摘要
为了了解陕西关中地区2000—2013年耕地复种的时空变化特征,以250 m 16 d最大值合成的MODIS NDVI影像为数据源,使用Savitzky-Golay迭代滤波技术重构了农作物NDVI曲线,应用二次差分法结合作物物候历,提取了14 a的复种指数。结果表明：关中地区复种指数空间上以西安市区为中心呈辐射状递减,一年两熟制耕地主要分布于海拔600 m以下的渭河阶地,其他地区主要实行一年一熟制;2000—2013年总体呈下降趋势,从2000年的156.4%下降到2013年的130%,在2005年前后,降幅分别为2%和15.7%,城镇化进程和经济型农业的推进是影响复种指数下降的主要因素;与统计资料相比,地市级尺度上平均相对误差为0.3%~15.1%。像元尺度上验证精度达到93.7%,研究结果能够为区域农业决策提供可靠的数据基础。
Multiple cropping is an efficient way to improve the crop yield for Guanzhong area of Chinese Loess Plateau. The spatiotemporal pattern change of multiple cropping in Guanzhong area from 2000 to2013 was investigated. Cropping index was employed to quantitatively assess the multiple cropping. The twi-difference algorithm was applied to estimate the cropping index based on the crop NDVI time-series reconstructed from 250 m 16 d MODIS NDVI datasets with the iterative Savitzky-Golay method. Results were as follows： the cropping index was shown to be the highest in Xi＇an City and it was decreased with the increase of distance from the city; the croplands with double seasons were mainly located in the Weihe River plain with an altitude of less than 600 m; the single-season croplands were primarily distributed over the loess ravine regions of the northern Guanzhong area,Qinling mountain area of the southern Guanzhong area and alluvial plain along the Yellow River（ eastern Guanzhong area）. The cropping index in 2000—2013 was found to reveal a two-stage downward trend. During 2000—2005,the cropping index was reduced very slowly and the rate of the decline was less than 2%; however,the decrease rate became high during 2006—2013 which reached 15. 7% in 2013. The development of urbanization and economical agriculture were demonstrated to significantly influence the decline of cropping index. Through the comparison with the statistics issued by the government,the average relative error of cropping index estimated from MODIS datasets was between 0. 3% and 15. 1% at the regionallevel,and the result also had an accuracy of 93. 7% at the pixel level. The presented results provided useful and reliable information for the decision making on spatially-targeted local agricultural planning.
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2016年第8期280-287,共8页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家高技术研究发展计划(863计划)项目(2013AA102401-2)
