秸秆还田配施化肥对黄褐土氮磷淋失的影响

Effects of Straw Return with Chemical Fertilizer on Nitrogen and Phosphorus Leaching from Yellow Cinnamon Soil

采用室内模拟装置淋溶土柱的方法,研究了水稻秸秆还田配施化肥对土壤氮磷淋溶迁移的影响。结果表明,土壤淋失液中总氮含量表现为:NS(无秸秆还田+优化施肥)处理>SF(秸秆还田+优化施肥)处理>SDF(秸秆还田+优化施肥量氮磷钾均减20%)处理>CK(无秸秆还田、无施肥)处理;土壤淋失液中可溶性磷和总磷含量均表现为:SF(秸秆还田+优化施肥)处理>NS(无秸秆还田+优化施肥)处理>SDF(秸秆还田+优化施肥量氮磷钾均减20%)处理>CK(无秸秆还田、无施肥)处理,并且呈现出随着时间的延长逐渐下降的趋势;经过淋溶后,表层土壤中全氮含量最高的是SF(秸秆还田+优化施肥)处理,为0.486g/kg,最低的是CK(无秸秆还田、无施肥)处理,为0.440g/kg,全磷含量最高的是NS(无秸秆还田+优化施肥)处理,为0.306g/kg,最低的是CK(无秸秆还田、无施肥)处理,为0.261g/kg;但表层土壤中速效磷含量最高的是SF(秸秆还田+优化施肥)处理,为29.353mg/kg,最低的是CK(无秸秆还田、无施肥)处理,为21.210mg/kg。研究结果表明,化肥施用量减少有利于降低土壤氮磷的淋失,在优化施肥量条件下,黄褐土实行秸秆还田会降低土壤氮素的淋失,但会提高土壤磷素的淋失。

Indoor simulated leaching approach of soil column was used to study effects of straw return with chemical fertilizer on nitrogen and phosphorus leaching from yellow cinnamon soil. The results showed that the total nitrogen concentration in soil leachate in different treatments listed in the following order： NS（with-out straw return ＋optimized fertilization））SF（straw return ＋optimized fertilization）〉SDF（straw return ＋ optimized fertilization which was reduced by 20%）〉CK（without straw return ＋without fertilization）, while the soluble phosphorus and total phosphorus content in soil leachate listed as follows： SF（straw return ＋ optimized fertilization）〉 NS （without straw return ＋ optimized fertilization） ） SDF （straw return ＋ optimized fertilization which was reduced by 20%）〉CK（without straw return ＋ without fertilization）, and decreased gradually as the extension of time. After leaching, the total nitrogen concentration of SF（0. 486 g/kg） was the highest and that of CK（0. 440 g/kg） was the lowest in surface soil, and the total phosphorus concentration of NS（0. 306 g/kg） was the highest and that of CK（0. 261 g/kg） was the lowest in surface soil, while the available phosphorus concentration of SF（29. 353 mg/kg） was the highest and that of CK（21. 210 mg/kg） was the lowest in surface soil. In conclusion, decreasing the amount of chemical fertilizer can reduce the leaching of soil nitrogen and phosphorus, and under the condition of optimized fertilization amount, straw return can decrease soil nitrogen leaching, but increase soil phosphorus leaching for yellow cinnamon soil.