INTERNATIONAL J OURNAL OF ENVIRONMENTAL SCIENCES Volume 3, No 3, 2012 © Copyright by the authors - Licensee IPA- Under Creative Commons license 3.0 Research article
ISSN 0976 – 4402
Assessment of soil physical properties under plantation and deforested sites in a biodiversity conservation area of north-eastern Bangladesh Rahman. M.H1 , Bahauddin. M2 , Khan. M.A.S.A1,3 , Islam. M.J4 , Uddin. M.B5 1, 2, 3, 5 - Department of Forestry and Environmental Science, School of Agriculture and Mineral Sciences, Shahjalal University of Science and Technology, Sylhet-3114, Bangladesh 3- Department of Disturbance Ecology, University of Bayreuth, University Str. 30, 95447 Bayreuth, Germany 4- Ministry of Planning, Government of the People’s Republic of Bangladesh, Sher-e-Bangla Nagar, Dhaka-1207, Bangladesh
[email protected];
[email protected] doi:10.6088/ijes.2012030133016 ABSTRACT Some selected physical soil properties viz. moisture content, particle density, organic matter, balk density and porosity between planted and deforested sites has been investigated at surface (0-10 cm) and sub-surface (10-30 cm) soil in a biodiversity conservation area (Tilagarh Eco-Park) of North-eastern Bangladesh. Moisture content at all the soil depths was significantly higher (p≤ 0.05) in planted sites than in deforested site. Forest plantation had a significant effect on soil binding process since a common trend of increment in soil particle density and bulk density were noticed; particle and bulk density of soil decreases if any land is deforested and remained deforested for a longer time. Deforested site contained lower mean soil organic matter than that of Garjan (Dipterocarpus turbinatus) and Sal (Shorea robusta) plantations. The highest value of organic matter was found at surface soil (0-10 cm depth) in both the Sal (2.24%) and Garjan (1.77%) plantations. The organic matter on both the plantations and deforested site decreased with the increase of soil depth. The mean value of soil porosity was significantly less in deforested site (0.47 gm/cc) than that in Sal (0.48 gm/cc) and Garjan plantation (0.49 gm/cc). Keywords: Moisture content, Organic matter, Soil particle density, Bulk density, Dipterocarpus turbinatus, Shorea robusta, Tilagarh Eco-Park 1. Introduction Forest soils in comparison to other soils are characterized by the presence of litter with an associated unique micro flora and fauna (Lutz and Chandler, 1946; Pritchett and Fisher, 1987), higher porosity, higher permeability, more stable soil aggregates and greater water holding capacity (Sozykin, 1939; Ivonin and Zasoba, 1989). The carbon- nitrogen ratio is generally wide and decreases as decomposition occurs in the forest soils, where in other soils this ratio is usually much lower (Pritchett and Fisher, 1987). Trees may play a major role in increasing soil fertility through the ecological and physicochemical changes they induce in soil (Singh et al., 2002). Litter fall is the main path for the return of dead organic matter and nutrients to the soil and humus formation in tropical forest systems (Spain, 1984). Soil physical properties have long been considered to exert great influence on the distribution, growth and development of trees. Tree cover in turn, influences the improvement of physical properties of soil (Rathod and Devar, 2003).
