جستجوی مقالات مرتبط با کلیدواژه « بیوماس » در نشریات گروه « کشاورزی »

To compare tolerance and sensitivity indices of sesame genotypes to water stress in Ahvaz (south-west of Iran) conditions, an experiment was conducted in Research Farm of Agricultural Sciences and Natural Resources University of Khuzestan, south-west of Iran, in summer 2018. The experimental design was split plot based on a randomized complete block design with four replicates. Experimental factors were three levels of irrigation (I1; fully irrigated, I2: changing altered irrigated and I3: fixed altered irrigated) in main plots and six sesame genotypes in subplots. The yield of studied genotypes showed a significant difference in different levels of irrigation. Genotype Shushtar produced the highest grain and oil yield and showed good performance in both normal and low irrigation conditions. The examined genotypes had significant differences in terms of Stress Sensitivity index (SSI), Tolerance Index (TI), Productivity Mean (PM), Harmonic Mean (HM), Yield Stability Index (YSI), Geometric Productivity Mean (GPM), Stress Tolerance Index (STI), Stress Damage Index (SDI), Modified Stress Tolerance for appropriate conditions (MSTI1), Modified Stress Tolerance for non-appropriate conditions (MSTI2), and Yield Reduction Index (YRI).  In general, the best indicator for evaluation of tolerance and susceptibility of sesame genotypes was stress tolerance index (STI). The most tolerant and sensitive genotypes were Shushtar and Halil genotypes, respectively.

In order to survey the efficacy of several pre-and post-emergence herbicides on weed control in the autumn cultivation of chickpeas, a split-plot experiment was conducted in a randomized complete block design with four replications in the Sararoud region during 2021–2022. The main plots contain two tillage systems (conventional tillage and no-tillage). The subplots include 12 herbicide treatments (Trifluralin, Trifluralin + Bethanal progress, Isoxaflutole, Isoxaflutole + Bethanal progress, Oxyfluorfen, Oxyfluorfen + Bethanal progress, Imazethapyr, Imazethapyr + Bethanal progress, Fluorochloridone, Fluorochloridone + Bethanal progress, Metribuzin, Metribuzin + Bethanal progress, and two controls (weed-free and weed-infested)). The maximum decline in weed dry weight was observed in tillage + Fluorochloridone, tillage + Isoxaflutole, tillage Oxyfluorfen, and no-tillage + Fluorochloridone at about 51%, 48%, 46%, and 45%, respectively. The greatest decrease in weed density is for tillage + Fluorochloridone and tillage + Oxyfluorfen + bethanal progress, tillage + Metribuzin + bethanal progress, tillage + Fluorochloridone + bethanal and tillage + Imazethapyr were registered with 47, 47, 43 and 40% reduction respectively. Conventional tillage reduced the density and dry weight of weeds, but this reduction was statistically significant for the dry weight of weeds. The highest yield of chickpea seeds in tillage + weeding, weeding, tillage + Trifluralin + bethanal progress, conventional tillage + Oxyfluorfen and no-tillage + Trifluralin + bethanal progress treatments are 846, 664, 528, 502 and 498 kg per hectare, respectively. The most effective herbicides in controlling weeds were Fluorochloridone, Isoxaflutole and Oxyfluorfen, and the highest yield of peas was recorded for Oxyfluorfen.

In order to investigate the effect of the growing day and plant density on some agronomic, morphophysiological and qualitative characteristics of the early-maturing line Soy-93-31 soybean, an experiment was conducted in the form of split plots in the form of a randomized complete block design in three replications. Two crop years 2017 and 2018 were implemented in Gorgan region. The first factor of growth days until harvest time includes five growth days (GDD) 2328, 2182, 1893, 1712 and 1499 resulting from the date of sowing (10, 24 June, 8, 12 July, 5 August) and the second factor is the distance between rows 24, 36 and 48 cm (42, 28 and 21 plants per square meter).in this experiment, grain yield, biological yield, number of pods per plant, number of seeds per pod, 1000 grain, oil yield, oil percentage and soybean fatty acids were measured. The results of this experiment showed that planting date and density had a significant effect on the percentage of soybean oil and fatty acids. The percentage of seed oil decreased with increasing planting time (delayed soybean) so that the highest percentage of soybean oil on 10 June and the lowest percentage of oil was obtained on 5 August. Also, based on the results of planting date and plant density had a significant effect on grain yield and grain yield components, the weight of 1000 soybeans decreased with delay in planting. With delay of sowing date in all densities, soybean grain yield decreased, so that the highest grain yield was observed on June 10 and the density of 42 plants per square meter (3760 kg.ha-1) and the lowest grain yield was observed. Soybean was obtained on August 5 and the density of 21 plants per square meter was (470 kg.ha-1). According to the results of this experiment, the planting date of 10 June and the density of 42 plants per square meter were the most desirable planting date and density to achieve maximum grain and oil yield.

