Showing 8 results for Zahedi
A. Karimi, E. Rowghani, M. J. Zamiri, M. Zahedifar,
Volume 8, Issue 1 (spring 2004)
Abstract
An experiment was carried out to determine the effect of substituting alfalfa hay (Medicago sativa) with Gundelia tournefortii hay (a range forage in Fars Province) in the ration of fattening lambs. Alfalfa hay was substituted with Gundelia tournefortii harvested at the final stages of flowering at various ratios (0, 25, 50, 75, and 100% dry matter basis) in the ration of fattening lambs. The rations (iso-nitrogenous and iso-energetic) were pelleted and each ration was fed for 75 days to 12 Shirazi Grey ram lambs with an average age of 136 days. The lambs were slaughtered and their feedlot performance and carcass characteristics were measured. Substituting alfalfa hay with Gundelia tournefortii hay did not significantly affect the mean daily weight gain, feed consumption, feed conversion ratio, dressing percentage, internal fat weight, carcass meat content, or meat DM and CP contents (p>0.05). However, backfat depth was significantly different among various rations (p<0.01). At present costs, the inclusion of Gundelia tournefortii in the ration of fattening lambs seemed to be cost-effective the cost of one kg DM of ration was 1266, 1155, 1050, 924, and 787 Rials for rations 1 to 5, respectively.
N. Zahedifard, S. J. Khajeddin, A. Jalalian,
Volume 8, Issue 2 (summer 2004)
Abstract
Satellite data use is finding global applications because they provide repeated cover, broad information, high electromagnetic spectral resolution, and software-hardware compatibilities. This study aims to evaluate of the Landsat TM data capabilities in land-use mapping of Bazoft River basin (Chahar Mahale Bakhtiary Province). Six spectral bands of the Landsate TM were employed to produce land-use map of the Region. The date of image acquisition was May 5th, 1998. Performance of the geometric correction completed with RMSE= 1.008 pixels. Various image enhacement methods (e.g. FCC, filtering and Vegetation Indices) were used to study the different land-covers. Field investigations were carried out using a GPS, 1:50000 scale topographic map and false color composites images. Heterogeneous land-use units were studied in 62 sample sites estimating percentage of vegetation cover. A regression analysis was performed between percentage vegetation covers and vegetation indices values of NDVI, RVI, SAVI, DVI, TSAVI1, NRVI and MSAVI2. Results show that NDVI, SAVI, TSAVI1, NRVI and MSAVI2 have high correlation coefficients. But RVI, DVI and PVI have low correlation coefficients. The resulting values of vegetation cover were density sliced to produce the land-cover map. After supervised classifications and density slicing of Vegetation Indices, classifacation accuracy was assessed and, finally, land-use map of the study area was produced with Hybrid classification method. Supervised classification with maximum likelihood method was the best technique for land-use mapping in the study area the total Kappa index was %87. In general, detection of some land-use classes through single date TM data is not feasible, these include: scattered forest trees with cultivated understory, annual grasses, and fallow lands. Also TM digital data are incapable of distinguishing small and separated rural constructions or soil-covered routes.
