Showing 6 results for Forestation
F. Kiani, A. Jalalian, A. Pashaee, H. Khademi,
Volume 11, Issue 41 (10-2007)
Abstract
To investigate the degree of forest degradation and the effect of land use change on selected soil quality attributes in loess-derived landforms, samples were taken from different land uses including forest, rangeland, degradated rangeland and farmland in Pasang watershed located in the Galikesh area of Golestan province (37°16'N, 55°30'E). The annual average temperature and mean precipitation of study area were 15°C and 730 mm respectively. Organic matter, pH, EC, CaCO3 and nutrients (N, P, K) as chemical indicators, hydraulic conductivity, bulk density and porosity as physical indicators and soil respiration as biological indicator were measured. The results showed that the amount of organic matter decreased three percent when it was turned from forest to farmland, and increased two percent from farmland to rangeland. The amount of CaCO3 in surface layer of deforested area was more than in the forest soils. The amount of soil N in forest and soil P and K in rangeland were higher than in other land uses. Bulk density and porosity in forest and MWD in rangeland were higher than in other land uses because of the decrease in organic matter due to farming activities. Soil respiration in forest was highest as compared to in other land uses. Difference of enzymes activities (L-asparaginase and Dehydrogenase) compared to microbial respiration indicates that enzymes activity is related to specific biological processes while soil microbial respiration basically depends on the general activity of soil microbial population. It could be concluded that amount of organic matter, soil N, bulk density, porosity, MWD, soil respiration and enzymes activities are suitable indicators for soil quality evaluation in this area.
S.h. Mohammadnejad Kiasari, M. Akbarzade, B. Jafari ,
Volume 11, Issue 42 (1-2008)
Abstract
The research design of elimination trail has performed in the form of randomized completely blocks design with 3 replications and 8 treatments ( species of needleleaves) in Kohsarkande forests of Neka, Mazandaran(North of Iran). For investigation of the plant biodiversity the treatments of needleleaves in this elimination trail, the aforestation of hard woods(Maple) and the bare area were selected. For determination of characteristics of top soil(0-10cm), a total of 24 samples of treatments were taken(per treatment 3 samples) and topsoil chemical properties such as EC, pH, T.N.V, caso4, P, K and organic matter were analized. To determin of plant biodiversity in these treatments Simpson´s index, N2 Hill´s index, Mc Arthur´s index and Shannon-Wiener function were used and for determination of species richness of these treatments Margalef ´s index and Menhinick´s index were employed. The results of this research showed that the treatments of the bare area, Cryptomeria japonica and Pinus pinaster with minimal survival and at least litter covering percentage have the highest biodiversity of plant covering on the floor of these treatments. The treatments of Pinus teada and the aforestation of hard woods(Maple) with maximum survival and the highest litter covering percentage have the lowest biodiversity of the plant covering on the floor of these treatments.
A Esmaeili, F Nasrnia,
Volume 13, Issue 48 (7-2009)
Abstract
Deforestation has been recognized as one of the biggest environmental problems in the world. It is also one of the main elements of land productivity changes and one of the biggest factors which threaten world's environmental diversity. In this study, based on environmental Kuznets theory, factors which may affect deforestation have been investigated. Results obtained from 71 studied countries show that environmental Kuznets curve was not true for them. Population growth helps the speed of deforestation while higher rate of GDP growth decreases its rate. Institutions which help with the improvement of democracy, individual assets, civil right and political liberty can decrease the pressure on natural recourses and deforestation.
Sh Mohammad Nejad Kiasari, M Safaee, Sh Nourozi, H Ahmadian, A Mataji,
Volume 13, Issue 48 (7-2009)
Abstract
Determination of suitable species is the most important factor in success of forestation in unfavorable conditions. One of the least costly and the shortest ways for introduction of adaptable species in an area is recognition of the plants that grow naturally. The objective in this study was to find out the effects of protection and water spreading operations on the quantitative improvement of Greek Juniper seedlings. In this study, the areas of water spreading station (Research station of Poshtkoh Water spreading) and an area in western section of water spreading station (an area as control) along the Poshtkoh watershed were chosen. The research was performed on counting of Greek Juniper (Juniper excelsa) in each of two areas. The ratio estimation method was used in a randomized systematic design in strips with the width of 50 meters and 200 meters apart for registration of qualitative parameters of Greek Juniper (Juniper excelsa). The total surface of areas was 600 ha and inventory with intensity of 16 percent has been done. This study showed that in spite of the less number of Greek juniper trees per ha in the station (0/104) in relation to the number of Greek juniper trees per hectare out of the station (0/666), the number of the Greek juniper seedlings in the station was eight times (8.34) more than the number of the Greek juniper seedlings out of the station. As to the effect of protection and water spreading operations on natural growth and increase of number of Greek Juniper seedlings in the station, forestation using this species in this area is recommended.
M. Ajami, F. Khormali,
Volume 16, Issue 61 (10-2012)
Abstract
In order to study land degradation from the soil genesis and micromorphological perspective, ten soil profiles were dug and described on five slope positions in both forest and deforested cultivated land. The soil samples were taken from all horizons for physico-chemical analysis and micromorphological studies. Forest soils had a well developed argillic and calcic horizons and also mollic epipedon. These soils were classified as Alfisols and Mollisols. Carbonate leaching into the depth of soil profile and translocation of clays to lower layers and formation of developed soils are by no means related closely with the dense forest cover and its subsequent landscape stability and favorable leaching conditions. Dominant soil orders in this area were Inceptisols and Mollisols. In cultivated landuse, no argillic horizon was observed except in toeslope position. Absence of argillic horizon or its elimination following deforestation is one of the most important and obvious pedogenetic evidences of land degradation after land use change. Outcropping of high carbonatic layers (calcic horizon), disappearance of mollic and formation of ochric epipedon, presence of redoximorphic features attributed to runoff in lowland, decrease of solum thickness, and change of soil color were the other pedogenic indicators for land degradation in the study area. Microscopic observations showed that granular and crumb microstructures with high porosity were converted to massive and compact ones with low porosity in the deforested area. Disappearance of clay coatings besides absence of excremental pedofeatures were the other important micromorphological evidences of erosion and land degradation.
A. Ashraf Amirinejad, S. Ghotbi,
Volume 22, Issue 2 (9-2018)
Abstract
The soil quality is defined as the ability of soil to function as an essential part of the human habitat. In this study, the effects of land use change (conversion of forest lands into agricultural lands) on the soil physical quality were studied in the Gilan-e-Gharb region. For this study, soil samples were collected from surface and subsurface layers of both land uses, and the peak and shoulder slope positions, in Miandar and Vidjanan catchments. Soil physical properties such as soil texture and particle size distribution, soil hydraulic conductivity, bulk density, mean weight diameter of aggregates, water holding capacity, and the soil organic carbon content were measured. The results showed that land use change of the forest to agricultural lands resulted in a sharp decline in the soil organic matter (52%) and an increase in silt and sand percentage and soil bulk density. Also, deforestation decreased the mean weight diameter of aggregates (from 0.39 to 0.14 mm in Miandar) and clay percent. It caused a reduction in the total porosity followed by a decrease of soil water holding capacity, and a decrease in the saturated hydraulic conductivity (from 10.34 to 1.86 cm/h), as well. In general, the results proved that the land use change from forest to agriculture severely decreased soil physical quality and its productivity.
