جستجوی مقالات مرتبط با کلیدواژه « Forage production » در نشریات گروه « آبخیزداری، بیابان، محیط زیست، مرتع »

Due to the extensive area of rangelands and constraints in time and cost, direct estimation of rangeland production through plot sampling becomes impractical. Therefore, indirect methods, such as estimating phytomass from plant dimensions, have been proposed. However, determining the optimal sample size for the clipping and weighing method poses a challenge. This study aimed to determine the minimum required sample size for this method and explore its impact on correlation and regression tests.

The study was conducted in four areas within the carbon sequestration project of Hossein Abad Sarbisheh, South Khorasan Province. Sampling was carried out during the full growth period of Atriplex canescens (Pursh) Nutt, a key plant species in the project. Initial sampling involved 10 samples to calculate the required sample size. A random individual of Atriplex was selected in each row, and its dimensions were measured. The entire aerial part of the plant was then clipped to estimate phytomass, which was subsequently weighed after drying. Correlation and regression tests were conducted to assess the relationship between plant dimensions and phytomass. Sample size was determined using power analysis with effect size, test power (60% and 80%), significant level of 0.05, and alternative hypothesis. The sample size was also determined through the drawing method. Subsequent samplings were conducted with increased sample sizes of 20 and 30. Coefficient of variation (CV) was used to evaluate sampling accuracy, and various model selection criteria were employed after regression analysis.

Initial sampling of 10 samples showed no significant correlation between height and phytomass of Atriplex (R = 0.45, t (8) = 1.42, p > 0.05 (2-tailed)). However, with increased sample sizes of 20 and 30, significant correlations were observed (R = 0.67, t (18) = 3.84, p < 0.01 (2-tailed)) and (R = 0.62, t (28) = 4.15, p < 0.01 (2-tailed)), respectively. The power of correlation and regression tests increased with larger sample sizes (correlation test power: 0.27, 0.93, and 0.99; regression test power: 0.29, 0.97, and 0.98, respectively). Harvey-Collier test indicated significant linear relationship between height and phytomass in the data of 20 samples (p > 0.05), but not in 30 samples (p < 0.05). A sample size of 23 to 36 was recommended to achieve 60% and 80% power. Sampling accuracy in plant height measurement was higher than phytomass, and it decreased as the number of samples increased.

The power of correlation and regression tests from 10 initial samples was found to be less than 0.50%, which is generally not recommended for conducting studies. The study suggests that using 10 samples is not advisable. Additionally, increasing sample size led to higher coefficient of variation (CV) for height and phytomass, indicating reduced sampling accuracy. In rangeland research, fatigue and decreased precision in subsequent estimations and samplings were observed. The drawing method was found insufficient in determining the required sample size for estimating Atriplex phytomass.

Rangeland create various products and services for the users, but currently livestock grazing (forage) is considered the first priority for the exploitation of rangeland. Paying attention to the differents types of services provided by rangeland and determining the economic value of these services helps managers in improving planning and optimal management, creating jobs and increasing the income of users. The purpose of the current research is to investigate the economic value and compare the income of forabge and medicinal production of Jalambadan rangeland in Joveyn County.

In order to determine the homogeneous areas of vegetation and to study more accurately and easily different parameters related to rangeland production, the rangeland was classified. Then the floristic list of plant types was prepared. Vegetation sampling was done in the representative area of each vegetation type using six 50-meter transects and 1×2 rectangular plots, and the number of plots was estimated to be 368 based on Cochran's formula. In order to calculate the annual plant production in each type of rangeland, the double method was used. Based on this, the amount of fodder production has been estimated in all the plots and only 25% of the plots were cut. In this research, 50% exploitation limit is considered. The estimation of the production of medicinal plants is different according to the organ used for them. Therefore, after identifying medicinal plants and edible organs, the appropriate production estimation method was chosen. Alternative cost method was used for economic estimation of fodder production. Therefore, among the exchangeable plants, the barley plant has been chosen as an alternative product due to its exchangeability in global and local markets. The market price method was used to determine the economic value of medicinal plants.

Six plant classes and 119 plant species were identified in the study area. The results showed that the total forage production rangeland was 1180 tons in the entire area of the and the available forage was 590 tons, and the average forage production per hectare of Jalambadan rangeland was 144 kg. The economic value of fodder available in the entire area of pasture is equal to 805,775,000 Tomans.  The economic value of each hectare of rangeland in terms of available forage was estimated as 98,241 Tomans. According to the results, the production of available medicinal plants is equal to 256 tons and its economic value is equal to 2,845,000,000 Tomans in 2019. The income of medicinal plants after deducting harvesting costs in 2019 was 1,440,000,000 tomans. The medicinal plants income per hactare estimated 175,672 Tomans. The results show that the exploitation of medicinal plants has 1.78 times higher income than the exploitation of forage plants.

