“…Identifying the major obstacles or opportunities at a grid scale can help in maximizing the productivity of cultivated land, optimizing the allocation of various physical resources, and decreasing production losses that are caused by inappropriate farming practices or land use patterns [15,17]. Some achievements have been made for single grain crop productivity spatialization, including paddy rice [15,18], maize [12,18], wheat [6,19,20], and barley [21], and multiple grain crops at global [17,18,22,23], national [24][25][26], and regional [5,15,27,28] scales because of the advantages of raster data. The estimation of the grain crop yield can be divided into five productivity levels, including photosynthetic productivity, light and temperature productivity, climatic productivity, soil productivity and land productivity [16].…”