秸秆还田与有机肥对黑土区土壤团聚性的影响

土地长期处于过度开垦状态,化肥大量施用,使土壤肥力下降,有机碳含量下降,作物产量降低。通过两组试验,1组施用有机肥,另1组秸秆全量还田,2组均以单施化肥处理(CK)作为对照。结果表明,秸秆还田和施用有机肥可增加黑土5 mm粒径大团聚体含量,有效缓解土壤大团聚体减少;有机肥和秸秆还田处理下机械稳定性团聚体平均重量直径(MWD)和水稳性团聚体MWD均高于CK;施用有机肥和秸秆还田显著提高土壤有机碳含量SOC,增幅2.4%～40.8%;施用有机肥和秸秆还田可有效提高作物产量,秸秆还田平均增产17.09%,施用有机肥平均增产23.41%。

Effect of straw returning and organic manure on soil aggregate in black soil area

Because the land was in the state of reclamation for a long time, the extensive application of chemical fertilizer made the soil fertility poor, the organic carbon content and the crop yield decreasing. Through two groups of experiments, one group is organic manure and the other group is straw returned to the field in full amount. Chemical fertilizer(CK) was compared with the two groups.The results of the three-year experiments were as follows: the percentage of large aggregates in black soil > 5 mm could be increased under the treatments of straw returning to the field and the application of organic manure, which could effectively alleviate the decrease of large aggregates in soil. The average weight diameter(MWD) of mechanically stable aggregates and MWD of water-stable aggregates under organic manure returning and straw returning treatment were higher than those under CK. Compared with CK, organic manure returning and straw returning significantly increased the content of organic carbon(SOC) by 2.4%-40.8%. Organic manure returning and straw returning can effectively increase crop yield, straw returning can increase the yield by 17.09% averagely, and organic manure returning can increase the yield by 23.41% averagely.