2024-03-28T22:37:14+04:30 http://jstnar.iut.ac.ir/browse.php?mag_id=58&slc_lang=fa&sid=1
58-1539 2024-03-28 10.1002
JWSS - Isfahan University of Technology jwss 2476-3594 2476-5554 10.47176/jwss 2011 15 55 Effects of Water Stress and Cycocel as a Growth Retardant on Growth of Two Olive Cultivars H.R. Memari E. Tafazoli A. Kamgar-Haghighi akbarkamkar@yahoo.com A. Hassanpour N. Yarami Many experiments have been carried out to decrease the negative effect of drought stress and obtain suitable growth under water deficit conditions. Application of plant growth regulators (especially growth retardants) is one of the proposed methods. This study was conducted to investigate the effect of Cycocel application on growth of two olive cultivars (Shengeh and Roghani) under water stress condition. The design of experiment was completely randomized with six replications (Factorial arrangement). Treatments included irrigation intervals (2, 4, 6, 8 weeks) and Cycocel concentrations (0, 500,1000,2000,4000 mg per litter). Some indices such as height, chlorophyll, leaf area, root, and shoot weight (fresh and dry) were measured. Results indicated that interaction of C.C.C treatment and irrigation intervals on height of olive cultivars was not significant, probably due to the response of these cultivars to concentrations of C.C.C. Although drought stress decreased the number of leaves in both cultivars, the application of CCC (500 mg per litter) thwarted the adverse effects of drought stress. Cycocel increased chlorophyll content significantly (500 mg per litter in Roghani and Shengeh and 6 weeks irrigation interval). Cycocel application decreased leaf area, but in Shengeh cultivar increased leaf area in 6 week irrigation interval. Overall, the results indicated that the application of Cycocel with concentration of 500 mg per litter in 6 week irrigation intervals in both cultivars (Roghani and Shengeh) was the best treatment for controlling the adverse effects of drought. Also, results indicated that such changes were dependent on Cycocel concentration and drought level. Water stress Growth retardants Cycocel Olive Roghani and Shengeh Chlorophyll 2011 4 01 1 11 http://jstnar.iut.ac.ir/article-1-1539-en.pdf
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JWSS - Isfahan University of Technology jwss 2476-3594 2476-5554 10.47176/jwss 2011 15 55 Evaluation of the Effects of Madden Julian Oscillation on the Occurrence of Dry and Wet Spells in Fars Province, Iran M. J. Nazemosadat mjnazemosadat@yahoo.com H. Ghaedamini Asadabadi The Madden Julian oscillation (MJO) is known as the primary mode of large-scale inter-seasonal variability in tropical regions, affectimg equatorial and sub-tropical climates. This study investigated the effects of the MJO on the occurrence of wet and dry spells in Fars province, central southern part of Iran, during November-April. Monthly precipitation data of nine stations spread over various parts of the province was analyzed during 1979-2005. Using two well-known MJO indices: MK and WH, the positive and negative phases of the MJO phases (enhanced and suppressed convective activity over the equatorial Indonesian region, respectively) were identified for monthly and seasonal scales. Precipitation-MJO composites were then constructed for the opposite phases. It was shown that for all the considered stations, seasonal precipitation during negative MJO phase was significantly greater (from about 2.5 to 6.0 folds) than the corresponding values during the positive phase. Moreover, the applied statistical tests proved that the frequency of wet or dry events was related to the prevalence of negative or positive MJO phase, respectively. As the positive MJO phase was engulfed, the probability of dry events varied from 60% to 84%. On the other hand, the probability of wet events was found to vary from 60% to 76% during the MJO negative phase. Madden Julian oscillation (MJO) Precipitation Dry spells Wet spells Iran Fars. 2011 4 01 13 26 http://jstnar.iut.ac.ir/article-1-1540-en.pdf
