Nutrient status assessment and mapping of intensively managed paddy soils in southeastern hilly areas of Bangladesh

Background: People living in the southeastern hilly areas of Bangladesh are primarily dependent on agriculture and face the problem of nutrient deficiency in soils. This research was conducted to assess the fertility status of paddy soils for better fertilizer management. Grid sampling (1 km x 1 km) was followed to collect soil samples, avoiding unusual spots (e.g., non-agricultural land, settlements, hills, and forests). In total, 300 samples were collected (150 from each upazila) to assess the status of soil physical properties (soil texture) and chemical properties (pH, electrical conductivity, organic matter, and nutrients [nitrogen (N), phosphorus (P), potassium (K), sulfur (S), magnesium (Mg), boron (B), and zinc (Zn)]). Results: Results revealed that most of the soils were sandy to silt loam in texture. The soils were found to be strongly acidic with values of 4.79 and 4.73 in Ukhiya and Teknaf, respectively. Most of the soils were found to be nonsaline, except the paddy soils close to the sea and/or salt-affected cultivated land. Soil organic matter in Ukhiya and Teknaf was low (1.47% and 1.43%, respectively). The soils in both upazilas were deficient in N, P, K, S, and Zn, but not in Mg in both upazilas and B in Teknaf. Conclusion: It is imperative that adequate amounts of nutrient provision are available to maintain soil health and produce a sustainable crop yield. We believe that these are the first digital soil maps developed at upazila level using ArcGIS software, which will be available for future reference.