Erratum to ''Runoff and losses of soil and nutrients from small watersheds under shifting cultivation (Jhum) in the Chittagong Hill Tracts of Bangladesh (original) (raw)
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Journal of Hydrology, 2003
The effect of traditional shifting cultivation practices using slash and burn (locally known as Jhum) on runoff and losses of soil and nutrients was investigated over two years in three apparently similar small neighboring watersheds of approx. 1 ha each in the Chittagong Hill Tracts (CHT) of Bangladesh. The experiment used a paired catchment approach, comparing the effect of a one-year clearing/cultivation with long-term fallow and mixed perennial vegetation. In the year of cultivation, peak discharges increased considerably and the loss of soil and nutrients were significantly accelerated. The median peak discharge increased by a factor 7 and annual runoff increased by approx. 16%. The direct runoff from small watersheds under long-term fallow and/or perennial vegetation may typically vary between 15 and 24% of the annual rainfall. The loss of soil material from watersheds under mixed perennial vegetation or fallow is typically about 3 Mg ha -1 y -1, whereas the loss during the ye...
This research reports the effects of shifting cultivation on soil environment collecting samples from 0-5 cm soil depth from five locations viz. at Burburichhara, Maichchari, Longadu, Sukurchhari and Muralipara in Rangamati district of Chittagong Hill Tracts (CHTs). Soil analyses showed that fungal and bacterial population, microbial respiration and active microbial biomass, maximum water holding capacity, conductivity and moisture contents were significantly (at least p≤0.05) lower in shifting cultivated soil compared to adjacent mixed tree plantations at all the sites. On an average in soils of 5 different shifting cultivated lands fungal population was 1.33x10 5 CFU/g dry soil and bacterial population 1.80x10 7 CFU/g dry soil and in mixed plantations fungal population was 1.70x10 5 and bacterial population 2.51x10 7 CFU/g dry soil. Organic matter and exchangeable Ca and Mg contents were significantly (at least p≤0.05) lower and bulk density significantly (at least p≤0.05) higher in shifting cultivated land in most of the locations compared to adjacent mixed tree plantations. Ratios of microbial respiration and organic carbon as well as active microbial biomass and organic carbon were distinctly lower and pH higher at 3 locations in shifting cultivated soils compared to mixed plantations. Findings of various soil properties, therefore, suggest that shifting cultivation has deteriorating effects on soil environment.
Problems and Prospects of the Hilly Watersheds in Bangladesh, Priorities for their Conservation
The forests of the Chittagong Hill Tracts (CHTs) in the southeastern part of Bangladesh occupy about 30% of the nation's total forest area and represent the most valuable watersheds in the country. Their importance lies not only in providing soil and water conservation for sustainable natural resources management in this part of the country but also in supporting the shifting cultivation subsistence farming of 13 forest-dwelling indigenous communities. Traditionally, the communities practice a farming method called jhum, which involves cultivation of food crops in forest land through clearing and burning of undergrowth in the dry season, usually leaving a fallow period (3-15 years) between successive crops on the same piece of land. However, over the last two centuries land use in the area has undergone tremendous change, including the clear felling of forest trees to make way for establishment of mostly monoculture plantations of valuable timber species such as teak (Tectona gr...
A comparative study of plant nutrient changes between the years 1991 to 2012 in the north-eastern piedmont soils of Anjamkhor Union, Thakurgoan district, Bangladesh was done to determine soil fertility degradation status. Plant nutrient status was compared based on soil analytical data from soil survey program of the Soil Resource Development Institute (SRDI), Ministry of Agriculture, Bangladesh. This comparative study results revealed that soil fertility status was higher during the period 1990's. Afterwards, soil fertility status has been changed with time causing fertility decline. Soil acidity, organic matter content and some plant nutrients have been reached beyond their critical levels. Soil organic matter has increased by 1% from the years 1991 to 2012 but present OM status is still low and inadequate (mean 1.
We report the effects of shifting cultivation on water quality in 16 creeks investigated once in 2007 and twice in 2008 in 16 apparently similar small neighboring watersheds, each of 3 to 5 ha, at four locations around Barkal sub-district under Rangamati District of Chittagong Hill Tracts in Bangladesh. Concentrations of SO 4 2and K + , and pH in creek water were lower, and NO 3 -N and Na + concentrations were higher in shifting-cultivation land compared to land with either plantation or natural forest or a combination of these cover types. Shifting cultivation effects on some water quality parameters were not significant due to change in land cover of the watershed between two sampling periods either through introduction of planted tree species or naturally regenerated vegetation. Conductivity and concentrations of HCO 3 -, PO 4 3-, Ca 2+ and Mg 2+ in creek water showed no definite trend between shifting cultivation and the other land cover types. At one area near the Forest Range Office of Barkal, creek water pH was 5.8 under land cover with a combination of shifting cultivation and plantation. At this area Na + concentration in shifting-cultivation land ranged from 32.33 to 33.00 mg⋅L -1 and in vegetated area from 25.00 to 30.50 mg⋅L -1 in 2007. At another area, Chaliatali Chara, SO 4 2concentration in a shifting-cultivation watershed ranged from 4.46 to 10.51 mg⋅L -1 , lower than in a vegetated watershed that ranged from 11.69 to 19.98 mg⋅L -1 in 2007. SO 4 2concentration in this shifting-cultivation area ranged from 1.28 to 1.37 mg⋅L -1 and in the vegetated area from 1.37 to 3.50 mg⋅L -1 in 2008.
Evolution of Agriculture in the High Barind Tract of Bangladesh
ISBN978-984-34-5158-3, 2018
The High Barind Tract is a distinct uplifted agro-ecological zone in Bangladesh, originally densely forested but with a long subsequent history of rainy season, transplanted, puddled rice cultivation. This has resulted in severely degraded soil properties important for non-rice crops. Water-use-efficiency is a crucial consideration for the region due to the limited soil water-holding capacity, recent depletion of groundwater reserves, limited surface water catchment and increasing effects of climate change. Research and development activities over the last four decades to alleviate these constraints are evaluated. Ever increasing demand for rice in Bangladesh has prompted double cropping of rainy season rice followed by irrigated post-rainy season rice. However, such double cropping further deteriorates soil properties, depletes groundwater reserves and is only marginally remunerative for resource-poor farmers. With appropriate agronomy and cultivar introduction various post-rainy season crops, including wheat, pulses, oilseeds and vegetables, can be more remunerative. Present status and future options for tree cultivation, livestock husbandry and homestead development are also given. Conservation agriculture techniques for soil improvement and improved methods of water capture and use are elaborated. Through soil improvement, better management of water, appropriate crop rotation and effective exploitation of solar energy and communications technology it is envisioned that this region can become a sustainably productive agricultural region with substantially improved livelihoods for its inhabitants. This overview provides a case study applicable to other distinct agro-ecosystems cleared of natural vegetation for agriculture, resulting in a deterioration of natural resources, but its restoration through agronomic and other measures.
This study reports the effects of shifting cultivation at slashing stage on soil physicochemical properties at Bandarban Sadar Upazila in Chittagong Hill Tracts of Bangladesh. At this initial stage of shifting cultivation no general trend was found for moisture content, maximum water holding capacity, field capacity, dry and moist bulk density, particle density for some chemical properties between shifting cultivated land and forest having similar soil texture. Organic matter was significantly (p≤ 0.05) lower in 1-year and 3-year shifting cultivated lands and higher in 2-year shifting cultivation than in adjacent natural forest. Significant differences were also found for total N, exchangeable Ca, Mg and K and in CEC as well as for available P. Slashed area showed higher soil pH.