mohammad bannayan

Drought in Iran is a climatic fact, and due to the growing water demand for the various sectors, the water scarcity problem will become more severe in the coming years. Due to the lack of water resources and proper use it, the importance of research on wheat irrigation by drip irrigation technique, has been increased in recent years. This study was carried out to investigate the effect of drip lateral distances and amount of net irrigation water on wheat crop water productivity in drip irrigation (tape) in two farms located in the Mashhad (MHD) and the Torbat-e-Heydariyeh(Jolgeh-Rokh) (RKH) with loam and clay loam soil texture respectively. The results of this study showed that the highest final net income was obtained in Mashhad (18183222 Rials) and in Torbat Heydariyeh (Rokh plain section) (15828426 Rials) from the treatment of 100 cm strip distance (drip method) with subsidies in mind. Therefore, tape distance of 100 cm was the most economical treatment in this study.

This study aimed to assess the environmental sustainability of wheat harvesting operation in rainfed and irrigated farming systems in three different locations in Iran, including Sari, Mashhad and Parsabad Moghan counties. Four sustainability indices of energy, emergy, exergy, and greenhouse gas emissions were investigated in this research. Results revealed that the energy efficiency of harvesting operation in irrigated systems was higher than that in rainfed systems. The emergy analysis results highlighted that the environmental sustainability indices for rainfed systems in Mashhad, Parsabad Moghan, and Sari were 0.047, 0.035 and 0.034, respectively. The values for the irrigated systems were 0.036, 0.035 and 0.034, respectively. The results of exergy analysis also indicated that the exergy efficiency of harvesting operation in rainfed and irrigated systems in Sari and Parsabad Moghan was higher than that in other areas by 56.07 and 128.72, respectively. Total GHG emissions of harvesting operation in Sari, Parsabad Moghan, and Mashhad in rainfed systems were determined to be lower than that in the irrigated systems (54.88, 47.64 and 36.03 kg CO2eq ha-1 versus 67.52, 66.56 and 59.22 kg CO2eq ha-1, respectively). In conclusion, the wheat harvesting system was environmentally more sustainable in Sari and Parsabad Moghan counties in rainfed and irrigated farming systems, respectively.

Drought in Iran is a climatic fact, and due to the growing demand for various parts of the water, the problem of water scarcity will become more acute in the coming years. Due to lack of water and for proper use of water resources, the importance of research on wheat irrigation by drip irrigation technique, has been increased in recent years. This study was carried out to investigate the effect of distance between drip lateral and amount of irrigation water on wheat water productivity in drip irrigation (tape) in two farms located in Mashhad (MHD) and Torbat-e-Heydariyeh(Rokh) (RKH) with Loam and clay loam soil texture respectively, were in the 96-95 crop year. The statistics design was complete blocks (factorial) and consisted of three lateral spacing (D1: spacing of 50 cm, D2: spacing of 75cm and D3: spacing of 100cm). The amount of irrigation water was also in three treatments (W1: 100%, W2: 75% and W3:50% of irrigation water requirement). The results showed that irrigation water treatment had significant effect on grain yield in both areas of the project and the highest yield was obtained from W1 treatment by 7537 and 5342 kg/ha in Mashhad and Torbat-e-Heydariyeh, respectively. Irrigation Lateral spacing also had significant effect on grain yield in both region and the highest yield was obtained from D1 treatment (7267 and 5920 kg/ha in Mashhad and Torbat-Heydariyeh, respectively). Interaction of irrigation water and Irrigation Lateral spacing (W-D) on water productivity in Mashhad region was insignificant but significant in Torbat-e-Heydariyeh region. The interaction showed that the best water productivity (1.72 and 1.52 kg/m3 in Mashhad and Torbat-e-Heydariyeh, respectively) was obtained in W3D1 treatment. Although W1D1 treatment (50 cm lateral spacing and 100% irrigation water) had the highest yield (8167 and 6104 kg/ha, respectively), they were in the c group in terms of productivity with W2D2 and W3D3 treatments.

