Effects of different straw mulch modes on soil water storage and water use efficiency of spring maize (Zea mays L.) in the Loess Plateau of China

The effects of different modes of straw mulch on soil water storage, grain yield and water use efficiency (WUE) of spring maize (Zea mays L.) were evaluated from 2007-2010 at the Dry Farming Base of Northwest A&F University, in the Loess Plateau of China. Seven treatments were conducted, including conventional tillage without straw mulch (CK), maize straw mulch for the whole year (WSM) at the rates of 4 500, 9 000 (S2) and 13 500 kg/ha (S3), and maize straw mulch only during growth period (GSM) at the rates of 4 500, 9 000 and 13 500 kg/ha. The results showed that the 3-year average soil water storage within the 200 cm soil depth for the WSM was increased when compared to the CK and GSM; the three-year average grain yield increased with straw mulch rate, and WSM and GSM increased the average grain yield by 4.4% and 2.0% when compared to CK; the WUE were also increased in straw mulch treatment; however, there were no significant differences in the grain yield and WUE between the S2 and S3. Therefore, the WSM mode with maize straw mulch rate of 9 000 kg/ha was preferable for the Loess Plateau of China with the precipitation lower than 390 mm during the growth period of spring maize.