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JWSS - Isfahan University of Technology jwss 2476-3594 2476-5554 10.47176/jwss 2011 15 55 Investigation into Effect of Collar in Controling Scour around Circular Bridge Pier at a 180 Degree Bend A. Masjedi drmasjedi2007@yahoo.com M. Gholamzadeh Mahmoodi Every year river flooding causes serious damage to the bridges at the time needed most. One of the most effective factors causing bridge failure is scouring around the piers in a river bend. One of the methods to decrease scouring around the bridge piers is fitting them with a coller on the piers. The collars protect the river bed against vortex flow in the vicinity of the pier base. An experiment was conducted to study lab flumes made of Plaxiglass with a 180 degree bend and 2.8 m central radius and a 0.6 m width. In this study, a 6cm diameter pier was placed with a circular collar with four different collar sizes in one position in bend with constant discharge and depth under clear-water conditions. The collar was placed at four different elevations. The soil material had a diameter of d50 = 2mm and geometric standard deviation of σg = 1.3. The results of the model study indicated that the maximum depth scouring was highly dependent on the experimental duration. It was observed that as the size of a collar plate increases, the scour decreases. So, minimum depth of scour is dependent on the 3D coller and -0.1D elevation. Circular collar results in maximum reduction in scour depth (93%) compared with no circular collar. Local scour Vortex flow 180 deg bend Circular collar. 2011 4 01 27 38 http://jstnar.iut.ac.ir/article-1-1541-en.pdf
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JWSS - Isfahan University of Technology jwss 2476-3594 2476-5554 10.47176/jwss 2011 15 55 Evaluation of Technical and Operational Issues in Some Qanats in Kerman Province M. Farzamnia masoud_farzamnia@yahoo.com F. Abbasi Qanat is a traditional structure that provides water without spending much energy and expense. Therefore, in eastern regions where there are no big rivers available qanat can play an important role in public economy and should be taken into consideration. The regions around Kerman such as Joupar, Mahan, Bam, Narmashir and Fahraj have many qanats with high discharges. Therefore, protection of this water resource is essential in view of either our cultural heritage or water resources. For this reason, in the present research exploitation problems, water distribution, planting pattern, and variation of water quality and quantity in 15 qanats of Kerman province were studied. Results showed that qanats’ discharges have changed in long run and had a noticeable decrease in the recent decade, and as a result planting pattern and areas in downstream fields have been changed. In the above mentioned fields, average water conveyance efficiency and roughness coefficient in water canals and mean application efficiency were 83.6 percent, 0.024 and 59.3 percent, respectively. Mean water productivity for cultivated crops such as wheat, alfalfa, sugar beet, grain corn, forage corn, watermelon was 0.43, 0.51, 0.31, 0.65, 4.75, 8, and for horticultural crops such as pistachio, almond, date palm, citrus, and stone and pome fruit was 0.52, 0.3, 0.66, 1.1, and 0.54 kg/m3, respectively. Based on the results, the main problems of qanats are the lack of necessary budget allocation by agricultural organizations, digging deep wells on qanats border, technical issues, exploitation, and maintenance management problems. Kerman Qanat Technical and operational issues Water used efficiency 2011 4 01 41 55 http://jstnar.iut.ac.ir/article-1-1542-en.pdf
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JWSS - Isfahan University of Technology jwss 2476-3594 2476-5554 10.47176/jwss 2011 15 55 Minimization of Reservoirs Sedimentation by Optimal Operation of Bottom Outlets E. Valizadegan evalizadegan@yahoo.com M. Shafai Bejestan H. Mohammad Vali Samani Reservoir sedimentation is an unavoidable problem which has unsuitable effects on reservoirs such as decreasing of reservoir useful volume, decreasing of dam stability, unsuitable operation of operational gates and penstocks and decreasing of flood control volume. The minimization of reservoir sedimentation is a nonlinear and constrained optimization problem. Constrains imposed include reservoir storage level and releases in each time, and reservoir storage level in the end of operational period. In this study, after calibration of GSTARS3 software, one of the newest mathematical model for simulation of river and reservoir sedimentation developed by USBR, for region of Voshmgir dam, results of running of software were converted as a part of