Drought as one of the most important natural disasters affects communities directly through changes in access to water resources, resulting in major damage to human life and natural ecosystems.Agricultulal vulnerability can be referred to the degree that agricultural systems may experience harm due to a stress. In this study, for the purpose of quantitative measurement of meteorological drought The standardized precipitation indices (SPI), rainfall anomalies (RAI) and annual precipitation criteria (SIAP) were used based on the monthly precipitation of 6 meteorological stations in Razavi and southern Khorasan provinces during 30 years (1364-1394)in Iran. Saffron relative yield index was used to study the effects of meteorological drought on agriculture. The severity of droughts was in severe and very severe mode. The SIAP, RAI and SPI indices have shown a trend consistent with the crop indices of saffron. However, the SIAP and SPI were more favorable in terms of the severity of estimated droughts with relative performance index. Drought indices in saffron producing cities in Razavi and South Khorasan provinces over the past 10 years have been significantly correlated with relative decline in saffron yield during this period. The results showed that in all the study locations the saffron production was low sensitive to drought in this period.

Considering population growth and urbanization development, one of the main requirements of the urban society is to create appropriate life condition for dwellers. The microclimate is considered as one of the factors that affect the activity of people in the environment and in terms of tourist and recreational industry, it is considered as an important source of economic. Many climatic parameters such as temperature, relative humidity, radiation and wind speed can affect the quality of people's recreational activities. So far, many studies have been conducted in the world about the positive effects of vegetation specially trees in the urban landscape on the optimizing of microclimate and human thermal comfort. The cooling mechanism of trees and clouds in an area mainly by directly shading the ground surface and indirectly by supplying humidity are similar. Thus, perhaps it be possible to calculate the changes in temperature and relative humidity based on cloud categories and impute it to tree canopy and vegetation size. The purpose of the present study was to answer followed questions, 1) does the use of single tree produce a sensible difference in temperature and humidity relative to open space? 2) Does the acacia tree as an indicator for a broad-leaved species compare to the pine tree as an indicator for the needle species in terms of the microclimatic variation of around themselves act differently? 3) Do the microclimatic elements (Temperature and relative humidity) under the canopies are comparable to various cloudiness conditions? The experiments were conducted at Ferdowsi University of Mashhad. The climate data under two species of false acacia (Robinia pseudoacacia) and pine trees (Pinus eldarica) and open space were received from Mashhad weather station over a period of 19 years, recorded and analyzed. In the comparison of the effects of vegetation and cloudy conditions on the temperature and relative humidity an assumption was proposed that has been mentioned in the following. The differences between the means of temperature and relative humidity obtained under SKC (Sky Clear) cloudiness conditions and in open space; under SCT (Scattered Sky) conditions and pine trees; and under BKN (Broken Sky) conditions and false acacia tree must be equal or these differences must be statistically not significant. In addition to the effect of tree canopy, the effects of days and hours on the temperature and humidity were investigated. To analysis and also mean comparison, SPSS 16 software was used. The results showed that the temperature (decreasing) and relative humidity (increasing) were significantly different among various cloudiness conditions during 19 years. The results also indicated that between the temperatures recorded under the canopy of pine and false acacia trees, and also among of recorded relative humidity in two trees specious with corresponding outdoor spaces there were significant differences. Also, there were no significant differences among the temperature of the clear sky and the partly cloudy with that of the mostly cloudy sky. Further, clear sky and mostly cloudy sky showed significant differences in terms of relative humidity. Mostly cloudy sky and the partly cloudy sky compared with pine and false acacia trees were about 4.6 and 4.5oC cooler, respectively. The cloud covers, also could enhance the more level of relative humidity in the environment in comparison with single tree canopy, so that were caused a wetter environment equal to16.6 and 8.4 percent, respectively. The results also showed that temperature and relative humidity created by the shade from false acacia and pine trees are not comparable with the same climatic factors created by partly cloudy and mostly cloudy skies. In the present study, false acacia as a broad-leaved tree compared with pine tree and also open space could cool the environment about 0.65 degree C more that is in line with previous studies that showed the microclimatic impact of vegetation depend on crown and leaf size. Temperature and relative humidity in vegetation (trees) and cloudy condition are not comparable with microclimate and their impact on the environment is not the same. The cloud covers, also could enhance the more level of relative humidity in the environment in comparison with single tree canopy, so that were caused a wetter environment equal to16.6 and 8.4 percent, respectively. This finding showed that climatic effects of cloud covers had no similarity compared with two studied trees species. It may also indicate that green space and greenery should not also be ignored in areas where cloudy skies are mostly present throughout the year.

