小麦/玉米轮作下秸秆还田对钾循环的影响

Effects of Returned-Straw on Potassium Cycle in Wheat-Maize Rotation Systems

摘要: 为探讨秸秆还田条件下农田生态系统钾循环规律，通过田间试验，研究了不同秸秆还田量对麦–玉轮作体系下农田生态系统钾循环的影响。结果表明，秸秆还田能增加不同土层中土壤不同形态钾含量，土壤水溶性钾、交换性钾及全钾含量随土层加深呈现增多趋势。从不同秸秆还田量来看，以150%秸秆还田处理的全钾含量增幅最大，以100%秸秆还田处理的土壤速效钾含量最高。秸秆不还田及还田量过低会导致土壤钾素表现为亏缺状态，土壤供钾能力降低。由于秸秆的截获作用，秸秆还田可以减少随径流及淋溶水带走的钾量，增加土壤的保水、保肥性能。150%秸秆还田在减少径流、淋溶量，降低随径流、淋溶水带走的钾素量最多，能保证土壤钾库一个相对较富集或盈余状态。

Abstract: In order to discuss potassium cycle in farmland ecosystem under returned-straw condition, we decorate field experiment to study effects of different returned-straw quantity on potassium cycle in wheat-maize rotation systems. The results showed that returned-straw could increase the contents of water-soluble potassium, exchangeable potassium and total potassium in different soil layers. The total potassium content increased the most when the straw was returned to the field by 150%, and the soil available potassium content was the highest when the straw was returned to the field by 100%. Straw no-returning to the field or too low amount of returning to the field would lead to the deficiency of soil potassium and decrease soil potassium supply capacity. Due to the interception of straw, straw mulching could reduce the amount of potassium taken away by runoff and leached water, and increase the water and fertilizer conservation performance of soil. 150% straw returning to the field could reduce runoff and leached amount, and reduce the amount of potassium carried away by runoff and leached water to the maximum, so as to ensure a relatively enriched or surplus state of soil potassium pool.