The Performance of Nutrient Index Value (NIV) in Evaluation of Dryland Fertility

Soil fertility represents the soil ability to provide optimal plant growth conditions. Information on soil fertility status and preparation of related maps, plays an essential role in sustainable agricultural planning, maximizing economic benefits, maintaining soil quality, and preventing environmental degradation.In order to evaluate soil fertility status in some drylands in south of western Azerbaijan province and north of Kurdistan province, 101 samples were randomly collected and different soil properties such as pH, electrical conductivity (EC), calcium carbonate equivalent (CCE), and total nitrogen (N), phosphorus (P), potassium (K), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) were measured.Nutrient Index Value (NIV) was used to interpret the results and map soil fertility.The results showed that 100% of the soil EC and pH of areas were classified in the low and high classes, respectively.Organic carbon (OM) and CCE were in the medium class in 72% and 61% of the areas, respectively.Total Nitrogen in 94% of areas in medium class, available P in 94% of areas in low class, K in almost 100% in high class, available Fe in 88% of areas in low class, Zn in 33% in low class, 39% in adequate class, and 28% in high class, Cu and Mn available in 100% of areas are in low class.It can be concluded that NIV method is useful to evaluate soil fertility status and its predictions conform to the reported critical level for rainfed wheat.