| The purpose of this paper is to explore the agricultural land transformation and its impact mechanism can provide scientific reference for the evolution of human land relationship and development of multiple functions of gully agriculture in the Loess Plateau. In this paper, Taking Yan'an City of loess hilly and gully region, which has a rapid development of gully agriculture, as the research area, 30 Landsat TM / OLI data in four periods of 2000-2005, 2005-2010 and 2010-2018 were selected, and the distribution range of gully farmland in the research area was extracted by CART decision tree classification method, and its spatial change was analyzed to construct the time of coupling time non-stationarity and spatial heterogeneity The geographically and temporally weighted regression model is used to explore the characteristics of the gully coupled human–environment system in Yan'an City, and to explore the driving force of the gully farmland expansion and its spatial-temporal differentiation pattern. The results show that: 1) During the past 20 years, the gully farmland in Yan'an City has been distributed and expanded in stages, with an overall fluctuating contraction trend, and the gravity center has moved northward as a whole; 2）The geographically and temporally weighted regression model coupled with time non-stationary and spatial heterogeneity has better fitting effect , which verifies its applicability in the study of spatiotemporal transformation driving force of farmland expansion. Social and economic factors are the main driving forces for the expansion and transformation of gully farmland in Yan'an City in the past 20 years, and they are increasing year by year; 3) The spatial-temporal distribution of the different driving factors of the gully farmland expansion transformation in Yan'an City has different influences. The intensity of the population factor and the slope factor is always in the dominant position, which is the main driving factor of the gully farmland expansion transformation. The high value distribution area of the land average GDP factor forms a funnel-shaped pattern of "core edge" in the north and the central and western regions, and its changes tend to "flow" to the core " In the Loess Plateau, the development and change of gully farmland are driven by many factors, and the regional background differences and different actors will promote the development and contraction of gully farmland in different directions, but in principle, they are driven by the major national and regional development policies better fitting effect , which verifies its applicability in the study of spatiotemporal transformation driving force of farmland expansion. Social and economic factors are the main driving forces for the expansion and transformation of gully farmland in Yan'an City in the past 20 years, and they are increasing year by year; 3) The spatial-temporal distribution of the different driving factors of the gully farmland expansion transformation in Yan'an City has different influences. The intensity of the population factor and the slope factor is always in the dominant position, which is the main driving factor of the gully farmland expansion transformation. The high value distribution area of the land average GDP factor forms a funnel-shaped pattern of "core edge" in the north and the central and western regions, and its changes tend to "flow" to the core " In the Loess Plateau, the development and change of gully farmland are driven by many factors, and the regional background differences and different actors will promote the development and contraction of gully farmland in different directions, but in principle, they are driven by the major national and regional development policies were different; 2)The geographically and temporally weighted regression model coupled with time non-stationary and spatial heterogeneity has better fitting effect , which verifies its applicability in the study of spatiotemporal transformation driving force of farmland expansion. Social and economic factors are the main driving forces for the expansion and transformation of gully farmland in Yan"an City in the past 20 years, and they are increasing year by year; 3) The spatial-temporal distribution of the different driving factors of the gully farmland expansion transformation in Yan"an City has different influences. The intensity of the population factor and the slope factor is always in the dominant position, which is the main driving factor of the gully farmland expansion transformation. The high value distribution area of the land average GDP factor forms a funnel-shaped pattern of "core edge" in the north and the central and western regions, and its changes tend to "flow" to the core " In the Loess Plateau, the development and change of gully farmland are driven by many factors, and the regional background differences and different actors will promote the development and contraction of gully farmland in different directions, but in principle, they are driven by the major national and regional development policies |
