缓控释尿素与普通尿素配施对双季稻生长、氮肥效率和土壤供氮能力的影响

Effect of combined application of slow/controlled release urea and conventional urea on the growth,nitrogen fertilizer efficiency and soil nitrogen-supplying capacity of double-cropping rice

通过田间试验,设置无氮肥(PK)、常规施肥(NPK)、缓控释尿素一次基施(T1)、80%缓控释尿素+20%尿素一次基施(T2)以及80%缓控释尿素基肥+20%尿素施追肥(T3),共5个处理,研究不同氮肥施用对双季稻的籽粒产量及其构成、氮肥利用效率和土壤供氮能力的影响。试验结果表明,与常规施肥处理相比,施缓释肥水稻产量明显提高,尤其是T2处理效果更好。T2处理早稻和晚稻有效穗数均是最高的,其次是T1、T3和NPK处理,PK处理最低。早稻缓释肥处理比NPK处理的籽粒吸氮量显著提高了18.5%~26.0%,秸秆吸氮量显著提高了12.7%~20.9%;晚稻缓释肥处理比NPK处理的籽粒吸氮量显著提高了24.4%~28.8%,秸秆吸氮量显著提高了18.4%~39.1%。T3处理晚稻秸秆吸氮量分别比T1处理和T2处理显著提高了17.5%和16.1%。施氮肥引起氮素在土壤中的累积,尤其是NPK处理,其氮素盈余量远高于施用缓释肥处理。无论是早稻还是晚稻,T3处理的氮肥表观利用率最高,其次是T2处理、T1处理,NPK处理最低。与NPK处理相比,施缓释肥处理的土壤水解性氮含量显著提高了12.8%~25.4%,铵态氮含量提高了177.7%~217.8%、硝态氮含量提高了94.2%~120.0%。T1处理水解性氮含量和硝态氮含量比T3处理分别显著提高了11.1%和13.3%,铵态氮含量比T2和T3处理分别提高了10.0%和14.5%。总之,在秸秆还田基础上,在施氮量相同的条件下,与常规一基二追氮肥施用方式相比,施用80%的缓控释尿素,配施20%的普通尿素一次性基施的施肥方法,能够保证水稻籽粒产量不下降的前提下,显著提升土壤供氮能力。

Through field experiments,five treatments were set up:no nitrogen fertilizer(PK),conventional fertilization(NPK),a single base application of slow/controlled release urea(T1),80%slow/controlled release urea+20%urea as a single base application(T2),and 80%slow/controlled release urea as base fertilizer+20%urea as top dressing(T3).These treatments were used to study the impact of different nitrogen applications on the grain yield and its components,nitrogen fertilizer efficiency,and soil nitrogen supplying capacity in double-cropping rice.The results showed that compared with conventional fertilization,the application of slow/controlled release fertilizer significantly increased rice yield,especially the T2 treatment.T2 had the highest effective panicle count for both early and late rice,followed by T1,T3,and NPK,with PK being the lowest.The nitrogen uptake of grain in the early rice from slow-release fertilizer treatments was significantly higher than that of NPK treatment by 18.5%to 26.0%,and the nitrogen uptake of straw was significantly increased by 12.7%to 20.9%;In the late rice,the nitrogen uptake of grain was also significantly higher than that of NPK treatment by 24.4%to 28.8%,and the nitrogen uptake of straw was significantly increased by 18.4%to 39.1%.The nitrogen uptake of straw in the T3 late rice was significantly higher than that in T1 treatment and T2 treatment by 17.5%and 16.1%,respectively.Nitrogen fertilization caused nitrogen accumulation in the soil,especially in the NPK treatment,where the nitrogen surplus was much higher than that in the treatments using slow/controlled release fertilizers.Whether in early or late rice,the apparent nitrogen use efficiency of the T3 treatment was the highest,followed by T2 treatment,T1 treatment,and the lowest in NPK treatment.Compared with NPK treatment,the soil hydrolyzable nitrogen content in the slow/controlled release fertilizer treatments increased significantly by 12.8%to 25.4%,ammonium nitrogen content increased by 177.7%to 217.8%,and nitrate nitrogen content increased by 94.2%to 120.0%.The hydrolyzable nitrogen content and nitrate nitrogen contents in the T1 treatment were significantly higher than those in T3 by 11.1%and 13.3%,respectively,and the ammonium nitrogen content was higher than those in T2 and T3 by 10.0%and 14.5%,respectively.In summary,based on straw return,under the same amount of nitrogen applied,the fertilization method using 80%controlled-release urea combined with 20%urea as a single base application can significantly enhance soil nitrogen supplying capacity while ensuring that the rice grain yield does not decrease,compared with the conventional method of one base and two top dressing applications.