秸秆堆沤还田对红壤烤烟农田生态系统磷素盈亏的影响

【目的】研究不同秸秆堆沤还田方式对红壤烤烟坡耕地磷素盈亏的影响，揭示秸秆堆沤还田下红壤烤烟农田生态系统磷素盈亏的特征，为滇中小流域面源污染防治提供科学依据。【方法】在自然降水条件下，研究不同秸秆还田密度（0.75和1.50 kg/m2）、不同秸秆粉碎粒度（1和5 cm）、不同秸秆堆沤处理（水、水与尿素）对红壤烤烟坡耕地径流泥沙磷素流失量、土壤磷素残留量、烤烟磷素吸收量和磷素盈亏的变化特征。【结果】施用1.50 kg/m2秸秆密度、5 cm秸秆粒度、加水堆沤较0.75 kg/m2秸秆密度、1 cm秸秆粒度、加水与尿素堆沤可有效降低产流产沙量（0.22%~43.26%）；施用0.75 kg/m2秸秆密度、5 cm秸秆粒度、加水堆沤可有效降低径流和泥沙磷素流失浓度（2.82%~66.67%、0.38%~57.53%）及流失量（最高分别降低63.89%和64.74%）；秸秆还田对各土层土壤总磷（TP）残留量的影响不同，总体上呈增加趋势；秸秆还田后，烤烟全磷（TP）含量的分布特征为叶>根>茎，1.50 kg/m2秸秆密度、1 cm秸秆粒度、水与尿素堆沤均可有效增加烤烟吸收TP含量（0.60%~49.76%）和土壤磷素盈余量（0.43%~13.97%）。【结论】秸秆堆沤还田可提高和维持红壤烤烟坡耕地土壤磷素水平，减少土壤磷素淋失，增强土壤供磷潜力，是削弱该流域农业非点源污染，综合利用秸秆资源，促进农业生态平衡发展的重要措施。

Effects of straw compost retting on phosphorus balance of fluecured tobacco farmland ecosystem in red soil

【Objective】 To study effects of different straw retting methods on the phosphorus balance of red soil fluecured tobacco farmland，to reveal the characteristics of phosphorus balance in the red soil flue-cured tobacco farmland ecosystem under straw retting，so as to provide a scientific basis for the prevention and control of non-point source pollution in small watersheds in central Yunnan.【Method】 Under natural rainfall conditions，different straw returning densities（0.75 and 1.50 kg/m2），different straw crushing particle sizes（1 and 5 cm），different straw heap retting processing（water，water and urea）were designed to study the effects of runoff and sediment phosphorus loss，soil phosphorus residue，flue-cured tobacco phosphorus absorption and phosphorus balance in the flue-cured tobacco slope farmland.【Result】 Given 1.50 kg/m2 straw density，5 cm straw particle size，water retting compared with 0.75 kg/m2 straw density，1 cm straw particle size，water and urea retting the runoff and sediment yield（0.22%-43.26%）could be effectively reduced.Given straw density of 0.75 kg/m2，straw particle size of 5 cm，and water retting，the phosphorus concentration loss （2.82%-66.67%，0.38%-57.53%）and phosphorus loss（the highest reduction was 63.89% and 64.74% respectively）in runoff and sediment could be effectively reduced.Effects of straw returning on soil total phosphorus（TP）residues in each soil layers were different，and the overall trend was increasing.After straw returning，the distribution of TP content was leaf>root>stem.The straw density of 1.50 kg/m2，straw particle size of 1 cm，water and urea retting could increase TP content in plant organs of flue-cured tobacco （0.60%-49.76%）and soil TP surplus （0.43%-13.97%）.【Conclusion】 Straw retting can improve and keep phosphorus in red soil flue-cured slope，reduce soil phosphorus loss and enhance soil phosphorus supply capacity，which is a significant measure to weaken agricultural non-point source pollution in the basin，comprehensively utilize straw resources，and promote the balanced development of agricultural ecology.