油菜秸秆还田对水稻根系、分蘖和产量的影响

Effects of oilseed rape straw incorporation on root, tiller and grain yield of rice

采用田间试验与栽培模拟试验相结合的方法,分析了油菜秸秆还田对水稻根系、分蘖和产量的影响.结果表明:水稻移栽后0～36 d,与秸秆不还田处理相比,油菜秸秆还田处理下水稻分蘖减少1～2个,根系单株伤流量降低1.0～8.6 mg,根系谷氨酰胺合成酶(GS)、谷丙转氨酶(GPT)和谷草转氨酶(GOT)活性分别降低0.10～6.11、0.06～0.31和0.52～0.84μmol·g^(-1)·h^(-1).水稻移栽后56 d,与秸秆不还田处理相比,油菜秸秆翻埋还田处理下水稻根系单株伤流量增加3.4～11.7 mg,根系GS、GPT和GOT活性分别增加0.34～0.78、0.13～0.45和0.18～0.20μmol·g^(-1)·h^(-1);油菜秸秆覆盖还田处理下水稻根系单株伤流量降低19～25 mg,根系GS、GPT和GOT活性分别增加0.16～0.34、0.08～0.21和0.06～0.32μmol·g^(-1)·h^(-1).油菜秸秆还田处理中,全量还田处理下的水稻产量最高,其中,与全量覆盖还田相比,全量翻埋还田处理下的水稻产量增加0.13～0.48 t·hm^(-2).可见,油菜秸秆还田会导致水稻生长前期根系活力下降、氮代谢酶活性降低,从而使水稻根系生长缓慢、返青延迟,但在中后期,随着根系活力和氮代谢酶活性的增强,秸秆还田会促进水稻根系生长;油菜秸秆还田对水稻产量的影响是多因素综合作用的结果,全量翻埋还田更适宜于四川油稻两熟轮作系统.

By field experiment and cultivation simulating,we analyzed the impacts of oilseed rape straw incorporation on root,tiller and grain yield of rice.Results showed that straw incorporation treatments decreased 1-2 in tillers and 1.0-8.6 mg per plant in bleeding sap.The activities of glutamine synthetase(GS),glutamic-pyruvic transaminase(GPT)and glutamic-oxalacetic transa-minase(GOT)of root in straw incorporation treatments were reduced by 0.10-6.11,0.06-0.31 and 0.52-0.84μmol·g-1·h-1 respectively as compared to control,during the earlier stage(0-36 d after transplanting)of rice growth.Compared to no straw incorporation treatment,the straw incorporation by plough method increased bleeding sap by 3.4-11.7 mg per plant,and increased the activities of GS,GPT and GOT by 0.34-0.78,0.13-0.45 and 0.18-0.20μmol·g-1·h-1 respectively.During the later stage(56 d after transplanting)of rice growth,straw incorporation treatments by mulching reduced bleeding sap by 19-25 mg per plant,and increased the activities of GS,GPT and GOT in root by 0.16-0.34,0.08-0.21 and 0.06-0.32μmol·g-1·h-1,respectively.The grain yield of total straw returning treatments(MF2 and FH2)were higher than other straw returning treatments.In comparison of MF2,the rice yield of FH2 was higher by 0.13-0.48 t·hm-2.Oil seed rape straw incorporation hindered rice root growth and delayed the reviving of rice after transplanting,by decreasing the activities of roots and nitrogen metabolizing enzymes during earlier stage.However,it promoted rice root growth by increasing activities of roots and nitrogen metabolizing enzyme during media and later stage.The increase or decrease of rice yield is a comprehensive balance of multiple factors in straw incorporation rice field.Total straw incorporation by plough method is one of the better straw returning manners for oilseed rape-rice rotation system in Sichuan Basin area.