Estimating crop water requirement, crop yield and their temporal and spatial variability using crop simulation models are essential for analysis of food security, assessing impact of current and future climates on crop yield and yield gap analysis, however it requires long-term historical daily weather data to obtain robust predictions. Depending on the degree of weather variability among years, at least 10–20 years of daily weather data are necessary for reliable estimates of crop yield and its inter-annual variability. In many regions where crops are grown, daily weather data of sufficient quality and duration are not available. In this way, gridded weather databases with complete terrestrial coverage are available which require comprehensive validation before any application. These weather databases typically derived from global circulation computer models, interpolated weather station data or remotely sensed surface data from satellites. The aims of this study were to evaluate differences between grided AgMERRA weather data and ground observed data and quantify the impact of such differences on simulated water requirement and yield of rainfed wheat at 9 different locations in Khorasan Razavi province.
AgMERRA dataset (NASA’s Modern-Era Retrospective analysis for Research and Applications) was selected as the girded weather data source for use in this study because it is publically accessible. We evaluated AgMERRA weather data against observed weather data (OWD) from 9 meteorological stations (Torbat Jam, Torbat Heydarieh, Sabzevar, Sarakhs, Ghoochan, Kashmar, Gonabad, Mashhad, and Neyshabour) in Khorasan Razavi province. For each weather variable (solar radiation, maximum temperature, minimum temperature, precipitation, and wind speed), the degree of correlation and agreement between OWD and AgMERRA data for the grid cell in which weather stations were located were evaluated. The intercept (b), slope (m), and coefficient of determination (r2) of the linear regression were calculated to determine the strength and bias of the relationship, while the root mean square error (RMSE) and normalized root mean square error (NRMSE) were computed to measure the degree of agreement between data sources. Crop water requirement or actual crop evapotranspiration (ETc) under standard condition was computed using CROPWAT 8.0. The CSM-CERES-Wheat (Cropping System Model-Crop Environment Resource Synthesis-Wheat) model, included in the Decision Support System for Agrotechnology Transfer (DSSAT v4.6) software package was used to calculate rainfed wheat yield. For each location in this study, rainfed wheat grain yield and water requirement were simulated using ground-observed and AgMERRA weather data and outputs were compared with each other.
The results of this study showed that AgMERRA daily maximum and minimum temperature and solar radiation showed strong correlation and good agreement with data from ground weather stations. AgMERRA daily precipitation had low correlation and good agreement (mean r2= 0.34, RMSE= 2.25 mm and NRMSE= 4.94% across the 9 locations) with OWD daily values, but correlation with 15-day precipitation totals were much better (mean r2 >0.7 across the 9 locations). There was reasonable agreement between a number of observed dry and wet days with AgMERRA compared to OWD. Results indicated that coefficient of variation of simulated water requirement and yield using AgMERRA weather data was remarkably similar to the degree of variation observed in simulated water requirement and yield using OWD at all locations (distribution of CVs in simulated water requirement and yield using AgMERRA weather data were within ±5% of the CV calculated for simulated water requirement and yield using observed weather data) except Torbat Jam, Torbat Heydarieh and Gonabad for water requirement and Mashhad, Kashmar and Ghoochan for yield. There was good agreement between long-term average yield simulated with AgMERRA weather data and long-term average yield simulated using observed weather data. For example, the distribution of simulated yields using AgMERRA data was within 10% of the simulated yields using observed data at all locations. Using AgMERRA weather data resulted in simulated crop water requirement that were not in close agreement with crop water requirement simulated with ground station data at two location including Gonabad and Torbat Heydarieh.
These results supported the use of uncorrected AgMERRA daily maximum and minimum temperature and solar radiation in areas that their weather stations only have a few years of daily weather records available or areas without weather station. Considering the advantage of continuous coverage and availability, use of AgMERRA dataset appears to be a promising option for simulation of long-term average yield and water requirement, as well as for assessing impact of climate change on crop production and also estimating the magnitude of existing gaps between yield potential and current average farm yield in Khorasan Razavi province. But they are not very reliable for accurate simulation of water requirement and yield in a specific year and estimate their inter-annual variation.

