Effects of tillage methods on crop yield and water use characteristics inwinter-wheat/summer-maize rotation system in the North China Plain

Four tillage methods - conventional tillage without straw (CT), conventional tillage with straw incorporation (CTS), rotary tillage with straw incorporation (RTS) and no-tillage with straw mulch (NTS) - were used to study the effects of tillage on annual yield and water use efficiency in winter-wheat/summer-maize cultivation system in the North China Plain. Results showed that different tillage methods significantly influenced winter wheat yield and water use efficiency. Different tillage methods did not significantly influence yield and water use of summer maize, tillage with straw incorporation increased yield of summer maize. Although differences in winter wheat yield under RTS, CTS and CT were not significant, fewer effective panicles of winter wheat yield under NTS led to significantly lower yield, compared with other treatments. Compared with CT, NTS decreased annual yield by 5.13%, while RTS, CTS increased annual yield by 2.69% and 2.33%. The tillage methods had significant effects on soil water content in winter-wheat season, but had no impact on soil water content in summer-maize season. Also NTS improved soil water content and water storage in winter-wheat season. Compared with CT, NTS increased soil water storage by 39.07 mm and 26.65 mm in two consecutive years. In terms of crop water use, soil water accounted for the largest proportion of winter-wheat water use, followed by irrigation and precipitation. While precipitation accounted for the largest proportion of summer-maize water use, some precipitation contributed to soil water storage. NTS improved soil water storage in winter-wheat and also limited soil water use, implying that water use was lowest under NTS during winter-wheat season. Compared with CT, NTS saved 22.40 mm of soil water in winter-wheat season and NTS also had the lowest annual crop water use. There was lower winter-wheat yield under NTS, the annual water use efficiency was also lower than the other treatments. In terms of annual yield and water use efficiency, there was the need to increase winter-wheat yield under NTS thereby increasing annual production. This is critical because of the high water-saving capacity of NTS, which is a key crop cultivation issue in the North China Plain.