Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

Shifting Cultivation Effects on Soil Environment in Upland Watershed of Bangladesh

S.M. Sirajul Haque
Institute of Forestry and Environmental Sciences, University of Chittagong, Chittagong 4331, Bangladesh

Sanatan Das Gupta
Institute of Forestry and Environmental Sciences, University of Chittagong, Chittagong 4331, Bangladesh

Sohag Miah
Institute of Forestry and Environmental Sciences, University of Chittagong, Chittagong 4331, Bangladesh

Abstract/ Executive Summary:

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 average in soils of 5 different shifting cultivated lands fungal population was 1.33x105 CFU/g dry soil and bacterial population 1.80x107 CFU/g dry soil and in mixed plantations fungal population was 1.70x105 and bacterial population 2.51x107 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 the soil environment.

Keywords: Shifting cultivation, Soil biological properties, Chittagong Hill Tracts, soil physico-chemical properties, Soil environment

Location: Burburichhara, Maichchari, Longadu, Sukurchhari and Muralipara in Rangamati district of Chittagong Hill Tracts (CHTs)

Start Date:

End Date:

Program Area: Crop-Soil-Water Management

Non-commodity: Impact

Objectives:

This research, therefore, aimed to determine effects of shifting cultivation on over all soil environments.

Methodology:

Due to repeated shifting cultivation as well as deforestation process in CHTs it was very hard to select a pair of site representing a shifting cultivated land and natural forest-covered area or mature plantation area side by side to find out the effect of shifting cultivation on soil environment. Therefore, to select such a pair site a reconnaissance survey was conducted in approachable locations of Rangamati district to determine the environmental change in soil due to shifting cultivation. Following described 5 pair sites were selected in the dry season for soil sampling in the district: Burburichhara shifting cultivated area with adjacent planted mixed forest This current year shifting cultivated area was located at Burburichhara in Barkal Upazila of Rangamati district with the geographical position of 22^o 43′07.03″N and 92^o 21′ 02.19″E. This was a hilly area having steep (125-55%) slopes with an elevation of 364 m on the north-west aspect. Existed vegetation on the land consisted of paddy (Oryza sativa spp.) and turmeric (Curcuma longa) as shifting cultivated crops, Gmelina arborea (gamar) and banana (Musa paradisiaca) seedlings and some grasses in patches. Adjacent planted mixed forest was on steep (25-55%) high hill facing the north-western aspect at 22^o 43′06.99″N and 92^o 21′01.50″E geographical positions. Vegetation consisted of Albizia lebbeck (koroi), G. arborea, and teak (Tectona grandis) along with bamboo, sungrass (Imperata arundinancea), banana etc. Tree canopy coverage was 98% and undergrowth coverage had 80% with 4 cm forest floor thickness. Maijchhari shifting cultivated area with adjacent planted mixed forest Maijchchari shifting cultivated area was located in Barkal upazila of Rangamati district at geographical 22^o 43'06.12″N and 92^o19′06.95″E position. The area possessed 25-55% hill slope on south-western aspect having current year shifting cultivated land with crops of paddy, turmeric and banana. The adjacent planted mixed forest was on medium high hill with 25-55% slope at geographical 22^o 43′06.06″N and 92^o 19′07.45″E position on south-west aspect. Vegetation of this area were teak, Syzygium cumini (jam), Lagerstroemia speciosa (jarul), Barringtonia acutangula (hijal) and Laena coromandelica (vadi), which provided 70% canopy coverage with 30% undergrowth. Longadu shifting cultivated area with adjacent planted mixed forest This pair site was situated at Longadu upazila situated to the north-western part of Rangamati district at geographical position of 22^o 50′06.14″ N and 92^o 17′04.17″ E on steep high hill facing south eastern aspect. This was a current year shifting cultivated land with crops of paddy, turmeric, banana etc. with no undergrowth. Adjacent planted mixed forest of teak and G. arborea was on steep (25-55%) high hill slopes on south–eastern aspect at geographical position of 22^o 45′05.12″ N and 92^o 18′05.45″ E. Tree canopy coverage on this hill was 70% with 40% undergrowth, mostly of herbs with very little or no litter on the forest floor. Sukurchhari shifting cultivated area with adjacent planted mixed forest This pair site was situated at Sukurchori, 7 km from Manikchari under Kutukchari Range under Un-classed State Forest Division on the way to Rangamati-ManikchariMohalchari-Khagrachari Road. This site was one year old shifting cultivated land on medium high hill on eastern aspect at geographical position of 22^o 40′05.22″ N and 092^o 07′ 02.35″ E. Paddy residues of the previous year was still existed on the land with 75% grass vegetation and 15% ground coverage, mostly of Eupatorium odoratum (asamlata) of 80 cm in height. Adjacent to this shifting cultivated area mixed planted forest of litchi (Litchi chinensis), jackfruit (Artocarpus heterophyllus), teak, G. arborea and Syzygium cumini (jam) were present on upper part of the medium high hill at 22^o 41′ 05.45″ N and 092^o 06′02.42″ E geographical positions. Tree canopy coverage of this plantation was 80% with full undergrowth coverage and 4 cm litter depth. Muralipara shifting cultivated area with adjacent bushy forest This site was 2 year old slashed and burnt area, situated at Mulari para on the way to Gagra, Kaptai Road, Phulgaji Forest Range under Jhum Control Division. In this shifting cultivated area vegetation was wild banana on eastern aspect of a medium high hill at geographical position of 22^o 34′09.42″ N and 092^o 06′02.29″ E. Sun grasses was the only vegetation on this land that provided 15% coverage. Area adjacent to this shifting cultivated land was consisted of only one 25 year old jackfruit tree with bushy undergrowth on medium high hill top at geographical position of 22^o 33′05.82″ N and 092^o 07′06.22″ E. This bushy vegetation covered a very small area. Soil sampling and analysis From each of the above mentioned 5 locations, 5 replicated soil samples were collected from a depth of 0-5 cm from each land use, mixed thoroughly to give a composite sample and brought to the laboratory in labeled poly bag sterilized with 95% ethyle alcohol. In the laboratory samples were divided into two sub-soil samples: one used for determination of physical and chemical properties and the other kept in incubator at 4^o C temperature for determining biological properties. In both the cases, 3 sub-samples were taken from each composite sample for determination of various parameters of soil and result expressed for each parameter based on oven dry basis.

