Impact of crop types on land subsidence: a case study of Nourabad aquifer, Iran

During the recent decades, subsidence has increasingly occurred in many countries around the world, with the case being even worse for developing countries like Iran. In Iran, the main factor contributing to the occurrence of land subsidence is excessive groundwater extraction of groundwater for agricultural activities. One of the best techniques for subsidence detection is differential interferometry. In terms of agricultural development, Nourabad is an important plain in Fars province, Iran, where land subsidence due to overconsumption of groundwater has been experienced during the recent past. Cropping pattern plays a significant role in the subsidence and acknowledging the critical state of water resources in Iran alongside the fact that the farming method, in terms of its water demand can greatly contribute to reduced level of local aquifer reserve and hence the occurrence of land subsidence, the present research seeks to investigate the effect of farming method (i.e., dry farming, irrigated farming, and summer crops farming) on the subsidence in Nourabad Watershed. Satellite images acquired by Sentinel-2 and Sentinel-1 were used. Data analysis was performed through radar data interferometry, support vector machine (SVM), and a hybrid of the two via spatial regression. Results of SVM showed that The maximum land subsidence recorded was approximately 10 cm per year was experienced on rice-farmed lands. Fields cultivated with rice exhibited a subsidence rate 50% higher than those with wheat") would emphasize the relationship between agricultural practices and environmental effects. Investigation of cropping pattern was showed The correlation between groundwater extraction and land subsidence was significant at p < 0.05".