Impacts of land consolidation in a semi-arid agricultural region of Türkiye using remote sensing analysis

Land consolidation (LC) activities are important for sustainable agricultural management, as they help improve irrigation, create more productive agricultural parcels, and increase yields. Combining small irregular parcels into larger, regular soil plots enables more efficient and sustainable agricultural practices. Fragmented land reduces productivity and contributes to irrigation inefficiency and soil erosion. This study analyzed the impact of LC on vegetation cover and moisture retention in agricultural land parcels across four villages in the Kızıltepe District of Mardin Province, which is located within the GAP region of Türkiye. This study evaluated changes in agricultural land parcels between 2015 and 2019 (pre-LC) and 2020 and 2024 (post-LC) for three different months (April, May, and June) using Sentinel-1 synthetic aperture radar (SAR) and Landsat-8/9 remote sensing datasets. Changes in the normalized difference vegetation index (NDVI), the normalized difference moisture index (NDMI), and the modified normalized difference water index (MNDWI) were observed, and their relationships with the SAR change data were checked using 944-pixel samples by Pearson's correlation coefficients. NDVI and NDMI changes showed strong positive correlations (> 0.70), while MNDWI changes showed weak correlations with Sentinel-1 SAR data for all 3 months. The results show that LC has positively affected agricultural productivity, particularly by improving water retention and plant health at the beginning of the agricultural season. Significant positive changes were seen in April. These indicate more suitable conditions for plant growth following LC and improved irrigation management. However, declines in vegetation health and moisture retention in May and June highlight ongoing water stress. Despite the positive effects of LC on improving irrigation infrastructure, further improvements in water management and sustainable practices are needed to fully alleviate moisture stress and ensure long-term agricultural sustainability. This study provides insight into the influence of LC on agricultural parcels and supports continued implementation of the GAP project to improve agricultural practices and water management in the southern Anatolia Region of Türkiye.