Mohammad Daneshi; Mojgansadat Azimi; Hamid Niknahad Gharehmakhor; Elham Faghani
Volume 30, Issue 4 , February 2024, , Pages 542-556
Abstract
Background and objectivesDue to the increase in the consumption of fossil fuels and chemical fertilizers, especially nitrogen-containing fertilizers, the entry of nitrogen into the cycle of ecosystems has been more than normal.Nitrogen deposition as a consequence of increasing nitrogen input to the atmosphere, ...
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Background and objectivesDue to the increase in the consumption of fossil fuels and chemical fertilizers, especially nitrogen-containing fertilizers, the entry of nitrogen into the cycle of ecosystems has been more than normal.Nitrogen deposition as a consequence of increasing nitrogen input to the atmosphere, can be a threat to ecosystems. It can affect soil properties, soil microorganisms and their activities, vegetation and animals. The aim of the present study is to investigate the effects of deposition of different rates of atmospheric nitrogen on the biochemical properties of a summer rangeland's soil. Methodology For this purpose, the seeds of Medicago sativa were planted in 36 pots containing rangeland soil in a completely randomized block design. Two months after seed germination in pots, six Nitrogen treatments included control,30, 60,90,120 and 150 kg ammonium nitrate/ha which dissolved in water were applied in 6 replications during a period of 75 days. At the end of experiment, some soil biochemical properties (acidity, electrical conductivity, absorbable phosphorus, total nitrogen, organic carbon and exchangeable potassium along with biomass and microbial respiration) and Root weight and depth factors were measured. Data analysis was done using analysis of variance method and mean comparison was done using Duncan's test. ResultsThe results demonstrated that increasing the level of ammonium nitrate deposition to 60 and 90 kg per hectare per year, despite the significant increase (p < 0.05) of organic carbon and total soil nitrogen, causes a significant decrease in other measured biochemical properties of the soil (p < 0.05). An increase in nitrogen deposition in the early stages may be partially responsible for root growth, but with nitrogen saturation in the soil and the occurrence of nitrate leaching, as well as the loss of soil fertility, unfavorable conditions for root growth are provided. With the increase of nitrogen deposition in the soil, up to the level of 60 kg /ha, the average respiration and microbial biomass increased, But at higher levels of nitrogen deposition, respiration and microbial biomass decreased.ConclusionIn case of an increase in mineral nitrogen deposition in the studied area, it is recommended to use the Medicago sativa in the improvement of vegetation restoration projects of summer rangelands to absorb the deposed mineral nitrogen in excess of the soil holding capacity, its alleviate negative consequences and creating a suitable root zone for the the activity of soil microbial.
Esmaiel Sheidai Karkaj; Hosein Rezaei; Hamid Niknahad Gharemakher; Isa Jafari Footami; Abolfazl Sharifian
Volume 26, Issue 4 , December 2019, , Pages 904-917
Abstract
Soil aggregate stability and soil structure considered as the key indicators of range soil health and counted as effective factors in soil erosion control. The present study was carried out to investigate the effect of exclosure on the stability of aggregates and soil structure in four areas of Golestan ...
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Soil aggregate stability and soil structure considered as the key indicators of range soil health and counted as effective factors in soil erosion control. The present study was carried out to investigate the effect of exclosure on the stability of aggregates and soil structure in four areas of Golestan province including Chaharbagh, Incheboron, Gomishan and Maravetapeh. Soil sampling was carried out from two depths of 0-20 and 20-40 cm by digging profile in random-systematic method along transects in each of exclosure and adjacent sites of quadruple areas. Aggregates stability was measured by the method of wet sieving in the laboratory. The results were analyzed statistically using independent and paired samples t-test for exclosure sites and adjacent exclosure sites as well as two corresponding depths, respectively. In the most of studied sites, the aggregate stability values were higher in the surface soil than the deep soil.The results indicated that the effect of rangeland exclosure on morphological changes and soil status indicating positive role in development of soil structure in all studied areas, however, these results were statistically significant only in the Incheboron and Gommishan area in view point of soil aggregate stability. The highest value of soil stability was in the first depth (4.52 mm) of Gomishan exclosure site and the lowest one was in the second depth (1.15 mm) in Gomishan grazing site. The final result showed that regardless of positive role of exclosure in promoting the stability of aggregate, factors such as geographic position of rangeland, climate, vegetation type and grazing conditions as the associated factors affecting the stability of aggregate and soil structure should be considered.