The aim of the present study was to investigate the interaction effects of vermicompost and phytoprotectants on the physiological responses of sugar beet (Beta vulgaris L.) at different levels of irrigation. 

Two-year research was conducted as a split-plot factorial experiment. Treatments were irrigation levels [irrigation at 90% field capacity (extra-watered), 70% field capacity (well-watered), 50% field capacity (moderate stress) and 30% field capacity (severe stress)], vermicompost [0 and 7 t.ha-1] and phytoprotectants [distilled water (control), zinc, silicon, glycine betaine, ascorbic acid].

The results showed that root yield in irrigated plants at 70% of field capacity was higher than other treatments. Also, the yield and dry weight of the roots were significantly increased by the application of phytoprotectants. Phytoprotectants and vermicompost had no effect on water use efficiency of root yield at 70 and 90% of field capacity, but, water use efficiency with glycine betaine at 50% field capacity and with silicon and glycine betaine at 30% field capacity with vermicompost application increased significantly. The effectiveness of glycine betaine for transpiration efficiency and sugar yield was higher than other treatments, regardless of irrigation. The highest root yield was obtained in the treatment of 70% field capacity and was significantly increased by the use of phytoprotectants and vermicompost.

Our findings show that the use of vermicompost and phytoprotectants (especially glycine betaine and ascorbic acid) could be effective in modulating water stress to sugar beet and help to have sustainable agriculture.

This study aimed to study the survival rate and stock assessment of Salmo trutta in Taleghan River using regional sampling and Binns and Eiserman methods (developped for assessment of trout fishes in the streams). For this purpose, the samplings were performed in 40 stations, but S. trutta was found only in three tributaries of Grab, Gateh-Deh and Deh-Dar in the Taleghan River using regional sampling and Binns and Eiserman methods. Therefore, the stock assessment study was delimited to these tributaries. Based on the results, the survival rate was calculated in the first –third year as 0.21, 0.6 and 0.25. Regional sampling method estimated biomass values of 3.98, 9.16, 0.84 kg/km for this fish in Grab, Gateh-Deh and Deh-Dar streams and Binns and Eiserman method estimate biomass values as 18.97, 32.89 and 12.39 for these three studied streams indicating a limited distribution and lower abundance of S. trutta stocks in the Taleghan River.

The current research goal at understanding the impact of an ascorbic acid foliar application under water deficit stress on corn plants at the field conditions.

The experiment was carried out as a split-plot based on a randomized complete block design with three replications at the Agricultural Research Station of Ardabil in the sweet corn (Hybrid Chase; the Seminis Company). The main plots were four levels of water deficit stress including irrigation after 70 (as control), 100, 130, and 160 mm evaporation from the class A pan, and the sub-plots were four levels of ascorbic acid as 0, 150, 200, and 250 ppm.

Foliar application of ascorbic acid had a significant effect on grain yield, seed attributes, plant height, biomass, pigment contents, and leaf area in corn plants under water deficit stress. Water deficit stress dressed grain yield, plant height, biomass, pigment contents, and leaf area. The heights grain yield was achieved at 70 mm evaporation from class A with foliar application of 150 and 250 ppm ascorbic acid. The heights of pigment contents were achieved at 100 mm evaporation from class A with foliar application of 150 ppm ascorbic acid, and also the heights leaf area of the corn plant was achieved at 100 mm evaporation from class A with foliar application of 250 ppm ascorbic acid. High significant correlations were observed between grain yield and seed attributes, plant height, biomass, and leaf area in the corn plant.

Although the foliar application of ascorbic acid reduced the water deficit stress effects, it also and improved the grain yield of the corn plant.

