Journal of Rangeland Science
Volume:11 Issue: 1, Winter 2021

Drought stress is one of the most important factors limiting the survival, growth and production of various crops and medicinal plants in the different habitats of Iran. This study was conducted to evaluate the effects of drought stress on seedling growth and physiological traits in four native thyme species as (Thymus kotschyanus, T. dianensis, T. lancifolius and T. pubescens). A factorial experiment was conducted using thyme species as main factor and three levels of water stresses namely well-watered (90% of field capacity), mild (70% FC) and severe drought stress (40% FC) as the second factor based on a Completely Randomized Design (CRD) with 3 replications in 2018, Khorramabad, Iran. Data collected for 14 morpho-physiological traits of the seedlings. The result of analysis of variance showed significant effects of species and water stress levels for all of the traits (p <0.01). The species by water stress interaction effects were significant for all of the traits except, carbohydrates and peroxidase indicating that the thyme species had different responses to water stress. Results of means comparison between water stress levels showed that the values of root length, root dry weight, root volume and physiological traits, as: leaf electrolyte leakage, carbohydrates, proline content and catalase activity were increased by drought stress and the higher values were observed in 40% FC, indicating that by increasing drought stress both root growth parameters and many physiological traits were significantly increased in all of the species, but, the leaf relative water content (RWC) and leaf pigments decreased. Results of species by water stress showed that the higher values of root length were obtained in T. daenensis and T. lacnifolius in severe stress (40% FC), respectively. However, in the same species, the higher values of roots dry weights were obtained in the mild stress (70% FC), respectively. For physiological traits, the higher values of (RWC), leaf electrolyte leakage, carbohydrates content and leaf pigments were obtained in T. lancifolius, indicating that this species was more tolerated to drought stress than the other species. It was concluded that species of T. daenensis and T. lacnifolius had produced longer roots in the severe drought stress. However, T. daenensis, due to higher areal part production and essential oil yield in the field, was recommended for domestication and cultivation in dryland farming system and semi-stepic rangelands of Iran.

This study was performed to evaluate the forage nutritive value of Cymbopogon olivieri before and after conducting the essential oil extraction in rangelands of Khuzestan province, Iran. In this study, the aerial parts of Cymbopogon olivieri were collected in flowering stage from 10 natural regions located in Khuzestan province in 2016. Regions included ChalGandali, TalkhabKalat, Bardmar, Morad Abad, Tembi, Dezful, Andika, Lali, Shoushtar, and Izeh. Essential oil composition was analyzed by GC/MS. The forage quality traits including Crude Protein (CP), Dry Matter Digestibility (DMD), Water Soluble Carbohydrates (WSC), Crude Fiber (CF), Acid Detergent Fiber (ADF), Neutral Detergent Fiber (NDF), and total Ash were measured. After normalizing the gathered data, the means of the traits were compared by Duncan’s multiple range test (p <0.05) in SAS software. The 21 components were identified in the essential oil of the plant species. The result showed that the highest mean values of CP, DMD, WSC, CF, ADF, NDF, and total Ash were obtained as 4.83%, 48.03%, 14.9%, 76.63%, 50.12%, 84.59%, and 3.98%, respectively. The result showed that phenological stage had significant effects on forage quality. The higher amount of NDF (77.01), ADF (40.54), and CF (63.64) were observed after essential oil extraction stage, but the higher amount of CP (3.31), WSC (11.99), and DMD (46.03) were observed before essential oil extraction. In this study the range of changes for CP ranged from 1.26 to 5.06, DMD between 45.89 to 49.27, WSC between 7.27 to 11.53, ADF 40.40 to 45.5, total Ash ranged between 3.14 to 4.94, CF ranged from 58.6 to 65.82 and NDF was in the range of 63.49 to 70.72. So, it was concluded that since the essential oil extraction led to decreasing of forage quality have more benefit for dairy and meat production.

