Spatiotemporal evolution of rice production geographical agglomeration in Chongqing based on spatial statistics

Knowledge about dynamic changes of geographical planting patterns of crops is a critical basis for planting adjustments and optimal configurations. Using ordered and spatial statistical methods, the spatial distributions, temporal evolutions, key production area transformations and geographical concentrations of rice production in Chongqing municipality were determined. Also the spatial evolution patterns and dynamics of rice production from 2000 to 2015 were quantified. The results showed that the cultivated area and rice production in Chongqing decreased before 2007, but gradually increased after 2008. During the study period, the spatial distribution patterns of yield per unit area, planting area ratio and total yield in Chongqing were all higher in the west than in the east, and then higher in the south than in the north. Using administrative districts as study unit, rice production areas were divided into 4 typical zones-large area with high yield, small area with high yield, large area with low yield and small area with low yield. From 2000 to 2015, the counties belonging to the large area with high yield type and large area with low yield was stable with some changed in rank of counties. However, the type of small area with high yield changed greatly, the counties number decreased from 8 in 2000 to 4 in 2015. The counties of the small area and low yield type most located in the hill area where the light, water conditions were relative poor. With the expansion of Chongqing City, some counties once were in the small area with high yield changed to the type of small area with low yield. Rice production center was located in the southwest of Chongqing and gradually moved to the northeast. While the degree of geographical aggregation of rice industry decreased gradually over time, the degree of spatial homogenization improved. Regional natural factors, social economy, planting technology development and government planning were the influencing factors of the patterns of rice industry. In future, different cultivation planning and optimal management measures were needed for different planting areas.