To evaluate maize hybrids response to salinity stress, a factorial experiment was performed with three replications at the Ardabil Agricultural and Natural Resources Research and Education Center during 2020. The first factors were six maize hybrids (SC647, TWC647, SC704, SC705, SC706 and SC715), and the second factors were three levels of salinity stress (0, 100 and 200 mM NaCl). Electrophoretic analyses by using 8% slab polyacrylamide gels indicated that three, two and one isoforms for superoxide dismutase (SOD), peroxidase (POX) and catalase (CAT) were observed, respectively, and for each isoform band the “density × area” scores onto gels were evaluated by MCID software as enzymatic activity. The applied salt stress reduced dry weight seedlings, but increased malondialdehyde (MDA), peroxide hydrogen (H2O2), and activity of SOD, POX and CAT isoforms. Significant correlations were observed between seedling dry weight and POX and CAT. The cluster analysis based Ward method was classified maize hybrids in two different groups. TWC647 hybrid with high biomass, high oxidative defense system and low MDA was salt-tolerance. The results indicated that salt-tolerance hybrids, which are associated with enhanced oxidative defense system.

Salinity stress is one of the main factors that limited crop production. Salt stress causes physiological effects by decreasing soil water potential. Azomite is an inorganic mineral that contains more than 60 forms of nutrients (macro and microelements). This material modifies and improves the soil, and the high ionic exchange capacity of this substance has resulted in some of it being used to reduce the effects of salinity stress. Mexican Parsley (Tagetes minuta) is a medicinal plant from Asteraceae family that used in the food and cosmetic industries. The purpose of this experiment was to investigate biochemical response and dry aerial biomass of Tagetes minuta under salinity stress and Azomite application.

A pot experiment was conducted at the research greenhouse of Ferdowsi University of Mashhad as factorial based on completely randomized design with three levels of salinity (0, 30 and 60 mM NaCl in irrigation water) and four levels of Azomite (0, 4, 8 and 12 g/kg soil) in three replications in 2018. The studied traits were included biochemical characteristics (RWC, Electrolyte leakage, chlorophyll a, chlorophyll b, carotenoid, total chlorophyll, antioxidant activity, total phenol, soluble carbohydrates, and proline) and dry biomass. Statistical analysis was performed using Minitab 17 software. The mean comparison was done by Bonferroni test at the 5% probability level. The figure drew by Microsoft Excel software.

The results of this experiment showed that the interaction effects of salinity and Azomite had a significant effect at a probability level of 1% on all of the studied traits. The highest amount of dry biomass (30.25 g.plant), RWC (74.2 %), chlorophyll a (7.5 mg.g-1FW), chlorophyll b (9.26 mg.g-1 FW), carotenoid (16.73 mg.g-1FW), total chlorophyll (33.39 mg.g-1FW) and essential oil content (0.46 %) were observed in treatment without salinity and 12 g/kg soil of Azomite. The highest amount of Electrolyte leakage (83.55 %), antioxidant activity (9727 %), Total phenol (95.10 mg.g-1FW), soluble carbohydrates (114.4 mg.g-1FW) and proline (0.12 µM/gDW) was observed on 60mM salinity and without the use of Azomite. NaCl stress can reduce nutrient uptake by the root of the plant and cause to decrease the growth of plants (Dry aerial biomass), RWC, Chlorophyll a, b, carotenoid and total chlorophyll and increase antioxidant activity, total phenol, soluble carbohydrates, and proline. Azomite in salinity stress increase water holding and inhibited the plants from Na uptake. Therefore it prevents plants from Na toxicity. The result of this study showed that the highest salinity level (60 mM NaCl) and application of Azomite especially at 12 g/kg soil level had the highest effect on ameliorating biomass and biochemical characteristics of the plant.

