جستجوی مقالات مرتبط با کلیدواژه "rangeland plants" در نشریات گروه "آبخیزداری، بیابان، محیط زیست، مرتع"

Agropyron pectiniforme and Elymus hispidus var hispidus are important and palatable species in Mazandaran province rangelands. This study aimed to select top populations for forage production and use them in rangeland breeding and rehabilitation programs. Seeds of native populations of Agropyron pectiniforme and Elymus hispidus var. Hispidus was planted in reticulated plastic trays and operated after emergence for a short period. In early spring, in the area of Poshtkuh research station in the southeastern altitude of Sari, were planted on two lines (repetitions) with a length of 20 meters so that 40 plants of each accession were placed on the planting line. Their distance on planting rows was 0.50 m, and the distance between the lines was considered one meter. The experiment was conducted during the years 2011-2015. In the first and second year, no plant data were recorded because of plant establishment. Evaluation criteria for plant selection were plant height at the time of cluster emergence, canopy cover, survival rate, forage production and seed production. Different phenological stages including vegetative stage, flowering, seed formation and fall regrowth were recorded in 7-10 days. The obtained data were statistically analyzed in SPSS16 software. The results of combined analysis of variance of data related to the performance of the evaluated factors showed that there was a significant difference at the (p < /em><0.01) between the populations of the studied species in terms of forage production yield, longitudinal growth, canopy cover, survival percentage, seedling strength, and seed production. There was no significant difference between different years in terms of the studied factors. There is a difference between some populations of the studied species in terms of phenological stages and these populations; the phenological stages have a delay of about seven days. Therefore, to produce and strengthen forage vegetation, the seeds of these populations can be used in the mountain rangelands of Mazandaran province.

Soil compaction reduces pore space in the soil and subsequently diminishes the diameter of capillary tubes in the soil. This limits the plantchr('39')s access to minerals and pore water. Hence, it is necessary to evaluate soil compaction in order to improve rangeland’s management as well as agricultural lands. In this study, soil compaction effect on root growth of five rangeland plant species, Ferula gummosa, Agropyrin elangatum, Medicago minima, Atriplex canescens and Atriplex lentiformis, at laboratory scale was investigated. First, three soil compaction levels (0.36, 0.47 and 0.56 persentage of porosity) for a loam-clay soil were provided using hammer dropping method within plastic pots. In the next step, three seeds from each species were cultivated in each plastic pot with three replications. After a period of 60 days, the length of main and subsidiary roots were measured. One way ANOVA test method was used for statistical analysis of data. Results shows a linear relationship between soil compaction and growth of main and subsidiary root for cultivated species. So, with decreasing in soil compaction degree, the growth of main and subsidiary root was significantly increased. Comparison of main and subsidiary root growth of the studied plant species showed that the growth of main root of Atriplex canescens was higher than other species in all soil compaction levels. Moreover, Atriplex canescens was only species in which its subsidiary roots length was not significantly different in all soil compaction levels. Also, in two plant species of Medicago minima and Atriplex lentiformis, there is not significantly different between the growth of their main roots in all soil compaction levels. Results showed that subsidiary root number increased with reducing soil compaction. The highest percentage of measured frequency in all plants is related to the subsidiary roots of 0-100 cm in porosity of 56%. Therefore, by increasing the amount of porosity and consequently increasing soil porosity, the conditions for longitudinal growth of the roots of rangeland plants are provided. However, the rate of root growth changes in the subsidiary roots is far greater than the main root.

Knowledge of preference value of plant species is one of the essential requirements for determining forage available and consequently, calculation of grazing capacity for rangeland habitats. This project was investigated in 36 species including of 21 perennials and 15 annuals species. For this purpose, during four-years period (2007-2010) in each month of the growing season (spring and summer) film was taken from a non-pregnant and non -lactating unit adult ewes (Lori)for at least 1800 seconds with an average weight of 50 kg inside the flock which were grazing in rangeland. Results indicated that annual grasses such as Boissiera squarrosa, Bromus danthonia, Bromus tectorum, Heteranthelium piliferum had the highest grazing time with a total duration of 3083 seconds compared to other species. Subsequent species including of Agropyron trichophorum with 2594 seconds, Bromus tomentellus with 1232 seconds, Onobrychis melanotricha with 681 seconds, broadleaf herbaceous annual such as Helianthemum ledifolhum, Viciea peregerina, Diplotaxis erucoides, talaspi perfoliatum, Minuartia obtusiloba with 670 second and Hordeum bulbosum with 565 second were ranked in the next. Finally, it was found that annual grasses and shrubs in May, perennial grasses in June, and broadleaf herbaceous annual in July have quite palatable and located in Class I. Also, total grasses and perennial forbs in July, annual forbs and shrubs in May and June have fairly palatable respectively which have located in class (II) and vegetative forms have palatable class III in other months.