Exploitation of medicinal plants is an activity with high economic value and is a good source of income for rangeland users. In addition to forage, as a source of income for the pastoralists, the harvesting of medicinal plants and their processing can be developed to reduce the pressure on the rangeland.

Fires occur as a threatening factor in natural resources on a large scale every year. This study aimed to determine the quantitative of fire effects on rangeland plants and determine the resistance of different rangeland species to fire to rehabilitate rangeland areas. This research was conducted in the rangeland site of Kaboudeh Olya village of Kermanshah province. This site was burned in 2016. A control rangeland with similar ecological characteristics and topography was selected in the adjacency of the burned site. Then, by determining the area of burn and control and using Random-Systematic Method, four 50-meter transects and 10 fixed 1×1 plots were established during three years (2017-2019). Statistics and evaluation of density, forage production, canopy cover, condition, and tendency of rangelands were done. Data were analyzed by SPSS software, and the means were compared with the Duncan test at a 5% level. The results showed a significant difference between control and fire treatments at 1%. Perennial grasses and herbaceous forbs in control and fire areas had a significant mean difference for density and canopy cover at 1%. Fire is affected perennial grasses and forbs by reducing the average canopy and production and indicates the sensitivity of this form to fire. The vegetative form of bushes had a significant difference at 1% for density and 5% for crown coverage in the two fields of control and fire. In the field of fire, the density, canopy, and production of bush plants had decreased. The fire had changed the species composition, removed or reduced the density and biomass of bushes and shrub plants. On the contrary, the fire caused an increase in the density, canopy cover, and production in annual grass and herbaceous plants. Fire-resistant species included perennial grass (Hordeum bulbosum and Elymus hispidus).

Calculating rangeland capacity and determining the allowable use for important rangeland species is necessary for sustainable range management. By having the rangeland capacity and presenting accurate management plans, the destruction of vegetation and soil and the reduction of water resources can be prevented. Suitable grazing intensity causes continuous and economic use in the rangeland. Therefore, a study was conducted on the effects of different harvest intensities on forage production of three species Halocnemum strobilaceum, Desmostachya bipinnata, and Aeluropus lagopoides Hormozgan province three years from 2008 to determine the most appropriate level of exploitation. Experimental treatments included four harvesting intensities of 25, 50, and 75% and control (without harvest). In each treatment, ten rootstocks of the species were considered replicates and evaluated on each of the dependent variables. The results were analyzed in SAS software. The results showed that harvest intensity affected the forage production and all treatments were significantly different from the control. Therefore, up to 50% of the allowable use for Aeluropus lagopoides and Desmostachya bipinnata, and up to 75% for Halocnemum strobilaceum is suggested to maintain the health and vigor of these species during the harvest years. According to the above findings, this allowable use can be considered for similar areas in terms of climate together with information about other plants.

One of the objectives in rangeland management is the accurate and rapid determination of forage production to determine grazing capacity. The relationship between forage production and morphological characteristics was investigated in this study. For this purpose, two grazed and non-grazed units were selected in the mountainous rangelands of Nazlouchay, Urmia. In each of them, the morphological characteristics of A. aucheri, as the only dominant plant species that accounts for more than 50% of the plant composition, were measured within 60 one-square-meter plots located along with 100-meter transects in July 2017. After cutting off bases growth, the dry weight of the samples was determined, and its regression relationship with morphological characteristics was examined using hierarchical regression. The results showed that it was possible to estimate A.aucheri  production in the unit where the plant bases were not grazed using multiple linear regression models based on diameter, average crown size (D1), collar diameter (D2), and height (H). In the grazed units, where plant bases were grazed in the fall of last year, only the average diameter of the crown (D1) and height (H) was validated with multiple linear regression models, as the best model with RMSE equal to 3.53 and coefficient of 0.52. Due to the relatively good performance of the model and the preference for combining several morphological features in production estimation, separating models into inside and outside the exclosure can play a role in rangeland monitoring and production estimation to calculate grazing capacity and assess the intensity of rangeland utilization.