In order to study the effect of silicon foliar application and Nitrocara biofertilizer on some morpho-physiological traits of wheat under different irrigation regimes, an experiment was conducted as a factorial split-plot, during two cropping years in research farm of Islamic Azad University, Zabol Branch, Iran. Experimental treatments included water stress (irrigation regimes after water depletion of 50, 75, and 90% of field capacity) in the main plots and silicon acid foliar application at three levels of 0, 1 and 1.5 mM and Nitrocara biofertilizer in two levels of inoculation and non-inoculation (one liter per hectare as seed) in subplots were assessed. The results showed that the non-inoculate seeds with Nitrocara under 50% irrigation regime and seed inoculation under 75% irrigation regime in the second year of the experiment resulted in the highest wheat grain yield with an average of 1901.5 and 1892.3 g/m2, respectively. The highest total biomass was related to the inoculation of seeds with Nitrocara along with the use of 1 mM silicon in the second year of the experiment under irrigation regime of 50% moisture depletion (8793.3 g/m2). In general, under low irrigation conditions, the use of Nitrocara biofertilizer as well as silicon foliar application led to improved physiological parameters and increased growth and yield indices of wheat in Sistan climatic conditions.

SALTMED model is one of the most practical tools for simulating soil salinity and crop production yield. Growth models are important and efficient tools for studying and evaluating the impact of different management conditions and scenarios on water, soil and plant relationships and can be used to make or predict appropriate management scenarios according to the region's conditions and to predict plant performance in the field. Since the performance of irrigation scenarios in field conditions are costly and time consuming, and due to the limited water resources in the country and the necessity of optimal water use in agriculture, using the efficient and generic models can be useful tool for simulating crop production and soil salinity variations. This research has been conducted in order to simulate soil salinity and yield production using SALTMED model in Azadegan Plain of Khuzestan province.

This study was carried out in wheat fields of Azadegan plain in Khuzestan province during 2014-2015 in three regions including Ramseh (as saline soil), Atabieh (as very saline soil) and Hamidieh (as control, non-saline soil). Three 10-hectare plots were selected in each area and a pilot with area of 2000 m2 was used for evaluation and measurement in each plot. First year data were used to calibrate the SALTMED model and second year field data were used to validate the model and to achieve the results in three conditions. The dominant soil texture in the area was clay loam. The quality of used irrigation water with average salinity of 2 dSm-1 was classified as C3-S1(high salinity with low sodium absorption ratio) and had no effect on wheat yield loss. In this study, version 3-04-25(2018) of SALTMED model was used and after calibrating in the first year, the results of simulated wheat grain yield and soil salinity variation values were used for model validation in different regions and in soils with different degrees of salinity, in the second year.

The average measured and simulated biomass yield in the first year were 6.6 and 6.1 t/ha, respectively. Furthermore, the average of measured and simulated of wheat grain yield was 2.9 and 2.6 t/ha, respectively. Some statistical indices including mean bias error, normalized root mean square error, and root mean square error for grain yield were 0.11, 0.04, and 0.12 t/ha, respectively. The values of the same statistical parameters for biomass were -0.49, 0.1, and 0.61t/ha, respectively. These results showed that the measured values of grain yield and wheat biomass were in good agreement with the simulated values using SALTMED model. The simulated and measured variations of soil salinity at three soil depths of 0-30, 30-60, and 60-90 cm, showed close agreement with each other in three layers. Root mean square error, normalized root mean square error, and mean bias error for soil salinity values were 1.3, 0.20, and -0.06, respectively. After calibrating the model in the first year, to validate this model in the second year, the results of three pilots locations in three regions of Ramseh (saline), Atabieh(very saline) and Hamidieh(non-saline) were used. Comparison of simulated and measured wheat grain yield and biomass values showed that there was no significant difference between simulated and measured values. The simulated values of grain yield and wheat biomass in the three non-saline, saline and very saline soils had high correlation with the measured values, indicating high accuracy and efficiency of this model in simulating grain and biomass yield in different degrees of soil salinity. Moreover, the trend of soil salinity changes simulated by the SALTMED model in three highly saline, saline and non-saline soils (for three soil layers) was close to the measured values. The SALTMED model with normalized root mean square error and mean bias error of 0.18 and -0.13, respectively, showed good accuracy in different salinity conditions. There was no significant difference (5% level) between the measured and simulated salinity values of the different soil layers. The mean standard error at the 0-30, 30-60, and 60-90 cm layers was 1.1, 1.05, and 0.81 dSm-1, respectively. Therefore, based on the results and statistical indices, it was found that SALTMED model had good accuracy and efficiency in simulating yield, biomass and soil salinity under different salinity conditions.