Received on October 2012 Published on November 2012
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Assessment of soil physical properties under plantation and deforested sites in a biodiversity conservation area of north-eastern Bangladesh
Bangladesh, a sub-tropical country, lies in the Indo-Gangetic plain of South Asia has small patches of forested areas but there are some contradictions about the actual forests coverage of the country (Mukul et al., 2008). By the last assessment of Bangladesh Forest Department the total area of forestland of Bangladesh is approximately 2.52 million ha of which the Forest Department manages 1.52 million ha (BFD, 2008 cited from Chowdhury and Koike, 2010). The tropical evergreen and semi-evergreen forests of Bangladesh occur in the hilly regions of the northeastern and southeastern region where evergreen plant species are mixed with deciduous tree species, in association with diverse herbs, shrubs, bamboo and rattan (Khan et al., 2007). To meet the huge population’s demand of the country, forest resources are depleted continuously at a higher rate through extraction of fuelwood, illegal logging, grazing, encroachment, etc. In this situation, Government of Bangladesh has taken a strategy to conserve the biological diversity of the country by providing protection adequately through various conservation strategies (Al-Amin et al., 2004) such as declaration of ‘protected area’ of all the natural forests by the year 2015. This is may be due to the commitments with different international organizations and conventions. Due to these commitments, Tilagarh Eco-Park (TGEP) declared as an Eco-Park recently in 2006 (Bahauddin, 2008). The objective of establishment of an Eco-Park is for the recreation of visiting people from home and abroad, as well as creating a centre for the dissemination of knowledge to people of all age groups about the habits and habitats of the plant and animal populations living there, and at the same time creating awareness about the need of conservation of biodiversity (Khair, 2006). Plantation has been a regular activity in the hill forests of Bangladesh since 1871. At present, plantation programs are being implemented on a massive scale under different development projects. Important plantation species include Tectona grandis, Gmelina arborea, Swietenia spp., Artocarpus chaplasha, Lagerstroemia speciosa, Shorea robusta, Albizia spp., Chichrassia tabularis, Xylia dolabriformis, Dipterocarpus turbinatus, Anthocephalus chinensis, Acacia spp., Eucalyptus spp., Hopea odorata (Khan et al., 2007). Plantations are known to bring about changes in edaphic, micro-climatic, floral, faunal and other components of the ecosystem through bio-recycling of mineral elements, environmental modifications and changes in floral and faunal composition (Shukla, 2009). Taking this hypothesis into consideration, physical analysis of soil in both the Dipterocarpus turbinatus Gaertn and Shorea robusta Gaertn plantation sites and deforested site was carried out to evaluate the status of certain physical properties of TGEP of northeastern Bangladesh. As no previous studies have been conducted in this aspect in the northeastern region of Bangladesh so, this study will be a base line study to analysis of soil physical properties under plantation and deforested sites. 2. Materials and method 2.1 Study site The Tilagarh Eco-park (TGEP) is located at North Sylhet Range-1 in Sylhet Forest Division under tropical evergreen and semi-evergreen bio- geographic zone. It is about 6 km from Sylhet city. Total area of Tilagarh Eco-park is 45.35 ha (112 acres); GPS location is between 23°55′ and 25°02′ North latitude, 90°55′ and 92°30′ East longitude. Soil ranges from clay loams to pale brown (acidic) clay loams on the hills. Red sandy clay contains granules of magniferous iron ore (Bahauddin, 2008). Soil pH ranges from 5 to 7.5. Climat ic conditions are warm and humid, April and May are the warmest and December and January are the Rahman. M.H, Bahauddin. M, Kha n. M.A .S.A , Islam. M.J, Uddin. M.B International Journal of Environmental Sciences Volume 3 No.3, 2012
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Assessment of soil physical properties under plantation and deforested sites in a biodiversity conservation area of north-eastern Bangladesh
