起身肥改善水稻根际土壤氮素分布与利用的研究

【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。

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

Objective] This paper was to explore the effects of nitrogen before transplanting on nitrogen distribution and utilization efficiency in the rhizosphere soil of rice , and to give guidance for application of nitrogen fertilizer . Method] The effects of nitrogen before transplanting application rate on spatio-temporal distributing of available nitrogen , utilization and yield were studied with Ningjing-2 utilizing the environment of breeding seedling through plastic-plate and transplanting with soil. Result] The results showed that nitrogen before transplanting could markedly improve nitrogen content in the rhizosphere soil of rice . Along with the days after transplanting adding , nitrogen content in soil that 1 cm apart from plant was falling . But , which of 4 , 7 cm apart from plant was first increasing then falling . The results also showed increasing nitrogen application rate increased total nitrogen accumulation and nitrogen utilization efficiency , but the yield wasn’t linear increased . Yield of NM(310.5 kgN /ha) was highest . Conclusion] The results suggested that 310.5 kgN /ha in seedling field could increase nitrogen content in the rhizosphere soil of rice ,accelerate tiller’s developing and enhance the rate of effective tiller . Nitrogen utilization efficiency and grain yield both were markedly increased .