In recent decades, dramatic global population growth along with other related factors such as economic and industrial development, land use/cover change has contributed to an overall effects on water security and environmental problems around the world. To sustainable water management, quantifying the impacts of human activities on local hydrological cycle and water yield is essential in order to control balance between water demand and supply and increasing water security. This paper aims to offer a better characterization of human activities on groundwater stress and sustainability. Herein, we presented an approach for evaluation of water budget to facilitate understanding of the entire flow system of the aquifer in order to inform sustainable water resources management. We used a simple approach for quantifying direct human-hydrologic interactions by analyzing the aquifers’ water budget including human withdrawals (Hout) and return flows (Hin) according to water-balance equation and then normalized them relative to the net flux (Net Flux). Based on the normalized values of human inflow and outflow, the water-use regimes can be classified as surcharged (S), depleted (D), natural-flow dominated (Nf), and human-flow dominated (Hf). In addition we determine groundwater overdraft as a ratio between human withdrawals (Hout) and Recharge (RT) in order to evaluate the flow condition relative to the human water use. Finally we considered two adaptation scenarios to investigate probability of shift of aquifers that are located to depleted regime area to natural-flow dominated area. The results show that half of the studied aquifers in the Karkheh River Basin are of natural-flow dominated type while the rest are depleted. The Asadabad aquifer shows the highest amount (471 mm/yr) of human withdrawals (Hout) in this basin; actually highest overdraft relative to natural recharge to aquifer. Based on investigation of adaption scenarios, we explored that considering adaptation scenarios and decreasing human activities between 10 to 30 percent can be very useful for some aquifers in this basin.

Changes of ET0 and its atmospheric control were investigated in six stations located in West Iran during the period of 1966-2100. The outputs related to HadCM3 under B2 emission scenario were downscaled through SDSM. The results revealed that ET0, as averaged across all stations, would increase by 5.12, 7.33 and 11.01% respectively over the early, middle and late 21st century relative to the baseline period (1966-2010). The results obtained through Mann-Kendall test revealed that there was an insignificant positive trend in ET0 at the level of 95% over 1966-2010 in most of the surveyed sites. This increasing trend could be explained by an upward trend in temperature and solar radiation vs. a negative trend of relative humidity within the study area. The increasing trend in ET0 will likely be significant during 2011-2040 and 2071-2100 while insignificant during 2041-2070. The occurrence of ET0 upward trend in the future is most likely due to temperature rise.

Agricultural biodiversity is considered as one of the key factors determining the sustainability of agroecosystems. Preservation of biodiversity and its effective management have an important role in achieving economical, social and environmental measures of agroecosystem sustainability, hence it is essential that through precise evaluation of diversity trend in agricultural landscapes, while its preservation, effective steps also accomplish to proper management of diversity with considering the regional characteristics. Hence, current study was carried out with the aim of evaluation and analysis the changes in crop biodiversity of Isfahan province during 2003-2012 using ecological indices of diversity, including Margalef richness index, Evenness index and Shannon diversity index. Evaluation of variation trends of study indices showed that during 2003-2012 period, crop area, evenness index, Shannon index and beta diversity of Isfahan crops have significantly decreased. The downward trend of Isfahan province’s crop plants Shannon index indicated that during this period, the crop species biodiversity of Isfahan province has decreased. As, the Shannon index value of Isfahan crop species was decreased from about 2.30 in initial years of 2003-2012 period up to 2.15 in its terminal years. Results showed that significant decrease in evenness of crop area distribution and also significant reduction of crop area due to continues droughts and land use changes are among the main reasons for decline in crop diversity of Isfahan province during study period. According to cluster analysis, the townships of Isfahan province were also classified into six groups regarding their ten years average of Shannon diversity index.

