耕作措施对小麦-夏玉米轮作下玉米籽粒灌浆特性及产量的影响

摘要

在小麦-夏玉米轮作制度下设计小麦季、玉米季免耕、旋耕、深耕、深松不同周年耕作组合方式(8个),以小麦季传统旋耕+玉米季免耕+秸秆不还田为对照,探索进一步挖掘夏玉米增产潜力的最佳耕作方式。结果表明,定位试验第3年与对照相比,W3 M2(小麦季深松+玉米季免耕+秸秆还田)的穗粒数、百粒质量分别增加了42粒和1.83 g,产量比CK提高了23.9%,其他耕作处理增产不显著。 Logistic方程模拟结果表明,W3 M2的灌浆持续期最长,比CK延长了2.18 d,平均灌浆速率和最大灌浆速率分别比CK提高了0.05,0.1 mg/(粒·d)。 CK、W1 M2(小麦季旋耕+玉米季免耕+秸秆还田)和W1 M1(小麦季旋耕+玉米季隔年旋耕+秸秆还田)在灌浆后期灌浆速率均持续降低,其中CK降低幅度最大,而其他5个处理则在灌浆40 d后灌浆速率稳定,降低缓慢。总体上,秸秆还田下,小麦播种前深松、玉米季免耕( W3 M2)耕作方式的玉米穗部性状改善显著,灌浆优势明显,增产潜力较大。%In order to research the most suitable tillage practices with crop residues to reach high and stable yield in summer maize,with eight different tillage treatments during wheat-maize whole season,the effect of tillage practices on grain filling and ear characteristics and grain yield in summer maize were studied. Compared with CK ( Rotary tillage at wheat season + direct seeding maize + no straw returning ) , all other treatments increased the grain yield,but only in W3 M2 ( Sub soiling tillage at wheat season + direct seeding maize + no straw returning) the increase reached significantly by 23. 9%. Based on the Logistic equation fitting,the grain filling duration in W3 M2 was the longest,with 2. 18 days longer than CK,and the average filling rate,maximum filling rate,kernel number of per ear and 100-grain weight were also increased by 0. 05,0. 1 mg/(per kernel·d),42 grains and 1. 83 g,respec-tively. The grain filling rate was continually decreased during the late grain filling stage in rotary tillage in only wheat season ( CK,W1 M2 ) and rotary tillage in both wheat and maize season ( W1 M1 ) ,especially in CK,the de-crease was fast. However,the grain filling rate of other treatments was rapidly decreased slowly after 40 days of grain filling. Therefore,the treatment W3 M2 ( Sub soiling tillage at wheat season+direct seeding maize + no straw retur-ning) could significantly improve both ear characteristics and grain filling,and have a great potential for increasing the yield of maize.