Optimized allocation for land use and resources use in north Guangdong karst area

Xiushui small watershed, a typical rocky desertification area in north Guangdong Province, is chosen as an example to research the land resources for optimizing the layout and countermeasures under different space-time scales in this paper. The results show that (1) Water is seriously short in the area. The area of land with low, middle and high soil moisture account for 79.94%、10.72%、9.35% respectively, which corresponding to ＜4.702, 4.702～8.05 and ＞8.05 in topographic index . (2) Slope land is the most important arable land in Xiushui small watershed. The landuse style should be allocated as follows: contouring farming or covering farming be adopted if the gradient is ＜10°; plant hedge be adopted if the gradient is 10°to 25°; reforest if the gradient ＞25°. On the other hand, as the altitude and irrigation affecting the crop, the farmland between 400 to 500 m in elevation is suitable for maize. In the area without irrigation, high water consumption crop should be planted in first half year and maize or other drought-enduring crop planted in second half year because there is more rainfall in first half year but little rainfall in second half year.