Moharam Ashrafzadeh; Hamid Niknahad; Mohammadjamal Saharkhiz; Majid ghorbani Nohouji; Gholamali Heshmati
Volume 26, Issue 3 , September 2019, , Pages 629-639
Abstract
Clematis ispahanica Boiss is a rare species of Ranunculaceae family, which has forage and medicinal value. The seeds of this species have a very low germination percentage because of dormancy. Therefore, increasing their germination percentage by laboratory methods can be effective in restoring this ...
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Clematis ispahanica Boiss is a rare species of Ranunculaceae family, which has forage and medicinal value. The seeds of this species have a very low germination percentage because of dormancy. Therefore, increasing their germination percentage by laboratory methods can be effective in restoring this plant. In the present study, considering the seed size of C. ispahanica , H2SO4 (96% ) for 5 , 10, 20 seconds , hot water (70 and 90 °C .) for 15 minutes, ethanol (96%) for 48hours, HCL ( for 2, 4 and 6 minutes), KNO3 (0.2%) for 48 hours, NaCl (50 milli molar) for 48hours, and scarification using sandpaper were tested to break the seed dormancy. Moreover, the seeds of this species were planted in different depths (1, 1.5 and 2.5 cm) and densities (30, 50 and 70 seeds per square meter). Data analysis was performed using SPSS software version 18 and by univariate analysis of variance and the Duncan test. According to the results, the most effective treatments to improve germination percentage and rate were KNO3, NaCl and scarification treatments. The depth of planting had a significant effect (P<0.05) on the germination percentage, but the density of planting had no significant effect on the germination percentage (P> 0.05). Due to the lack of use of chemicals in scarification using sandpaper treatment, it has an advantage over other effective treatments, recommended to break seed dormancy and increase its germination percentage. Considering the weight of a thousand seeds (3.73gr), 1.12 kg/ha seed (equivalent to 30 seeds per square meter) in the depth of 1.5 cm is proposed for the planting of this species in the study area.
Moharam Ashrafzadeh; Hamid Niknahad Gharemakher; Gholamali Heshmati; Mohammadjamal Saharkhiz; Majid Ghorbani Nohooji
Volume 26, Issue 2 , July 2019, , Pages 432-446
Abstract
Clematis ispahanica is a rare, palatable, and endangered species of Iran. In this research, the distribution of this species was investigated in rangelands of Bavanat and Mehriz cities in Fars and Yazd provinces. For vegetation sampling, the study areas were classified and 30 plots (2 × ...
