耕作方式和秸秆还田对黄淮海夏大豆产量和土壤理化性状的影响

Effects of tillage and straw returning on soybean yield and soil physicochemical properties in Yellow-Huai-Hai Rivers Valley

在徐州麦豆一年两熟区进行田间定位试验(2012-2016年),采用两因素试验设计,研究了不同耕作方式(免耕和旋耕)和小麦秸秆还田量(不还田、半量还田和全量还田)对大豆产量和土壤理化性状的影响。结果表明:与旋耕处理相比较,免耕处理对大豆产量、土壤有机质含量和土壤速效K含量没有影响,但减少了土壤NO_3^--N含量,增加了土壤NH_4^+-N含量、土壤速效P含量和播种期至苗期的土壤容重。与不还田处理相比较,秸秆还田处理提高了大豆单株荚数、百粒重和产量以及土壤有机质含量和土壤速效K含量,降低了土壤NO_3^--N含量、NH_4^+-N含量和初花期至初熟期土壤容重。免耕和秸秆还田均降低了土壤p H值、播种期至初花期土壤温度,增加了播种期至初花期土壤湿度。秸秆不还田下免耕处理大豆单株荚数、百粒重、产量、土壤有机质含量、土壤p H值和土壤NO_3^--N含量较旋耕处理显著下降。与之不同,秸秆还田下免耕处理土壤湿度、土壤有机质含量、土壤速效P含量高于旋耕处理,土壤温度、土壤NO_3^--N含量和土壤NH_4^+-N含量低于旋耕处理,而免耕处理与旋耕处理间大豆产量和土壤速效K含量差异均不显著。其中,免耕+秸秆全量还田处理土壤温度、土壤p H值最低,土壤湿度、土壤有机质含量最高。因此,在黄淮海夏大豆区推广免耕技术时,应与秸秆覆盖,尤其是秸秆全量覆盖相结合,同时,在生产中需要注意N肥的补充。

A five-year field study with two factorial design was conducted to investigate the effects of different soil tillage（ rotary tillage,RT and no tillage,NT） and wheat straw returning（ no straw returning,M0; half straw returning,M1; total straw returning,M2） on soybean yield and soil physicochemical properties under wheat-soybean double cropping system in Yellow-Huai-Hai Rivers Valley（ Xuzhou）. The results showed that compared with rotary tillage,no tillage had no effects on soybean yield and the concentrations of organic matter and available K in soil,but resulted in lower NO3^--N,and higher NH4^＋-N content in soil,an increased available P and soil bulk density during sowing to V6. Compared to no straw returning,pod number per plant,100-seed weight,yield and the content of soil organic matter and available K were increased,content of soil NO3^--N and NH4^＋-N,soil bulk density during R1 to R7 were decreased in the treatment of wheat straw returning. Moreover,no tillage andstraw returning decreased soil p H and soil temperature during sowing to R1 and increased soil humidity during sowing to R1. Pod number per plant,100-seed weight,yield,soil organic matter content,soil p H and soil NO3^--N content in no tillage treatment were higher than those of rotary tillage treatment under no straw returning. However,compared with rotary tillage,no tillage increased soil humidity,the content of soil organic matter and available P,and decreased soil temperature,the content of NO3^--N and NH4^＋-N content under straw returning. There was no significant difference in soybean yield and soil available K content between rotary tillage and no tillage treatments. Compared with NS ＋ M1,NS ＋ M2 decreased soil p H and soil temperature,and increased soil humidity and soil organic matter content. Hence,no tillage in combination with straw returning,especially total straw returning,should be used and more nitrogen fertilizer should be applied in the Yellow-Huai-Hai River Valley.