| Capital farmland construction can improve the quality of capital farmland in the southwestern region of China which restricted by topography and human activities.However,in the process of capital farmland construction,the decline of soil fertility due to disturbance of the soil layer structure in newly capital farmland,pursuit of“high-standard”land consolidation and neglect of landscape integration with the land consolidation areas become new issues that need urgent attention in the construction of capital farmland.Therefore,this research select the typical area of high standard capital farmland construction in western Chongqing as study area.According to the land use distribution maps before and after land consolidation(2017 and 2018)obtained by remote sensing interpretation,survey research,descriptive statistical analysis and geostatistical methods were employed to ddivide the study area into land consolidation zones based on the spatial distribution characteristics of soil nutrient content.Land consolidation measures in the different zones were proposed.Then the soil fertility restoration effect in the short term after the construction of capital farmland was evaluated.The land use structure optimization model,GM(1,1)model,and minimum cumulative resistance model were used to optimize the landscape pattern of the study area from the patches and corridors,and to partition the ecological function.Then the analytic hierarchy process were used to evaluate the landscape elements and the landscape pattern.Finally,the ecosystem service value evaluation method was used to analyze the improvement effect of ecosystem services in the study area after the optimization of landscape pattern and the implementation of individual ecological technologies.Which can provide a scientific basis for the follow-up high standard capital farmland construction.The main results are as follows:1.Based on the spatial distribution characteristics of soil organic matter in each soil layer before land consolidation,the land consolidation zoning was divided,and the soil fertility effects of different planting models in the short term after land consolidation were evaluated.The results show that:(1)This research focused on the spatial autocorrelation distribution characteristics of surface soil organic matter,supplemented by the lower and middle layers.The study area was divided into five land consolidation subdivisions:priority consolidation area,moderate consolidation area,key consolidation area,comprehensive consolidation area and optimization adjustment area,and land improvement measures for different subdivisions were proposed.(2)After the construction of capital farmland,the average range of soil organic matter(SOM)and total nitrogen(TN)of each soil layer were between 13.47-16.88 and 0.92-1.10 g/kg,which were lower than the content of SOM and TN before consolidation and showed a spatial decrease in a large area,and only the small areas in the central and eastern regions increased.Therefore,fertilization measures should be proposed for different land use types after land consolidation.(3)The SOM and TN contents of different land use types showed that the SOM and TN contents of each soil layer of rice were significantly higher than abandoned land(CK)and other planting models,which became the optimal planting mode that can quickly fertilize in the short term under the new consolidation,followed by lemon and watermelon planting mode.2.The land use structure optimization model was used to optimize the land use structure(patch),and the corridor optimization was carried out through the identification of ecological source areas,potential corridors and ecological nodes,and then the ecological function zones were divided.The results show that:(1)The land use structure optimization model was used to optimize the number of land use types.Three scenarios were considered:only economic benefits(scenario one),both economic and ecological benefits(scenario two),and only ecological benefits(scenario three).After comparative analysis,the scenario two tended to be the relative optimal scenario.(2)The number of ecological source areas in the study area was small,the ecological corridors had poor connectivity to ecological source areas,and important ecological nodes were seriously disturbed by human activities,and the transmission of ecological information was blocked.Therefore,the number of ecological sources should be increased,existing sources should be strengthened,and interference with human activities should be reduced.In addition,at the ecological nodes where potential corridors and existing corridors intersect,roadside green belts can be built to enhance the connectivity of existing corridors.Meanwhile,the number of corridors should be increased,ecological corridors should be arranged reasonably,and a complete ecological network system should be established.According to the simulated potential ecological corridor,the overall layout of the ecological corridor construction plan in the study area is proposed as the spatial pattern of“two vertical and three horizontal”.