جستجوی مقالات مرتبط با کلیدواژه "range improvement" در نشریات گروه "اکولوژی"

The present study was conducted to investigating the effect of ecological factors on the distribution and morphological traits of Reseda lutea L. as a medicinal and industrial plant in rangeland of Darab. Two habitats were selected, and two transects were established in each habitat, ten plots with 2x1 m2 were established. In each plot the number of spurs, the canopy cover and the height of the spurs, and 40 soil samples were taken from the depth of plant rooting to determine soil characteristics. In order to investigate the relationship between morphological traits, density and cover with the soil properties of the habitats, multivariate ranking methods were used. Redundancy Analysis (RDA) method was used to rank morphological traits with environmental factors. All statistical calculations for ranking were done using CANOCO software version 5. The results showed that the coverage percentage and density of the R. lutea are 32.27% and 5.8% respectively. The average of plant height, canopy diameter, inflorescence length and the number of flowering branches are 55.37, 71.65, 35.42 and 63.67 cm, respectively. Spurs is distributed in acidic soils (6.1-7.75), with an average electrical conductivity of 0.62 ds/m and an average of organic carbon of 0.45. The amount of potassium and phosphorus ranges from 110 to389 and 6 to 21 ppm. Spurs is distributed in the altitude range of 1124 to 1225 meters with an average 1179.43. Height and canopy diameter are more influenced by silt and soil OC and less influenced by potassium and phosphorus. The number of flowering branches, density and canopy cover are more influenced by EC and less influenced by height. The results of this study can be used into consideration by natural resource managers in order to investigate the growth of this species in the improvement and restoration of rangeland in similar areas.

Banqueting operations play an important role in the improvement of rangelands. In this regard, the present study was conducted with the aim of investigating the effect of the improvement operation of banqueting on vegetation characteristics in the rangelands of Fasa. Two areas were selected including area with banqueting operation and control, in each area 3 transects with 100 meters length were established. Along each transect, 10 plots of 2 x 2 m2 were established. In each plot, the characteristics of percentage cover and density of all observed species, percentage of stones and pebbles, litter and bare soil were measured. For evaluate plant composition in two areas, plant functional types were used.  Statistical analysis was done using statistical software.  42 plant species were observed in the banqueting area and 33 species were observed in the control area. The results of the t-test showed that there was a significant difference between the canopy percentage, density, litter, stones and pebbles, and bare soil in the banqueting and the control areas (P <0.01). The canopy cover, density of plant species and the amount of litter in the banqueting area increased by 30.57, 3.13 and 3.16%, respectively. The banqueting area has significantly improved the coverage of perennial and annual species compared to the control area. The banqueting area, has improved the palatability classes II significantly compared to the control area. According to the ecological indicators considered in this study, banqueting area operations are recommended to restore vegetation in arid and semi-arid areas.

Astragalus kahiricus is a high quality forage species that has a wide spread in the northeast, north, center, southeast and central part of the Iran. This palatable plant is heavily grazed in all phonological stages by livestock. In this study the effect of rainwater harvesting methods including furrow, pitting and crescent pond and planting season on establishment of A. kahiricus in Kalmand bahadoran were evaluated. The seeds were scratched in vitro according to germination studies. The scratched seeds were compared as split plot design with main treatment of cultivation date in autumn and late winter 2013 and sub treatment of pitting, furrow, crescent pond in three blocks. In the spring, the number of established plant in each plot was counted and analyzed. Based on the results autumn planting been more successful than spring planting. Although 18% of the seedlings were generated in the crescent pond and there were better results than the other treatments, but only 4% of the seeds were established due to drought. Generally low seed establishment suggests that rainfall collecting with seeding in regions with average rainfall less than 100 mm encounters with a high risk. In these areas should be evaluated methods of potted seedlings combined with rainwater harvesting.

Allelopathy has rarely been challenged in range improvement despite being the main concern in the restoration of rangelands. In this research the potential allelopathic impact of Artemisia aucheri on seed germination and the initial growth of Bromus tomentellus and Bromus inermis was examined. For this aim, the aerial parts powder of Artemisia aucheri (stem, leaf and seed) collected from habitats during the flowering stage (the end of November) was prepared. Also, distilled water was used as control. A completely randomized design was carried out using six treatments and four replications in the laboratory of seed ecology at the faculty of natural recourses in 2011. The research results showed a significant effect of the aqueous extracts of Artemisia aucheri on seed germination percentage, seed germination rate, plumule and radicle length, and seed vigor of the two species. The germination percentage, seed germination rate, plumule and radicle length, and seed vigor of Bromus tomentellus and Bromus inermis were significantly reduced under the aqueous extracts of Artemisia aucheri.