data file to an optimization model by a mediator computer program. After running the optimization model, results were converted to GSTARS3 by another mediator computer program. Then, GSTARS3 was run again with new data file, obtained from running the optimization model. Results of running of GSTARS3 were converted to the optimization model again. The continuation of this process (loop) finished when the desired accuracy was obtained. In other words, the optimum condition was obtained when the running of this loop finished. The constrained optimization problem changed to unconstrained problem using penalty function method. The Powell method, a method of direct search methods, was used to solve this unconstrained optimization problem. Capabilities of the model were demonstrated through its application to the Voshmgir dam in Gorgan for a 12 month period to obtain the optimal operation policy for minimization of reservoir sedimentation. Sedimentation Minimization Optimization Optimal operation Voshmgir dam GSTARS3. 2011 4 01 57 67 http://jstnar.iut.ac.ir/article-1-1543-en.pdf
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JWSS - Isfahan University of Technology jwss 2476-3594 2476-5554 10.47176/jwss 2011 15 55 Comparison of Some Methods for Estimation of Daily Pan Evaporation: Case Study in Kerman Region M. Shadmani S. Marofi smarofi@yahoo.com In this research, based on the observed data of Class A pan evaporation and application of non-linear regression (NLR), artificial neural network (ANN), neuro-fuzzy (NF) as well as Stephens-Stewart (SS) methods daily evaporation of Kerman region was evaluated. In the cases of NLR, ANN and NF methods, the input variables were air temperature (T), air pressure, relative humidity (RH), solar radiation (SR) and wind speed (U2) which were used in various combinations to estimate daily pan evaporation (Ep) defined as output variable. Performance of the methods was evaluated by comparing the observed and estimated data, using determination coefficient (R2), root mean square error (RMSE) and mean absolute error (MAE). Based on the observed data at Kerman meteorological station, the monthly and annual average evaporation values of the region were 272 and 3263 mm, respectively. The results of this study indicated that NF method is the most suitable method to estimate daily Class A pan evaporation. The statistics criteria of this model which is constituted based on the 5 input parameters were R2 = 0.85, RMSE=1.61 and MAE= 1.24 mm day-1. The sensitivity analysis of NF model revealed that the estimated EP is more sensitive to T and U2 (as the input variables), respectively. Due to weak accuracy of SS method, a new modification step of the model was also developed based on the SR and T in order to have a more exact daily evaporation estimation of the region. However, the result of the modified model was not acceptable Evaporation estimation Neuro-fuzzy Artificial neural network Non-linear regression Stephens-Stewart method. 2011 4 01 69 84 http://jstnar.iut.ac.ir/article-1-1544-en.pdf
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JWSS - Isfahan University of Technology jwss 2476-3594 2476-5554 10.47176/jwss 2011 15 55 Effect of Pistachio Waste on Some Soil Physical Characteristics and Compactability of Two Soil Types H. Shirani Shirani379@yahoo.com E. Rizahbandi H. Dashti M.R. Mosaddeghi M. Afyuni Organic matters are the most important factors that affect soil compactability and physical characteristics. In order to study the effect of pistachio waste on physical characteristics of two soils, a factorial experiment was conducted in a completely randomized design with three replications in a greenhouse. The treatments included pistachio waste at 4 levels (0, 3, 6 and 9 w/w %) and two types of soil texture (silty clay loam and sand).The results showed that the bulk density of sandy soil was decreased at high levels of waste application before compaction but had no significant effect on the bulk density of clay soil. The penetration resistance of both soil types was decreased by pistachio waste application. Soil water holding capacity increased and moisture curves shifted up for higher levels of organic matter application, while compaction curve reciprocally shifted into the lower levels by incorporation of wastes into the soils. At higher levels of organic matters, maximum bulk density was decreased and critical moisture was increased specially in fine texture soil. After compaction, the application of pistachio waste significantly reduced penetration resistance in silty clay loam soil relative to control but in sandy soil its effect on penetration resistance was only significant at maximum level (9 %). Pistachio waste Physical soil characteristics Soil texture Compaction 2011 4 01 85 98 http://jstnar.iut.ac.ir/article-1-1545-en.pdf
