Effect of conservation and conventional tillage on soil water storage, water use efficiency and productivity of corn and soybean in Northeast China

The dominant factors affecting crop production in Northeast China are the low amount of rainfall in spring and high loss of soil water through evaporation during summer, both of which contribute to the lower soil water use efficiency (WUE). The objective of this study was to evaluate the long-term effects of no-till (NT), reduced tillage (RT) and conventional tillage (CT) on soil water storage (SWS), WUE, and soybean and corn yields in Northeast China from 2009 to 2011. The soil water contents under NT were higher than CT, especially in the 0-30 cm soil. SWS was lower in spring and autumn but higher in summer and it was influenced by both rainfall and tillage practices. NT had the greatest SWS and CT the least, with RT having intermediate values in the 30-cm surface. Leaf area index was higher for CT compared with the RT and NT in corn, but it was higher for RT than CT and NT in soybean. The evapotranspiration in the crop growing seasons was higher for NT and RT than for CT in the two corn years (2009, 2011), but no differences were found in the soybean year (2010). The WUE was greatly affected by weather conditions, (i.e., 64% lower in the wet year), and also affected by tillage; that is, CT and RT were 36 and 15% higher than NT in 2009, but no differences in other years. We conclude that RT was a good compromise for both soybean and corn crops, as it was associated with higher economic returns for farmers. Further research is required to compare the effect of the conservation tillage on the WUE and economic returns for other locations in Northeast China. © 2013 Copyright Taylor and Francis Group, LLC.