coolest months of this area. The tropical monsoon climate prevails in the area with average maximum temperature of 31.6˚C and average minimum temperature of 19.9˚C. The average annual rainfall is 3937 mm, most of which falls between June-September (BBS/UNDP, 2005). 2.2 Research methods 2.2.1 Selection of soil sampling sites Soil samples were collected from two plantation sites viz. Sal (S. rabusta) plantation and Garjan (D. turbinatus) plantation sites and deforested site. Sal and Garjan plantation are selected because of they are dominant in the TGEP During dry season, from the first week of January 2010 to the last week of May 2010 samples were collected from selected plantation sites and deforestation site at two different depths viz. surface soil (0−10 cm) and subsurface soil (10−30 cm). Total 90 samples (30 from each land use and 15 from each depth) were collected from 3 land-use sites. Plot size was 20m × 20m. Then each five samples were mixed to prepare one composite sample. In this way total 90 samples were converted into 18 composite soil samples for convenient laboratory analysis. Soil samples were collected by using properly labeled poly-bag and soil core. Samples were collected into air tied poly bags to prevent the loss of soil moisture. 2.2.2 Soil sample preparation In the laboratory, collected moist soil samples were firstly sieved through 10mm mesh sieve to remove gravel, small stones and coarse roots and then passed through 2 mm sieve. Then the sieved samples were dried under room temperature. 2.2.3 Determination of soil physical properties Soil samples were analyzed chemically to determine the soil moisture content, particle density, organic matter, bulk density and porosity of soil by conventional methods of soil chemical analysis. While studying soil profile, 4 profiles were studied for differentiation of soil horizons by digging at right angles and with the help of conventional methods. The data were then analyzed statistically (One way ANOVA test was done to know the significance difference among the soil samples of 3 different land uses using SPSS-17.0 package) and then compared using Duncan's multiple range test (Duncan 1955; Steel and Torrie 1980) and finally arranged systematically. 2.2.4 Soil moisture content (MC) % Moisture content was determined from samples collected into air tied poly bags. At first exactly 50 gm of field moist soil polybags were taken in pre-weighted porcelains. The soil in porcelains was then dried in an electric oven at 105°C for 48 hours; then cooled it for few minutes and weighed again. The weight of porcelains was then excluded from total weight to get the weight of dried soil. Moisture that was dried up or moisture content of the soil was determined from the difference of initial and final readings. These results were then multiplied by 100 and divided by the weight of dried soil to get the moisture content in percentage. Calculate the moisture content of the soil as a percentage of the dry soil weight (Huque and Alam, 2005). MC%= {(W2-W3)/ (W3-W1)} x 100………………………. (1) Rahman. M.H, Bahauddin. M, Kha n. M.A .S.A , Islam. M.J, Uddin. M.B International Journal of Environmental Sciences Volume 3 No.3, 2012
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Where, W1 = Weight of Petridis (gm), W2 = Weight of moist soil + Petridis (gm) and W3 = Weight of dried soil + Petridis (gm). 2.2.5 Particle density (PD) (gm/cc) To determine particle density, 5 gm of dry soil was taken into a 10 ml graduated measuring cylinder. In another graduated cylinder, 10 ml of distilled water was taken and poured into the first graduated cylinder until volume reaches to 10 ml mark. Finally, particle density was calculated dividing weight by volume of soil (volume of water left in the second cylinder) (Huque and Alam, 2005). 2.2.6 Organic Matter (OM) Soil organic matter was determined by the Walkley-Black's wet oxidation method adopted from Nelson and Sommers (1996). 2.2.7 Bulk Density (BD) (gm/cc) Bulk density is a measure of the weight of the soil per unit volume (gm/cc), usually given on an oven-dry (110° C) basis (Huque and Alam, 2005). Bulk density = (Weight/Volume) gm/cc………………… (2) Dry Weight = W2 -W1 …………………………….. (3) Where, W2 =Weight of the oven dry soil + Weight of the soil Petridis, W 1 = Weight of the soil Petridis and volume= πr²h (h= 10cm for 0-10cm depth and 20 cm for 10-30cm depth, π=3.14 and r=1cm) 2.2.8 Porosity (PO) (gm/cc) Porosity= {1- (Bulk density/particle density)} x 100………………….. (4) 3. Results 3.1 Soil moisture content On Sal and Garjan plantation and deforested site, moisture contents in all the soil depths were significantly higher (p≤ 0.05) in Garjan plantation than in deforested site (Table 1). Moreover, mean soil moisture contents at all the depths were significantly higher in plantation forest area than in deforested site. Irrespective of soil depth, moisture contents in Sal plantation ranged from 16.75% to 17.29%; Garjan plantation ranged from 16.43% to 18.08% and those values in deforested site ranged from 14.01% to 14.03%. Moisture content in soil gradually decreased in general with the increase of the depth in Sal plantation and no significant variation in deforested site except 10–30 cm depth in Garjan plantation, where moisture content increased slightly than that of 0–10 cm depth. Garjan plantation contained highest percentage of moisture (18.08%) followed by Sal plantation (16.75%) and deforested land (14.03%) respectively. On the other hand, the value of one-way ANOVA test for moisture contents (%) on different land-use patterns irrespective of soil depth is F=2.99 and significance value is 0.08.
