增苗减氮对稻田氮素流失及利用效率的影响

Increasing Transplanting Density and Reducing Nitrogen Fertilizer: Effect on Nitrogen Loss and Nitrogen Use Efficiency in Paddy Field

研究旨在探讨增苗减氮的栽培方式对水稻的氮素流失及吸收利用的影响,为水稻氮磷流失防控奠定基础。采用小区试验研究了不同增苗减氮处理对地表径流氮素流失、水稻氮素吸收量和利用效率、土壤氮素平衡的影响。结果表明,随着施氮量的减少和秧苗数的增加总氮流失量显著降低,插秧前流失量占全生育期60%以上,总氮流失量最高为常规处理(T2)达到11.80 kg/hm^(2),T3~T6处理比T2降低13.42%~53.52%。与T2处理相比,T3~T6处理氮肥农学效率提高2.86%~28.99%,偏生产力提高3.40%~24.98%。随着施氮量的降低和秧苗数的增加氮素盈余量降低,T2~T6处理氮素盈余量分别为20.55 kg/hm^(2)、15.23 kg/hm^(2)、16.10 kg/hm^(2)、6.33 kg/hm^(2)和-10.62 kg/hm^(2)。该试验表明适度的增加秧苗密度、减少氮肥投入能够减少氮素流失,提升氮素利用效率,保障土壤氮素平衡。

This study aims to lay a foundation for the prevention and control of nitrogen and phosphorus loss in paddy field. The plot experiments were conducted to investigate the effects of different treatments of increasing transplanting density and reducing nitrogen fertilizer on the nitrogen loss by surface runoff, nitrogen utilization efficiency of rice, and soil nitrogen balance. The results show that the total nitrogen loss is significantly reduced due to the decreasing of nitrogen application and the increasing of seedling number. The nitrogen loss before transplanting accounts for more than 60% of the whole growth period. The total nitrogen loss of the conventional treatment(T2) is the highest, reaching 11.80 kg/hm^(2), and those of T3-T6 treatments are reduced by 13.42%-53.52% compared with T2. The agronomic efficiencies of nitrogen fertilizer of T3-T6 treatment increase by 2.86%-28.99% and nitrogen partial productivity increases by 3.40%-24.98% compared with T2.The nitrogen surplus decreases with the decreasing of nitrogen application amount and the increasing of seedling number. The nitrogen surplus of T2 to T6 is 20.55 kg/hm^(2), 15.23 kg/hm^(2), 16.10 kg/hm^(2), 6.33 kg/hm^(2),-10.62 kg/hm^(2), respectively. Therefore, properly increasing seedling density and decreasing nitrogen input could reduce nitrogen loss, improve nitrogen use efficiency and guarantee soil nitrogen balance.