Introductionin current situation when world is facing massive population, producing enough food and adequate income for people is a big challenge specifically for governors. This challenge gets even harder in recent decades, due to global population growth which was projected to increase to 7.8 billion in 2025. Agriculture as the only industry that has ability to produce food is consuming 90 percent of fresh water globally. Despite of increasing for food demand, appropriate agricultural land and fresh water resources are restricted. To solve this problem, one is to increase water productivity which can be obtain by irrigation. Iran is not only exempted from this situation but also has more critical situation due to its dry climate and inappropriate precipitation distribution spatially and temporally, also uneven distribution of population which is concentrate in small area. The only reasonable solution by considering water resources limitation and also restricted crop area is changing crop pattern to reach maximum or at least same amount of income by using same or less amount of water. The purpose of this study is to assess financial water productivity and optimize farmer’s income by changing in each crop acreage at basin and sub-basin level with no extra groundwater withdrawals, also in order to repair the damages which has enforce to groundwater resources during last decades a scenario of using only 80percent of renewable water were applied and crop area were optimize to provide maximum or same income for farmers.
Materials and methods The Neyshabour basin is located in northeast of Iran, the total geographical area of basin is 73,000 km2 consisting of 41,000 km2 plain and the rest of basin is mountains. This Basin is a part of Kalshoor catchment that is located in southern part of Binaloud heights and northeast of KavirMarkazi. In this study whole Neyshabour basin were divided into 199 sub-basins based on pervious study.Based on official reports, agriculture consumes around 93.5percent of the groundwater withdrawals in Neyshabour basin and mostly in irrigation fields, surface water resources share in total water resource withdrawals is about 4.2percent, which means that groundwater is a primary source of fresh water for different purposes and surface water has a minor role in providing water supply services in the Neyshabour basin. To determine crop cultivation area, major crops divided into two groups. two winter crops (Wheat and Barley) and two summer crops (Maize and Tomato). To accomplish land classification by using supervised method, a training area is needed, so different farms for each crop were chosen by consulting with official agricultural organization expert and multiple point read on GPS for each crop. The maximum likelihood (MLC) method was selected for the land cover classification. To estimate the amount of precipitation at each 199 sub-basins, 13 station data for precipitation were collected, these stations are including 11 pluviometry stations, one climatology station and one synoptic station. Actual evapotranspiration (ETa) is needed to estimate actual yield (Ya). Surface Energy Balance Algorithm for Land (SEBAL) technique were applied on Landsat 8 OLI images. To calculate actual ETa, the following steps in flowchart were modeled as tool in ArcGIS 10.3 and a spreadsheet file. To estimate actual crop yield, the suggested procedure by FAO-33 and FAO-66 were followed. Financial productivity could be defined in differently according to interest. In this study several of these definition was used. These definitions are Income productivity (IP) and Profit productivity (PP). To optimize crop area, linear programing technique were used.
Results and discussion average actual evapotranspiration result for each sub-basin are shown in context. In some sub-basins which there were no evapotranspiration are shown in white. And it happens in those sub-basins which assigned as desert in land classification. In figures 8 and 9 minimum amount of income and profit productivity for wheat and barley is negative, this number means in those area the value of precipitation is higher than value of evapotranspiration, so lower part of eq. 21 and 22 would be negative and in result water productivity would be negative. Since most of precipitation occurs during cold season of the year these numbers are expected. Two sub-basins of 43 and 82 has the value of negative, it means in these two sub-basins groundwater are recharging during the year 2014-2015.The maximum value of income and profit productivity belong to wheat and barley which are winter crops and mostly rain fed, so amount applied water would be so low and in result productivity increased. Among the summer crops maize has the most income and profit income which can be interpret due to their growing period and the crop types. Maize has around 110 days to reach to maturity and harvest, on the other hand tomato needs 145 days to harvest. Some plant is C3 and some are C4. C4 plants produce more biomass than C3 crops with same amount of water which leads to more productivity. The results showed that tomato should have the most changes in area reduction (0.2) and maize should have no changes in both scenarios. Crop area should reduce to 66percent of current cultivation area to maintain ground water level and only 6percent reduction in cultivation area would result in 20percent groundwater recharging.
Conclusion to save groundwater resources or even retrieve the only water resource, cultivation area must reduce if the crop pattern will not change. In this study only four crops were studied. It seems best solution is to introduce alternative crop.