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Table 1: Moisture contents (%) at two soil depths in Sal plantation, Garjan plantation and deforested site Land-use pattern Sal plantation Garjan plantation Deforested site
Soil depth (cm) 0-10 10-30 0-10 10-30 0-10 10-30
R1
R2
R3
Mean
15.71 15.47 14.64 18.00 14.96 13.48
22.72 21.49 16.28 17.39 13.89 13.97
13.44 13.28 18.35 18.84 13.16 14.63
17.29±2.79a 16.75±2.45a 16.43±1.07a 17.25±0.63 18.08±0.41a 14.01± 0.52 a 14.02±0.27 14.03±0.33a 16.1±0.66
Total
Average of mean 17.02±1.66
Key: R1 , R2 , R3 denotes replication which contains composite of 5 sample plots. Means with the same letter (a) is significantly different with each other at p≤ 0.05 according to Duncan’s Multiple Range Test (DMRT). 3.2 Soil particle density Plantation had an important role in soil binding since a common trend of increment in soil particle density was noticed across the three site floor covering at both depths (Table 2). The mean value of particle density was significantly (p≤ 0.05) less in deforested site (2.64 gm/cc) than that in Garjan (2.79 gm/cc) and Sal plantation (2.88 gm/cc), with no statistically significant variation between the last two types. That means the particle density of soil decreases if any land is deforested and remained deforested for a longer time. The inconsistency in particle density at the study site may be due to the inherent differences among the land-use patterns. The value of one-way ANOVA test on different land-use patterns irrespective of soil depth is F= 1.44 and significance value is 0.27. Table 2: Soil particle density (gm/cc) at two soil depths in Sal plantation, Garjan plantation and deforested site Land-use pattern Sal plantation Garjan plantation Deforested site
Soil depth (cm) 0-10 10-30 0-10 10-30 0-10 10-30
R1
R2
R3
Mean
2.63 3.12 2.63 2.94 2.5 2.77
2.5 2.94 2.5 2.77 2.38 2.63
2.77 3.33 2.77 3.12 2.63 2.94
2.63±0.08 a 3.13±0.11 c 2.63±0.08 a 2.79±0.01 bc 2.94±0.10 2.50±0.07 a 2.64 ±0.01 2.78±0.06 ab 2.77±0.1
Total
Average of mean 2.88±0.12
Key: R1 , R2 , R3 denotes replication which contains composite of 5 sample plots. Means with the letters (a, b, c) are significantly different with each other. Differences are significant at p≤ 0.05 according to Duncan’s Multiple Range Test (DMRT). 3.3 Organic matter concentration in soil Table 3 shows organic matter concentration in soil in both the plantations and deforested site. On Sal plantation, there was significant (p≤ 0.05) difference in organic matter between 0–10 cm and 10–30 cm soil depths. On Garjan plantation and deforested site slightly difference in the concentration was found between depths. The highest value of organic matter was found at surface soil (0-10 cm depth) in both the Sal (2.24%) and Garjan (1.77%) plantations. The content of organic matter was lower in deforested site ranged from 0.23% to 0.31% (average mean 0.27%) respectively. The organic matter on both the plantations and deforested site Rahman. M.H, Bahauddin. M, Kha n. M.A .S.A , Islam. M.J, Uddin. M.B International Journal of Environmental Sciences Volume 3 No.3, 2012
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decreased with the increase of soil depth. In respect of soil d epth (10-30 cm), statistically significant variation among the values of organic matter in Sal and Garjan plantation and deforested site was also found. Visually Garjan plantation contained highest percentage of organic matter (1.67%) followed by Sal plantation (1.41%) and deforested site (0.23%) respectively. Assessment of one-way ANOVA test on different land-use patterns irrespective of soil depth is F= 63.74 and significance value is 4.65. Table 3: Organic matter (%) at two soil depths in Sal plantation, Garjan plantation and deforested site Land-use pattern Sal plantation Garjan plantation Deforested site Total
Soil depth (cm) 0-10 10-30 0-10 10-30 0-10 10-30
R1
R2
R3
Mean
Average of mean 1.825 ±0.18
2.24 1.41 1.77 1.67 0.31 0.23
2.26 1.43 1.81 1.71 0.32 0.24
