Soil Fertility Levels in Bangladesh for Rice Cultivation

Determination of soil fertility with minimum data set for crop zoning and devising fertilizer recommendations as well as soil fertility evaluation method based on soil properties. The data were collected from existing literatures and scoring was done on 0–100 scale. The lowest score was assigned for the minimum value of tested attributes and then gradually higher scoring values. Arithmetic, weighted, geometric and most minimum of mean scores were calculated and their performances were compared with grain yield of dry season irrigated (Boro) rice. Soil fertility in 10-12 and 39-52% areas in Bangladesh are very low and low, respectively. Medium fertile and fertile soils are distributed in 17-41% and in about 8% areas of the country. About 55% soils scored 70–95 (medium to high SOC) and the rest belongs to inferior quality. In some areas P build up has taken place (25% areas), but widespread K mining. Sulphur and Zn status in about 40% areas are low to very low (scored <35 and <40). Soils of the major areas of the country are with low pH (5.0-6.0) and CEC in the range of 15-25 cmolc kg-1. Weighted mean score and most minimum of eight attributes score showed good relationships with dry season irrigated rice yields than other tested methods indicating that this technique can be used for soil fertility rating in tropical countries.