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JWSS - Isfahan University of Technology jwss 2476-3594 2476-5554 10.47176/jwss 2011 15 55 Sustainability Assessment and Cropping Pattern Determination in Farming Systems Based on the Optimization of Soil and Water Resources Utilization Using Non-linear Mathematical Programming Models A. Amini Fasakhodi amini@1tr.ui.ac.ir S. H. Nouri Studying the sustainability of farming systems entails the integrated assessment of the strong interdependence between their environmental, economic and social attributes. Optimum allocation of water resources in a farming system improves the conservation and sustainability status of resources in addition to reducing the socio-economical damages. In order to analyze and assess the different aspects of farm management and agricultural systems planning, a number of mathematical programming models have been developed in recent decades. The purpose of this article was to assess and analyse the sustanability and determine the appropriate pattern of cropping in a rural farming system, namely, south Baraan located in the east of Isfahan city. In order to incorporate environmental, economic and social dimentions, two criteria of maximum net return and employment creation per unit of agricultural water consumption were defined as system’s sustainability indicators. Thus, the ratios “net return / water consumption” and “employment / water consumption” were optimized by using single and multiple objective fractional programming models. The economic and social efficiency of each unit of agricultural water consumption was computed and compared in several single and multiple objective scenarios of linear and fractional programming models, and finally the most appropriate patterns of cropping for the region were determined based on the available land, water and human resources of the region. Sustainability assessment Farming systems Optimal cropping pattern Fractional programming Multiple objective programming. 2011 4 01 99 111 http://jstnar.iut.ac.ir/article-1-1549-en.pdf
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JWSS - Isfahan University of Technology jwss 2476-3594 2476-5554 10.47176/jwss 2011 15 55 Micromorphology of the Loess Derived Soils Affected by Land Use Change: A Case Study in Agh-Su Area (Golestan Province) S. Shamsi Mahmoodabadi shamsisomaye@yahoo.com F. Khormali In order to study the effects of different land uses on soil development, a loess hillslope was selected in Agh-Su area, eastern Golestan Province. Six profiles in four land uses including pasture, Quercuse natural forest, Cupressus artificial forest and a cultivated land, were dug and studied. Samples from different horizons were collected for physico-chemical and microscopic analyses. Important physical and chemical attributes such as bulk density (Bd), mean weight diameter (MWD), Organic carbon (SOC), cation exchange capacity (CEC), soil calcium carbonate (CCE) and available P were compared in land uses. Organic matter, CEC and MWD were significantly lower in the cultivated land use. Organic matter content in the forest and pasture area was considerably higher than that of cultivated land use. Soil profile development studies revealed that forest soils were highly developed. Quercus natural forest soils were classified as Calcic Argixerolls. Unlike cultivated soils which showed the minimum development and were classified as Typic Calcixerepts, formation of argillic horizon with dominant speckled b-fabric in the natural forest indicated the high landscape stability. Crystallitic b-fabric of horizons showed the absence of enough leaching of carbonate and the subsequent migration of clay particles. Intense erosion of the surface horizons of cultivated land use resulted in the outcropping of the subsurface carbonate rich horizon preventing soil development. The soils of pasture and Cuprecuse soils had mollic epipedon and were classified as Typic Calcixerolls with moderate development. Micromorphological properties of soils can help consider changes in pedogenic processes occurring under different land covers. Land use Soil micromorphology Loess Soil development 2011 4 01 111 125 http://jstnar.iut.ac.ir/article-1-1550-en.pdf
