等高绿篱技术保水抗旱效益研究

季节性干旱与水土流失并存是目前三峡库区面临的重要生态问题之一，严重影响了库区社会经济的可持续发展。等高绿篱技术是目前国内外广泛采用的一种十分有效的坡耕地植被恢复和水土保育技术，被认为是三峡库区农业生态系统持续发展的有效途径之一。选择新银合欢、黄荆和马桑3种绿篱，探讨其水土保育功效及抗旱效益。结果显示，等高绿篱具有显著的拦沙淤土效益，10年左右的时间，土坎高度增至近80 cm，减缓坡度20°左右。与对照相比，栽种绿篱后，土壤有机质增加52%~65%，土壤容重减小14%~17%，尤其是非毛管孔隙增幅达135%~216%，等高绿篱模式下土壤保肥增肥效益显著，土壤结构改善明显。在旱季绿篱处理下地表土壤含水量高于对照达123%，蓄水保墒能力大大增强。按等高绿篱模式增加有效土层60 cm计算，新银合欢、黄荆和马桑3个处理增加土壤水总库容分别为271、257和247 mm，有力增强了土壤的抗旱性能。在绿篱-桔园系统下柑桔座果率比对照增加12%，其平均单产比对照高15%。

ON BENEFITS OF WATER CONSERVATION AND DROUGHT-RESISTANCE BY THE TECHNIQUE OF CONTOUR HEDGEROW

The coexistence of seasonal drought and soil and water losses is an important ecological problem in the Three Gorges Reservoir area now,which badly threatens the sustainable development of society and economy in the reservoir area.Contour hedgerow，a common and effective technique around the world,is often employed to restore plant cover on cultivated slope land and conserve water and soil resources.And it is considered as an available way to realize sustainable development of agroecosystem in the Three Gorges Reservoir area.Three hedges of 〖WTBX〗Leucaena leucocephala,Vitex negundo〖WTBZ〗 and 〖WTBX〗Coriaria sinica〖WTBZ〗 were selected to discuss the benefits to soil and water conservation and drought resistance in this research. The results showed that the effect of sediment trapping and depositing by contour hedgerows was significant.The height of silt had increased to 80 cm and the gradient had been eliminated 20° after 10 years.Compared with the control,within the contour hedgerow treatments,soil organic matter increased from 52% to 65%,soil bulk density decreased from 14% to 17%, and soil non capillary porosity increased from 135% to 216% especially.The effects of fertilizer maintenance and improvement under the contour hedgerow system were significant and soil structure was improved obviously.In dry season,surface soil water content within the contour hedgerow treatment was 123% higher than the control,which reflected the high capability of water conservation of contour hedgerow treatments.According to the effective thickness of soil layer of 60 cm,soil water total volumetric capacity in the treatments of 〖WTBX〗Leucaena leucocephala,Vitex negundo〖WTBZ〗 and 〖WTBX〗Coriaria sinica〖WTBZ〗 increased 271,257 and 247 mm respectively,which then improved the soil ability of drought resistance greatly.Under the system of hedgerow orange, fruit setting percentage and average yield increased 12% and 15% respectively compared to the control.