This study was conducted on the south slope of the Al-Jabal Al-Akhdar (the Green Mountain) rangelands, northeast Libya to investigate changes in perennial plant species richness, landscape function and soil surface condition in order to determine whether exclosures are effected strategy for the improvement and rehabilitation of rangeland ecosystem at the regional level. Four study sites are positioned along a strong north-south rainfall gradient. A total of 28 monitoring sites were reinstalled and assessed between May and December 2014, the sites were then initially installed and assessed between the period of May and December 2006. The monitoring site layout is based on the Western Australia Rangeland Monitoring System (WARMS). The response variables measured were those included in the protocols of Landscape Function Analysis technique (LFA). Based on the results, LFA indices were in the low and medium scales in all of the monitoring sites within the exclosures. Notably, it is considered a good comparison tool for what it is currently occurring at the target grazing areas. No changes in perennial plant species richness amid the study areas, with the exception of the Thahar Altair area (TT). Overall, in estimation, at least 10 years of protection from grazing is required in the highest rainfall area (Maduar Zetun), and a considerably longer period in the lower rainfall areas to the south before vegetation cover and soil surface conditions recover sufficiently to be re-exposed to grazing. Consequently, grazing should be controlled to conserve national forage resources.

Most of rangeland soils are limited in their ability to supply adequate nutrients to plants. Soil conditioners have been shown to alter soil fertility and plant characteristics. This investigation aimed to evaluate the influence of two soil conditioner on nutrition value of N. schoberi and A. podolobus. For this, two separate experiments for each species were carried out in greenhouse using completely randomized design with three replications during 2018 and 2019. Treatments were four levels of wheat straw Biochar (WSB), as well as, lignite at rates of 0, 1.25%. 2.5% and 3.75% w/w added to clay loam soil. In the end of vegetative stage and before flowering, plant samples were taken and their Crude protein (CP) and Acid detergent fiber (ADF) content were measured and then Dry matter digestibility (DMD) and Metabolizable energy (ME) were calculated. Data were analyzed by One-way analysis of variance (ANOVA) and the means were compared using Duncan's test. The results demonstrated that WSB addition had no effect on nutrition value of both species. By application of Lignite, CP content of N. schoberi enhanced up to 44.45%, than that for control. The effect of lignite addition on nutrition value traits was high for N. schoberi. But this material had no effect on A. podolobus quality traits. Based on our findings, application of Lignite at 3.75 (w/w) recommended to improve soils of rangeland for cultivation of N. schoberi in dry-lands plantation projects or the conversion of dry lands to arable pastures.

Trend of vegetation in typology scale has remained uncertain especially in arid ecosystems. Therefore, we aimed to asses two vegetation indices including as the Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI). Trends and their rates of indices in vegetation types were analyzed by the Mann–Kendall test and Theil–Sen trend estimator. To this end, first we determined the typologies maps of Sirjan Plain catchment based on field operations then, Moderate Resolution Imaging Spectroradiometer (MODIS) monthly data with the spatial resolution as 250 m × 250 m from 2000 to 2019 were organized into the NDVI and EVI time series to investigate the trend. The results showed that some vegetation types which had not a distinct trend, were random and time-independent however, the Alhagi camelorum type demonstrated the EVI and NDVI annual increase by 0.0009 and 0.0011 year-1 respectively. The other types that changed dimensionally associated with stochastically, had different slopes of increase according to Theil–Sen estimate. The most increased rate of the NDVI was attributed to Artemisia sieberi- Amygdalus lycioides- Ebenus stellata type (0.0015 year-1) whereas, for the EVI Artemisia aucheri-Astragalus parrowianus, Zygophyllum eurypterum- Artemisia sieberi- Astragalus arbusculinus, Dendrostellera lessertii-Noaea minuta, Artemisia sieberi- Zygophyllum eurypterum and Cornulaca monacantha-Salsola orientalis types were increased by 0.0008 year-1. Of note, sudden NDVI and EVI changes (out of confidence level of Theil–Sen estimate) were observed for majority of types especially in 2008 and 2017. More investigations on environmental data and human activity in the mentioned years affecting as turbulator of majority of types, are recommend.

The information about the forage quality of rangeland species is essential to supply a reasonable diet to livestock and determine thestocking rate and grazing time on rangelands. Salsola turcomanica is one of the important species of semi-arid rangelands in the Western part of Golestan province, Iran. The present study was conducted to provide information about the nutritive value of S.turcomanica at different growth stages in 2019. Plant samples (with three replications) were randomly collected in four growth stages (vegetative stage, early flowering, late flowering and seed maturity) from Gomishan rangelands during the summer and autumn 2019. Seven quality indices, including Acid Detergent Fiber (ADF), Crude Protein (CP), Dry Matter Digestibility (DMD), Metabolizable Energy (ME), Digestible Energy (DE), Total Digestible Nutrient (TDN) and Ash content (Ash) were analyzed. Data analysis was performed using One-way analysis of variance (ANOVA) method and mean comparisons were done by Duncan test. The results demonstrated that there are significant differences among phenological stages for all the traits (p <0.05). The results demonstrated that the content of CP (from 25.66% to 8.33%), DMD (from 84.45% to 56.31%), ME (from 12.35 to 7.57 MJ/Kg), Ash (from 40.03% to 35.60 %), DE (from 36.17 to 24.12 Mcal/Kg) and TDN (from 82.55% to 53.41%) were decreased by the progress of growth stages. Regarding its growth seasons and high values of CP, ME and DMD in all phenological stages, it is suggested that this species can have aprominent place in the grazing livestock diet in semi-arid rangelands.