(3)The study area can be divided into four ecological function regionalization based on the minimum cumulative resistance value:ecological core area,ecological control area,ecological transition area,and ecological occupancy area.Taking ecological function zones as the main part,supplemented by land consolidation zoning,combined with the results of patch optimization and corridor optimization,different consolidation measures(such as topsoil stripping and backfilling,slope reduction and adjustment of land use structure,etc.)were recommended for different ecological function zones.3.The land use transfer matrix before and after consolidation were carried out,and the landscape elements and landscape pattern before and after the optimization of the land use structure in the study area were assessmented by establishing the landscape element evaluation index system and landscape pattern evaluation index system.Based on which,the spatial allocation of individual ecological measures was carried out.The results show that:(1)The land use type of newly added orchards in the study area is mainly transferred from dry land and paddy fields,which were transferred by 48.30 and 23.12 hm~2respectively.In addition,in order to facilitate the production management of the orchard,facilities for agricultural land were added.Land for transportation and water conservancy facilities also increased slightly.At the same time,the existing ecological source areas(arbor woodland,river water surface and reservoir water surface)were effectively protected.The significant reduction in the area of arable land(dry land and paddy field)and the significant increase in the area of orchards resulted in large changes in land use types.The land use structure tended to be simple,and the dominant land use types(orchards)were increasingly controlling the study area.The research area gradually transformed from traditional to diversified in agriculture.(2)Benefited from the measures such as merging fields,decrease slopes,building roads and ditches,and adding new ecological sources in the construction of capital farmland,the overall score of landscape element quality improved by 27.53 points.Among which,the land leveling score increased the most,with 23.55 points,while the scores in the other three areas increased by 1.10,1.34,and 1.54 points respectively.The agricultural production capacity of the study area,and the regional ecological landscape level were improved.(3)After land consolidation,the total number of patches in the study area decreased,while the degree of landscape fragmentation decreased,and the degree of connectivity and aggregation increased.The landscape types between the patches were more concentrated and their shapes tended to be simpler,which was conducive to mechanized operations.At the same time,the uniformity of landscape patch distribution becomes larger,and the landscape types tend to diversify.(4)In order to improve the anti-jamming capability of the ecosystem and the ecological level of land consolidation in the future,and promote the balanced layout of the ecological network planning,based on the spatial location of the ecological function zone,combined with the characteristics and optimization needs of each zone,an ecological-oriented basic farmland landscape ecological design and engineering technology model were recommended to improve the ecological environment(such as ecological slopes,ecological roads and ditches,and ecological ponds).4.Using the evaluation method of ecosystem service value,the effect of ecosystem service improvement in the study area was evaluated from the perspective of landscape pattern change,individual ecological construction implementation and comprehensive effects.The results show that:(1)After the adjustment of land use structure,benefiting from the contribution of the orchard,the value of ecosystem services increased by11.4701 million yuan,a growth rate of 29.4%.Among the types of ecosystem services,with the exception of a 35.0%drop in food production value,other ecosystem service types are increased.Among which,water supply,climate regulation and biodiversity increased obviously,reaching 202.9%,171.6%and 115.5%respectively.The ecosystem service value of each ecological function zone also increased,and the ecological core zone,ecological control zone,ecological transition zone and ecologically occupable zone increased by 7.4%,22.6%,75.1%and 60.0%respectively.In terms of spatial distribution,the area where the ecosystem service value per unit area was at a high level and above accounted for 69.0%of the research area,which was 50.4 percentage points higher than that before the consolidation.The ecological value-added area accounted for 54.8%of the total area,and the conservation area accounted for 39.1%of the total area.(2)The value of ecosystem services of individual ecological technologies(ecological slopes,ecological roads and ditches,and ecological ponds)were greatly increased,increased by456.6%,149.0%,and 3126.3%respectively.Under the premise of ensuring food production and suitability,various measures obtained the increase in the value of other ecosystem service types,and achieved better economic and ecological benefits.(3)After the construction of high standard capital farmland,the total value of ecosystem services in the study area increased by 11.8235 million yuan,a change rate of 30.3%,under the influence of landscape pattern optimization measures and individual ecological technology measures.The decrease in cultivated land area and the increase in the area of ecological source areas reduced the value of food production,while other values increased.The value of ecosystem services in each ecological function zone also increased with the implementation of optimization measures.The ecological core zone,ecological control zone,ecological transition zone and ecologically occupable zone increased by 8.1%,23.8%,75.4%and 60.6%,respectively.Which indicate that the ecological land improvement measures in the study area can effectively enhance the overall ecosystem service value of the study area. |
PDF Full Text Request