N Pourghasemin, M Zahedi,
Volume 13, Issue 47 (4-2009)
Abstract
This experiment was conducted at the Agricultural Research Station of Isfahan University of Technolgy in 2006 to evaluate the effects of planting pattern and the level of soil moisture on two safflower cultivars. A factorial split plot arrangement was used in a randomized complete block design with three replications. Two planting patternS (flat and bed planting) and two levels of soil moisture (irrigation after 80 and 100 mm cumulative evaporation from Class A pan) were considered as the main factor and two safflower cultivars (IL 111 and Kosseh) as minor factor. Each plot in flat planting consistedof six rows, spaced 25 cm apart with plants 8 cm apart and in bed planting consisted of four rows, spaced 45cm apart with plants 5 cm apart. The duration from planting to button formation, 50% flowering, and 100% flowering stage were significantly shorter in 45cm bed planting than in 25cm flat planting. The duration from planting to all growth stages was less in IL 111, compared to Kosseh cultivar. The level of soil moisture did not affect the duration of any growth stages. Plant height, leaf area index, plant dry matter, number of buttons per plant, number of grains per button, grain weight, and harvest index were higher in flat planting, compared to bed planting. Plant height, plant dry matter, number of buttons per plant, number of grains per button, grain weight, and harvest index were reduced as the level of soil moisture was decreased. Leaf area index and plant dry matter were not significantly affected by the level of soil moisture at 50% flowering stage. Regardless of the level of soil moisture and cultivar, the grain yield was 36% more in flat planting than bed planting. The grain yield was more at higher level of soil moisture and also in Kosseh than in IL 111. The oil percentage and oil yield was higher in flat planting, compared to bed planting and also in Kosseh than in IL 111. The oil percentage was not significantly affected by the level of soil moisture. However, the oil yield was decreased as the level of soil moisture was reduced. The highest amount (1168 kg/ ha) of oil yield was obtained from Kosseh in flat planting and the lowest amount (417 kg/ ha) was achieved from IL 111 in bed planting. The results from this experiment show that to obtain the optimum yield from summer planting in areas with similar conditions to that of this study the 25cm flat planting compared to the 45cm bed planting, and Kosseh compared to IL 111 cultivar seems to be superior.
M Gorgi, M Zahedi, A. H Khoshgoftarmanesh2,
Volume 14, Issue 53 (fall 2010)
Abstract
An experiment was conducted in order to evaluate the effects of increased concentration of potassium and calcium in hydroponic nutrient solution on the response of safflower to salinity. The experiment was carried out in a glasshouse using a completely randomized design. Four saline treatments (Johnson solution containing 100 mM of NaCl, Johnson solution containing 100 mM of NaCl + 10 mM potassium, Johnson solution containing 100 mM of NaCl + 5 mM calcium, Johnson solution containing 100 mM of NaCl + 10 mM potassium + 5 mM calcium) and Johnson solution without any addition of salt as control. Leaf area per plant, shoot and root dry matter was decreased in saline treatments. The concentration of potassium and calcium in the plants were decreased but those of sodium were increased at salinity. The extent of shoot and root dry mater reduction with salinity was less in saline treatment with additional calcium alone. The addition of potassium into the nutrient solution could not mitigate the negative effects of salt stress on the plants. Increasing the concentration of both potassium and calcium in saline nutrient solution resulted in a greater reduction of shoot dry matter. The results showed that the negative effects of salinity may be alleviated by increasing the concentration of calcium in nutrient solution.
M. Zahedifar , N. Karimian , A. Ronaghi , J. Yasrebi , Y. Emam ,
Volume 14, Issue 54 (winter 2011)
Abstract
The effect of phosphorus (P) (0, 25, and 50 mg kg-1 soil as Ca(H2PO4)2) and organic matter (OM) (0, and 2% w/w feedlot cattle manure) on P and zinc (Zn) distribution in different parts of wheat plant (Triticum aestivum L.) at various growth stages and its relationship with soil P and Zn were determined in greenhouse condition. In all pots, shoot P concentration decreased as plant growth proceeded. Phosphorus concentration of shoot and flag leaf decreased from 7th to 9th stage of growth, whereas that of spickle increased. Spickle P uptake and Zn uptake of stem, shoot, flag leaf, and spickle increased with proceeding of wheat growth. Phosphorus uptake of shoot increased from 3th to 9th growth stages, whereas P uptake of stem and flag leaf decreased from 7th to 9th growth stages. Soil P and Zn concentrations increased with application of P and OM and plant growth. The trend of P and Zn changes in shoot, stem and flag leaf was similar. It is, therefore, concluded that analyzing flag leaf for P and Zn concentrations be used for prediction of plant nutritional status of those nutrient elements in cases where such information is needed.
