Ns处理稻田TN流失量分别降低了19.1%和47.6%，氮肥表观利用率分别提高了15.3、3.9个百分点，氮素盈余量分别降低了6.8%和38.1%，且土壤有效氮含量和水稻产量均有增加的趋势。研究表明，基肥"干施湿混"结合追肥"以水带氮"的农艺深施技术能降低稻田田面水中氮素浓度，提高氮肥利用率，减少氮肥损失，是一项值得推广的操作简便、绿色增效的施肥技术，再配施缓控释氮肥，能进一步降低田面水中氮素浓度和氮肥损失，同时能减少氮肥用量。

Effects of agronomic deep application and combined application of controlled release nitrogen fertilizer on rice yield and nitrogen loss in a paddy field

The study investigated the effect of agronomic deep placement of basal fertilizer(dry fertilization and wet mixing) and topdressings(fertilization before irrigation), combined with application of control released nitrogen(N) fertilizer on N loss and uptake. A plot experiment was conducted with four treatments:no N fertilization(N0), conventional N fertilization(Nc), agronomic deep fertilization (Nd), and agronomic deep fertilization combined with slow controlled release N fertilizer(reduced 10% N rate, Ns). The effects of agronomic deep fertilization of N and its combination with controlled release N were studied concerning the speciation and concentration of N in surface water, N loss from the paddy field, apparent N use efficiency, N surplus, soil available N content, and rice yield. Compared with conventional fertilization, the Nd and Ns treatments reduced the total nitrogen(TN) concentration in surface water of the paddy field in the high-risk period(within 7 days after basal fertilizer, within 5 days after tiller fertilizer, and within 4 days after panicle fertilizer) by 18.5% and 49.8%, respectively. These treatments also mainly decreased the total dissolved nitrogen, especially NH₄⁺-N. TN loss from paddy fields treated by Nd and Ns decreased by 19.1% and 47.6%, apparent N use efficiency increased by 15.3 and 3.9 percentage points, and N surplus decreased by 6.8% and 38.1%, respectively. The available N contents and rice yields showed increasing trends. The findings verified that agronomic deep placement of N can reduce N concentrations in surface water and N loss from paddy fields and can increase N use efficiency. The simple, green, and efficient fertilization technology is worthy of promotion. If combined with slow controlled release N fertilizer, the technology can further reduce N concentration in surface water and N loss from paddy field, as well as N fertilizer use rate.