Effects of Tillage Managements in Wheat and Maize Rotation Crop System on Leaf Senescence Biological Characteristics During Grain Filling in Maize

In order to explore the most suitable tillage managements to reach high and stable yield in summer maize in Shandong province,a semi-humid and drought-prone area of the North China,with the traditional tillage( rotary tillage at wheat season + direct seeding maize + no straw returning) as control,the effects of tillage managements( i. e. no tillage,subsoiling tillage,deep tillage) during wheat-maize whole season on the ear leaf senescence,accumulation and translocation of dry matter and grain yield of summer maize were studied. It was found that W3M2( Sub soiling tillage at wheat season + Direct seeding at maize season + no straw returning) not only significantly increased SOD activity and soluble protein content of ear leaf,but also decreased the content of MAD and delayed the ear leaf senescence. Both W4M4( Deep tillage at wheat season + Deep tillage at maize season + straw returning) and W1M1( Rotary tillage in wheat season + Rotary tillage in apart maize season + straw returning) recorded the highest dry matter production and followed by W3M2 and W3M3( Sub soiling tillage at wheat season + Sub soiling tillage at apart maize season + straw returning),while CK and W1M2( No-tillage at wheat season + Direct seeding at maize season + straw returning)recorded the lowest value. The highest and lowest allocation proportion of dry matter to grain( harvest index) was recorded in W3M2 and W4M4,respectively. The grain yield of W3M2 and W1M1were the highest,with the increase of23. 90% and 9. 87% compared with CK respectively. In the whole,W3M2 could effectively maintain physiological function of leaf,even at late grain filling stage,and accelerate the allocation of dry matter to grain,which causes a significant increase in grain yield. The results would give some suggestion for adopting an appropriate tillage and residue management for the two rotation cycle of wheat- maize system in North China.