Ahmad Zare; Seyed Amir Mousavi
Abstract
An experiment with 10 constant temperatures (5, 10, 15, 20, 25, 30, 35, 40, and 45°C), was conducted in 2019 at the Agricultural Sciences and Natural Resources University of Khuzestan based on completely randomized design (CRD) with 8 replications to investigate germination and determine the cardinal ...
Read More
An experiment with 10 constant temperatures (5, 10, 15, 20, 25, 30, 35, 40, and 45°C), was conducted in 2019 at the Agricultural Sciences and Natural Resources University of Khuzestan based on completely randomized design (CRD) with 8 replications to investigate germination and determine the cardinal temperature of Physorhynchus chamaerapistrum (Boiss.) Boiss. The highest seed germination was 86% at 25°C. Germination percentages at temperatures of 10, 15, 20, 30, 35, and 40°C were 77%, 83%, 85%, 85%, 34%, and 13%, respectively. No germination was observed at 5 and 45°C. The relationship between imbibition time and cumulative germination percentage was described by a three-parameter sigmoid equation. According to this equation, the results indicated that the shortest time required to reach 50% germination (T50) was observed at 25 and 30°C (33 and 34 hours), and the longest at 10 and 40°C (106 and 141 hours). T50 for temperatures of 15, 20, and 35°C was predicted to be 76, 37, and 51 hours, respectively. According to the dent-like model, the base temperature, lower optimal temperature, upper optimal temperature, and ceiling temperature were predicted to be 16.5, 22.91, 29.52, and 43.45°C, respectively. The results of this study showed that this plant could have the highest germination percentage from November to January, considering the growth conditions. Therefore, during these months, plans for managing this rangeland plant (seed dispersal and rangeland restoration) and issues related to grazing management should be considered.
hamed farzi; reza tamartash; zeinab jafarian; Mohammad reza Tatian
Abstract
Restoring vegetation can change the structure and dynamics of vegetation, as well as the change in other parts of the ecosystem such as soil. The success of recovery efforts will be achieved when assessing the characteristics of ecosystems over time and comparing with the control areas. Therefore, the ...
Read More
Restoring vegetation can change the structure and dynamics of vegetation, as well as the change in other parts of the ecosystem such as soil. The success of recovery efforts will be achieved when assessing the characteristics of ecosystems over time and comparing with the control areas. Therefore, the aim of this study was to investigate the effects of reducing plant cover and soil carbonation in rangelands of the southern slopes of central Alborz. Sampling from vegetation during the growing season of May and May was done in a systematic-random manner in 400 plots of 2 m2, along 40 transects of 100 meters. In each plot, crown cover percentage, species presence, functional characteristics of species including vegetative form, distribution type, pollination type and biological form were recorded. During each transect, two soil samples were harvested at different depths of 0-15 and 30-30 cm in different treatment and control areas. A total of 160 soil samples were collected from four different regenerative operations including clamping, seeding, grazing management, grazing and a natural rangeland as a control site. . showed that biological measures significantly changed the canopy cover percentage of three herbs. In the meanwhile, the Graminea strain in the regeneration zone and the legumes of Leguminosae and Cruciferae in the area had a significantly higher mean canopy percentage. The percentage of organic matter and the amount of organic carbon sequstration in the two depths of the soil and bottom of the soil in different biological operations at level have a significant difference.
esmaeil sheida karkaj; javad motamedi; fateme alilu; hamid sirusi
Abstract
Grazing management is one of the basic elements in managing rangeland ecosystems. Proper use of grazing lands in order to achieve optimal efficiency and maintain the sustainability of rangeland ecosystems is the purpose of grazing management. In order to evaluate the response of vegetation to grazing ...
Read More
Grazing management is one of the basic elements in managing rangeland ecosystems. Proper use of grazing lands in order to achieve optimal efficiency and maintain the sustainability of rangeland ecosystems is the purpose of grazing management. In order to evaluate the response of vegetation to grazing in summer rangelands of Chahar Bagh region of Golestan province, vegetation density, vegetation cover and functional properties were measured at five different grazing sites. Thus, using the statistics method of samples and regarding the size of the dominant plants canopy, 20 plots 1*1 meter by using a systematic- random method was considered in order to do sampling in each site and the density, and vegetation cover were recorded within each plot. Finally, parameters were analyzed using Duncan test and analysis of variance and the vegetation compositions of sites were compared using cluster analysis and Jaccard's coefficient of similarity. Results showed that the grazing intensity have significant effect on the vegetation. As grazing intensity increased, the density of desirable species decreased and density of undesirable species increased. So, the enclosure site had the highest desirable species density. Moreover, some functional types such as perennials, Hemicryptophytes, Chamephytes, grasses and decreaser plants significantly reduce with increasing grazing intensity. The greatest increase belongs to grasses with density of 9.8 and class I of palatability with density of 22.8 in enclosure site. Between functional groups, grass life form had the greatest increases in enclosure site with the cover of 19.65 percent. According to results of clustering and similarity index, pen surrounding and watering sites had similar vegetation composition. Enclosure and key area also had similar composition. In general, it can be concluded that increase in grazing intensity has caused negative changes in vegetation in study sites and the changes in watering area, village vicinity and pen area clearly observed. So, using of the management methods in order to improve vegetation indices and pushing it toward balance is recommended.