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JWSS - Isfahan University of Technology jwss 2476-3594 2476-5554 10.47176/jwss 2011 15 55 Phosphorus Fractions and Availability in Some Calcareous Soils in Hamedan Province M. Samavati m.samavati2000@gmail.com Hosseinpur Phosphorus is often considered the most limiting soil nutrient for plant productivity. Several extractants have been typically used to measure available P. Organic and inorganic P fractions are not measured by common soil test, and thus fractionation schemes using various extractants have been developed over years to quantify the different chemical forms of P in soils. The objectives of this research were: i) to investigate the effect inorganic P fractions on Phosphorus availability ( Olsen procedure), and ii) to evaluate the relationships between these P fractions and Garlic (Allium sativum) plant indices. Soil inorganic P fractions were determined in 30 surface soil samples (0-30 cm) from various regions of Hamedan Province. Inorganic P fractions included dicalcium phosphate (Ca2-P), octa calcium phosphate (Ca8-P), P adsorbed by Al oxide (Al-P), P adsorbed by Fe oxide (Fe-P), P incorporated into Fe oxide (O-P), and apatite (Ca10-P). Total P and Organic P were measured in these soils. In order to evaluate the availability of different forms of P to plant, a pot experiment was conducted on Garlic plant. The treatments including two rates of P (zero and 150 mg kg-1) and 9 soils from 30 soil samples were arranged in a factorial experiment in a completely randomized design with three replicates. The results showed the total P with an average of 1501 mg kg-1 soil, and organic P comprised 19 % of the total P. The inorganic P fractions (Ca2-P), (Ca8-P), (Al-P), (Fe-P), (O-P), (Ca10-P) and residual phosphate (Res-P) comprised 4.7, 20, 8.7, 3.0, 2.8, 24 and 18 % of total P, respectively. Most of the inorganic P occurred as Ca-P and comprised 49% of total P. The correlation study between different P fractions showed that Ca2-P, Ca8-P, Ca10-P, and Al-P were significantly correlated with Olsen-P. This suggested that probably Olsen procedure essentially removed some P from these fractions. The results of pot experiment indicated that plant indices (relative yield and Yield efficiency) were significantly correlated with Ca2-P, Ca8-P and Olsen-P (P ≤ 0.05). P availability in the studied soils was influenced by Ca2-P and Ca8-P which could be used in a long period of time by plant. Phosphorus inorganic forms Available P Garlic. 2011 4 01 127 138 http://jstnar.iut.ac.ir/article-1-1551-en.pdf
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JWSS - Isfahan University of Technology jwss 2476-3594 2476-5554 10.47176/jwss 2011 15 55 Changes in Soil Quality Indicators by Reclamation of Salt–Affected Land in Abarkooh Plain, Central Iran J. Fallahzade jaber84023@yahoo.com M. A. Hajabbasi The salt–affected lands in arid regions of central Iran are characterized by low rainfall, low fertility, high evaporation and salinity. The cultivation of salt–affected lands may have a major influence on soil quality. The aim of this study was to determine the response of soil quality indicators to reclamation and cultivation of salt–affected lands occurring in Abarkooh plain, central Iran. Soil quality indicators were evaluated in three land use systems including salt-affected land, wheat, and alfalfa fields. Composite soil samples were collected at 0–10, 10–20, 20–30, and 30–40 cm layers and analyzed for soil organic carbon, total nitrogen, carbohydrate, particulate organic carbon in macro-aggregates (POCmac) and micro-aggregates (POCmic), organic carbon mineralization and wet aggregate stability. The cultivation of salt–affected land caused a significant decrease in electrical conductivity at all layers and increased the amount of soil organic carbon, total nitrogen, carbohydrate, POCmac, POCmic, and organic carbon mineralization. At all layers, the POCmac/POCmic ratio in the alfalfa fields was higher than that in the wheat fields. The cultivation of salt-affected land caused a significant increase in soil aggregate stability (MWD) at all layers. In most cases, the amounts of soil organic matter and MWD were greater in alfalfa than in the wheat fields, reflecting a better soil quality and thus higher potential for increasing soil organic carbon sequestration in the alfalfa fields Land reclamation Soil quality Salt–affected land Soil organic matter Particulate organic carbon 2011 4 01 139 150 http://jstnar.iut.ac.ir/article-1-1552-en.pdf