Rosa persica Michx. ex Juss. is an aggressive plant species in Iranian rangelands. Several controlling methods have been suggested to stop its expansion. This study examined the short-term effects of fire, tilling, cutting, and herbicides as a means of controlling Rose persica on the richness, evenness and diversity of R. persica communities in rangelands of Iran. The experiment was arranged using a split-plot design with fire (burning and control) as main plot and four treatments (cutting, tilling and glyphosate herbicide and control) as subplots based on a completely randomized block design with four replications over three years (2013-2015) in khosbijan, Iran. The Margalef, Sheldon, and Shannon-Wiener indices were used to assess the species richness, evenness, and diversity, respectively. We found that treatments had a different effect on the plant community composition. Prescribed fire coupled with other treatments had a significant effect on species diversity rather than control (p <0.01). This finding indicated the significant effect of prescribed fire on the plant diversity indices. Mean of diversity was higher in burning alone (3.181). The highest value of evenness was related to the chemical treatment without fire (0.582) and the highest richness was related to the control (11.114). Also, the lowest values of diversity, evenness and species richness occurred by cutting without burning (2.582), control area without applying other treatments (0.258) and herbicide without burning (7.921), respectively. Therefore, plant diversity was increased using each treatment. This may be due to reduction of R. persica frequency. Despite the increasing of species diversity after applying treatments, it should be acknowledged that due to lack of desirable species gene pools and colonization of ruderal species, the vegetation composition won't be necessarily desirable. Therefore, in R. persica communities, the restoration of these communities should be considered after the controlling of the R. persica.

Studying the phenology of valuable native plants which are on the verge of extinction, is very important and effective for better introduction and protection of them. Fritillaria raddeana is one of the native bulbous plants with ornamental and medicinal value in Iran. The aim of this study is to investigate the phenological stages of F. raddeana as a first step to protect it and later to introduce it. In a natural habitat, in northern Khorasan province, Iran, six zones were selected at a distance of 1000 m from each other, and five plants were selected and coded in each zone. To provide a standardized phenological description of the species, this study used the BBCH scale. In total, from sprouting to winter rest, six main principal stages were described for sprouting, leaf development, inflorescence emergence, flowering, fruit development, fruit maturity, senescence, and beginning of dormancy stages and within them, 15 secondary growth stages were described. Data were collected once a week in the course of the vegetative season and with a 30-day interval during the dormant season for two consecutive years (2015-2017). Additionally, we measured some traits of plant growth. During the first year, sprouting and subsequent leaf development began in late March and the inflorescence emerged in the middle of April. The full bloom occurred in the first half of May and then seed formation (in the late of May). The summer dormancy was triggered in late spring. During the second year of study (2016-2017), the results showed the growing stages start with a delay of 5-8 days compared with the previous year. In addition, the means of studied growth plant traits such as leaf number, plant height, flower stem length, flower number, and flower diameter were significantly higher in the first year than in the second one.

Forest grazing of cattle, horse and sheep is allowed under certain strict regulations. Black locust forests have major importance amongst domestic forestry (Central Europe), as their habitat are situated on less productive sand soils. In most cases there are no other option than setting trees next to the grazing areas. Black Locust (Robinia pseudoacacia) leaves and the herbage of Gramineae amongst the trees provide excellent supplemental feed at the beginning and in the last period of grazing season. It can be well integrated into rotational grazing system, thus grazing season can be prolonged with two months. Digestibility of black locust is significantly lower than alfalfa because of its high lignin content. The protein level however is remarkably high (20%) during spring. Despite its lower feeding value it is still a considerable forage due to its role as rumen filling feed, and also because other valuable plants also available during forest grazing. Black locust trees contain poisonous compounds in the crust. Such compounds are robiine and fazine. Diverse rangelands with clump act major role in healthy grassland ecosystems. Foliage provides basic forage and shade at once. Ground water usage of trees also discussed as they might be competitors of the basic grassland association.