Trade-off Between Farmland Grain Provision And Soil Conservation Services In Plateau Mountainous Area

Grain production of farmland in plateau mountainous area is the basis for maintaining the sustainable use of regional cultivated land resources.However,traditional evaluation method of food provision service(FPS)was difficult to express the change of grain supply capacity with the change of slope and measures in plateau mountainous area.Taken Xinping County of Yunnan Province as an example,based on the spatial database construction and field survey monitoring,this study evaluated FPS and soil conservation service(SCS)by slope and soil and water conservation measures(SWC measures),and estimated the trade-off relationship between them.By setting different simulation scenarios,we compared and evaluated the two ecosystem services of study area.Finally,the optimal management model of farmland land in the county was obtained,which provided theoretical basis for plateau mountain arable land management and land use planning.The main research conclusions are as follows:(1)Corn yield gradually decrease with the increase of slope,and the corn yield of farmland with SWC measures was higher than that farmland without SWC measures.When slope increased by 5°.corn yield decreased by 1337kg·ha-1 in farmlands with SWC.and by 1681 kg·ha-1 in farmlands without SWC measures.Through regression analysis,it was found that the grain yield of farmland in the whole county has a large fluctuation range,especially the farmland without SWC measures on steep slope.(2)FPS showed a trend of increasing first and then decreasing as the slope increases.Farmland with SWC measures were mainlv concentrated below 15°,which was a kev area for providing food production.After the slope>15°,the FPS has dropped significantly.SCS were reduced as the slope increases,and SCS of farmland with SWC measures were higher than those without SWC measures.Farmland>15° was the main area where soil erosion increases in plateau mountains.It can be seen that maintaining the grain output of farmland below 15° in the plateau mountainous area,and rectifying the farmland>15° was the key to increasing grain yield and reducing soil erosion.(3)Combined with current project in our country,this paper set up seven kinds of simulation scenarios to compare the two ecosystem services of farmland under different scenarios.When the steeper of farmland returns to grassland steeper,FPS loss smaller and more SCS increased.When the steeper of farmland construct SWC measures,the increase of FPS and SCS was greater.The study also showed that the effect of SWC measures under the same slope were better than the return to grassland.And the grain yield could be significantly improved.Ecosystem service benefits of the farmland will be improved regardless of the returning of the farmland or the construction of SWC measures When>15° farmland without SWC measures construct SWC measures,FPS and SCS will reached a maximum,which is the best farming mode to maintain sustainable use of farmland.At present,the governance policies of farmland in the plateau mountains were all linked to the slope.Due to the lack of data,previous studies havd rarely started from slopes and measures.In this study,the research on FPS and SCS of farmland under different slopes and SWC measures in the plateau mountainous areas showed that the current grain yield and erosion amount of farmland were very different.At the same time,through the comparative simulation of scenario simulation,the optimal tillage mode of farmland in plateau mountainous areas was obtained.This study will help to improve the accuracy of mountain ecosystem service assessment and trade-off analysis,while facilitating the use of land use planning by managers and stakeholders.