秸秆还田方式对土壤磷素有效性及吸附解吸特性的影响

Effects of Straw Return Methods on Soil Phosphorus Availability and Adsorption-Desorption Characteristics

摘要:

本研究基于长期定位试验，设置秸秆移除(T1)、轮耕翻埋还田(T2)、秸秆碎混还田(T3)、全秸秆粉碎覆盖还田(T4)、留高茬全秸秆还田(T5)、秸秆条带覆盖(T6)和秸秆全量深翻还田(T7)共7个处理，探索在土壤磷素有效性方面最佳的秸秆还田方式。结果表明，秸秆还田可提高土壤速效磷和全磷的含量，促使磷活化系数显著升高，提高土壤磷的有效性。土壤速效磷在T4、T5和T7处理中显著提高了138.92%、171.79%和140.36%，土壤全磷在T4、T6和T7处理中显著增加了31.82%、15.15%和31.82%，土壤磷活化系数在T4、T5和T7处理中显著提高了81.61%、134.31%和81.02%(P<0.05)。秸秆还田可显著降低土壤对磷的吸附能力，提高解吸能力，其中T4和T7处理磷素有效性较高(P<0.05)。综合来看，全秸秆粉碎覆盖还田(T4)和秸秆全量深翻还田(T7)方式是东北西部地区相对最佳的还田方式。

Abstract:

To explore the optimal method of straw return for enhancing soil phosphorus effectiveness, this study was based on a long-term field experiment with seven treatments:straw removal(T1), conventional tillage with straw return(T2), straw shredding and mixing(T3), full coverage of straw powder(T4), leaving tall stubble with full straw return(T5), straw strip covering(T6), and deep plowing with full straw return(T7). The results indicated that straw return increased soil available phosphorus and total phosphorus content, significantly raising the phosphorus activation coefficient and enhancing soil phosphorus effectiveness. Soil available phosphorus increased significantly by 138.92%, 171.79%, and 140.36% in treatments T4, T5 and T7, respectively. Soil total phosphorus increased significantly by 31.82%, 15.15%, and 31.82% in treatments T4, T6 and T7, respectively. The soil phosphorus activation coefficient increased significantly by 81.61%, 134.31%, and 81.02% in treatments T4, T5 and T7, respectively(P<0.05). Straw return significantly reduced soil phosphorus adsorption capacity and increased its desorption capacity, and the effectiveness of T4 and T7 treatment of phosphorus was higher(P<0.05). In summary, full coverage of straw powder(T4) and deep plowing with full straw return(T7) are relatively optimal approaches for straw return in the western regions of Northeast China.