稻草还田免耕抛秧对土壤剖面氮、磷、钾含量的影响

【目的】探讨稻草还田免耕对稻田土壤剖面氮、磷和钾的影响。【方法】对连续2年和7年结合稻草还田常耕抛秧和免耕抛秧试验的水稻土剖面氮、磷、钾进行了研究。【结果】免耕表层0-4（5）cm土壤全氮、全磷、碱解氮和速效磷含量显著高于常耕土壤。稻草还田免耕0-4（5）cm土壤的全钾含量显著高于常耕土壤，速效钾含量与稻草还田常耕差异不明显，但显著高于普通常耕土壤。免耕5-20 cm层土壤全氮、全磷、全钾、碱解氮和速效磷含量低于常耕土壤。普通免耕Aa层（耕作层）土壤速效钾含量显著低于常耕土壤。免耕的Ap层（犁底层）、W层（潴育层）和C层（母质层）碱解氮和速效钾含量高于常耕土壤。【结论】稻草还田免耕抛秧协调土壤氮、磷和钾的效果比普通免耕好，有利于土壤肥力的提高，稻草还田免耕抛秧是稻田免耕栽培的发展方向。

Effects of No-Tillage and Rice-Seedling Casting with Rice Straw Returning on Content of Nitrogen, Phosphorus and Potassium of Soil Profiles

【Objective】 The objective of this study was to understand the effects of no-tillage and rice-seedling casting with rice straw returning on nitrogen, phosphorus and potassium of paddy soil profile.【Method】Contents of nitrogen, phosphorus and potassium of paddy soil profile soil of conventional tillage of rice-seedling casting and no-tillage of rice-seedling casting experiments that lasted two and seven years were investigated. 【Result】Contents of total nitrogen, total phosphorus, alkaline-hydrolysable nitrogen and rapidly available phosphorus in 0-4(5) cm soil layer of no-tillage treatments were higher than those of conventional tillage. Contents of total potassium in 0-4(5) cm soil layer of no-tillage with rice straw returning treatment were significantly higher than those of common conventional tillage. Contents of rapidly available potassium in 0-4(5) cm soil layer of no-tillage with rice straw returning treatment were lower than that of conventional tillage with rice straw returning, but significantly higher than that of common conventional tillage. Contents of total nitrogen, total phosphorus, total potassium, alkaline-hydrolysable nitrogen and rapidly available phosphorus in 5-20 cm soil layer of no-tillage treatments were lower than those of conventional tillage. Content of rapidly available potassium in Aa layer (cultivation layer) of common no-tillage treatment was lower than those of conventional tillage. Contents of alkaline-hydrolysable nitrogen and rapidly available potassium in Ap layer (plow pan), W layer (waterlogged layer) and C layer (parent material layer) were higher than those of conventional tillage. 【Conclusion】The effects of no-tillage of rice-seedling casting with of rice straw returning on coordinate soil nitrogen, phosphorus and potassium are superior to that of common no-tillage of rice-seedling casting, and no-tillage of rice-seedling casting with rice straw returning is advantageous to the improvement and development of soil fertility. No-tillage of rice-seedling casting with rice straw returning is a development direction of paddy field no-tillage.