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

The physical properties of soil 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 of bushy hill forests. Soil samples were collected from three different depths （0-5 cm, 5-15 cm and 15-30 cm）, digging three profiles in each land use for determining moisture content, organic matter content and particle density. Maximum water holding capacity, field capacity, dry and moist bulk density and porosity were determined only for the surface soils. Moisture content at all the soil depths was significantly higher （p≤ 0.05） in orange orchard than in forest on both the slopes. Orange orchard contained lower mean soil organic matter than forest on 55% slope, while it contained higher values on 35% slope compared to forest. The highest value of the above two properties was found at surface soil in both the land uses on both the slopes, decreasing with the increase of soil depth. On both the slopes maximum water holding capacity and porosity of surface soil and particle density at all soil depths were lower in orange orchard compared to those in forest. Field capacity values of surface soil did not show consistency in trend for the differences between the two land uses on both the slopes. Bulk density value of moist and dry surface soil was higher in orange orchard than in forest on both the hill slopes.

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.

Soil chemical properties under modern and traditional farming systems at Khagrachari,Chittagong Hill Tracts,Bangladesh

Land degradation in Chittagong hill tracts has been taking place due to shrinkage of forest cover, policy weakness, population explosion, and inappropriate hill farming system. Modem farming system in the Chittagong hill tracts like Sloping Agricultural Land Technology （SALT） is practiced to provide a new strategy for developing lands for economic productivity and bio-diversity conservation through establishment of ecological community rather than traditional shifting cultivation which is no longer sustainable according to the carrying capacity of ecosystem of Chittagong hill tracts. This study is to find out changing trends of soil chemical properties of sites under modem and traditional farming systems at Khagrachari district of Chittagong hill tracts. The result of the research shows that Sloping Agricultural Land Technology has significantly higher capacity of production due to the presence of the highest percentage of organic carbon, organic matter, compared with shifting cultivated site. The study recommends that shifting cultivation may be changed into a relatively stable semi-permanent farming system through developing participatory integrated farming systems to establish stable production environment in the Chittagong Hill Tracts.