Effects of conservation tillage on corn and soybean yield in the humid continental climate region of Northeast China

Soil quality and crop yield improvements through use of conservation tillage have been widely documented in the world. As the "bread basket" of the northern region of Northeast China, located at 47 degrees N, China's arable Black soils are consistently and intensively tilled and have been seriously degraded and eroded. Wide spread adoption of conservation tillage in this area will occur only if acceptable yields are demonstrated with its use. In this study, corn (Zea mays L.) and soybean (Glycine max Merril.) yield with no-till (NT), reduced-till (RT) and conventional tillage (CT) were compared from 2004 to 2010 on two separate areas, sloping and nearly flat farmland. Soybean yields increased significantly and, in contrast, corn yields decreased significantly under NT compared to CT. The average increase of soybean yield was 8.9% on the flat farmland and 13.8% on sloping farmland. The average corn yield decrease was 28.4% on the flat farmland and 15.7% on sloping farmland. A significant increase in soil moisture and decrease in soil temperature was found in the early growing season for NT compared to RT and CT. NT decreased surface runoff and increased soil water storage, which boosted soybean yield on the sloping farmland. Our study demonstrated NT was an effective and beneficial soil tillage practice and should be widely applied for soybean production in the northern region of Northeast China, where the sloping farmlands are mainly distributed with soybean as the main crop. (C) 2011 Elsevier B.V. All rights reserved.