玉米秸秆及其生物炭还田对黑土理化性质及玉米产量的影响OA北大核心CSTPCD

In order to solve the problems such as the decrease of organic matter quantity,the deterio-ration of topsoil structure and the decrease of soil fertility,a total of 7 treatments were set up:no straw and biochar addition(ck),0.25%straw addition(CS1),0.53%straw addition(CS2),0.2%bio-char addition(BC1),0.37%biochar addition(BC2),0.27%straw+0.1%biochar(CB1)and 0.13%straw+0.19%biochar(CB2).Based on a 4-year field positioning experiment,the effects of different application amounts of corn straw and biochar on soil physicochemical properties,soil aggregates and its carbon and nitrogen,and corn yield were studied.The results showed that compared with ck,straw and biochar returning significantly increased soil organic carbon(SOC)(by 5.67%-23.20%,)pH,cation exchange capacity(CEC),nitrogen and phosphorus contents.Soil structure was improved by straw and biochar returning,and soil bulk density(BD)was significantly reduced.Compared with ck,the proportion of>2 mm large aggregates was increased by 19.56%-32.67%,and the stability of aggregates was improved,and the carbon and nitrogen of 2-0.25 mm large aggregates and 0.25-0.053 mm micro-aggregates significantly increased(except CS1).Except for CS1 treatment,other straw and biochar returning treatments significantly increased corn yield by 15.53%-19.83%.Pearson correlation analysis showed that corn yield was significantly positively correlated with nitrogen and phosphorus nutrients,CEC and pH,and significantly negatively correlated with BD.Compared with straw application alone,BC2 treatment had more significant effects on increasing SOC,nitrogen,CEC,pH and soil structure.Therefore,returning straw and biochar to the field can effectively im-prove soil physicochemical properties and increase the storage capacity of SOC and nitrogen nutri-ents in soil aggregates,thus contributing to improving soil fertility and crop yield.