Effect of Temperature on Phenology in Triple-Awned Grass (\u3ci\u3eStipagrostis plumosa\u3c/i\u3e)

Phenology of triple-awned grass in different stages of vegetative growth, flowering and seed falling was investigated. Each phenological stage was related to minimum and maximum air and soil surface temperatures. Soil surface temperature was measured two times per day during different seasons. Climate data were obtained from the nearest weather station. The study was carried out in sand dunes of band-e-rig of Kashan in the central region of Iran. This species is important in terms of wind erosion control and livestock feeding in arid areas. The results showed that air temperatures ranged from –22 oC to 41.5 oC and soil temperature varied from –3 oC to 52 oC during the growth stages

Variation in the Quality of Forage of Six Rangeland Species in Different Phenological Stages

An understanding of forage quality is fundamental to the measurement of grazing capacity. In addition, knowledge of forage quality is necessary for planning grazing and developing range improvement and development programmes, such as planting and seeding of rangelands. Among the different factors that affect forage quality, phenological stage is particularly important (Cook, 1972; Caballero et al.,2001). The objective of this study was to investigate the effects of plant species, phenological stages and life form on forage quality indices

Effect of water stress on seed germination of Artemisia spicigera & Artemisia fragrans

Physiological effect of five levels of water stress (0,-0.3,-6,-9 and -1.2MP) was studied on seed germination and tigella as well as radicule growth length in two different Artemisia species namely: Artemisia spicigera and Artemisia fragrans. Polyethylene glycol (PEG) was used to provide appropriate water potentials. A total of 50 seeds were sown from each Artemisia species. Experimental design was a factorial one of complete randomized design. Maximum germination rate was obtained at -0.3 MP. Germination rate, and tigella & radicule growth lengths declined with decreasing water potential level. Artemisia spicigera was more resistant to water stress in comparison with Artemisia fragrans

Runoff and sediment yield modeling using WEPP in a semi-arid environment (Case study: Orazan Watershed)

Water erosion is a major environmental problem in many parts of the world. Majority of semi-arid countries are concerned because of their specific climate and soils sensitivity, but also because of the recent intensification of human activities and agricultural practices. Accurate estimation of water erosion for various land-use and climate scenarios is so an important key to define sustainable management policies. In the last decades, several studies have been carried out to build models suitable for quantifying sedimentation. Among these models, the Water Erosion Prediction Project (WEPP), is a physically based, distributed-parameter model that has been developed and mainly validated in America. Only few studies have investigated its applicability to environmental conditions that differs from those where the model was developed. The aim of this work is to test the efficiency of WEPP model to predict runoff and sediment yield at catchment scale in a semi-arid area. Continuous simulations have been conducted between 1996 and 2005 in Orazan Watershed. Comparison between predictions and measurements indicates that WEPP under-estimates sediment volumes of 23% and over-estimates runoff volumes of 27%. Results shows that sediment yield and Runoff outputs are relatively well predicted but lack of input data to run WEPP model is an important challenge in Iran conditions

Effect of proline, soluble carbohydrates and water potential on resistance to salinity of three Salsola species (S.rigida, S. dendroides, S.richteri)

Abstract Various resistances to salinity are due to plants genetically variations, and selection on the basis of one factor will not be a suitable criterion in measurement of resistance to salinity, therefore in choosing resistant varieties, it is necessary to notice to a set of resistant indexes to salinity, creating changes in physiology, anatomy and morphology of plant species. This research was conducted using a factorial experiment based on CRD design with 4 replication at research institute of forests and rangelands. Experimental treatments included a combination of three species (S.rigida, S.dendroides and S.richteri) along with 7 salinity levels of 0, 100, 200, 300, 400, 500, and 600 mM concentrations. The purpose of this research was to investigate metabolites, accumulation in terms of compatibility or incompatibility value for salinity stress in three species. The results of physiology features measurement demonstrated that S.dendroides water potential is more than two others. Comparing of the measured characteristics, averages demonstrated that S.rigida and S.dendroides have reposed in one statistical group in terms of proline concentration and significant different have with S.richteri. Also, increasing salinity levels leads to the highest proline concentration in S.richteri in salinity treatment of 400 mM. In all three species, it is seen that salinity increase reduces plants soluble carbohydrates concentration rate and it reveals that salinity have a negative effect on these materials