Soil contamination by heavy metals is a major environmental problem in the world. In polluted environments, especial plant species can grow, adapt, absorb, and uptake heavy metals. This study was carried out to investigate the phytoremediation potential of plant species including Acantholimon olivieri (Jaub. & Spach) Boiss., Astragalus glaucacanthus Fisch., Ebenus stellata Boiss., Scariola orientalis (Boiss) Sojak subsp Orientalis. and Stipa barbata Desf in Ahangaran lead and zinc mine, Malayer Province. For this purpose, in polluted and controlled sites, the sampling of aerial and underground tissue was performed in a completely randomized block design with three replicates in summer 2015. The results indicated that in polluted sites, lead and zinc concentrations in aerial and underground tissues were higher as compared with control site. Among the study species, Astragalus glaucacanthus Fisch., had the highest value of lead and zinc absorption in aerial tissue (118.6 and 190.69 mg/kg dry matter, respectively) and Scariola orientalis (Boiss) Sojak subsp Orientalis., had the highest value of lead and zinc absorption in underground tissue (41.07 and 67.76 mg/kg dry matter, respectively). Also, Astragalus glaucacanthus Fisch., Acantholimon olivieri (Jaub. & Spach) Boiss., and Ebenus stellata Boiss., had the highest translocation factor of lead (3.39, 3.19, 3.16) and zinc (3.24, 3.06, 2.92), respectively. Our results clearly showed that these three mentioned species could be used to refine the soils polluted to lead and zinc in similar conditions.

Total Petroleum Hydrocarbons are toxic and persistent pollutants that is a fundamental threat to the ecosystem. Phytoremediation, the use of plants for remediation of contaminated soils, effective and affordable way to reduce soil pollution. In this study, the potential pasture plants Agropyron intermedium and Dactylis glomerata on phytoremediation of soil contaminated with crude oil at different concentrations (20, 30, 40 and 50 percent) for 120 days were studied. At the end of the study, changes in biological factors (shoot height, shoot dry weight and root dry weight) of each species and changes petroleum hydrocarbons in soil were measured and results were analyzed using SPSS software. The process of decay kinetics curves percent of petroleum used to calculate the time it takes to analyze petroleum hydrocarbons were evaluated. The results showed that three main factors biological factors both studied species in treatments were significantly different compared to control. Analysis of changes in petroleum hydrocarbons indicated that Agropyron intermedium in the treatment of 20% by reducing the oil in the soil with 79.8 percent and in the treatment of 50% by reducing the oil in the soil with 58.5 percent, the phytoremediation ability of Agropyron is better than Dactylis glomerata. The results of the analysis of soil samples petroleum and fitted with three zero-order kinetic model, first order kinetic and Higuchi model, in both species showed that the first-order kinetic model is the best model to simulate the changes of the hydrocarbon Petroleum soil.

Nowadays, heavy metal contaminated soils is one of the most important concerns of the world and cleaning these soils with minimum environmental damage is necessary especially in urban and agricultural regions through advanced biological methods. Phytoremdiation is one of the modern technologies that could be used in large scale with minimum damage to environment. High concentration of cadmium, as an environmental pollutant, could be harmful for human and animals. Regarding to this reason, a study was carried out on 11 plant species in Irankouh region at three sites including three levels of high, medium and low cadmium contamination. The bioaccumulation of cadmium in shoots and roots of plants, and translocation factor were measured. According to the results, Astragalus glaucanthus, Ebenus estellata and Acantholimon sp. showed the highest values of cadmium concentration (1.40, 1.53 and 1.97 mg/kg dry matter), and also the highest translocation factor (2.09, 1.37 and 12.6), respectively. Because of the high values of biomass and bioaccumulation, these three plants are recommended for phytoremediation of cadmium-contaminated soils under the same conditions.

Determination of grazing capacity in rangelands is an important factor for livestock husbandry. Improved forage quality is an important goal for improving animal performance. The aim of this study was to assess near infrared reflectance spectroscopy (NIR) as a rapid and reliable method for estimating quality parameters in nine range species as three grasses Bromus tomentellus، Agropyron intermedium and Dactylis glomerata، three forbs Achillea millefolium، Coronilla varia، Centaurea virgata and three shrubs Scariola orientalis، Artemisia aucheri and Thymus kotschyanus. NIR calibrations were derived for crude protein (CP)، dry matter digestibility (DMD) and acid detergent fiber (ADF). To maximize variability of samples for analysis، were collected at three phenological stages as initiated growth، full flowering and seed ripening in ranges of central Alborz (Taleghan). Samples were dried and grinded using standard laboratory methods. A sub samples were analyzed using standard laboratory chemical procedures to estimate CP، DMD، ADF and total ash. The other sub samples were scanned by means of a 20-filter set of the Inframatic8620. NIR spectra were recorded for each sample. A separate independent set was used for predictions. The calibrations obtained from this study had a high level of accuracy based on coefficient of determination (R2)، standard errors of calibration (SEC) and standard errors prediction (SEP). SEC were ranged from (0. 15 to 1. 09)، (0. 21 to 0. 86)، (0. 83 to 3. 94) and (0. 52 to 4. 96) and SEP were ranged from (0. 13 to 0. 75)، (0. 17 to 0. 61)، (0. 62 to 3. 34) and (0. 31 to 3. 84) for CP، Ash، DMD and ADF، respectively. The correlation values between laboratory data and NIR prediction was very high for all traits in particular for CP. The results confirm that NIR can use a rapid، precise and cost effective method for measurement quality traits in range species.