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JWSS - Isfahan University of Technology jwss 2476-3594 2476-5554 10.47176/jwss 2011 15 55 Effectiveness of Arbuscular Mycorrhizal Fungi in Phytoremediation of Zinc Polluted Soils Using Maize (Zea mays L.) M. Zarei mehdizarei20@yahoo.com N. Saleh-Rastin GH. Savaghebi A greenhouse experiment was conducted in factorial experiment arranged as a completely randomized design (CRD) to evaluate the role of tree indigenous arbuscular mycorrhizal fungi (AMF) species originated from a polluted soil in phytoremediation of zinc polluted soils using maize as a host plant. The experiment consisted of plants inoculated with AMF (G1(Glomus intraradices), G2(Glomus mosseae) and G3(Glomus versiforme)) and G0 as non-inoculated plants and 5 levels of zinc (0, 10, 50, 100 and 500 mg kg -1) in non-sterilized sandy loam soil with three replications. According to the results of greenhouse experiment, the zinc and phosphorus uptake and also the biological yield of maize plants were significantly increased by inoculation with AMF in comparison with non-inoculated plants and also no zinc toxicity symptoms were observed. Uptake, translocation, and phytoextraction efficiency of plants inoculated with G. intraradices was more than the other treatments up to the level of 100 mg kg -1, but at the level of 50 mg kg -1 these amounts were highest in plants inoculated with G. mosseae. The efficicncy of three AMF in zinc uptake was highest at the low level of zinc. In general, under the high soil pollution (500 mg kg-1), G. mosseae was the most effective fungal species in Zn extraction and translocation while G. intraradices had the highest effectiveness for accumulation of Zn in the roots. The overall situation of G. versiforme was mostly between the two other fungal species. Arbuscular mycorrhizal fungi Phytoremediation Zinc Maize 2011 4 01 151 168 http://jstnar.iut.ac.ir/article-1-1553-en.pdf
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JWSS - Isfahan University of Technology jwss 2476-3594 2476-5554 10.47176/jwss 2011 15 55 Comparison of Artificial Neural Network and Regression Pedotransfer Functions for Prediction of Cation Exchange Capacity in Guilan Province Soils S. Moallemi N.Davatgar n_davatgar@yahoo.com Measuring the cation exchange capacity (CEC) as one of the most important chemical soil properties is very time consuming and costly. Pedotransfer functions (PTFs) provide an alternative to direct measurement by estimating CEC. The objective of this study was to develop PTFs for predicting CEC of Guilan province soils using artificial neural network (ANN) and multiple-linear regression method and also determine whether grouping based on soil textural class and organic carbon content improved estimating CEC by two methods. For this study, 1662 soil samples of Guilan province were used from soil chemistry laboratory database of Rice Research Institute. 1109 data were used for training (the development of PTFs) and 553 data for testing (the validation of PTFs) of the models. The results showed that organic carbon was the most important variable in the estimation of cation exchange capacity for total data and all classes in textural and organic C groups in both methods. ANN performed better than the regression method in predicting CEC in all data, and grouping of data only improved the prediction of PTFs in Sand and Sandy clay loam classes by ANN method. Cation exchange capacity Pedotransfer functions Artificial neutral network Regression Soil properties 2011 4 01 169 182 http://jstnar.iut.ac.ir/article-1-1555-en.pdf
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JWSS - Isfahan University of Technology jwss 2476-3594 2476-5554 10.47176/jwss 2011 15 55 Assessing procedures of Estimating Pre-compaction Stress of Soil Amended with Organic Manures Using Data from Plate Sinkage and Confined Compression Tests N. