滨海盐碱地棉花秸秆还田对土壤理化性质及棉花产量的影响

在滨海盐碱地定点设置连续3年棉花秸秆还田和未还田2个处理,研究其对0~60 cm土层土壤理化性质和棉花产量的影响。结果表明,连续3年棉花秸秆还田显著降低0~30 cm土层土壤容重和0~10 cm土层0.25 mm土壤微团聚体含量;显著提高0~10 cm土层5 mm土壤大团聚体含量。在0~20 cm土层,3年秸秆还田显著提高棉花播前和各生育阶段土壤有机质、硝态氮、铵态氮和速效钾含量,平均分别比对照提高13.45%、18.57%、22.80%和22.57%;降低土壤速效磷和含盐量,平均分别比对照降低18.29%和16.59%。在20~40 cm土层,3年秸秆还田显著提高土壤硝态氮和铵态氮含量,平均比对照提高37.20%和31.62%;显著降低土壤含盐量,平均比对照降低19.06%。在40~60 cm土层,3年秸秆还田显著提高土壤硝态氮和铵态氮含量,平均分别比对照提高38.26%和24.83%。3年棉花秸秆还田分别比未还田显著提高棉花籽棉产量11.57%、19.01%和13.24%和皮棉产量18.56%、19.78%和18.73%,但对棉花单铃重和衣分无显著影响。

Effects of Cotton Stalk Returning on Soil Physical and Chemical Properties and Cotton Yield in Coastal Saline-Alkali Soil

A continuous three-year field experiment of cotton-residue incorporation in coastal saline-alkali land was conducted, with two treatments: residue removal and residue incorporation. The successive cotton stalk returning significantly decreased soil bulk density in 0-30 cm soil layer and soil micro-aggregates with particle size <0.25 mm in 0-10 cm soil layer, while significantly increased the content of soil macro-aggregates with particle size >5 mm in 0-10 cm soil layer. Compared with the control (residue removal), the treatment of cotton residues incorporation significantly increased soil organic matter, nitrate nitrogen, ammonium nitrogen and available potassium by 13.45%, 18.57%, 22.80%, and 22.57%, respectively, while decreased soil available phosphorus and salinity by 18.29% and 16.59% at pre-sowing and each growth stage in 0-20 cm soil layer. Soil nitrate nitrogen and ammonium nitrogen were increased by 37.20% and 31.62% and soil salinity had a reduction of 19.06% after successive cotton stalk returning for three years in 20-40 cm soil layer, and also significantly increased by 38.26% and 24.83% in 40-60 cm soil layer. Successive cotton stalk returning significantly increased seed cotton yield by 11.57%, 19.01%, and 13.24% and lint yield by 18.56%, 19.78%, and 18.73% in three years, but not affected single boll weight and lint percentage.