Source of Information: Journal of Forest and Environmental Science Vol. 30, No. 2, pp. 179-188, May, 2014

Article Link (Online Journal): http://dx.doi.org/10.7747/JFS.2014.30.2.179

Funding Source:

Budget:

Total Budget (Tk.) :

Achievement/Findings:

No doubt that shifting cultivation deteriorates soil environment through loss of vegetation and soil fertility, but this cultivation system cannot be stopped completely in CHTs, because this is the widely practiced primary occupation and major economic activities of the indigenous people in CHTs over the last several centuries. This cultivation system thus becomes the only source of sustenance for most ethnic backward people in this hilly region without the knowledge of modern cultivation. However, their indigenous knowledge in managing forest land is admirable, since they do minimum tillage for growing crops and manage community based forest sustainable way through community’s prepared rules and regulations. With the settlement of plain land people and fast growth of their own families, this hilly region becomes over populated in comparison to cultivable land and has reduced the choice of shifting at present from one to other place as they did in the past. Thus lands are not getting any rest period to regain its fertility due to repeated cropping and people clear more forests for their livelihood. Under the circumstances the only option to increase permanent vegetated area through encouraging naturally regenerated hundreds of species which grow following monsoon rains in this only mountainous region of the country with the aim to stop deterioration of soil biological and physicochemical properties. To keep overall environment with respect to natural resources at optimum condition in this upland watershed shifting cultivation is to be restricted to only on gentle sloping land with the adoption of long cycle and creating alternative employment opportunities to the shifting cultivators for their livelihood at their door step through developing landscaping and tourism facilities in this mountainous region. However, to achieve such benefits and services in this distinct region from plain land geographically, culturally, demographically, economically, administratively, legally and historically, require political decision from all parties at local and national level with the assistance of international environmental associations.

Knowledge Management: Journal