2.22 1.39 1.73 1.63 0.3 0.22
2.24 ±.01 f 1.41 ±.01c 1.77±0.02 e 1.72±0.03 d 1.67±0.02 0.31±0.01b 0.27 ±0.2 0.23±0.01 a 1.27±1.8
Key: R1 , R2 , R3 denotes replication which contains composite of 5 sample plots. Means with the letters (a, b, c…..) are significantly different with each other. Differences are significant at p≤ 0.05 according to Duncan’s Multiple Range Test (DMRT). 3.4 Soil bulk density Bulk density value of surface soil in Sal plantation was significantly (p≤ 0.05) higher than that in Garjan plantation and deforested site on both the soil depth. The difference in bulk density value in 0-10 cm soil was larger than 10-30 cm soil depth (Table 4). The mean value of bulk density was significantly less in deforested site (1.36 gm/cc) than that in Garjan plantation (1.38 gm/cc) and Sal plantation (1.46 gm/cc), with no statistically significant variation between the last two types. That means the bulk density of soil decreases if any land is deforested and remained deforested for longer times. The value of one-way ANOVA test on different land-use patterns irrespective of soil depth is F= 0.46 and significance value is 0.64. Table 4: Bulk density at two soil depths in Sal plantation, Garjan plantation and deforested site Land-use pattern Soil depth R1 R2 R3 Mean Average of (cm) mean b Sal plantation 0-10 1.61 1.62 1.66 1.63 ±0.02 1.46 ±0.01 10-30 1.31 1.25 1.30 1.28 ±0.02a Garjan plantation 0-10 1.72 1.47 1.46 1.55±0.08b 1.38±0.01 10-30 1.26 1.12 1.24 1.21±0.04a Deforested site 0-10 1.52 1.54 1.47 1.51±0.02b 1.36±0.01 10-30 1.16 1.19 1.26 1.21±0.03a Total 1.40±0.04 Key: R1 , R2 , R3 denotes replication which contains composite of 5 sample plots. Means with the letters (a, b) are significantly different with each other. Differences are significant at p≤ 0.05 according to Duncan’s Multiple Range Test (DMRT). Rahman. M.H, Bahauddin. M, Kha n. M.A .S.A , Islam. M.J, Uddin. M.B International Journal of Environmental Sciences Volume 3 No.3, 2012
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Assessment of soil physical properties under plantation and deforested sites in a biodiversity conservation area of north-eastern Bangladesh
3.5 Soil porosity The study showed that the values soil porosity varied for plantation and deforested sites irrespective of soil depths. The mean value of porosity was significantly (p≤ 0.05) less in deforested site (0.47 gm/cc) than that in Sal (0.48 gm/cc) and Garjan plantation (0.49 gm/cc), with no statistically significant variation between the last two (Table 5). The value of oneway ANOVA test on different land-use patterns irrespective of soil depth is F= 0.05 and significance value is 0.94. Table 5: Porosity at two soil depths in Sal plantation, Garjan plantation and deforested site Land-use pattern Sal plantation Garjan plantation Deforested site
Soil depth (cm) 0-10 10-30 0-10 10-30 0-10 10-30
Total
R1
R2
R3
Mean
Average of mean 0.48 ±0.05
0.38 0.58 0.34 0.56 0.39 0.57
0.34 0.57 0.41 0.59 0.35 0.54
0.39 0.60 0.47 0.60 0.43 0.56
0.37±0.01 a 0.58±0.11b 0.40±0.04 a 0.49±0.04 b 0.58±0.01 0.39±0.03a 0.47±0.04 0.56±0.10b 0 .48 ±0.02
Key: R1 , R2 , R3 denotes replication which contains composite of 5 sample plots. Means with the letters (a, b) are significantly different with each other. Differences are significant at p≤ 0.05 according to Duncan’s Multiple Range Test (DMRT). 4. Discussion and conclusion Present study clearly indicates that tree plantations have great effect on the characteristics of soil physical properties as plantations maintain and adding necessary nutrition into soil through organic matter and its further decomposition. Moisture content was found to be higher in the two plantation sites than deforested site because of the presence of fully and partially decomposed litter covers over the soil, which help to hold the moisture and also gradually decreased in general with the increase of the depth. The evidence of decreasing moisture content with the increase in soil depth