A. Hassanpour, M. Zahedi, A. H. Khoshgoftarmanesh,
Volume 18, Issue 68 (summer 2014)
Abstract
In a pot experiment, the effect of soybeans, mung beans and beans on the corn and sunflowers in a cadmium contaminated soil was studied in a completely randomized design with three replications. The treatments consisted of intercropping of corn and mung bean corn and beans, corn and soybean, sunflower and mung bean, sunflower and beans, sunflower and soybean monoculture of corn, and monoculture of sunflower. There were significant effects of cocropping of companion crops on shoot dry weigh, the concentration of cadmium and zinc and the chlorophyll content of corn and sunflower. In this study the shoot weight of corn grown with bean and soybean and that of sunflower grown with bean plants was decreased as compared to the related monocultures. The concentration of cadmium was increased in the corn grown with soybean or mungbean and in sunflower grown with soybean. Co- cropping with bean plants had no significant effects on the concentration of cadmium in corn or sunflower. Among companion crops, the concentration of cadmium was higher in bean plants compared to those of soybean and mungbean plants. The chlorophyll content in the leaves of corn plants grown with mungbean was increased with an increase in cadmium concentration. However, this trend was not observed in other treatments. The results of this study show that co- cropping with either soybean or mungbean may increase cadmium uptake by corn and sunflower which in turn may increase the risk of inflowing of toxin cadmium into the food chain. However, further study needs to re-evaluate the effect of these companion crops on the distribution of cadmium in the edible parts of corn and sunflower.
E. Zahedi, F. Jahanbakhshi, A. Talebi,
Volume 20, Issue 77 (Fall 2016)
Abstract
In this research, to locate and prioritize suitable areas for flood spreading in Mashhad plain, 10 criteria were used including land use, slope, alluvium thickness, distance to well, distance to subterranean, distance from the village, water table drawdown, permeability coefficient, electrical conductivity, and drainage density. Weighting process was done by Analytic Network Process (ANP) and fuzzy logic. After preparing and weighting the maps of all appropriate measures for locating suitable areas of flood spreading maps based on fuzzy logic and analytic network process model, the final map was prepared for prioritizing suitable areas for flood spreading. Then by applying the limiting layer that is a combination of three criteria of land use, slope and geomorphology, the final map of suitable areas for flood spreading was prepared and prioritized. The results showed that among the 10 factors influencing flood spreading, the thickness of alluvium criteria by weight of 0.27 was identified as the most effective layer in suitable areas for flood spreading. Most of the suitable regions located in slope less than 3% that represents its considerable impact in implementation of flood spreading. Mashhad plain potential for flood spreading, after removing exception areas (40.8% of total area), were defined in four inappropriate, relatively appropriate, appropriate and perfectly appropriate classes, that include 2.7, 25.9, 26.5 and 1.5% of the plain area, respectively.
S. Zahedi, K. Shahedi, M. Habibnejhad Roshan, K. Solaimani, K. Dadkhah,
Volume 21, Issue 4 (Winter 2018)
Abstract
Soil depth is a major soil characteristic commonly used in distributed hydrological modeling in order to present watershed subsurface attributes. It strongly affects water infiltration and accordingly runoff generation, subsurface moisture storage, vertical and lateral moisture movement, saturation thickness and plant root depth in the soil. The objective of this study is to develop a statistical model that predicts the spatial pattern of soil depth over the watershed from topographic and land cover variables derived from DEM and satellite image, respectively. A 10 m resolution DEM was prepared using 1:25000 topographic maps. Landsat8 imagery, OLI sensor (May 06, 2015) was used to derive different land cover attributes. Soil depth, topographic curvature, land use and vegetation characteristics were surveyed at 426 profiles within the four sub-watersheds. Box Cox transformations were used to normalize the measured soil depth and each explanatory variable. Random Forest prediction model was used to predict soil depth using the explanatory variables. The model was run using 336 data points in the calibration dataset with all 31 explanatory variables (18 variables from DEM and 13 variables from remote sensing image), and soil depth as the response of the model. Prediction errors were computed for validation data set. Testing dataset was done with the model soil depth values at testing locations (93 points). The Nash-Sutcliffe Efficiency coefficient (NSE) for testing data set was 0.689. The results showed that land use, Specific Catchment Area (SCA), NDVI, Aspect, Slope and PCA1 are the most important explanatory variables in predicting soil depth.
