Abu Zofar Moslehuddin

Groundwater–soil–crop relationship with respect to arsenic contamination in farming villages of Bangladesh – A preliminary study

To clarify the groundwater-soil-crop relationship with respect to arsenic (As) contamination, As concentration was measured in tubewell (TW) water, surface soil from farmyards and paddy fields, and fresh taro (Colocasia esculenta) leaves from farmyards in the farming villages of Bangladesh. The As concentration in TW water from farmyards was at least four times higher than the Bangladesh drinking water standard, and the concentration in fresh taro leaves was equal to or higher than those reported previously for leafy vegetables in Bangladesh. As concentration of surface soils in both farmyards and paddy fields was positively correlated with that of the TW water. Further, the concentration in surface soil was positively correlated with levels in fresh taro leaves in the farmyard. This study, therefore, clarified the groundwater-soil-crop relationship in farmyards and the relationship between groundwater-soil in paddy fields to assess the extent of As contamination in Bangladeshi villages.

Variation in Arsenic Concentration Relative to Ammonium Nitrogen and Oxidation Reduction Potential in Surface and Groundwater

Abstract Arsenic (As), ammonium‐nitrogen (N), nitrate‐N concentrations, and oxidation–reduction potential (ORP) in the water samples from the river, pond, dug well, and shallow and deep tube wells (TW) were investigated in a farming village of southwestern Bangladesh. Concentrations of As and ammonium‐N were the highest, whereas ORP was the lowest in the shallow TW water among the water sources. The ammonium‐N concentration correlated positively with the As concentration and negatively with ORP for all samples, irrespective of the water sources. A rise in the ammonium‐N concentration was hypothesized to enhance microbial activity, which in turn would lower ORP, and then As was released from sediments to the surrounding water in a reducing condition. The source of ammonium‐N in the shallow TW water was identified as N fertilizer, based on the δ15N analysis. Thus, the influence of N fertilizer application on As contamination in groundwater was suggested.

Quantity–Intensity Relationships and Potassium Buffering Capacity of Four Ganges River Floodplain Soils

Ganges river floodplain soil extends from Nepal through India to Bangladesh, which is a good niche for rice–rice and rice–wheat cropping systems in Asia. Application of potassium (K) fertilizer does not give any yield benefits to rice and wheat grown on most of the Ganges floodplain soils in Bangladesh. Understanding of soil K dynamics in this soil is important for the development of K management for rice–rice and rice–wheat cropping pattern in the region. Four Ganges floodplain soils, Sara clay loam, Ghior clay loam, Gopalpur silt, and Ishurdi silt loam, were evaluated for labile K (ΔK0), K intensity ( ), change in solution (ΔK), equilibrium exchangeable K (EKo), magnitude of conversion of solution K to exchangeable K (α), and potential buffering capacity of K (PBCK). The four soils had exchangeable K [ammonium acetate (NH4OAc extracted)] of 0.17 to 0.43 cmol kg−1, with the least in Ishurdi silt loam and the most in Ghior clay loam. The greatest ΔK0 (−0.81 cmol kg−1) was observed in Gopalpur silt, and the least (−0.25 cmol kg−1) was found in Ishurdi silt loam soil. The four soils exhibited equilibrium values of 0.007 to 0.021 (mmol L−1)1/2, with the least in Ishurdi silt loam and the greatest in Gopalpur silt soil. The greatest EK0 (0.66 cmol kg−1) was observed in Ghior clay loam, and the least (0.21 cmol kg−1) was in Ishurdi silt loam. Four soils were also different in the magnitude of conversion of solution K to the exchangeable K (α), being the greatest (67%) in Ghior clay loam and the least (25%) in Gopalpur silt soil. The tested soils were similar in PBCK [36.80–39.39 cmol kg−1/(mmol L−1)1/2]. The characteristics of ΔK0, , ΔK, EKo, α, and PBCK in the studied soils varied with the depth. Future research is needed to calibrate the characteristics of K dynamics for soil fertility management and to predict how long a nonresponsive soil can meet crop K demand for rice–rice and rice–wheat cropping systems.

Potassium chemistry in some important paddy soils of Bangladesh

Abstract Ten important paddy soils, seven from floodplains and three from terrace areas, were studied for different forms, and release and fixation behavior of potassium (K). Floodplain soils had higher amounts of total K [39.2 to 68.5 cmol(+)kg‐1] than did terrace soils [25.8 to 37.6 cmol(+)kg‐1]. Almost the same trend was observed for mineral and nonexchangeable K. Six out often soils were found to be deficient in available K. Release and fixation behavior of K varied due to variation in the contents of minerals affecting K chemistry in the soils. Based on K form and release and fixation behavior, soils were characterized in relation to K fertility. All three terrace soils had low reserves of both mineral and nonexchangeable K and the release potential was also low, available K was low in two and medium in the other. Soils of Old Brahmaputra Floodplain and Meghna Estuarine Floodplain had available K below the critical level, medium mineral K, low nonexchangeable K, low release potential and high fixatio...

