A decade-long spatial analysis of opportunistic rice cultivation in a water-stressed agricultural landscape.

Abstract

Rice cultivation is a highly criticized sector of agriculture in Iran. Despite the intensifying drought conditions, Central Iranian farmers continue to prioritize rice cultivation due to its substantial economic benefits, affecting the structure and configuration of irrigated agricultural landscapes. In a river catchment, we mapped rice fields over a 10-year period (2014-2023) using Landsat-8 OLI images, with mapping accuracy metrics showing kappa coefficients above 81.75 and overall accuracy above 92.78. Spatial analysis of the layers revealed the following: (1) an inconsistent pattern of rice cultivation over the study period, with more than 51% of the total agricultural area experiencing rice cultivation only once; (2) a contiguous area of high suitability for opportunistic rice cultivation along the main river of the region based on frequency hotspot analysis; and (3) years with larger rice cultivation resulted in more fragmented rice landscapes due to the incentive to cultivate smaller, scattered plots in newly accessible areas. Our results demonstrate that increased water availability does not necessarily translate to improved landscape structure; as rice cultivation expands, the landscape becomes more fragmented.