Spatial-temporal characteristics and policy implication for non-grain production of cultivated land in Guanzhong Region

Non-grain production of cultivated land (NGPOCL), as a severe threat to food security, has attracted great attention in China and other countries of the world. Although some scholars have focused on the NGPOCL, few studies performed the analysis at the plot scale across the whole region. This study takes Guanzhong Region as the study area and carries out a comprehensive analysis of NGPOCL according to the framework of "phenomenon-cause-countermeasure". According to the land-use map, the range of cultivated land was delineated; based on the 16-day time resolution MODIS vegetation index data, the NGPOCL range was further extracted from the cultivated land by distinguishing the grain/non-grain crops according to their seasonal variation characteristics on the vegetation index. Some spatial statistical methods were used to analyze the spatial-temporal characteristics of NGPOCL in the study area from 2000 to 2018, and it was observed as follows. Firstly, the NGPOCL problem in Guanzhong Region was getting worse during the study period, and the NGPOCL severity and area increased by 10.79% and 31.30% respectively. Secondly, the NGPOCL process showed significant temporal and spatial heterogeneity. The gravity center for NGPOCL was gradually shifted from Chunhua County to Xi'an City in the southeast. Meanwhile, the spatial autocorrelation of NGPOCL was weakening, and Moran' I was declining year by year. These indicated that the NGPOCL had been fully rolled out in the Guanzhong Region, and it had evolved from the past adjacent expansion to the current full bloom. As for the driving mechanism, while those natural factors determined the skeleton of the NGPOCL pattern, social and economic factors played an important role in the evolution process following, and different industrial policies have dominated the NGPOCL expansion at different stages. In the future, it is necessary to pay attention to the impact of industrial policies on NGPOCL and consider the demands of urbanization for non-grain agricultural products properly, so as to develop the characteristic agricultural products industry in a reasonable and compliant manner.