基于RS和GIS的北京冬小麦面积多尺度时空变化研究

为了解小麦在不同空间尺度上的时空分布特征，基于冬小麦统计和遥感监测数据，利用空间统计分析方法，分别从北京市、区县和乡镇三个尺度，评价了2009-2014年冬小麦面积空间分布变化特征。结果表明：（1）北京市冬小麦面积从2009年的61 971.02 hm下降到2014年的26 814.87 hm，减少了56.73%；冬小麦成片种植的地块数量从11 243块降低到4 914块，减少了56.29%；地块平均面积也从4.76±0.19 hm减少到1.22±0.05 hm，降低了74.29%；（2）通州区、大兴区、房山区和顺义区的冬小麦面积减少量占总减少量的87.43%；每个乡镇的平均冬小麦面积从2009年的1 066.28±153.63 hm降低到2014年的388.21±59.17 hm，且大于1 000 hm和500~1 000 hm的乡镇数分别约减少了2/3和1/2；（3）四个典型乡镇冬小麦面积也均呈极显著减少趋势，地块平均面积降低幅度均在70%以上，并且面积大于5 hm的地块数量占总体的比例减少至不足8%。这说明2009-2014年北京市冬小麦种植面积显著减少，种植区域破碎化趋势严重。

Multi-Scale Temporal and Spatial Variation of Winter Wheat in Beijing Based on RS and GIS

In order to understand the distribution characteristics at different spatial scales properly,this research was conducted to evaluate the spatial variations of winter wheat growing area from 2009 to 2014 on three different scales:Beijing,district and township,by using the way of spatial statistical analysis. The results showed that:The acreage of winter wheat in Beijing was reduced from 61 971.02 hectares in 2009 to 26 814.87 hectares in 2014 by 56.73%. The number of winter wheat parcels was decreased from 11 243 to 4 914 by 56.29%,and the average size of parcels was decreased from 4.76±0.19 hectares to 1.22±0.05 hectares by 74.29%. The reduction of winter wheat area in Tongzhou district,Daxing district,Fangshan district and Shunyi district accounted for 87.43% of the total amount of cultivated land loss,and the average area was decreased from 1 066.28±153.63 hectares in 2009 to 388.21±59.17 hectares in 2014 for each town. The number of towns where have winter wheat area over 1 000 hectares and 500-1 000 hectares has dropped by about 2/3 and 1/2,respectively. In the four typical towns,all the winter wheat area exhibited a significant decrease tendency. Moreover,the average parcels size was reduced by more than 70%,and the parcels over 5 hectares took the portion of less than 8% of the overall areas. This research showed that the cropping area of winter wheat in Beiing decreased significantly,and the planting region had a fragmentation trend.