Comparative analysis of some selected macronutrients of soil in orange orchard and degraded forests in Chittagong Hill Tracts,Bangladesh

Status of organic carbon (C), total nitrogen (N), available potassium (K), calcium (Ca) and phosphorus (P) in three different depths (0-5 cm, 5-15 cm and 15?30 cm) on two hill slopes of 35% and 55% in orange orchard cultivated by the Mro tribe of Chittagong Hill Tracts (CHTs) were evaluated and compared with those in degraded bush forests, through digging three profiles in each land use. The content of all the five nutrients was found to be higher in the soil of orange orchard than in the soil of forest. But the variation was not consistent for both the slopes. The content varied depth wise also, having the highest value in surface soil in case of both the land uses on both the slopes. A mean available K content was significantly higher in orange orchard than in forest on 55% slope, while it was lower on 35% slope. Surface soil contained the nutrients of K and Ca with the amount of 0.2905-mg·g^(-1) soil and 3.025-mg·g^(-1)soil respectively in the orchard, while 0.1934-mg·g^(-1) soil and 1.6083-mg·g^(-1) soil were respectively in the forest. Organic carbon and total nitrogen were found more or less similar in surface soil on both the land uses showing a slight difference. Available P was found only in orange orchard, and in forest it was too little in amount to detect by the spectrophotometer. The degraded forests were poor in nutrient content due to high rate of soil erosion, which would be possible to be improved by bringing it under tree cover as proved by the adaptation of orange orchard there.

Comparative evaluation of physical properties in soils of orange orchard and bushy forest in chittagong hill tracts, Banglandesh

对孟加拉国丘陵地带Mro部落经营的桔园与灌木林35%和55%两种坡地土壤物理性质进行了比较与评价。每一块用地内挖掘3个土壤剖面采集不同深度(0-5cm,5-15cm and 15-30cm)的土壤样品,测定土壤水分、有机质含量和土壤密度。最大持水量、田间持水量、干或湿土壤容重和土壤孔隙度的测定仅限于表层土壤。两种坡地桔园3个深度的土壤水分含量均显著高于灌木林地相同深度的土壤水分。桔园在55%坡地内土壤有机质含量低于林地含量值,而在35%坡地内的含量值则高于林地值。两块样地内上述两项测定值均在表层土壤中最高,且随土层深度的增加而降低。与灌木林地比较,桔园地表层土壤最大持水量、孔隙度和3个不同深度的土壤密度均较低。两块用地内不同坡地的表层土田间持水量有所差异,且桔园地干或湿表层土壤容重高于林地内的数值。表5参23。

Natural Resources Depletion in Hill Areas of Bangladesh:A Review

Hilly or mountainous terrain occupies around 12% of the area of Bangladesh.Natural resources associated with Bangladesh's hill are forest resources,biodiversity,minerals,and agricultural crops.Natural resources have been exploited in the recent four decades due to excessive clearing of hill forest cover,resulting in loss of species richness, impacts related to increased water flow variability, increased hill slope erosion and flooding intensity, and a gradual decrease in the extent of hill area in Bangladesh.This review explores the major causes and effects of depletion of natural resources by linking drivers,pressures and the related impacts.A review has been conducted to structure the effects on the hilly areas and describe the responses to minimize them in the associated DPSIR framework.Population growth has been identified as a major driver contributing to high deforestation rates.This may negatively effect agricultural productivity and increase the frequency of serious flooding.Slash and burn cultivation also impacts the regeneration of evergreen forests,which may accelerate soil erosion. Due to this and other factors,local people are facing a deficits of natural resources(food,fodder,fuel wood and water),which exacerbates the effects of poverty. Future research should try to facilitate decision making for sustainable utilization of natural resources management in the hilly areas of Bangladesh. Additional conservation measures should be developed to increase the resilience of ecosystems at national and regional levels.

孟加拉吉大港山区Khagrachari的现代和传统农业系统中土壤化学性质(英文)

由于森林覆盖面积的缩减,制度上的缺陷,人口增加和不合理的山区农业系统等因素,吉大港山区植被严重退化。孟加拉吉大港山区正在实践现代农业体系(如坡地农垦技术),它通过建立生态群落(而非传统轮垦)提高经济产量和生物多样性,这种现代农业体系提供了一种新土地开发策略。本研究对孟加拉吉大港山区Khagrachari的现代和传统农业体系中的土壤化学性质变化进行对比分析。与传统轮耕相比,实行坡地农业耕地技术的土地有较高的生产容量,含有较高的有机碳和有机物。在吉大港山区,通过发展综合农业生态系统建立稳定的生产环境,可以将轮作耕地变为相对稳定的半永久性的农业系统。