Forage quality of three life forms of rangeland species in semi arid and semi humid regions in different phenological stages

For determination of grazing capacity, information of forage quality is essential which is influenced by various factors. The main objective of this research was investigation on effects of species, phenological stages, and life form on values of forage quality indices of six range species. Species were two grasses (Bromus tomentellus and Dactylis glomerata), two forbs (Ferula ovina and Coronilla varia) and two shrubs (Salsola rigida and Artemisia aucheri). Samples were collected from two highland ranges of Gachsar and Vard Avar. They were dried, grained and analyzed in Laboratory. The results showed that forage quality indices values including crude protein (CP), acid detergent fiber (ADF), dry matter digestibility (DMD) and metabolizable energy (ME) were significantly differed among species, phenological stages, and life forms (

The study of Forage Quality of Smirnovia iranica In Different phonological stages in sandy areas-case-study: Band-e-Rig-Kashan

Smirnovia iranica, a native valuable woody species from Fabaceae, is an adaptable plant of central sandy areas of Iran. On other hand, this species could be markedly considered from different view points of forage production, soil conservation and medicinal applications. The current research was carried out in Band-e-Rig of Kashan, Iran to evaluate Smirnovia iranica properties including crude protein (c.p), NDF, ADF, P, K, ME and DMD in different phonological stages in order to find its forage quality for livestock nutrition. The result of chemicals analysis indicates that there is a significant difference among different phonological stages of S.iranica in terms of its properties. As the plant age is increased, c.p, ME and DMD are decreased while NDF and ADF are increased. This leads to reduction of S.iranica forage quality, since there is not significant difference between flowering and growth stages in view point of their c.p, ME, DMD, NDF and ADF, also according to increase of P and K in flowering stage, it seems that this stage could be considered as favorable time for S.iranica utilization by livestock

Evaluation of desertification intensity based on soil and water criteria in Jarghooyeh region

Desertification refers to land degradation phenomenon in arid, semi-arid and dry sub-humid areas, resulting from various factors including climate variation and human activities. For evaluation and mapping of desertification many research have been conducted leading to regional and local models. In this research, among different existing methods IMDPA‌ was selected and desertification intensity was evaluated on the basis of 2 criteria and 8 indices including: soil (soil depth, Electrical Conductivity, texture and gravel percentage) and water (groundwater table decrease, EC, Cl concentration, Sodium Absorption Ratio). Each criterion was assessed based on the selected indices which result in qualitative mapping of each criterion cased on geometric average of the indices. Finally, sensitive map of region was extracted using geometric average of all criteria. Thematic databases, with a 1:50000 scale resolution, were integrated and elaborated in a GIS based on arc/info8, arc view3.2 and especially ILWIS. Analysis of desertification criteria in Jarghooyeh region showed that among study criteria, soil criterion is a major problem in the study area with a geometric average of 2.25 which shows medium class while water criterion with a weighted average of 1.14 stands in low class of desertification. Also, the results showed that that Electrical Conductivity index with quantitative value of 3.54 classified in very high class of degradation, and ground water recession with quantitative value of 0.05 classified in low class of desertification were the most and the least effective factor on land degradation among studied indices respectively

Seed dormancy-breaking and germination requirements of

Dormancy breaking and germination requirements were investigated in seeds of Ferula ovina and Ferula gummosa. Seeds of rather species were collected from north and eastern-north rangelands of Iran. Seeds of each of the species were subjected to different treatments including various levels of GA3, chilling and combination of GA3 and chilling (GA-chilling). In contrast to treated seeds, non-treated seeds did not germinate. Germination of both species increased at higher concentration of GA3. In the case of Ferula ovina the highest germination percentage was obtained when the seeds were treated with 1000 ppm GA-chilling with 76% of germination. For Ferula gummosa seeds, the highest germination percentage was found when exposed to 1500 ppm GA-chilling with 53% germination. Both species well responded to different periods of cold stratification (30/60 days), especially F. ovina with 36% and 55% germination, respectively. The results suggest that F. gummosa has deeper dormancy. For both species, germination rate was positively correlated with germination percentage. Keywords: Chilling; Dormancy; Ferula ovina; Ferula gummosa; GA3; Germinatio