was also revealed by Haque (1997); Chowdhury et al., (2007); Shaifullah et al., (2008). Jonston and Alongi (1995) also analyzed that the soil moisture content was higher due to the presence of vegetation. Watt et al., (2005) found significant impact of vegetation on soil particle density in their study on sustainability of plantation forests through identification of site quality indicators influencing productivity in New Zealand. They recorded higher soil particle density in forested land in comparison to that of degraded and barren land which is similar to the findings of plantation soils in present study. Results of the present study described that, on the deforested site, particle density was found lower due to the open surface soil and absence of root activities of the vegetation. On the other hand higher particle density in Sal plantation is due to the presence of more decomposed litter cover in Sal plantation. The amount of organic matter in soils represents a balance between primary productivity, as influenced by environmental conditions (Bulluck et al., 2002) and biologically- mediated decomposition processes (Sanginga et al., 1992; Schroth et al., 2002). The chief source of organic matter in forest soil is from the litter fall from the trees, which particularly more on the surface soil this also true for the present study findings. Osman et al., (2002) worked under Acacia auriculiformis, Acacia mangium, Eucalyptus camaldulensis, Pinus caribea and Dipterocarpus costatus plantations of Chittagong and Cox’s Bazar Forest Divisions of Rahman. M.H, Bahauddin. M, Kha n. M.A .S.A , Islam. M.J, Uddin. M.B International Journal of Environmental Sciences Volume 3 No.3, 2012
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Bangladesh found organic matter content in the 0-15 cm soil depth ranges from 0.53 to 0.63%, 0.45 to 0.59%, 0.50 to 0.72%, 0.41 to 0.64% and 0.31 to 0.55%. On the deforested land, bulk density was found lower may be due to the open surface soil and absence of root activities of the vegetation. Bulk density was found in Sal plantation than Garjan due to the presence of more decomposed litter cover in Sal plantation. Brown and Lugo (1990), Davidson and Ackerman (1993), Rosell and Galantini (1997), Batjes and Dijkshoon (1999), Feller et al., (2001) reported higher soil bulk densities from natural forests to cultivated areas. Mongia and Bondopadyay (1994) reported that the replacement of virgin forest with highly valued plantation species viz., Pterocarpus dalbergiodes, S. robusta, T. grandis and Elaeis guinensis plantation in Andaman led to a rapid deterioration in soil physical properties and found that bulk density of the surface soil increased to 1.30 gm/cc, 1.49 gm/cc, 1.35 gm/cc and 1.28 gm/cc in plantations respectively, compared to bulk density of 1.05 gm/cc in the virgin forest. Singh et al., (2001) found highest bulk density in both degraded and slightly degraded land compared to undisturbed site. Finally, considering all of the soil physical parameter, it is understood that Sal (S. robusta) plantation is more suitable for this site than Garjan (D. turbinatus) plantation. The study concluded that an in-depth knowledge of the local soil characteristics and associated soil biology is essential for a better prediction and management of long-term potentiality of forest. So, further study needs to carry out on the impact of vegetation and land use variation on biological properties and erosion rate of the forest soil and seems this study will be help the forest authorities to future management aspect as a base line study in this eco-park. 5. References 1. A.D. Mongia., & A.K. Bandyopadhyay., (1994), Soils of the tropics, Vikas Publishing House Pvt. Ltd., Jangpura, New Delhi, India, pp 202. 2. Al-Amin M, Alamgir M, & Patwary M R A., (2004), Composition and status of undergrowth of a deforested area in Bangladesh, Asian journal of plant sciences, 3(5), pp 651-654. 