Deep placement of controlled-release fertilizer increases nitrogen (N) use efficiency in rice planting but is expensive. Few studies on direct-seeded rice have examined the effects of deep placement of conventional fertilizer. With prilled urea serving as N fertilizer, a two-year field experiment with two N rates (120 and 195 kg/hm²) and four basal N application treatments (B50, all fertilizer was broadcast with 50% as basal N; D50, D70 and D100 corresponded to 50%, 70% and 100% of N deeply placed as basal N, respectively) were conducted in direct-seeded rice in 2013 and 2014. Soil N distribution and plant N uptake were analyzed. The results showed that deep placement of basal N significantly increased total N concentrations in soil. Significantly greater soil N concentrations were observed in D100 compared with B50 at 0, 6 and 12 cm (lateral distance) from the fertilizer application point both at mid-tillering and heading stages. D100 presented the highest values of dry matter and N accumulation from seeding to mid-tillering stages, but it presented the lowest values from heading to maturity stages and the lowest grain yield for no sufficient N supply at the reproductive stage. The grain yield of D50 was the highest, however, no significant difference was observed in grain yield, N agronomic efficiency or N recovery efficiency between D70 and D50, or between D70 and B50, while D70 was more labor saving than D50 for only one topdressing was applied in D70 compared with twice in other treatments. The above results indicated that 70% of fertilizer-N deeply placed as a basal fertilizer and 30% of fertilizer-N topdressed as a panicle fertilizer constituted an ideal approach for direct-seeded rice. This recommendation was further verified through on-farm demonstration experiments in 2015, in which D70 produced in similar grain yields as B50 did.

深层放置控释肥料可提高水稻种植中氮素的利用效率，但价格昂贵。很少有关于直播水稻的研究检查过常规肥料的深层施用的影响。以造粒尿素作为氮肥，进行了两年的两次氮肥田间试验（120和195 kg / hm ²）和四种基础氮肥施用方式（B50，所有肥料均以50％为基础氮素播种; D50，D70和D100分别对应于深施为基础N的氮的50％，70％和100％）和2013年的水稻种子。分析了土壤氮素分布和植物吸收氮素。结果表明，深施基础氮明显增加了土壤中的总氮浓度。在分iller中期和抽穗期，距施肥点0、6和12厘米（横向距离）处，D100中的土壤氮浓度明显高于B50。从播种到分mid中期，D100表现出最高的干物质和氮积累量，但是从抽穗到成熟阶段，它呈现出最低的值，而在繁殖阶段，由于没有足够的氮供应，谷物的产量最低。D50的籽粒产量最高，但是，D70和D50或D70和B50之间的籽粒产量，N农艺效率或N回收效率没有显着差异，而仅一次追施D70比D50节省的劳动力更多在D70中使用的是其他处理中使用的两倍。以上结果表明，将70％的氮肥作为基肥深施，将30％的氮肥作为穗肥追肥，是直播水稻的理想方法。该建议在2015年的农场示范实验中得到了进一步验证，其中D70的产量与B50相似。D50的籽粒产量最高，但是，D70和D50或D70和B50之间的籽粒产量，N农艺效率或N回收效率没有显着差异，而仅一次追施D70比D50节省的劳动力更多在D70中使用的是其他处理中使用的两倍。以上结果表明，将70％的氮肥作为基肥深施，将30％的氮肥作为穗肥追肥，是直播水稻的理想方法。该建议在2015年的农场示范实验中得到了进一步验证，其中D70的产量与B50相似。D50的籽粒产量最高，但是，D70和D50或D70和B50之间的籽粒产量，N农艺效率或N回收效率没有显着差异，而仅一次追施D70比D50节省的劳动力更多在D70中使用的是其他处理中使用的两倍。以上结果表明，将70％的氮肥作为基肥深施，将30％的氮肥作为穗肥追肥，是直播水稻的理想方法。该建议在2015年的农场示范实验中得到了进一步验证，其中D70的产量与B50相似。D70比D50节省了更多的劳动力，因为在D70中仅施用了一种追肥，而在其他处理中则是两倍。以上结果表明，将70％的氮肥作为基肥深施，将30％的氮肥作为穗肥追肥，是直播水稻的理想方法。该建议在2015年的农场示范实验中得到了进一步验证，其中D70的产量与B50相似。D70比D50节省了更多的劳动力，因为在D70中仅施用了一种追肥，而在其他处理中则是两倍。以上结果表明，将70％的氮肥作为基础肥料深施，将30％的氮肥作为穗肥追施，是直播水稻的理想方法。该建议在2015年的农场示范实验中得到了进一步验证，其中D70的产量与B50相似。