氮肥后移对稻鱼共生模式下水稻和禾花鲤鱼生长及田间水质环境的影响OA北大核心CSTPCD

[Objective]This study aims to explore the effects of postponing nitrogen fertilization in the rice-fish co-culture system on rice(Oryza sativa)yield and grain quality,nitrogen utilization rate,fish survival rate,fish yield,fish meat quality,as well as paddy field water quality.This research would provide a theoretical basis for stabilizing rice and fish yields and improving nitrogen utilization efficiency in rice fields under the rice-fish co-culture system.[Method]The study used hybrid rice'Taifengyou 208',conventional rice'19 Xiang'and Cyprinus carpio variety'Ruyuanshili 1'as experimental materials.Based on a total nitrogen application rate of 150 kg·hm-2 for early season and 180 kg·hm-2 for late season,three experimental treatments were designed:No nitrogen fertilizer application(M0),one-time basal nitrogen fertilizer application(M1,the top dressing fertilizer was not added),and postponing nitrogen application(M2,the mass ratio of basal fertilizer and top dressing fertilizer was 7∶3).[Result]Compared to the M1 treatment,M2 treatment was more beneficial for improving the rice tiller numbers,leaf SPAD values and nitrogen absorption and utilization efficiency(REN)at heading stage,the REN of M2 treatment increased by 25.82%-91.11%and 62.74%-67.35%in early and late rice growing seasons respectively.There was no significant difference in milling quality and appearance quality of rice between M1 and M2 treatments.M2 treatment significantly increased the paddy water electrical conductivity,total nitrogen,ammonia nitrogen,and nitrate nitrogen contents at rice panicle initial stage(P<0.05),while significantly reduced the crude fat content in carp meat(P<0.05).However,it had no significant effect on the survival rate or yield of fish.[Conclusion]In the rice-fish co-culture system,postponing nitrogen application can stabilize rice and carp yield,improve nitrogen use efficiency,and reduce crude fat content of carp meat,with no significant effect on rice quality or the protein and total amino acid contents of carp meat.