8Ha L Z, Jian Y C, Zhou R L. Soil properties, crop productivity and irrigation effects on five croplands of inner mongolia[J]. Soil and Tillage Research, 2007, 93(2): 346-355.
9Liangzhi Y, Stanley W. Assessing the spatial distribution of crop areas using a cross-entropy methnd[J]. International Journal of Applied Earth Observation and Geoinformation, 2005, 7(4): 310-323.
10Zeyaur R, Khan, John A. Combined control of striga hermonthica and stemborers by maize-desmodium spp. Intercrops [J]. Crop Protection, 2006, 25(9): 989-995.
