Factor Decomposition and Temporal-Spatial Variation of Grain Production in Jiangsu
江苏省粮食生产时空变化的耕地利用因素分解

To examine links between grain production and cultivated land use, we used the LMDI approach and decomposition analysis based on grain production calculating models. Temporalspatial variation in grain production in Jiangsu province was studied by quantifying four factors: grain yield per hectare (intensity effect), cultivated land area (scale effect), planting structure (structure effect) and multiple-cropping index (degree effect). The results show that three major phases were categorized according to the dynamic trajectory of grain production since the economic reforms of 1978: rapid increase (first stage: 1978-1984), stable increase (second stage: 1984-1997), and fall then recovery increase (third stage: 1997-2009). Aggregate intensity effect was the largest and only positive contributor to total grain increment throughout 1978-2009, whereas the other three negatively affected grain production. In absolute terms, the remaining three effects lead to grain reduction as follows: scale effect > structure effect > degree effect. Spatially, southern Jiangsu's grain production was shrinking when northern Jiangsu experienced a compensating increase during the latter phase. A higher positive intensity effect and degree effect were observed in northern Jiangsu, while southern Jiangsu generally had a higher negative scale effect and structure effect, even with the negative degree effect in Tai-Lake surroundings. We outline some policy implications that would enhance food security for Jiangsu province: intensification of cultivation via yield increases and multiple cropping;restriction on cropland conversion to other land uses;modern mass production in northern Jiangsu facilitated by land-saving spatial development and the creation of non-farm jobs;and multifunctional land use in southern Jiangsu in response to the demands for both productivity increase and ecological services.