Land degradation assessment in South Punjab, Pakistan: a comparative analysis of rain use efficiency and weighted overlay methods

The sustainability of the land needs to be kept in mind as the land is a pressing global issue, with productivity on some lands declining by as much as 50% due to soil erosion and desertification. Currently, 25% of the world’s land is degraded, affecting 3.2 billion people. This study aims to identify the factors contributing to land degradation in South Punjab, through two different methods, between 2001 and 2018, utilizing remotely sensed datasets. Firstly, the variables necessary to assess land degradation, as defined by the United Nations Convention to Combat Desertification (UNCCD), i.e. Soil Organic Carbon (SOC), Land use (LU) and Net Primary Productivity (NPP) were analyzed for the years 2001 and 2018 the main findings included that the land fertility factor in the area was most impacted in Rajanpur, and it also witnesses very low SOC levels. But, on the other hand, degradation levels are higher in western Rahim Yar Khan and northeastern Bahawalpur. Moreover, the trend of NPP in Rajanpur and Bahawalpur is higher than in Rahim Yar Khan. In terms of land use changes, the study uncovers the most rapid urbanization in Rahim Yar Khan. Secondly, this study assesses the level of degradation in the study area via Rain Use Efficiency (RUE) analysis, where areas with lesser RUE are the most stressed and degraded. The fact that even the very low and low RUE classes formed the bulk of the study area in 2001 and 2018, shows that these zones are the most degraded owing to low precipitation, higher temperature trends and low SOC levels. Most of the degraded lands as highlighted through weighted overlay (WOL) analysis, are also the same as those drawn from RUE. This land degradation analysis through two different methods further shows how SOC levels and climatic stresses have an impact on the region's ability to keep the plant cover. The study highlights the significance of regular monitoring of the status of land degradation in the drylands, as their economy relies on agriculture and livestock herding, both of which are vulnerable to the vagaries of climate change. Policymakers must utilize data from such analysis for mitigation plans to fight the menace of desertification and drought in the region while ensuring the food security of its residents.