M. A. Tarafder
SSO
Soil Science Division, Bangladesh Institute of Nuclear Agriculture (BINA)
Habibr Rahman
PSO
Soil Science Division, Bangladesh Institute of Nuclear Agriculture (BINA)
Mahbubr Rahman Khan
SSO
Soil Science Division, Bangladesh Institute of Nuclear Agriculture (BINA)
Long-term changes in soil characters in the upper 100 cm layers of the different physiographic units were evaluated using 290 soil samples from 29 soil series collected in 2017-18 in order to find out whether the soils have undergone any degradation in Bangladesh during 1967 to 2017. Changes in particle size distribution, soil pH, electrical conductivity, organic carbon, total nitrogen, available phosphorus, Exchangeable potassium, available sulphur, Exchangeable sodium and Exchangeable calcium contents were evaluated.
Over the 50 years period, soil pH changed in all the physiographic units, showed a larger decline in the surface soil layers. Considerable variation was observed in the sand, silt and clay distribution of the different soil series in Bangladesh. The clay content decreased for most of the soil series and silt content increased for all depth sampled in 2017. Soil organic carbon (OC) decreased with the increased soil depth. OC ranged from 0.40 to 2.77% at surface layer and 0.31 to 1.63% at deeper soil. Highest OC found in Bharella and the lowest from Gopalpur series. C, N ratio in 83% soil samples was not more than 10 at surface layer and only one series Atwari was 11 at deeper layer. Total N (TN) content for these soils was very low to optimum, TN decreased with increased soil depth, ranged from 0.048 to 0.335% at surface layer and 0.04 to 0.16% at deeper layer.
Available P (AP) content for these soils was better than TN, 75.8% soil contained medium to very high AP at 0-10 cm depth and 44.8% at deeper soil. AP ranged from 3.6 to 69.8 ppm at surface layer. Highest AP was found in Pirgacha series and the lowest in Pritimpasha series. At deeper layer AP varied from 1.95 to 40.37 ppm, Highest AP was also found in Pirgacha series and the lowest in Pritimpasha series at 0-100 cm depth. Like AP, 72.4% soils contained medium to high Available S (AS) at surface and 62% medium to optimum at deeper soil. AS ranged from 7.9 to 44.2 ppm at surface layer, highest AS was found in Ghior series and the lowest in Tarakanda series. 55.1% of the studied soil contained medium to very high K and Na, 41.3% of it contained medium to high Ca.
The values of soil pH, AP, OC and TN contents were lowest in the highland and increased at the medium lowland and lowland. The medium lowland had highest level of exchangeable Na, while exchangeable K and Ca levels were highest in the lowland position. Generally, the soils of Bangladesh are most degraded in OC, TN, exchangeable cations and clay contents. Available phosphorus changed positively or negatively at various physiographic units. The natural and anthropogenic effects played important roles in the trends and rates of soil degradation in Bangladesh during the period of more than 50 years from 1967.
Soil series, Nutrient depletion, 50 years, Physical and Chemical properties
All over the Bangladesh
Crop-Soil-Water Management
Land degradation
Project completion report submitted to PIU-NATP II, BARC, 2018
19,75,124.00
Report/Proceedings