Farmland changes and the driving forces in Yucheng, North China Plain

Taking Yucheng, a typical agricultural county in Shandong Province as a case, this study applied Logistic regression models to spatially identify factors affecting farmland changes. Using two phases of high resolution imageries in 2001 and 2009, the study obtained the land use and farmland change data in 2001-2009. It was found that the farmland was reduced by 5.14% in the period, mainly due to the farmland conversion to forest land and built-up land, although part of forest land and unused land was converted to farmland. The results of Logistic regressions indicated that location, population growth and farmer income were main factors affecting the farmland conversion, while soil types and pro-curvature were main natural factors controlling the distribution of farmland changes. Regional differences and temporal-spatial variables of farmland changes affected fitting capability of the Logistic regression models. The ROC fitting test indicated that the Logistic regression models gave a good explanation of the regional land-use changes. Logistic regression analysis is a good tool to identify major factors affecting land use change by quantifying the contribution of each factor.

Impact of slope farmland use change on ecosystem services value in China,2000-2020

Slope farmland is an important component of farmland resources in China.The utilization and change of slope farmland have significant effects on ecosystems,and understanding the impact of slope farmland change on ecosystem services(ESs)is critical for effective land utilization and ecosystem protection.This study aims to analyze slope farmland changes in China between 2000 and 2020 and quantify the impact of these changes on ESs by the use of a land use dynamic attitude study,and an ecosystem services value(ESV)equivalent.Results show that the area of slope farmland in China was mainly concentrated on slopes of 2°-6°,and exhibited a downward trend between 2000 and 2020.There were significant differences in the spatial distribution of the farmland,which was mainly located in the Taihang,Qinling,Wushan,and Xuefeng mountains.ESV increased by$179.235 million due to the conversion between slope farmland and forest,grassland,and construction land from 2000-2010.Conversely,from 2010 to 2020,ESV decreased by$2613.919 million due to the conversion of forest and grassland to slope farmland as well as the conversion of slope farmland to construction land.

2000-2020年中国建设用地扩张侵占耕地的时空特征及其与粮食产量的空间关系

Construction land expansion is a key driver of urbanization and industrialization,yet it poses the risk of losing farmland and cascading impacts on food supply.The spatial char-acteristics of farmland occupied by construction land and its association with grain yield in China were unclear.We analyzed the characteristics of farmland converted into construction land,and its relationship with grain yield in China for 2000-2020.Construction land increased in area in central and western regions of China,and farmland decreased in area in south-eastern China.The expansion of construction land in the North China Plain,Northeast China Plain,and the Loess Plateau,occurred at the expense of farmland.Except the southeast coast of China,grain yield increase was only weakly dependent on farmland area.Patterns in which farmland was converted into construction land and grain-yield change were highly coupled in southeastern coastal China,Sichuan Basin,Shandong Peninsula,and the Hu Huanyong Line.It should be noted that expansion in construction land area does have some influence on grain production;ultimately it is greatly affected by yield per unitarea.

Farmland dataset reconstruction and farmland change analysis in China during 1661-1985

This research reconstructs China＇s provincial farmland dataset in the last 300 years （1661-1985） by applying factor correction, citing replacement, linear interpolation, cohesion and contrast, man-land relationship test, farming trend test, provincial administrative area adjustment, etc. on available farmland data based on China＇s current provincial administrative boundary. Based on this dataset, a quantitative analysis has been applied to study the farm- land amount and its change Characteristics at both national and provincial level. Three con- clusions are derived： （1） Along with the rapid population growth, national farmland amount has increased by about 320% in the last 300 years from 424,480 km2 in the early Qing Dy- nasty to 1,368,600 km2 in 1985. Comparing with global and national farmland datasets, in terms of the overall trend of national farmland growth, very low deviation exists but significant variances do appear for some provinces. （2） At the beginning of the Qing Dynasty, China＇s farming activities mainly existed in the Yangtze River Plain, the North China Plain, the Guanzhong Basin and the Yinchuan Plain. Thereafter, reclamation activities expanded to outer agricultural areas. Regarding of the growth rate, national farmland increase can be divided into five phases. National policy, disasters, wars, and economic development, are the main factors affecting farmland changes. （3） Significant regional variances exist in farmland changes. In the space shaped by the average farmland amount and the average annual change rate of farmland, the nation can be divided into six areas.