| Karst environment has two sides, one is beautiful natural scenery, the other is fragile eco-environment which need to protect. There are serious soil and water loss in karst fragile eco-environment, and different degrees of rock desertification are widely distributed in fragile areas. In order to make local residents can live for a long time, it needs a lot of manual repair to govern widely rock desertification areas, improve environment and protect fragile karst. Two typical karst landforms of plateau-mountain karst and plateau-gorge karst were selected to established Salaxi demonstration in Bijie and Huajiang demonstration in Guanling-Zhenfeng of Guizhou, and studied technology of water and soil conservation of hedgerow, to find better measures to control water and soil erosion. Chaoying watershed was selected in salaxi demonstration and Dingtan watershed was selected in Huajiang demonstration from 2012 to 2015. With theory support of ecological restoration, water and soil conservation, biological engineering, land consolidation and rehabilitation, geographical science and so on, base literature review, field investigation and monitoring, hedgerow planting experiment, analysis on soil properties and data, to finish literature collection, field investigation and monitoring, experimental analysis etc. To solve problems of hedgerow selection, space structure design of hedgerow planting, conservation benefit analysis of hedgerow on study of hedgerow in karst slope. It analysis the relationship between hedgerow and the characteristics of water and soil in rocky desertification environment; using Rosa Roxburghii Tratt, Pyracantha SPP, Vetiver Grass, Pennisetum hydridum and Bromus cartharticus to build hedgerow, with qualitative and quantitative, analysising hedgerow influence in quantity of soil and water loss, soil properties(bulk density 、 porosity 、 nutrient content and distribution 、 shear behavior、soil anti-scourability). It constructed the model of hedgerow in rocky slope according to the characteristics of study, also carried out demonstration. Through specific monitoring and evaluation, analysis effect of hedgerow water and soil conservation. Finally it complete the suitable optimization and the best effect of hedgerow planting in rocky slope. Also it accomplished optimization of space structure of hedgerow, the highest benefit, the best effect of water and soil conservation. Analysising the influences and contents of affecting hedgerow benefit with comprehensive factors. To provide a new technology and mode for the further research on future rocky desertification control, technology of water and soil conservation in the whole rocky desertification areas from Guizhou Province to southwest of China.① Rocky desertification slope hedgerow varieties selection. Rocky desertification slope alley cropping in the variety choice, on the basis of the local natural conditions, the first choose local native species; The second is to use in the study of demonstration area anti-freeze drought-tolerant choice or breeding varieties; The third introduce suitable for local natural condition of plant varieties; In fourth in the first three under the condition of at least one chooses the breed of the future with greater economic benefits. Increased by choosing plant species on the local environment suitability, in alley cropping can guarantee a higher survival rate of planting, in achieving hedgerow water soil fixation effect and enhanced under the condition of extreme climate adaptability, appropriate increase economic income of local residents. Rocky desertification slope alley cropping established a screening survey, research proof and practical three-dimensional way of species selection, the study sites to choose in the study area with prominent characteristics, combined with the characteristics of the local plant species, compared to traditional hedgerow species and the advantages and disadvantages of them in the same karst environment, selecting the most advantage of species as a hedgerow.② Space of the rocky desertification slope alley cropping structure. On rocky desertification slope of hedgerow space structure type dense planting hedgerow, bringing height collocation type hedgerow, hedgerow intercropping type, interval hedgerow, fill in the blanks hedgerow, terrance and plant hedge, and other forms of several kinds of spatial layout. For different types of alley cropping in the row spacing, planting distance, spacing, width, height of hedgerow and content, such as limit. The use of space in the different stages of hedgerow, adopted the way of bringing collocation, in the early stage of main use is given priority to with grass hedgerow, the intermediate stage mainly grass hedgerow gradually develop into predominantly shrub hedgerow, late stage formed mainly shrub hedgerow space configuration is more stable.③ Hedgerow varieties. Hedgerow design implementation in terms of portfolio of Rosa Roxburghii + Lolium perenne L., Rosa Roxburghii + Pyracantha fortuneana(Maxim.) Li, Pyracantha fortuneana(Maxim.) Li + Tall fescue, Tall fescue + Lolium perenne L., Pennisetum sinese Roxb + Amorphafruticosa L, Lonicera Japonica + terrance and various patterns. Different combination modes of hedgerow is suitable for growing on the specific conditions of land use type, the weather slants cold some Salaxi demonstration plant cold type of herb and small shrub combination pattern, the altar at the top of the dry heat of Huajiang demonstration area small watershed planting heat model of the combination of herbs and shrubs.④ The marked effects of rocky desertification slope hedgerow solid soil to hold moisture. Rocky desertification slope alley cropping can effectively reduce the runoff and sediment loads. First is water interception of hedgerow itself has the function to the partial slope of rainfall interception in large quantities and flow; Followed by the hedgerow planting increased soil porosity, soil water storage ability raise, water performance is enhanced; Again is to increase the hedgerow planting vegetation coverage, the precipitation directly effect on the ground to get reduced, both can reduce runoff and reduce sediment loads. Compared with normal farming land use type, the function of alley cropping decreased flow basic between 30% and 60%, the highest close to 70%;Alley cropping of sediment reduction effect on average about 70%, the highest close to 90%.⑤ Hedgerow and rocky desertification environment special relationship. Considering the particularity of karst environment, due to the distribution of rocky desertification, under the condition of low vegetation coverage area coverage of the soil is relatively low, the surface soil loss is serious, causes in theory should be the area of serious soil erosion, found in the actual monitoring, serious shortage, a lot of serious soil erosion area of erosion and even can not meet the minimum erosion under the corresponding erosion strength grade. In this area, alley cropping on the one hand, it is difficult to grow successfully, even if successful, solid soil water effect, it is hard to get.⑥ Hedgerow monitoring and evaluation system. Rocky desertification in the study of slope of hedgerow monitoring through the index selection, experiment design, experiment process, data analysis and a series of steps. Main analysis in monitoring the hedgerow related with solid soil water conditions and the basis of the relevant conditions, in the aspect of quantitative analysis to form a set of monitoring data. In the aspect of evaluation system to build the combination of qualitative analysis and quantitative monitoring, in the rocky desertification slope alley cropping ecological benefits, especially the soil and water conservation benefit evaluation form a recycled evaluation system. Although in the way of monitoring or evaluation system was carried out in some studies, but relative to the alley cropping with a slope of rocky desertification research, still exists many deficiencies, need to continue to study in the future. The content involves the monitoring mode of complement and improve the evaluation system.⑦ Other content in the research of rocky desertification slope hedgerow. In the process of research, solid soil water surrounding the alley cropping technology as the center, the research content is focused on hedgerow and solid soil to hold moisture. For some other important research content related to hedgerow not in-depth research, especially in the hedgerow soil fertility to maintain and add fertilizer(keep) of soil nutrients content can continue to study in the future research. In seed selection of hedgerow, while taking into consideration the local suitable for plant varieties of hedgerow plant selection, but on the whole the varieties suitability analysis of the environment of the karst, the karst environment conditions, the whole area of shrub community occupies the plant type of advantage, karst environment is the most natural recovery plant community structure. In the future how to rocky desertification in the study of slope hedgerow is combined with the advantage of the karst area shrub, realize the new way of soil and water conservation, development of karst area of shrub resources, is a significant research content. |
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