Spatial-temporal Dynamics Of Spring And Summer Maize Cropping System And Its Response Mechanism In North China

Based on county-level crop statistics and other ancillary information in North China,spatial distribution of maize in the major maize-growing areas(latitudes 32°-42° N,Longitude 113°-117° E)was modeled within 5' × 5' grid cells for the period 1980–2010 by using a cross-entropy-based spatial allocation model(SPAM-China).With the aid of the SPOT/VGT NDVI ten-days' composed time-series data collected from April 2000 to March 2010,we built classification rules to identify the main maize types,and analysis maize Planting Patterns change in North China and their effects on yield.Then based on the Panel Data model,the genetic factors of maize cropping change in North China were analyzed from the aspects of climatic factors,production factors,regional economic factors,regional social factors and national policy elements.The main conclusions are as following:(1)Maize planting area increased significantly(3.6×106 hm2)and concentrated at central and southern in North China during 1980-2000.And it shows latitudinal variations(located at 32°N~36°N)and steady growth along longitude at the range of 113°E~117°E;At latitude,the maize planting core maintained at 36 °N.Similarly,maize is mainly distributed in the east longitude 113°~ 117°.(2)From 2000 to 2010,spring maize area account for 17% to 27% of the total maize area,is mainly distributed in Hebei and Shandong Province;Meanwhile,summer maize area also increased about 0.87×106 hm2 in the south part of North China.Increased spring maize and decreased summer maize were mainly converted from the previous summer maize in the spring and summer maize hybrid area,which was accounting for 92% and 87% of the increase of maize acreage.It can be inferred that single-cropping system for spring maize is taking place previously double cropping system(winter wheat and summer maize)in north and middle part of North China.(3)The spatial panel model results show: The variation of Maize Planting Area in North China is effected positively by GST,Irrg,Fert,Pest,Mach,Spec,Labr,Value,while effected negatively by GSP,Energy,Urban,and Agricultural policy.Spec and Fert had the highest contribution rate to maize acreage in North China,accounting for 45.18% and 42.22%.On the contrary,Energy generated a strong inhibitory to maize acreage in North China,accounting for 16.06%.What's more,the result of spatial error parameter presents that the maize acreage of local area can be influenced oppositely by the neighbor region's maize acreage.(4)The county scale results show: The increase of spring maize planting area are mainly distributed in the south of Henan and so on,mainly with the local climate suitability,geographical location,is closely related to the economic development and regional positioning;Reduced summer maize planting area mainly distributed at the junction of Hebei,Henan and Shandong province,and associated with the rapid development of urbanization,industrialization,the reduction in cultivated land area,fewer people engaged in agriculture and other factors.