深耕对夏玉米产量形成及土壤理化性质的影响

Effects of deep tillage treatments on summer maize yield and soil physicochemical properties

[目的]研究深耕对夏玉米产量构成和土壤理化性状的影响。[方法]利用耕作定位第7年的试验(2009-2015年),设常规耕作+秸秆还田(CT)、深耕+秸秆还田(DT)、深耕+秸秆不还田(NDT)、隔年深耕+秸秆还田(ADT)4种耕作方式进行田间试验。[结果]深耕能显著提高夏玉米产量,平均比CT增产17.6%,增产的原因是穗数、行粒数和百粒重穗行数的显著提高增加12.5%,行粒数多7.4%,百粒重提高5.6%;DT和ADT处理比NDT处理平均增产7.9%,DT与ADT间差异不显著。从增产机理上分析,深耕能显著提高夏玉米LAI(叶面积指数),灌浆期平均提高了11.0%;深耕打破犁底层,耕层厚度增加了58.9%,有效耕层土壤量增加59.2%,容重下降了10%以上,显著提高根系活力。同时深耕+秸秆还田即提高土壤有机质含量,又增加了土壤酶活性。10~40cm土层有机质含量提高了10%以上,0~20cm土层土壤酶活性增加了5%以上。[结论]隔年深耕是豫西地区一种节本增效的耕作模式。

[Objectives]The present research was aimed to determine the effects of four tillage treatments on yield of summer maize and soil physicochemical properties.[Methods]Four different treatments,including rotary tillage with straw return(CK),deep tillage with straw return(DT),deep tillage(NDT)and alternative year deep tillage with straw return(ADT),were adopted in the fields that has been conducted site-specific trials for successive seven years(2009-2015).[Results]The results showed that the three deep tillage treatments significantly improved summer maize yield up to 17.6% compared with CK by increasing the numbers of ears per hm2,kernels per row,and 100-grain weight.Grain yields in DT and ADT treatments were averagely increased by 7.9% compared with NDT treatment,while no significant difference was detected between DT and ADT..Statistical analysis on the change of yield components indicated that deep tillage treatments significantly improved root activity and leaf area index during grain filling stage.Moreover,the treatments improved soil physicochemical properties.Compared with CK,soil thickness and effective topsoil quantity were increased by 58.9% and 59.2%,respectively in deep tillage topsoil treatments which also produced a decrease of bulk density by 10%.Soil contents of organic matter in 0~40 cm soil layer was increased by more than 10%,and soil enzyme activities in 0~20 cm soil layer was induced by more than 5%.[Conclusion]In summary,the application of alternative year deep plowing with straw return can be used as an effective way to keep higher efficiency of plowing with less cost in the west of Henan.