With regard to two adverse climatic phenomena of urban heat islands and global warming that has been leading to increase temperature in many cities in the world, providing human thermal comfort especially in large cities with hot and dry climates, during the hottest periods of the year is crucial. Mainly vegetation with three shading, evapotranspiration and wind breaking can affect micro-climate. The aim of this study was to asses and simulate the impact of existing and proposed vegetation on the human thermal comfort and micro climate changes in some residential areas of Mashhad during the hottest periods of the year by using a modeling and computer simulation approach.
This research was performed in the Ghasemabad residential area, Andisheh and Hesabi blocks, and in the hottest period of the year 2012 in Mashhad. Recorded data in the residential sites along with observed data from Mashhad weather station that included temperature, relative humidity, wind speed and direction. Soil data (soil temperature and humidity, soil\ type), plant data (plant type, plant height, leaf area index) and building data (inner temperature in the building, height and area buildings) as input data were used in the ENVI-met model. Both two sites, Andishe and Hesabi residential blocks, with vegetation (different trees and bushes plants, for example Acacia, ash, sycamore, mulberry, chinaberry, barberry, boxwood and Cotoneaster that all of them are tolerant and semi-tolerant to drought) about 20% were simulated. Regarding the area of simulating, 3 receptors were considered in per sites. Simulation was commenced from 6 AM and continued until 18 pm, but just data of 11-15 hours were analysed (the hours of peak traffic).
Analysis of outputs data revealed that the temperature of two residential sites in all three receptors during the study were almost the same. In general, the maximum temperature difference between receptors was obtained at 13 hour. The trend of relative humidity changes was very similar in both residential sites. In these two sites the most differences in the relative humidity was obtained at 12 oclock.. In addition, the trend of Predicted Mean Vote (PMV) in Andisheh residential block showed that these changes in central and south-west part of the site were similar. The simulation with vegetation in the sites, also, showed that the trend of temperature and relative humidity changes were similar. The trends of temperature changes in residential site, Hesabi, in the defined receptors were very similar. So that temperature increased from 12 oclock to 15. While the trend of relative humidity changes was quite the reverse. This study results showed that the difference in temperature, relative humidity and PMV between measured and simulated data were minimal in both residential sites. Moreover, the data comparison of PMV indicated that in both residential sites, despite of simulation with vegetation, the human thermal comfort did not improve, so that these sites were in the range of extreme heat stress. There are several reasons to justify this issue, such as the percentage and the type of vegetation, factors related to the topography and geography of area, building distribution and density, type and color of the building materials and surfaces, etc. However, in this part of the study, other factors were constant, except vegetation. It seems that with increase of percentage and the ratio of vegetation, changes in temperature, relative humidity and other micro-climate factors, are created, but sometimes for the reasons stated, the temperature during the hottest period of the year is too high so that increase in vegetation will have little impact on outdoor thermal comfort. It might be the simulated area on these sites as well as the type and the ratio of the selected species to reduce the temperature and increase the relative humidity have been not adequately represent all conditions which be able to improve thermal comfort.
In this study eventually we can conclude that in the simulated sites with about 20 percent vegetation cover,, despite the slight decrease and increase in temperature and relative humidity, respectively compared with the real sites, the thermal comfort range was similar. It is advisable in the future studies to simulate the green area in shape of the vertical and horizontal, changes in species composition in green area like trees, shrubs, and cover plants and also the test of different combinations of type and percentage of vegetation.

