起身肥改善水稻根际土壤氮素分布与利用的研究

Favorable Effect of Nitrogen Before Transplanting on Nitrogen Distribution and Utilization Efficiency in Rice Rhizosphere Soil

【目的】探讨起身肥对移栽后水稻根际土壤氮素分布与利用的改善作用,为氮肥的精确合理施用奠定基础。【方法】以宁粳2号为材料,通过塑盘穴播育秧带土、带肥移栽,研究不同起身肥水平下植株周围土壤矿质态氮浓度的时空变化及起身肥对水稻氮肥利用率和产量的影响。【结果】施起身肥后均能显著提高移栽后水稻根际土壤氮素浓度。随移栽后时间推移,距植株1 cm处土壤氮素浓度呈下降趋势,而距植株4和7 cm处土壤氮素浓度呈先升后降态势。与非起身肥处理相比,起身肥能够极显著地促进水稻对氮肥的吸收和利用。水稻吸氮量、基蘖氮肥利用率和水稻产量以施适量起身肥处理最高。其基蘖氮肥利用率高达27.17%,比非起身肥处理高15%,差异极显著。产量为8 814.0 kg.ha-1,比非起身肥处理高529.5 kg.ha-1。【结论】秧田施起身肥310.5 kgN.ha-1,可以提高水稻生育前期根际土壤矿质态氮浓度,促进分蘖的早生发快,增加分蘖成穗率,显著提高氮肥利用率和水稻产量。

[Objective] The study was conducted to investigate the improvement of the application of nitrogen fertilizer before transplantation on nitrogen distribution and utilization efficiency around the soil of rice and to give guidance for nitrogen fertilizer application. [Method] The Japonica variety of Ningjing-2 was conducted in this study, and effects of nitrogen before transplanting on spatio-temporal distributing of mineral nitrogen, nitrogen fertilizer utilization efficiency and grain yield were studied with raising seedling by means of plastic-plate and transplanting with soil. [Result] The results indicated that nitrogen fertilizer before transplantation could improve nitrogen content in the rhizosphere soil of rice. Along with the process days after transplantation, nitrogen content in soil 1 cm apart from the plant declined, while 4, 7 cm apart from plant it increased first and then declined. The study also demonstrated that the application of nitrogen fertilizer before transplantation could promote the nitrogen assimilation and utilization. Scientists compared it with rice and without it. Tests showed itcould achieve the highest nitrogen assimilation, basal-tillering nitrogen fertilizer utilization efficiency and grain yield with proper nitrogen fertilizer before transplantation. With this, there was 27.17% of basal-tillering nitrogen fertilizer utilization efficiency and 8 814.0 kg·ha^-1 of grain yield. Yield increased 15% and 529.5 kg·ha^-1 respectively compared with that of without nitrogen fertilizer before transplantation. [ Conclusion] This study suggested that it could increase mineral nitrogen content in the rhizosphere soil of rice, accelerate filler＇s development, and enhance the rate of effective tillers with 310.5 kgN·ha^-1 in seedling field. It can improve nitrogen utilization efficiency and grain yield distinctly.