According to the results and statistical indices, SALTMED model had good performance and accuracy in simulating grain yield, biomass and soil salinity variations in different soil salinity conditions and so it can be used to predict wheat yield, yield components and soil salinity in different soil condition with different degrees of soil salinity to sustain soil and water and improve water productivity in similar areas.

Due to the limitations of field measurements of vegetation, the application of plant indexes to estimate rangeland biomass using satellite data can be very useful in rangeland studies. For this purpose, it is necessary to identify appropriate vegetation indices. The aim of this study is to investigate the possibility of estimating rangeland biomass using plant indices obtained from digital data of Landsat 8 satellite and determining the most appropriate ones in semi-arid regions of the northeast of the country. For this purpose, the average values of plant indices NDVI, TDVI, SAVI, ARVI, EVI, OSAVI, IPVI, GRVI, and GNDVI within each unit of one hectare of the studied basin network were calculated. Then, the correlation of these values with the average measured field values of these units was examined by linear regression, and the regression model of each index was determined to estimate biomass. Finally, the results were validated and a field biomass map was prepared for each index. The results showed that all indexes had a high and acceptable correlation with real biomass data. Based on the validation results, the SAVI plant index with a coefficient 0.79 and root-mean-square error of 14.73% was the most suitable plant index for estimating biomass in the region. By using the wavelengths located in the blue band, these indicators modify the effect of dust in the calculations, which reduces the atmospheric effect and improves the results of calculating the NDVI index, and it can be called the modified NDVI index. According to the results, plant indices obtained from the ratio of near and visible infrared bands are highly correlated with biomass. In general, the shorter the wavelengths used by plant indices, the lower the accuracy of estimates in arid and semi-arid regions.

Chia (Salvia hispanica L.), has achieved economic importance due to the products which are obtained from its leaves with antioxidant capacity and especially its seeds, because they contain omega 3. However, there is a lack of information on optimal agronomic management practices and especially the influence of water availability on its establishment and production. To evaluate the effect of various moisture regimes on some growth and physiological parameters of the medicinal plant of chia, a greenhouse experiment conducted at the university of Agriculture and natural Resources of Tehran, based on randomized complete blocks design with three replications.The treatments incorporate moist regimes that have been applied at 66, 57 and 43 and 35% Levels of soil Field capacity. Results demonstrated that diverce moisture regimes had a meaningful influence on most pre-examined parameters. Relative water content (RWC), the total biomass of plant, plant height, accessory branch, node number and the ultimate Leaf area decreased with increasing drought stress such that the lowest value of stated parameters is obtained in the 43% soil Field capacity. Also the highest value of ELI and root weighthad been obtained through 43% soil Field capacity. The lowest value of Fo and Fv/Fm was observed and affiliated with 66% and 43% soil Field capacity, respectively. Generally, concerning the decreasing trend of growth and physiological parameters of chia in response to drought stress and intolerance in severe water stress, it seems, in the growing stage, it needs to sufficient moisture to maintain the membrane function and Photosynthetic processes.

Wild Pistacia (Pistacia atlantica Desf.) from the Anacardiaceae family is drought and frost tolerant tree species. Due to the dormancy caused by physiological processes and hard and oily coating of the seeds, the reproduction and production of seedlings of this species are facing major obstacles. In this study, the effect of sowing bed, planting date and different pretreatments on wild pistachio seeds were studied in Tabriz's Elgolian nursery. In order to implement the experiment, a factorial design in a randomized complete block design with five replicates and three treatments including planting bed in three levels, planting date in two levels and pre-treatment in four levels were used. During the growing season, the diameter of the collar and seedling height were measured monthly. Also, the daily average germination, seed percentage and seed germination rate were also calculated. At the end of the growing season, biomass of the root and biomass of the stem were measured. Using gibberellic acid as a pretreatment increased seed germination percentage. In addition, the best vegetative traits were the planting bed 1 (1,1,1) and pretreatment 3 (cold, scraping and gibberellic acid) which are recommended for improving the growth and the rate of yield of wild pistachio seedlings in Elgoli nursery in Tabriz.

Pennyroyal (Mentha pulegium L.), Labiatae family, is widely used as a vegetable and medicinal herb. This plant commonly grows in the wet soils such as ditches, riversides and ponds. It is indigenous to the Central, Southern and Western Asia, North Africa, Ethiopia and the Canary Islands. It can also be found in Alborz, North and Northeast regions of Iran. The aerial parts of the plant are used as pharmaceutical and flavoring substances. The aim of this research was to find the best level of nitrogen fertilizer regime, harvesting time and plant density for pennyroyal plant in Rasht area.