In this study, changes of aridity index (AI), reference evapotranspiration (ET0) and precipitation were investigated in six stations located in the west and northwest of Iran over 1966-2010, 2011-2040, 2041-2070 and 2071-2100 periods. The outputs of HadCM3 under A2 and B2 emission scenarios were downscaled using statistical downscaling approach by Statistical downscaling model (SDSM). Mann-Kendall trend test was applied to assess the significance of trends of aridity index, reference evapotranspiration and precipitation in 1966-2010. The results of Mann-Kendall test revealed that there was a significant decreasing trend in AI and precipitation at the level of 95% over 1966-2010 in most of the surveyed stations. The negative trends of AI during winter, spring, summer and autumn were significant at five, four, zero and two of six surveyed stations, respectively. This indicates that reduced wintertime aridity index plays an important role in downward trend of annual aridity index in the studied area. The results also showed that AI, averaged across all stations, would decline by 8.0, 14.7 and 34.3% under A2 and 12.6, 12.5 and 20.1% under B2 over the early, middle and late 21st century relative to the baseline period (1966-2010), respectively, indicating a drier climate in northwest and west of country over the 21st century. On seasonal scale, the greatest decrease of AI is expected in summertime under A2 and springtime under B2 over the 21st century. AI, averaged over all stations, will most likely approach 0.2 indicating a severe reduction of aridity index in the studied area under A2. In some regions such as Tabriz, increased ET0 and decline of precipitation will cause a shift from semi-arid to arid climatic condition over the 21st century.

Leaf area index, light extinction coefficient and radiation use efficiency are important eco-physiological characteristics for realization of crops growth, development and radiation absorption. In order to determine the leaf area index (LAI), light extinction coefficient (K) and radiation use efficiency (RUE) of saffron during the first and second growing seasons, four experiments were started in 2011 and ended in 2014, at the Research Farm of the Agriculture Faculty, the Ferdowsi University of Mashhad, Iran. Saffron corms with weights between 13 to15 g and density of 50 plant.m2 were cultivated in 2011 and 2012. In all experimental years during the growing season, crop sampling was taken for required measurements including the leaf area index and shoot dry weight of saffron once every 14 days. The results showed that by increasing the age of saffron from 1 year to two years, the maximum LAI of saffron increased from 0.33 to 1.81, and light extinction coefficient decreased from 1.20 to 0.54. The increasing trend of LAI was coincident with fraction of absorbed radiation for all four years of the experiment. In the first and the second growing seasons, the amount of fraction of absorbed radiation gradually increased with increasing LAI and at 1083 and 1034 GDD reached its maximum value, respectively. In saffron farms when the plant was one year old and two years old, the mean value of RUE was 0.68 and 1.73 g.MJ-1 PAR, respectively. These results indicate that by increasing the saffron age and LAI, the value of K decreases and consequently radiation absorption and use efficiency will‎ increase.

In order to study the effects of different irrigation regimes and nitrogen fertilizer levels on yield and yield components of chickpea (ILC482)، a field experiment involving chickpea genotype ILC482 was conducted as factorial arrangement based on a randomized complete block design with four replications in the Agricultural Research Station، Ferdowsi University of Mashhad during growing season of 2012-2013. Experimental treatments were including nitrogen fertilizer (as urea) at three levels: 30، 75، 150 kg N ha-1 and irrigation regimes at three levels: full irrigation، irrigation at flowering، irrigations at both flowering and podding. Studied traits were included seed yield، biological yield، harvest index، 1000- seed weight، seeds per pod، pods per plant. The results showed that the different irrigation regimes and nitrogen fertilizer levels had significant effect on seeds per pod، pods per plant، 1000- seed weight، seed weight per plant، seed yield، biological yield and harvest index. Interaction between irrigation and nitrogen was significant except for harvest index. In this study، the highest values of the traits (except for biological yield) were obtained under full irrigation along with 75 kg N ha-1. In addition، applying irrigation at flowering accompanied with 150 kg N ha-1 decreased yield and its components. Full irrigation plus 150 kg N ha-1 produced highest (8. 9 t ha-1) biological yield، while grain yield was 1854 kg ha-1. Overall، full irrigation along with nutritive optimal levels، especially nitrogen at 30 and 75 kg ha-1 levels، during critical growth periods of chickpea could increase grain yield of chickpea.

