Impacts Of Farmland Drainage Ditch Connectivity On The Output Of Nitrogen And Phosphorus

As a space carrier for human life and production,land is the most fundamental natural resource for human society to survive and develop,and it is also a link between the interaction of elements of ecological environment.The regional characteristics of land use are closely related to the local natural,economic and social culture.In recent years,with the rapid development of economy,the rapid growth of population and the acceleration of urbanization process,the contradiction between the increasing demand for land resources and the reduction of supply is becoming more and more obvious,which not only restricts human social and economic development,Large impact,a series of land use and ecological problems have emerged.From the perspective of landscape ecology,due to the irrational use of the region to make the various elements of the system have been disturbed,accompanied by environmental pollution problems,ecosystem damage,traffic congestion,urban heat island effect,a variety of natural disasters continue Aggravated and other issues,leaving the region's landscape ecological function and economic and social function weakened.Landscape ecology is a science that combines the spatial analysis of geography with the functional analysis in ecology and focuses on the influence of landscape structure on ecological processes.The core research question is:which kind of influence is the ecological process and its spatial pattern and its change,How the ecosystem is affected by human activities and so on.The rapid development of the Yangtze River Delta region exposed the shortcomings of land use management,reflecting unreasonable factors of the existence of the original land use planning.Using RS to obtain real-time spatial geography data,coupled with powerful spatial information processing and analysis function of GIS,the shared boundary and connectivity as the starting point,the Yangtze River Delta region due to changes in land use structure of the landscape structure,and then based on the three types of landscape type,landscape structure and landscape function,the ecological disturbance intensity evaluation model was constructed to analyze the change of ecological disturbance intensity in the Yangtze River Delta region in the past 30 years,and tries to study the land use strategy of mitigating ecological disturbance from the aspects of land use change,spatial layout optimization and space use control.The results show that:(1)The longest shared boundary type is changed from 1985 to cultivated land-construction land,farmland-forest land to construction land in 2015-cultivated land,construction land-forest land boundary,indicating that the Yangtze River Delta land use advantage landscape type From the cultivated land,forest land and water landscape dominated into arable land,woodland and construction land landscape dominated,and construction land expansion is its main driving factor.(2)During the period from 1985 to 2015,the construction land of the Yangtze River Delta area increased significantly in the disturbance of cultivated land and showed a significant increase in medium density and high density area and a significant decrease in low density area.The boundary between the occurrence of disturbance and the level of density is significantly reduced.The construction of the non-agricultural process of cultivated land is the main reason leading to this phenomenon.(3)Based on the landscape pattern analysis method of land use sharing boundary,it is very important to analyze the landscape pattern from the boundary characteristics of its type,length and shape to measure the temporal and spatial heterogeneity of landscape pattern change and landscape ecological disturbance Dynamic and Landscape Interference Spatio-temporal Differentiation of Existing Methods.(4)Using the minimum cost model,the land use type,elevation and slope as the resistance surface,through the cost of the distance we found that the Yangtze River Delta region in the past 30 years,high level of connectivity decreased significantly,low connectivity area is growing.(5)Based on the landscape type,landscape structure and landscape function,the evaluation model of ecological disturbance intensity was constructed,which is used to analyze the changes of the ecological disturbance intensity in the Yangtze River Delta region in 1985 and 2015.We have been affected by the disturbance degree in the Yangtze River Delta region in the past 30 years,Especially in Shanghai and Shanghai(Nantong,Suzhou,Jiaxing),the Shanghai area is in a strong disturbance state,and its surrounding urban ecological land distribution is also subject to strong ecological disturbance.The research content is conducive to the new situation under the eastern part of China's urban land resources and rational use of decision-making basis for the sustained and rapid development of the local economy to provide strong support.