潮土区小麦-玉米轮作周年秸秆还田及施钾效应研究

Effects of Straw Returning and Application of Potassium Fertilizer under Wheat-Maize Rotation in Fluvo-aquic Soil Area

在山东省西部潮土区研究了小麦-玉米周年轮作模式下连续两年4个种植茬口秸秆全还田和施用钾肥对耕层土壤钾素状况、作物产量及土壤-作物系统钾素平衡的影响。结果表明:定位两年后,秸秆还田及施用钾肥均可不同程度地提高土壤速效钾和缓效钾含量,其中秸秆还田配施钾肥(NPKst)处理提高幅度最大;小麦或玉米产量各个茬口均以NPKst处理最高,不施钾肥秸秆不还田(NP)处理最低。施用钾肥小麦平均增产8.03%,玉米平均增产2.92%;秸秆还田条件配合施用钾肥,小麦平均增产14.13%,玉米平均增产6.99%。施用钾肥秸秆不还田(NPK)处理和NPKst处理第一种植季的钾肥当季回收率分别为31.8%、24.4%,4个种植季钾肥累计回收率分别为39.2%、25.3%。定位两年后,单施钾肥处理(NPK)土壤钾素平衡达到-481.2 kg/hm2,秸秆还田配施钾肥处理(NPKst)土壤钾素平衡达到74.2 kg/hm2。为实现化肥使用量零增长目标,秸秆还田配施钾肥是维持潮土土壤钾素持续供应的有效措施。

A field experiment was conducted under the wheat-maize annual rotation model in the fluvo-aquic region of western Shandong Province. The experiment continued for two years to investigate the effects of all straw returning and potassium fertilization（ NPKst） on the potassium status,crop yield,and potassium balance in the soil-crop system. The results after two years of positioning showed that the straw returning and application of potassium fertilizer could increase the content of available potassium and slow-acting potassium in different degrees,of which,the NPKst treatment had the largest increase. The yield of wheat or maize was the highest under the NPKst treatment and the lowest under the NP treatment with no straw returningand no potassium application. In the case of only applying potassium fertilizer（ NPK）,the average yield of wheat and maize increased by 8. 03% and 2. 92%,respectively; but when combined with the straw returning,that increased by 14. 13% and 6. 99%,respectively. The recovery rates of potash fertilizer of NPK treatment and NPKst treatment at the first planting season were 31. 8% and 24. 4%,respectively. The cumulative recovery rates of the NPK and NPKst treatments in the four planting seasons were 39. 2% and 25. 3%,respectively. After two years,the potassium balance in soil reached-481. 2 kg/hm2 under the NPK treatment and74. 2 kg/hm2 under the NPKst treatment. To achieve the goal of zero growth in the amount of chemical fertilizer,returning straw into field and applying potassium fertilizer simultaneously should be an effective measure to maintain the continuous supply of potassium in fluvo aquic soil.