Wheat is the world's most important strategic products that are of particular importance in the diet. Wheat in rain fed agriculture is of main pillars so that these parameters can be fed as the only source of water. This study on 6 synoptic Station the provinces of North, Razavi and South Khorasan. In this study are used of 25 years of 6 synoptic stations meteorological data of Khorasan and wheat yield the years 1362 to 1387. First, Evaluation of rainfall data during wheat the growth period and water requirement satisfaction index (WRSI) in the area of precipitation and Evaluation evapotranspiration product. The results of the long-term average of Birjand station 44.72 percentage, that the lowest among the studied stations on the appropriate region of wheat planting is not dryland has been accompanied by high risk. The stations studied the long-term average of Mashhad and Ghochan 92.87 and 92.27% of the highest value of this index are based on these regions are highly suitable for dryland wheat and low risk are important for dryland cultivation of wheat.

Nitrogen (N) fertilizer that used to raise seed yield can affect weed competition. In order to study the effect of N arte and growth habits on dry bean competitiveness, a two-year field experiment as complete block design were conducted with factorial arrangement and three replications at a field experiment of Tarbiat Modares University in 2009 and 2010. First factor included determinate erect (cv. D81083) and indeterminate semi-erect (cv. Gholi) dry bean growth habits. Second factor was N application rates at 0, 25, 50 and 100% of recommended N rate on the basis of the grain yield goal for each genotype. Third factor was redroot pigweed densities of 0, 2 and 14 plants m-1. N application increased leaf chlorophyll and leaf area index for both bean genotypes when they grown under no and low weed density. Under high weed density, the maximum N application compared with no N application increased leaf chlorophyll for Gholi cultivar; however leaf chlorophyll for D81083 line increased at 50 and 100 % of maximum N requirement. Under high weed pressure, N application had no significant effect on leaf area index for D81083 line and decreased the leaf area index for the Gholi cultivar. The increase of weed density decreased leaf area index in both bean genotypes. An increase in N fertilizer increased seed number and see yield for both bean genotypes when they grown under no and low weed density. The maximum seed yield loss associate with redroot competition obtained at high N rate and high weed pressure.

Determination of the best amount of n itrogen (N) fertilizer appl ication in maize that results in h igh grain yieldunderweed competition is of great importance. In order to study the effect of weed competi tion on ma ize performanceandidentifying whether or not N application rate affects by weed species, an experiment was conducted in 2008 at the Research Field of Tarbiat Modares University. The experi ment was establ ished as a randomized completeblockdesign with factorial arrangement of treatments and three repl ications. First factor was N fertil izer at the three following rates: 138, 184 and 230 kg N ha- 1. Second factor consisted of two weed species; i.e. redroot pigweedandproso-millet. Third factor was planting each weed species at low and high densities. Yield and yield components of maize was assessed atfinal harvest.Results indicated that weed competition significantly reduced maize grain yield compared to230kgN ha-1 controltreatment. Thehighest grain yield (1077gm-2) wasachieved intreatment 230kg N ha-1 whilethe lowestyieldsbelonged tohighdensitiesofredrootpigweed andproso-millet fertilized with 184and 230kgN ha-1,respectively (643and 565gm-2). Increasing milletdensity resulted in significant lossofmaize grain yield only.Maize grainyields in competition with lowdensitiesofproso-millet andpigweed were 800and 795gm- 2, respectively which reduced to 693gm-2 when weed densities increased. Difference in N application rate did not cause significant differences in yield components of maize under weed competition. However, high densities of proso-millet and redroot pigweed resulted in significant reductions ofthenumber ofrows per earand thenumberof grainsperrow,respectively. Overall, results indicated that in fieldswhere anitrophilespecies isthedominant weed species, increasingN application ratebeyond theoptimum ratenot onlydoesnot increase maize grain yield but also reduces its yield and causes pollution ofenvironment.