3. Bahauddin M., (2008), Assessment of tree diversity of Tilagarh Eco-Park, Sylhet. BSc (Hon’s) Dissertation, Department of forestry and environmental science, School of agriculture and mineral sciences, Shahjalal university of science and technology, Sylhet, Bangladesh. 4. Batjes N H, & Dijkshoorn J A., (1999), Carbon nitrogen stocks in the soil of Amazon Region, Geoderma, 89, pp 273-286. 5. Bangladesh Bureau of Statistics/United Nations Development Programme (BBS/UNDP), (2005). Compendium of environment statistics of Bangladesh, Ministry of planning, Government of the people’s republic of Bangladesh, Dhaka, Bangladesh. 6. Bangladesh Forest Department (BFD), (2008), Ministry of environment and forest, Government of the people’s republic of Bangladesh, Dhaka, Bangladesh. http://www.bforest.gov.bd. Accessed 2 July 2011. 7. Brown S, & Lugo A E., (1990), Tropical secondary forests, Journal of tropical ecology, 6, pp 1-32. Rahman. M.H, Bahauddin. M, Kha n. M.A .S.A , Islam. M.J, Uddin. M.B International Journal of Environmental Sciences Volume 3 No.3, 2012
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8. Bulluck L R, Brosius M, Evanylo G K, & Ristaino, J B., (2002), Organic and synthetic fertility amendments influence soil microbial, physical and chemical properties in organic and conventional farms, Applied soil ecology, 19, pp 147-160. 9. Chowdhury M S H, & Koike M., (2010), An overview on the protected area system for forest conservation in Bangladesh, Journal of forestry research, 21(1), pp 111–118. 10. Chowdhury M S H, Halim M A, Biswas S, Haque S M S, Muhammed N, & Koike M., (2007), Comparative evaluation of physical properties in soils of orange orchard and bushy forest in Chittagong Hill tracts, Bangladesh, Journal of forestry research, 18 (3), pp 245−248. 11. Davidson E A, & Ackerman I L., (1993), Changes in soil carbon inventories following cultivation of previously untilled soils, Biogeochemistry, 20, pp 161-193. 12. Duncan D B., (1955), Multiple ranges and multiple F-tests, Biometrics, 11, pp 1-42. 13. Huque F M I, & Alam M DU., (2005), A handbook on analyses of soil, plant and water, Bangladesh-Australia Centre for Environmental Research (BACER-DU), Dhaka, Bangladesh, pp 246. 14. Feller C, Albrecht A, Blanchard E, Cabidoche Y M, Chevalier T, Hartmann C, Eschenbrenner V, LarreLarrouy M C, & Ndandou J F., (2001), Soil organic carbon sequestration in tropical areas. General considerations and analysis of some edaphic determinants for Lesser Antilles soils, Nutrient cycle of agro ecosystem, 61, pp 19-32. 15. Lutz H J, & Chandler R F., (1946), Forest soils, John Wiley and Sons, New York, U.S.A. pp 514. 16. Haque S M S., (1997), Afforestation effects on former agricultural soils. Ph.D. Dissertation, Department of plant and soil science, University of Aberdeen, U.K., pp 269. 17. Ivonin V M, & Zasoba V V., (1989), Soil Conservation functions of Steppe forest plantation, Soviet soil science, 21, pp 26-38. 18. Khair A., (2006), Ecopark. Banglapedia: National Encyclopedia of Bangladesh. Asiatic Society of Bangladesh. Ramna, Dhaka. http://www.banglapedia.org/httpdocs/HT/ E_0019.HTM.Accessed 2 July 2011. 19. Khan M A S A, Uddin M B, Uddin M S, Chowdhury M S H, & Mukul S A., (2007), Distribution and status of forests in the tropics: Bangladesh perspective, Proceedings of the Pakistan academy of science, 44(2), pp 145–153. 20. Mukul S A, Uddin M B, Uddin M S, Khan M A S A, & Marzan B., (2008), Protected areas of Bangladesh: Current status and efficacy for biodiversity conservation. Proceedings of the Pakistan Academy of Science 45(2), pp 59–68. 21. Nelson D W, & Sommers L E., (1996), Total carbon, organic carbon and organic matter. In: Methods of soil analysis, Part 3- Chemical methods. Soil science society of America, Madison.
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Assessment of soil physical properties under plantation and deforested sites in a biodiversity conservation area of north-eastern Bangladesh
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