(Festuca ovina) is one of the most important and palatable rangeland species in the rangelands of Mazandaran province and has a wide range of distribution in mountain rangelands that, in addition to nutritional value for livestock, plays a role in the breeding and rehabilitation program of mountain rangelands. Due to the importance of this species, several populations of F. ovina species, whose seeds were collected from different rangelands of the province, were planted in plastic trays. After germination and a short period of operation, in early spring, in the area of Poshtkuh research station in the southeastern heights of Sari, they were planted on two 20-meter-long lines so that 40 bases of each accession were placed on the planting line. Their spacing on rows of 50 m and line spacing of 1 m were considered. The experiment was conducted during 2011-2015. The evaluation began in the spring of 2013. Evaluation criteria for plant selection were phenological stages, plant height at the time of cluster emergence, canopy level, forage production, and seed production. Various phenological stages, including vegetative stage, flowering, seed formation, and fall regrowth, were recorded with weekly reference from the bases that have been nailed for this purpose. The obtained data were statistically analyzed in SPSS16. The results of the combined analysis of variance of the data related to the performance of the evaluated factors showed that there is a significant difference at the level of (p≤0.01) between the six populations of the studied species. The highest amount of canopy cover, plant height, viability, seed production, and forage production is related to the population of Siahsang rangeland, and the lowest values of the mentioned factors are related to the populations of Kangeloo and Doona rangelands. Therefore, to produce and strengthen forage vegetation, the seeds of this population can be used in the mountain rangelands of the central regions of Mazandaran province.

Regardless of rangeland plant production, it is not possible to plan and manage livestock and rangeland. Attention to rangeland forage production is essential for efficient and effective rangeland management. This importance is determined by identifying the relationship between forage production of plants and climatic variables which affect them in the field. For this purpose, the annual forage production values of rangeland index species were measured in Omidabad Eastern site during the years of 1998-2008 for 10 years in the national plan for rangeland assessment of different climatic zones and their re-measurement during the years of 2017-2018 for two years by cutting and weighing in 60 random plots of two square meters along four 300-meter tracts. The amount of rainfall and monthly temperature in this time interval were also calculated using the data of Abadeh meteorological station in all months separately each year. The amount of annual dry forage production of each species as a dependent variable and the amount of rainfall and temperature calculated as independent variables and relationships between them were investigated using a linear multivariate regression program in SPSS software. The results showed that rainfall, winter, and fall temperatures had a significant effect on species production and spring rains as well as the temperature of the growing season, in April and May, alone did not affect the forage production of the species and based on the results research, with the availability of rainfall and temperature data, the annual forage production of the studied species and the annual production of the coming years can be estimated with high accuracy.

Invasive species are the major threats to natural ecosystems worldwide. Pteridium aquilinum has the widest distribution of any pteridophyta in the world. This study aimed at investigating the impact of Pteridium aquilinum invasion on species composition, richness and diversity, and forage production in summer rangelands of Bandpay Babol, Mazandaran province, Iran. Vegetation was sampled in four invaded vegetation types including Fagus orientalist forest, Crataegus shrubland, Crataegus+Berberis shrubland, and rangeland. Also, vegetation sampling was done in surrounding uninvaded rangelands. The cover of species was estimated in 1 m2 plot for herbaceous and 25 m2 for shrubs. In all plots, the cover of P. aquilinum was estimated and then all fronds were cut at ground level, counted and frond length was measured. The forage of palatable species was measured by clipping and weighing. Findings showed different species composition among invaded and uninvaded areas. A total of 25 species were found only in invaded areas whereas only 11 species were detected in surrounding uninvaded rangelands. Cover, density and height of P. aquilinum fronds significantly influenced the species composition. Annuals significantly decreased by Pteridium aquilinum invasion. Except for Crataegus+Berberis shrubland, in other invaded areas the forage production was not significantly different from that in surrounding uninvaded rangeland. There was a reduction of desirable rangeland species due to P. aquilinum invasion. Also, we found that species richness significantly increased when invaded by Pteridium, while the diversity significantly decreased. The current understory floristic composition showed a low potential to support future restoration after P. aquilinum control. This result emphasizes the need for adding the seeds of desirable species

Rangelands as a source of meat, forage, water and soil play a significant role in the country's economy, but the increase in the number of livestock and livestock in the rangelands has eliminated the balance between production and harvest. In this research, the effect of rangeland projects on various indices such as plant diversity, condition, rangeland trend, production and canopy cover percentage in five rangeland (Tajrud, Sangolabad, Ali Abad, Garmab and Dochahi) located in Torbat Heydarieh county has been investigated. For this purpose, after measuring the mentioned indices in the rangelands (treatment) and their adjacent sites as a control, statistical analysis were performed using t-test. The results of the comparison of the mean vegetation percentage indicate that the canopy cover percentage of the planted area with the rate of 51/64% is higher than the ungraded area with a rate of 47.5% with a significant canopy at 5%. Also, despite the high number of production in the area with a plot (73.08 kg / ha), compared to the area without design (67/99), this difference is not significant. The average score of the score for the area inside the project (27.4) and outside the plan (23.4) are not statistically significant with each other. The implementation of rangelands in three regions from all five regions has been proven to negatively affect rangeland tendency. Also, the implementation of the rangeland scheme has significantly increased the Shannon-Wiener heterogeneity indices and Simpson's uniformity in the design, rangeland has not changed significantly in the Margalaf richness index.