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Clematis ispahanica is a rare, palatable, and endangered species of Iran. In this research, the distribution of this species was investigated in rangelands of Bavanat and Mehriz cities in Fars and Yazd provinces. For vegetation sampling, the study areas were classified and 30 plots (2 × 3 m) were established using random- systematic sampling method in key areas. Soil samples were taken at the depth of 0-30 cm (based on the depth of rooting). Independent t-test was used to compare soil chemical properties of the two regions. Principal component analysis (PCA) was used to determine the most effective factors affecting soil properties of the two regions.The effect of phenological stage, area, and interaction between phenological stage and area on forage quality indices (CP, DMD, ME and ADF) was determined using a General Linear Model (GLM). The interaction of area × phenological stage on forage quality was investigated using a completely randomized design. The results demonstrated that the best spatial distribution pattern of this species was the northern slopes and relatively flat topography. Our results revealed that this species was found in non-saline soil (EC<2), sandy loam, loamy sand and sandy textures with a pH of 8.6-8.9, %0.4-%0.7 organic carbon, %0.09-% 0.13 nitrogen, 13.9-22.1 ppm phosphorus, %42-%59 calcium carbonate, and 2-2.45 mg/lit potassium. The results of PCA indicated that soil organic carbon (OC), electrical conductivity (EC), and acidity (pH) were the most effective components of the soil in two study areas. The results demonstrated that in the growth and flowering stages, forage quality indices of this species in Bavanat area were significantly higher than those of Mehriz area, but in the seeding stage, the study indices in Mehriz area was higher as compared with Bavanat area. No significant correlation was found between soil chemical properties and forage quality indices. Thus, it can be concluded that the effect of climate on forage quality indices is higher than edaphic factors. In general, it can be stated that the high forage quality of C. isphanica can be one of the reasons putting this species at risk of extinction.
Zahra Jafari; Hamid Nik Nahad Gharemakher; Samira mesri
Volume 23, Issue 4 , March 2017, , Pages 680-688
Abstract
This research was aimed to study the vegetation changes under grazing and non-grazing conditions during five years in order to evaluate vegetation improvement or destruction over time.The study of vegetation changes was carried out inside and outside the exclosure within the sample units. Each sample ...
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This research was aimed to study the vegetation changes under grazing and non-grazing conditions during five years in order to evaluate vegetation improvement or destruction over time.The study of vegetation changes was carried out inside and outside the exclosure within the sample units. Each sample unit consisted of two parallel transects with 20 quadrates. Within each quadrate, the canopy cover percentage and composition percentage of each species were estimated. The forage yield was measured by clipping and weighing using one-square-meter quadrates. No significant difference was recorded for the canopy cover of inside and outside the exclosure. Statistical analysis was performed in a completely randomized block design and no significant differences were found among the study years. However, significant differences were found for forage yield of inside and outside the exclosure. Therefore, the reduction in forage yield of outside the exclosure is directly related to the intensity of utilization. The life form of species was determined based on Raunkiaer's system. Hemicryptophytes was the dominant form in the study area. The results showed that although the exclosure caused to improve rangeland vegetation, the difference between inside and outside the exclosure was not significant. Generally, the results indicated that vegetation changes in the study area were slow and gradual and exclosure could not be considered as an improvement method in short-term. Direct human intervention is required for the restoration of rangelands, located in arid regions.
Moharam Ashrafzadeh; hamid niknahad; fazlolllah ahmadi mir ghaed; somayeh jafari
Volume 23, Issue 3 , January 2017, , Pages 636-644
Abstract
The use of nature in a way that is least harmful to the environment and the best efficiency is achieved for humans is possible when all factors and phenomena involved in environment are considered in the planning of land.For this purpose, this research was aimed to assess the ecological capability for ...
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The use of nature in a way that is least harmful to the environment and the best efficiency is achieved for humans is possible when all factors and phenomena involved in environment are considered in the planning of land.For this purpose, this research was aimed to assess the ecological capability for the rangelands of Lar city in the Baluch region using the Analytic Hierarchy Process (AHP) based on the principles of land use planning. Initially, the information layers including vegetation, climate, geology, landform, soil, and erosion were prepared in Arc GIS. Then, the weighting of evaluation criteria was performed in the Expert Choice software based on the Analytic Hierarchy Process (AHP). In the next step, the weights of evaluation criteria were extended to the layers and analysis was performed in Idrisi. According to the obtained results, the ecological capability of the study rangelands for range management development was classified into five classes, namely high suitable (78.5 ha), suitable (321ha), moderately suitable (71.25 ha), low suitable (172 ha), and not suitable (1445.4 ha), respectively. In addition, our results showed that attention to climatic and edaphic conditions as well as socio-economic issues are important and necessary for the implementation of any range management plan in this region.