Analysis of Track and Variation of Paddy Production Gravity Centre of China from 1949 to 2009

Movement path and offset distance of the planting area, production, yield per unit gravity centre was studied by using paddy planting area,production and yield per unit of 31 provinces (cities,autonomous regions) data from 1949 to 2009. The results displayed that: (1) the gravity centre of paddy planting area and production has been moving to northeast from 1949 to 2009. (2) The track of paddy yield per unit gravity centre moved to east before 1970's and move back after that in the north- south direction; In the east- west direction, the range movement of paddy yield per unit gravity centre fluctuated rise-decline between about 33-34°N. (3) By comparing the offset distance of gravity centre, the variation of paddy yield per unit gravity centre was the largest, followed by the yield every year, while the excursion distance of paddy plant area was the least; by comparing the offset direction, the years of moving to the northeast and southwest more than move to the southeast and northwest, it indicated that the imbalance of paddy production in the northeast and southwest was more serious. (4) Plant area and production of paddy change faster in the south- north direction than the east-west direction, while the paddy yield per unit change faster in the east-west direction than the south-north direction.