Soil organic carbon stock assessment for soil fertility improvement, ecosystem restoration and climate-change mitigation

Food insecurity, land degradation, desertification, and climate-change are prevalent in Eritrea. Though SOC stock is very crucial for soil fertility improvement, ecosystem restoration and climate-change mitigation, the status of it in different land uses in Eritrea is unknown. Thus, the study collected 64 surface soil samples from rainfed, irrigated, enclosure and grazing land uses from Keren subzone, Eritrea, and analysed for SOC. The ANOVA test results showed that land uses had very highly significant effects on SOC stock (p < 0.001). Rainfed and irrigated cropping recorded the minimum and maximum mean SOC stocks, 6.57 and 25.29 Mg ha-1, respectively. This implies that shifting from rainfed to irrigated agriculture would not only contribute to soil fertility improvement, increased yield, and food security but also to climate-change mitigation. Converting the 2500 hectares rainfed land in the study area to irrigated, would store 46,800 Mg C and offset 171,756 Mg CO2 emission. Grazing and enclosure land uses with 18.53 and 18.92 Mg SOC stocks ha-1, respectively, had no significant difference between them (Tukey test) which indicates poor enclosure management. Thus, the study realizes that irrigated agriculture with good agronomic practices is helpful to improve soil quality and mitigate climate-change. © The Authors, published by EDP Sciences.