关键词: 干旱, 土地可持续利用, 红壤丘陵区

Abstract:

In view of sustainable land use, the frequencies, characteristics and reasons of drought are studied in red earth hilly area of southern China. The intensity of drought restricting to land use and its temporal and spatial variations, relation between the pattern of land use and the degree of drought as well as measures taken to control drought are dealt with in this paper. Yujiang County of Jiangxi Province was chosen for a case study, the regional drought was assessed by using quantitative methods such as Zi index, coefficient of variation and departure value of precipitation. High frequency and types of drought in the hilly area are distinguished during the period 1951 to 2000. Compared to the case of northern China, the degree of drought was more tiny and alleviated. Drought restricts the three dimensional distribution of landuse and consumably occupies cultivated land resource. Restricting strength index (K) was used to quantify the effect of drought on the restricting degree of agricultural land. Taking a very drought year, the results indicated the K value of the effect of drought on paddy rice is 0.08～0.11, belonging to low restricting strength;that on the dryland is 0.46, high restricting strength; and on farmland for comprehensive evaluation is 0.21, moderate restricting strength. The reasons of drought in red earth hilly area are becauseof the seasonal change of atmosphere circumfluence in eastern China, lower availability in soil moisture,inappropriate human activities and lack of socio-economic ability in combating drought. The regional drought has a high tendency as the human-controlling factors change their condition. Such measures to alleviatethe drought should be taken as follows: (1)including seepage control of dykes several hundred kilometers long in the area, intensification of canalized irrigation networks and development of mini electromechanical irrigation project in hummocks; to perfect irrigation canal system and expand irrigated area by diverting other water resources;(2) to construct small scale water storage ponds in remote and high hummocks; (3) to popularize water-saving agricultural techniques such as intercropping forest and grain plant straw mulching technique, drought-resistant crop(e.g. peanuts)selecting, terracing and scale pitting; (4) to control strictly dryland development in the area and return part of cultivated land to forest on north-south hummocks; and (5) to increase appropriately the ratio of land used for construction and optimize the structure of landuse.

Key words: drought, sustainable land use, red earth hilly area