| We evaluated the effect of different modes of cropping systems using straw mulch on the soil temperature, soil water and grain yield of spring maize（zea mays L.） in 2007—2010 at the Dry Farming Base of Northwest A&F University, Heyang County in the Weibei Highland region of China. Seven treatments were used, including conventional tillage（CK）, maize straw mulching at the rates of 4500（S1）, 9000（S2） and 13 500 kg·hm-2（S3） year-round（both fallow and growth period）（QSM） and 4500（S4）, 9000（S5） and 13 500 kg·hm-2（S6）during the growth period（SSM）. The results showed that the cooling effect of treatments with SSM increased with the rate of straw mulching, and decreased with the soil depth at 0~25 cm soil profile. The low temperature effect of treatments showed a trend of large changes early, and small ones late during the growth period changes at 0~15 cm soil layers. The daily average soil temperature of different treatments at 0~5 cm soil depths was the lowest at 6：00, and the difference was the smallest compared to the CK treatment; the temperature was the highest at 14：00, and the difference was also the largest; the temperature at 20：00 was medium. Compared to the CK with QSM, the 3-year mean soil water storage within the 200 cm soil depth for the S1, S2 and S3 treatments was increased by 7.6 mm, 10.8 mm and 12.3 mm, respectively, over the fallow season; the 3-year mean soil water content within the 20 cm soil depth during the growth period was increased by 3.9%, 8.5% and 11.8%, respectively. The 3-year mean soil temperature and soil water content with SSM showed a similar changing trend compared to the QSM, which was overall less for the SSM than for the QSM. The variance analysis showed that compared to the SSM, the QSM was significantly superior（P<0.05）. Our findings suggested that the farmers should adopt the QSM mode to optimize the efficiency of straw mulching. In addition, the maize straw mulching rate of 9000 kg·hm-2 could be the optimal for the Weibei Highland region, China. Our study provides scientific reference for the application of straw mulch in other dryland farming regions throughout the world. |
