秸秆还田配施氮肥对黑钙土有机碳及微生物量碳氮的影响

Effect of straw returning with nitrogen on organic carbon and microbial biomass carbon and nitrogen in chernozem

【目的】为完善黑钙土地区秸秆还田技术,提升黑钙土可持续生产能力提供理论和实践依据。【方法】以吉林省典型黑钙土为供试土壤,采用室内培养法研究秸秆与2种氮肥(尿素和磷酸二铵)配施对黑钙土有机碳(SOC)和微生物量碳氮的影响。【结果】黑钙土SOC含量随秸秆添加量的增加而增加,增幅达6.27%~31.84%。尿素和磷酸二铵配施显著提高了黑钙土SOC含量,且磷酸二铵的提升效果更好。秸秆还田增加了黑钙土微生物量碳(SMBC)和微生物量氮(SMBN)含量,且添加量越高,二者增幅越大。秸秆添加使黑钙土SMBC含量增加了64.66%~196.46%,SMBN含量增加了102.58%~195.84%。氮素配施显著提高了黑钙土的SMBC和SMBN含量,且磷酸二铵的提升效果优于尿素。根据SMBC/SMBN值,判断黑钙土中微生物群落以真菌为主。【结论】氮素配施降低了黑钙土的SMBC/SMBN值,说明施氮有利于提高黑钙土微生物区系。

【Objective】Aiming at providing theoretical and practical basis for improving straw returning technology and enhancing the sustainable production capacity of soil in chernozem area.【Method】A typical chernozem soil in Jilin Province was used as tested soil to study the effects of adding different proportion of straw and two nitrogen fertilizers(urea and diammonium phosphate)on organic carbon(SOC)and microbial biomass carbon and nitrogen in chernozem by incubation experiment.【Result】The contents of SOC in chernozem were increased with the increase of straw addition with the increase of 6.27%to 31.84%.The combined application of urea and diammonium phosphate significantly increased the content of SOC in chernozem,and the improving effect of diammonium phosphate was better.Meanwhile,the contents of microbial biomass carbon(SMBC)and microbial biomass nitrogen(SMBN)in chernozem were increased after straw returning,and the contents were increased greatly with the increase of straw addition.The addition of straw increased the SMBC content in chernozem by 64.66%to 196.46%,and SMBN with 102.58%to 195.84%.The combined application of nitrogen significantly increased the contents of SMBC and SMBN in chernozem,and the promoting effect of diammonium hydrogen phosphate was superior to that of urea.According to the SMBC/SMBN ratio,it could be concluded that the microbial community in chernozem was dominated by fungi.【Conclusion】The combined application of nitrogen decreased the SMBC/SMBN ratio of chernozem,which indicated that nitrogen application exhibited positive effect on improvingmicroflora of chernozem.