جستجوی مقالات مرتبط با کلیدواژه « plantation » در نشریات گروه « آب و خاک »

This study was carried out in order to investigate the biodiversity of arbuscular mycorrhizal fungi (AMF) in natural oak forest, broad-leaved plantation, needle-leaved plantation, agricultural and rangeland land uses in Lene habitat, Chardavol city, Ilam province. For this purpose, five mixed soil samples were randomly collected from each land use at soil depths of 0-5 and 5-15 cm and the characteristics of soil and AMF were investigated. Wet sieving and sucrose method were used to extract AMF and their identification was done based on spore morphological characteristics such as shape, color, size, number of wall layers, thickness of wall layers and hypha shape. Totally 19 AMF species belonging to eight genera including Glomus, Acaulospora, Claroideoglomus, Rhizophagus, Septoglomus, Dentiscutata, Paraglomus, Entrophospora were identified. The results showed that spores abundance and biodiversity of AMF were different in different land uses. The highest spore density was related to natural forest (78.12), broadleaf forestry (66.28) and pasture (57.48), and the lowest was related to agriculture (50.96) and needle-leaved plantation (28.16). It was also found that the abundance of symbiotic AMF was the highest in the natural forest (16.6) and rangeland (15.8) and the lowest in the agricultural (11.6) and needle-leaved plantation (14.4) land uses. Shannon-Weiner and Simpson's diversity indices in natural forest, rangeland and plantation were significantly higher than agricultural land use. According to the results, there was no significant difference between the two depths of soil samples in spore density and biodiversity indices. The results also showed that the change in land use had negative effect on the diversity and abundance of symbiotic AMF. Therefore, to preserve biodiversity of AMF, it is recommended that natural forests be under more protection.

The current study is conducted to identify and compare soil quality index in different land covers including three afforestation masses (Alnus subcordata, Populus deltoids a Taxodium distichum) and a natural mixed stand (Quercus, Carpinus betulus, Parrotia persica) located in Caspian forest seed center (Amol Province). In each of the masses, along four 200-meter transects, four soil samples (with a 20×20 m2 quadratic sampler with 10 cm depth) at 60-m intervals were taken. A total of 16 samples were collected from each forest. The soil properties including bulk density, organic carbon, total nitrogen, nitrate, ammonium, papulation of earthworms, and soil microbial respiration were measured in vitro. Finally, using the obtained values, rate of mineralization of the soil carbon, as well as the soil quality index were measured for each of the studied masses. ANOVA analysis of the physical, chemical and biological properties of the soil samples, taken from different forest stands, indicated significant statistical difference between them at level of 99%. Alnus Subcordata significantly showed the highest soil quality index (5.84 at 95%). Other masses, i.e. Populus deltoids, natural mixed, and Taxodium with quality indices values of 5.26, 4.66, and 4.40, respectively, were the next ones in the categories. The results indicated the very effective role of Alnus Subcordata forest cover in improving the quality of soil ecosystem.

This study was conducted to compare soil properties and diversity of arbuscular mycorrhizal fungi (AMF) associated with Cercis griffithii in two natural and plantation sites. For this purpose, soil samples were taken from C. griffithii rhizosphere. (0-30 cm) and transported to the laboratory for physiochemical analysis and spore extraction using wet sieving and centrifugation techniques. AMF were identified using morphological features. Furthermore, soil spore density, root length colonization, species richness, Shannon-Wiener and Simpson diversity indices, and Paulo evenness were considered. Significant differences were observed between soil nitrogen, potassium, CaCO3 and organic carbon, clay contents and bulk densities in two studied sites. In natural site, soil organic carbon, nitrogen, phosphorus, potassium and sand were higher but CaCO3 content was lower compare to plantation site. Shannon-Wiener diversity index and root length colonization were significantly different between two studied sites and natural stand had higher values compared to the plantation site. Based on the PCA (Principle component analysis) soil potassium, organic carbon, CaCO3 and soil texture were the most effective factors on stands of C. griffithii.

Land use change in the northern part of Iran has changed the quality of soil. The aim of this study was to investigate the impacts of different kinds of land use/cover, i.e. virgin natural forest, degraded natural forest, alder plantation, sequoia plantation, improved fallow and home garden areas on soil biological characters in plain area of northern Iran. For this, 30 soil samples were taken from a depth of 0-10cm in the studied land use/covers. Density and biomass of earthworm ecological groups, soil nematodes density and the rate of carbon dioxide emission were evaluated from top soil during 4 seasons. Also, some physicochemical properties were measured at the laboratory. The maximum of earthworms density, (3 n m-2), earthworms biomass (38.76 mg m-2), nematodes density (457 in 100 g soil), and the emission of carbon dioxide (0.47 mg CO2-C gsoil−1 day−1) belonged to Alder land cover. In all the studied land use, every three groups of earthworms and nematodes had jointly the highest activity in the spring and autumn, while the highest amount of carbon dioxide emissions was recorded in the summer. PCA showed the highest positive effect the soil pH, nitrogen and nutrients with biological properties. As a result, it can be concluded that plantation with Alder species is a good way to improve biological indicators and maintain soil quality in degraded areas of forests in the northern Iran with similar condition.

Because of deforestation and reduction of forest areas, plantation is a vital issue for now and the future. The evaluation of planted species is very important to creation of forests with better quality and quantity in the future. Soils, as an important part of the ecosystems, are affected by tree species with differences aboveground and below ground biomass, under same field condition .Biological properties are good indices to assessment of soil quality and health. In this study the effects of different forest covers including natural forest, hardwoods and softwoods plantations, on variability of fine roots biomass, ecological group's earthworm's density/biomass and nematodes abundance were considered.
Soil samples were excavated in sixteen points from 0-15 cm (top soil) depth, for each forest covers including Carpinus betulus (hornbeam) - Parrotia persica (iron wood) as a natural stand, Fraxinus excelsior (ash), Acer velutinum (maple) hardwoods and Pinus brutia (pine), Cupressus sempervirens (cypress) softwoods plantations, located in Wood and Paper Company of Mazandaran. Soil moisture, pH, organic carbon, total nitrogen and biological indices (fine roots biomass, earthworm's density/biomass and nematodes abundance) were measured and recorded at the laboratory.
ANOVA results for soil physico-chemical properties showed significant statistical differences related to forest covers. So that the highest values of soil moisture, organic carbon and C/N ratio were found under pine plantation. Also the higher values of soil pH and total nitrogen were detected in Carpinus betulus - Parrotia persica natural stand. Greater amounts of fine root biomass (89.68 g m-2), earthworm's density (1.81 n m-2)/biomass (24.17 mg m-2) and nematodes abundance (603.37 n m-2) were found in Carpinus betulus - Parrotia persica natural stand. Also maximum epigeic density (1.43 n m-2)/biomass (19.25 mg m-2), were found under Carpinus betulus - Parrotia persica natural stand and ash plantation. Higher anecic earthworm's density (0.37 n m-2)/biomass (4.92 mg m-2) recorded in Carpinus betulus - Parrotia persica natural stand. The endogeic species were not observed under different forest covers. Greater amounts of nematodes abundance (603.37 n m-2) were recorded in Carpinus betulus - Parrotia persica natural stand. The finding of correlation between biological indices and other studied properties indicating that biological characters are influenced by soil water content and chemistry under different forest covers.
The findings of this study are showing the considerable effect of natural forest covers on soil biological properties and quality. In addition, in degraded areas of northern Iran, planting of Fraxinus excelsior species can be considered due to improvement and conservation of soil biological indices, quality and health.