This study was conducted as a split-plot experiment based on randomized complete block design with three replications in Faculty of Agriculture, University of Guilan. The main plots included two harvesting times, the subplots were four levels of Nitrogen fertilizer including control (without fertilizer), 50, 100 and 150 kg ha-1 Nitrogen and the sub-subplots were plant density at 3 levels; 10, 14 and 18 plants m-2.

The results showed that triple interaction of nitrogen, plant density and harvest time had significant effect on dry weight. The highest dry weight (1909 kg ha-1) were obtained by 150 kg ha-1 net nitrogen with the density of 18 plants per m2 for the first harvest. Moreover, 50 kg ha-1 nitrogen fertilizer treatment with 10 plants per m2 showed lowest amount of dry weight (396.66 kg ha-1) in the second harvest time. However, the interaction of nitrogen and planting density revealed significant effect on fresh yield and leaf area. The highest yield (8071 kg ha-1) was related to 150 kg ha-1 nitrogen treatment with the density of 18 plants m-2. About physiological traits, the results claimed that treatments significantly affected the essential oil percentage, total chlorophyll, total phenol, nitrogen and calcium elements. The highest essential oil content (2.66%) was exhibited by the treatment of 150 kg ha-1 nitrogen with plant density of 10 plants m-2. In addition, the essential oil yield was also influenced by the interaction effect of harvest time and planting density. The highest yield (25665/075 milliliters ha-1) was found by the plant density of 18 plants m-2 from the first harvesting time.

Finally, according to our results, the best treatment was first harvesting time, 150 kg ha-1 nitrogen with the density of 18 plants m-2, which can be recommended for the planting program of aromatic pennyroyal.

Maize is one of the important cereal crops in Iran. Moghan, in Ardabil province, is an appropriate region to grow it in the country. Redroot pigweed (Amaranthus retroflexus L.) is one of the major noxious weed in maize fields worldwide and also in Iran. To study the interference of effect of this weed on maize seed yield and its morphological characteristics, a factorial experiment based on randomized complete block design with three replications was carried out at the research field of Agricultural and Natural Resources Research Center of Ardabil (Moghan) in 2012. The experimental factors were maize plant densities with four levels (70000, 75000, 80000 and 85000 plant.ha-1) and redroot pigweed densities with four levels (0, 4, 8 and 12 plant/m per row). The results showed that increasing density of maize and redroot pigweed, grain yield, biological yield and chlorophyll content of maize leaves were significantly reduced. The highest grain yield (11.88 t.ha-1) at density corn of 80000 plants.ha-1 of maize under weed free condition and lowest grain yield (7.92 t.ha-1) at maize density of 75000 plants.ha-1 with the presence of the 12 plant/m per row of redroot pigweed. The highest biomass of redroot pigweed (497.8 g/m per row) was produced at density of 85000 plants.ha-1 of maize with the presence of the 12 plant/m per row of redroot pigweed. Generally, the results of this research showed that 80000 plants.ha-1 of maize resulted in highest control of redroot pigweed and grain yield.

Rapeseed is the most important edible oil source after soybean and palm in the world and is the most widely cultivated oilseed crop in Iran. The objective of this study was to adapt and test the ability of the AquaCrop model to simulate canola grain yield, biomass and soil water content. In this study, the dynamic simulation model AquaCrop for plant growth under conditions of limited water spring was used in climate Tabriz. The experimental design included four treatment I1, I2, I3 and I4 respectively regular watering of rape, 20, 35 and 50 percent less than its potential needs in four replicates in a randomized complete block design was carried out for two years 2010 and 2011. AquaCrop model using the measured data in 2010 calibration and validation data were measured in 2011. Based on found results, the AquaCrop model predicted the GY at maturity with a good precision and soil water simulated by AquaCrop tends to follow closely the trend in the measured data. In general, statistical indicators NRMSE and d for the final performance of the product (7.05%, 0.96), soil water content (16.03% and 0.77), respectively. Also Errors in the model’s evaluation such as average NRMSE statistics were for dynamic biomass in the calibration and validation process 29.31 and 20.38%. The overall results showed that AquaCrop is a valid model and can be used with a reliable degree of accuracy for optimizing canola grain yield production and water requirement in the region Karkag of Tabriz.