Trace elements in Bangladesh paddy soils

Abstract A study was carried out to investigate the status of four micronutrients, iron (Fe), copper (Cu), manganese (Mn), and zinc (Zn), and five other trace elements, cobalt (Co), chromium (Cr), nickel (Ni), lead (Pb), and strontium (Sr), in paddy soils of Bangladesh. Soil samples were digested by hydrofluoric acid (HF)‐nitric acid (HNO3)‐perchloric acid (HClO4) for determination of total contents of the nine elements, while DTPA, ASI and 0.1 Mhydrochloric acid (HC1) methods were used for determination of available Fe, Cu, Mn, and Zn. Total trace element contents were found to vary with physiography on which soils are distributed. In general, Ganges Tidal Floodplain soils had the highest content, whereas terrace soils had the lower content. Among the soil properties examined, clay content had a good relation with total trace element contents in the topsoil, except for Sr. Based on the variation with physiography or clay content, the nine trace elements could be grouped into six groups: Cu, Fe and Zn, Pb...

Fixed ammonium in some Bangladesh soils

Y Nitrogen is the most deficient element and the most limiting factor for crop production in Bangladesh. The total N content in Bangladesh soils ranges between 0.02 and 0.12% (Ahsan and Karim 1988). The low N content indicates the presence of a small organic N pool and suggests that inorganic N plays an important role as a N source for crops. Contribution of “fixed” or “nonexchangeable” NH4 + to the N economy of soil has been reported for many tropical soils (Rodrigues 1954; Moore and Ayeke 1965; Dalal 1977; Sahrawat 1995). However, there are few reports on fixed NH4 + status in Bangladesh. In the present study, therefore, attempts were made to collect data on fixed NH4 + of some major soil series from the important physiographic units of Bangladesh.

Phosphorus status of some paddy soils in Bangladesh

Abstract Phosphorus status of Bangladesh paddy soils covering the major paddy soil types was assessed in terms of parent materials and physiography. Total P concentration ranged from 172 to 604 mg kg−1 in the topsoil and from 126 to 688 mg kg−1 in the subsoil, and varied with the physiography to which the soils belonged. In most soils, the available P concentration was much higher for the topsoil than for the subsoil. The inorganic P concentration was higher than the organic P concentration, except for one soil series from the Old Himalayan Piedmont Plain, and was significantly and positively correlated with the total P concentration. Among the inorganic forms, only the concentration of Al-bound P showed a significant correlation with that of available P based on the Bray P-2 method in both topsoil and subsoil. In general, the P status was critically low in paddy soils of the terrace area. Normal growth of paddy rice in this area is expected to be difficult without application of P fertilizer.

Quantity-intensity relationship for characterizing ammonium chemistry of Bangladesh soils in reference to clay mineralogy

Abstract Ammonium chemistry in surface soils collected from major soil series of Bangladesh was studied in terms of quantity-intensity (Q/I) relationship. Soils were classified according to physiography and parent materials; calcareous floodplain soils were dominated by mica and smectite, while non calcareous floodplain soils, terrace soils, and hill soils were dominated by mica or kaolinite and lacked smectite as a major clay mineral. Different Q/I parameters were obtained between soils of smectitic and non-smectitic types. Soils of smectitic type had a high potential buffering capacity which kept the equilibrium activity ratio at a low and fixed level.. The content of labile ammonium was high and estimated to increase with increasing addition of NH4 +. In contrast, soils of non-smectitic type with a low potential buffering capacity showed a considerable variation of both the equilibrium activity ratio and labile ammonium content, as affected by the application of NH4 +. Based on the ammonium chemistry, ...

Soil Health and Food Security: Perspective from Southwestern Coastal Region of Bangladesh

Bangladesh has a primarily agrarian economy. Agriculture is the single largest producing sector of the economy. Soil is the predominant aspect for a successful crop production; whereas, good soil health is a prerequisite for sustainable agriculture and food security. On the other hand, more than 30 % of the cultivable land in Bangladesh is in the coastal area. Out of 2.86 million hectares (ha) of coastal and off-shore lands about 1.056 million ha of arable lands are affected by varying degrees of salinity. Hence, this chapter would deal with status of soil parameters including soil salinity, its threat to sustainable crop production and food securities. Then the focus shifts to find out possible ways and few recommendations towards improving the soil health as well as reduction of the risk in southwestern coastal region of Bangladesh.

Physiography, Forests, and People in Teknaf

The Teknaf peninsula, which is located in the farthest southeastern corner of Bangladesh, has a diversified physiography exhibiting hills, piedmont plains, tidal floodplains, and beaches. The climate is subtropical, with temperatures ranging seasonally from 15 °C during the winter to 33 °C during the summer and very heavy rainfall (about 4000 mm). The peninsula, which experiences frequent cyclones, is vulnerable to climate change. More than 30% of the area consists of forests that are highly degraded as a result of various human activities as well as climate change such as frequent cyclone. Poverty is one of the major issues in the peninsula, with approximately 38% of the population living below the poverty line. Livelihoods center on agriculture, forest-related activities, and collection of marine resources. Although human settlements have existed in this area from ancient times, after 1990, extensive settlement has occurred in and around the forests. Apart from Bengalis, other ethnic groups living in the peninsula include the Chakma, Rakhine, and Rohingya groups.