Mechanism And Technology Of Agroforestry Allocation Based On Soil Water Storage In The Karst Desertification Control

Water is not only one of the driving forces for rocky desertification,but also a key limiting factor for karst habitat reconstruction and vegetation restoration.The karst area has poor soil water retention capacity and lacks surface water resources.The traditional agroforestry model has caused a series of ecological problems due to unreasonable configuration.Based on cross-disciplines such as geography,hydrology,ecology,etc.as the theoretical support,in the mountainous area of the Guizhou Plateau,which represents the overall structure of the karst environment in southern China,Bijiesala was chosen for the problems of unclear agroforestry allocation mechanism,unreasonable structure allocation,and lack of configuration technology.Xi,Guanling-Zhenfeng Huajiang and Shi Bingkarst are the research areas.Through intercropping experiments,the basic frontier research,common key technology research and development,application demonstration and industrialization promotion of agroforestry based on soil water storage in the management of rocky desertification Carry out full chain design,integrated deployment,and sub-modules to advance research work.The focus is on the effects of soil water occurrence in agroforestry under continuous drought conditions,the mechanism of the agroforestry allocation of soil water,the mechanism of soil water storage,and the development and application demonstration verification of the configuration technology of water-saving agroforestry.Systematic research,with a view to providing scientific and technological reference for the national rock desertification control project.(1)The allocation mechanism of agroforestry is mainly reflected in the adaptability of agroforestry to the karst heterogeneous soil moisture environment.Under continuous drought conditions,soil moisture is consumed from the surface.Compared with monoculture,the rate of soil water loss in each agroforestry model is lower,indicating that agroforestry can adapt to the karst continuous drought soil by delaying the rate of soil water loss.Moisture environment.In the Guanling-Zhenfeng Huajiang River,the surface and second layer of soil moisture loss rate is greater in about 4 days of continuous drought,while the surface and second layer of soil moisture in Bijie Salaxi and Shibing Karst areas is lost in about 7 days of continuous drought the rate was large.After 10 days of continuous drought,the soil moisture content of each agroforestry model was still higher than that of the corresponding single cropping model,indicating that intercropping under fruit forests can enhance the drought resistance of agroforestry systems and produce a good soil water storage effect.(2)Agroforestry can enhance soil water storage capacity.From the perspective of the water conservation function index,the Sala Creek performance is: walnut + ryegrass(0.9)> walnut + tall fescue(0.48)> walnut soybean(0.4)> walnut + potato(0.28)> walnut single crop(0.08),Huajiang: Zanthoxylum bungeanum + Hot pepper(0.83)> Zanthoxylum bungeanum + Peanut(0.79)> Dragon fruit + Sweet potato(0.5)> Zanthoxylum bungeanum(0.36)> Dragon fruit single crop(0.17),Shi Bing: Pear + Ryegrass(0.78)> Pear + Pseudostellaria heterophylla(0.73)> Pear + soybean(0.61)> Pear monocropping(0.01),it can be seen that the agroforestry model has a stronger soil water storage capacity than the monocropping model.Among them,the intercropping ryegrass shows soil water The ability to accumulate is most prominent.Studies have shown that the mechanism of the impact of agroforestry on soil water storage performance is that agroforestry promotes soil water storage by improving soil physical structure,increasing soil water storage capacity,and reducing soil inefficient evaporation.(3)The soil infiltration capacity of each model has a certain difference,but it is still higher than the corresponding single crop,indicating that agroforestry has the effect of improving the soil infiltration performance of economic forest land,but the degree of improvement is different due to different intercropping vegetation under the economic forest.Through principal component analysis,comprehensive parameters for calculating soil infiltration performance were obtained.The Sara River is: 0.251β1 + 0.249β2 + 0.257β3 + 0.257β4,the Huajiang is: 0.251β1 + 0.25β2 + 0.253β3 + 0.252β4,Shi Bingwei : 0.25β1 + 0.25β2 + 0.252β3 + 0.251β4.The comprehensive score of the model in the Sara River is: walnut + tall fescue(1.6035)> walnut + ryegrass(1.2283)> walnut + soybean(0.8123)> walnut + potato(0.8084)> walnut single crop(0.6522),Huajiang is: Zanthoxylum bungeanum + Chili(1.4199)> Zanthoxylum + Peanut(1.3345)> Dragon Fruit + Sweet Potato(1.2881)> Single Pepper(0.8439)> Single Dragon Fruit(0.5996),Shi Bingwei: Pear + Taizishen(0.4046)> Pear + Ryegrass(0.3563)> Pear + Soybean(0.2088)> Pear monoculture(0.1746).(4)Agroforestry has an inhibitory effect on soil evaporation,but there are differences due to different agroforestry models.Agroforestry complex management forms a plant isolation layer on the surface of the soil,hinders the water-heat exchange between the soil and the atmosphere,has the effect of significantly reducing ground temperature and radiation,and can increase the relative humidity of the air.On a clear day,there is a clear peak in the daily evaporation of each mode around 14:00,while on a cloudy day,the change curve of each mode is relatively smooth,and there is no obvious peak.Agroforestry has an inhibitory effect on soil evaporation,but there are differences in different agroforestry models.The intercropping sweet potato under the Huajiang Dragon Fruit has the strongest soil evaporation inhibition ability,and the Sarah Creek and Shibinglin grass models have the strongest evaporation inhibition ability.(5)Propose and optimize the technology of species allocation based on soil water storage,compound farming technology of agroforestry based on water retention and solid soil,dwarfing technology of agroforestry based on efficient use of water,and data monitoring technology.Plateau mountain area and Dolomite karst area for application verification.Through the application of technology,a total of 23 hm2 demonstration area of mountain agroforestry has been built,which has produced obvious results in terms of ecology,output and people’s recognition.The ecology of the demonstration site has been significantly improved,the soil bulk density of the agroforestry land has been reduced,the porosity has been improved,and the soil water storage capacity has been improved overall;the output rate of land per unit area has been increased,which has increased the sense of acquisition of the people Finally,the people actively participated agroforestry.