The current study was carried out in three locations of Fars province included Eghlid, Shiraz and Lar which have a cold, mild and hot-dry climate, respectively. The General Circulation Model HadCM3 under three emission scenarios A2, B1 and A1B in three future periods (2011-30, 2045-65 and 2080-99) was applied. APSIM crop model was also used to simulate the growth and yield of wheat. The Averaged across locations, scenarios and periods in the future, a rising trend was simulated for biomass and grain yield compared with the baseline largely owing to the increasing carbon dioxide concentration (531 ppm). As an example, the highest biomass and grain yield was observed with 2786 and 1051 g.m-2, respectively in Eghlid in 2080-99 under the A2 scenario. Furthermore, considering that the rate of photosynthesis will be increased by increasing the carbon dioxide concentration in the future period, it will have the rising trend compared to the baseline period. According to the result of simulations, the highest increase in LAI was obtained under A2 scenario for 2080-99 in all of locations (23.23%) while the lowest increase in LAI under A2 and B1 observed for 2011-30 (10.83%). The growth and relative growth rates will be increased by increasing of photosynthesis rate and biomass in the all future periods under different emission scenarios. Overall, the results showed that increasing the carbon dioxide concentration in the future resulted in increased NAR. Accordingly, the highest and lowest NAR was simulated for 2080-99 and 2011-30, periods.

Vegetation is one of the criteria indicating the production potential of the land. So that the quality and quantity of vegetation in each region is a criterion for determining its production potential. In this research, vegetation indices of Landsat 8 digital data were used to estimate vegetation cover and biomass in the protected area of the central Alborz in June 2016. To study the correlation between vegetation cover and biomass with satellite data, 27 samples were obtained randomly in the region. Linear regression was used to determine the relationship between cover percentage and biomass values with remotely sensed vegetation indices. The results showed that among selected vegetation indexes,  Enhanced vegetation index (EVI) and Visible atmospherically resistant index (VAR) had the highest correlation coefficient with vegetation percentage 0.53 and 0.52, respectively. Therefore, these vegetation indices are appropriate for estimating vegetation cover at a 5% significance level. And in calibration, the correlation coefficient for the wet weight of vegetation and the indices of Global environment monitoring index (GEMI), Simple ratio (VR) and Enhanced vegetation index (EVI) were 0.43, 0.41 and 0.41, respectively even though their estimations were unsuccessful in the validation stage. According to the results of this research, it is recommended that the indicators for the estimation of the quality and quantity of vegetation should be used in which the atmosphere and soil impacts are considered.

In order to assess the effects salicylic acid (SA) on corn, weeds, and some herbicide efficiency, a factorial experiment with two factor as randomized complete block (RCB) designed with three replications was conducted research field of university of Tabriz- Iran in 2015. The first factor 10 levels including 8 herbicide treatments (Bentason, Nicosulfuron, 2,4-D + MCPA, Bromoxynil + MCPA, Rimsulfuron, Nicosulfuron + Rimsulfuron, Mesotrion + S-metolacholor + Terbuthlazine, Udosulfuron + Foramsulfuron + Tincarbason), and 2 controls treatments (weed free and weed infest), and the second factor was SA with 2 levels (0 (distilled water), and 1 mM SA). Results show that SA can increase corn leaf area, and dry weight of leaf and stem. This increase was outstanding in herbicides that could successfully control weeds. SA in weed infested treatment, increased common lambesquraters (Chenopodium album L.) density and dry weight, as the main weed species observed in the field. So in presence of weeds, SA is more benefit for weeds. Nicosulfuron was weak in weed control, and SA application increased weeds density and dry weights. Bromoxynil + MCPA, Mesotrion + S-metolacholor + Terbuthlazine, and 2,4-D + MCPA were successful herbicides in reduction weeds density and dry weight, and their efficiency was not reduced in presence of SA. Therefore, in herbicide treatments with weak efficiency in weed control, usage of SA is more benefit for weeds. According to obtained results, applying SA is not recommended with weak efficiency herbicides in weed control.