Spatiotemporal Changes And Attribution Analysis Of Cultivated Land In Black Soil Area Of Northeast China

The Northeast black soil region is an important high-yield area and the largest commodity grain production base in China.Due to global climate change and human activities,issues such as the thinning of black soil thickness,soil structure degradation,serious decline in organic matter content,and increased wind and water erosion have emerged.This has led to the intensification of fragmentation of cultivated land in black soil areas,which has affected modern and intelligent agricultural machinery operations.Spatiotemporal change analysis is the basis and key for monitoring,evaluating,and protecting cultivated land quality.This study focused on the Northeast black soil area as the study area,and used land use data to extract the distribution of cultivated land in 1990,1995,2000,2005,2010,2015,and 2020.The spatiotemporal changes of cultivated land were analyzed from the perspective of quantity and space,and the basic laws of spatiotemporal changes of cultivated land in Northeast black soil were obtained.Based on the spatiotemporal characteristics of changes,typical change time stages were divided,and influencing factors were screened.The explanatory power and interaction effect of factors affecting cultivated land change were obtained by using factor detectors and interaction detectors in Geodetector.The main research content and conclusions are as follows:(1)Analysis of spatiotemporal changes in cultivated land based on quantity characteristicsThe dynamic change analysis method of cultivated land area,the relative change analysis method,and the cultivated land transfer analysis method are used to analyze the change in cultivated land quantity.The results shown that,in the past 30 years,the quantity of cultivated land in the black soil region has fluctuated in a wave-like manner,and the periods with the most drastic changes occurred from 1990-1995,2000-2005,2010-2015,and 2015-2020.The net increase in the cultivated land area over the past 30 years was 445,080 hectares.At the urban scale,the number of cities with an increase in cultivated land only accounted for 30%,and most cities have experienced a certain degree of cultivated land loss.The changes in the cultivated land area in most areas during each period were positively related to the changes in the entire black soil region’s cultivated land area,with a few changes in the opposite direction.The dynamic changes of cultivated land in the past 30 years mainly occurred among three land types:cultivated land,forest land,and grassland.The majority of the increase in construction land came from cultivated land.(2)Analysis of spatiotemporal changes in cultivated land based on space characteristicsSpatial autocorrelation,spatiotemporal change complexity,and landscape pattern index are used to analyze the spatial changes of cultivated land.The results shown that,cultivated land in the past 30 years had significant spatial autocorrelation.With 2010 as the boundary point,the spatial correlation of cultivated land gradually decreased in the first half period and gradually increased in the second half period.More than 90% of the regions had relatively simple cultivated land changes.The overall complexity of the eastern region was lower,and the cultivated land close to cities had higher complexity.The western region had more concentrated and complex changes,and cities such as Chifeng,Tongliao,Hinggan League,and Baicheng were typical.The areas with higher complexity were generally concentrated in the 30 km buffer zone of water sources,distributed along river belts,or distributed in clusters near lakes.The analysis of the changes of the landscape pattern index of cultivated land in the black soil of Northeast China reveals that the changes of the Songnen Plain and some cities in the Liaohe Plain fluctuate greatly and the fragmentation of cultivated land deepens,while the aggregation of cultivated land in the rest of the region is gradually improving and the fragmentation is effectively controlled and gradually reduced.(3)Attribution analysis of spatiotemporal changes in cultivated landUsing Geodetector for attribution analysis.The results shown that,temperature,slope,and elevation were the main natural factors affecting the changes in cultivated land in the Northeast black soil region.However,the influence of natural factors on land use change gradually decreased over time,and was overtaken by social and economic factors such as GDP and grain production.All the interactions among the influencing factors showed an enhancing effect.With the passage of time,the interaction effects among natural factors gradually decreased,and the interaction between social and economic factors and natural factors became the dominant factor driving land use change.