جستجوی مقالات مرتبط با کلیدواژه "lime" در نشریات گروه "جنگلداری"

In Hirkan forests, fine-grained clayey soils have created many problems in construction projects, especially road construction, due to their swelling, and have caused the instability of the road surface and as a result, the pavement has been damaged. Fine-grained soils are problematic due to unfavorable technical properties, especially plastic properties, low permeability, low strength, changes in pore water pressure, changes in volume, texture, chemical properties, and grain structure, and may present complex engineering problems for construction. One of the ways to improve the swelling characteristics of the soil is soil stabilization. Soil stabilization is the use of natural or synthetic additives to improve the mechanical properties of soil. Lime and plant waste are cheap, available and easy to use materials.

In this research, a fixed amount of three percent hydrated lime along with reed plant ash from Phragmites australis with a mixing ratio of three, six, nine and twelve percent to the road bed soil of the study area located in the educational and research forest of Sari University of Agricultural Sciences and Natural Resources - Darabkala was added and then soil mechanics tests including: Atterberg limit, standard compaction test, California bear ratio(CBR) test and uniaxial compressive strength(UCS) test were performed in three repetitions after the processing period. In this research, a constant amount of three percent hydrated lime along with reed ash with a mixing ratio of three, six, nine, and twelve percent was added to the road bed soil of the study area.

The results show that the liquid limit and plasticity index decreased and placticity limit of the soil increased. The maximum dry weight of the samples decreased with the increase of reed ash, and the highest value of 14.52 KN/m3 was recorded and the lowest value of 11.97 KN/m3 was recorded in the soil sample with 3% lime and 12% reed ash. In CBR test, an increasing trend was recorded from 4.9% to 9.7% in the soil sample containing 3% lime and 12% reed ash. The result of the uniaxial compressive strength test in three time periods of 7, 14 and 28 days on the samples shows that the highest value of uniaxial compressive strength is 2.6 Kg/cm2 in the sample containing 3% lime and 6% reed ash after 28 days.

Based on the findings of this research, it was concluded that reed ash can be used as a suitable pozzolanic material to stabilize the bed soil of the forest roads in the study area, and the ratio of three percent lime and six percent ash can be used for 28 days to stabilize the bed clay.

Nowadays, the oak decline phenom in the Zagros region of Iran has converted into a serious crisis that needs more attention and research to provide forest managers with solutions. The aim of the study was to understand the soil quality and leaf nutrients of declined oak stands (Quercus btantii) in the Kohmareh Sorkhi region. To do so, soil samples were taken from the under of the healthy and declined trees’ crowns and then soil characteristics including moisture content, pH, electrical conductivity (EC), organic carbon, nitrogen, phosphorus, potassium, gypsum, calcium carbonate, calcium, and magnesium contents were measured and compared. Morover, NPK content was measured on taken leaves from each trees. The results indicated that soil moisture, EC, gypsum, lime, P, K, Ca, and Mg contents had significant differences. Although gypsum and lime contents were higher in the declined stands compared to the healthy ones, moisture content, EC, P, K, total Ca, and Mg content were higher in the healthy stands. The leaf nutrient statistical analysis demonstrated that the dieback individuals suffer phosphorus shortage, but N and K content were the same as the healthy ones. Given that some shortages were observed in the nutrient elements such as P, K, Ca, and Mg in soils under the crown of declined trees and P in their leaves, it seems that the nutrient shortage has an important role in the oak decline since the greatest shifts were recorded for which.

Knowledge of soil chemical properties is important for understanding its engineering characteristics in road construction. Reflectance spectrometry is a non-destructive, fast and environment friendly method, but unfortunately no research has been conducted to use this tool to estimate the forest soil characteristics in Iran. The present study was conducted to investigate the ability of VNIR spectrometry to estimate some chemical properties including organic matter, CaCO3, pH and EC in the forest soil. For this purpose, 45 soil samples were collected from Namkhaneh series in Kheyroud Forest and those properties were measured by standard methods. The reflectance of sample was measured in dark room using Fieldspec ASD spectroradiometer. PLSR (Partial Least Squares Regression) method was used to predict soil properties in reflectance and first derivative mode. The results of RPD shows that OM has a very good estimate in two modes of reflectance spectra and derivative reflectance spectra (PRD>2) and pH, EC have acceptable estimate (1.42), but CaCO3 has poor prediction in two modes of reflectance spectra and derivative reflectance spectra (PRD<1.4). In general, based on the results of this study, spectrometry can be used to predict the above-mentioned properties except CaCO3 as a fast and an acceptable method and this method can simultaneously estimate several soil properties.