Practicing land degradation neutrality (LDN) approach in the Shazand Watershed, Iran

Neutralizing land degradation due to overexploitation of natural resources is an acceptable strategy under developing conditions. However, this important approach has not been adequately introduced and adopted in the world. The present study therefore aimed to calculate Land Degradation Neutrality (LDN) for the Shazand Watershed with an area about 1740 km² located in central arid and semi-arid region of Iran. The LDN status was basically assessed using three indicators, viz. land use and land cover, soil organic carbon and land productivity using Land Cover/Use Changes (LUC), Soil Organic Carbon (SOC) and Net Primary Productivity (NPP) metrics for two sub-periods during 2000 to 2016. Towards this, 140 soil samples were then taken from the top 30-cm of the soil from homogeneous units representing an area ≥ 1-km² for four different main land uses including irrigated farms, rain fed farms, range lands, and orchards. Consequently, SOC and various soil properties such as sand, silt, clay, gravel, bulk density (BD), pH, electrical connectivity (EC), calcium carbonate (CaCO₃) and nitrogen (N) were analyzed. NPP metric was also obtained using MODIS satellite images for three periods of 2000-2008, 2008-2016, and 2000-2016. The results of combination of study metrics indicated that net loss occurred in irrigated lands, rain fed lands, and range lands in the first eight-year period (2000-2008) and in contrary a balanced and stable situation in the second eight-year period (2008-2016). Overall, the LDN status in the Shazand Watershed was in a net loss situation during the period from 2000 to 2016 in irrigated lands, rain fed lands, and range lands covered areas of 12,290, 44,170 and 66,630 ha, respectively.