小麦、夏玉米两茬轮作耕作措施对土壤氮、钾养分及玉米产量的影响

为了探索山东省半湿润易旱区夏玉米高产稳产适宜耕作措施，将冬小麦和夏玉米两季耕作技术作为一体，设置了10种耕作措施，比较分析不同耕作措施对夏玉米不同生育期土壤全氮、速效钾含量时空变化和产量的影响。耕作试验（一周年）结果表明：各耕作处理总体上表现为玉米拔节期土壤全氮含量较高而灌浆期较低，土壤速效钾为玉米灌浆期最高。不同耕层土壤氮、钾分布也存在明显差异，各耕作处理土壤浅耕层0～20cm土壤全氮和速效钾含量均明显高于深耕层20～40cm土壤，与深耕层土壤相比，土壤浅耕层全氮含量受耕作措施影响更明显。各耕作处理中，传统耕作和A，B，R（小麦季深松＋玉米季深松＋秸秆还田）较更有利于增加玉米浅耕层土壤全氮含量，而传统耕作深层土壤全氮含量最低；A4B2R（小麦季深耕＋玉米季免耕＋秸秆还田）耕作处理较有利于增加浅耕层和深层（0～40cm）i壤速效钾含量。对照处理籽粒产量显著低于其他耕作处理，而其他耕作处理间籽粒产量差异不显著。

Effects of Tillage Managements in Wheat-maize Whole Season on the Soil Nitrogen and Potassium in Summer Maize

In order to explore the most suitable tillage to reach high and stable yield in summer maize in sub-humid and drought areas in Shandong Province, with ten different tillage treatments during wheat-maize whole season, the effects of tillage managements on the soil total nitrogen, available potassium and grain yield in summer maize were studied. Among all tillage managements, the soil total N was the highest at grain filling stage and the lowest at jionting stage, and the available K was the highest at filling stage in maize season. The soil N and K content in each soil layer were significantly different. The soil total N and available K content in the 0-20 cm soil layer was higher than that in the deeper layer (20-40 cm). Conventional tillage management (CK) and A3B3R i.e. subsoiling tillage at wheat season + no-tillage at maize season + straw returning both showed highest total N in the 0-20 cm soil layer, but the total N in the deeper soil layer of CK was the lowest. A4B2R i.e. rotary tillage at wheat season + no-tillage at maize season + straw returning showed highest available K in the 0-40 cm soil. The yield of CK was significantly lower than all other tillage managements, but all other tillage managements had no significant difference.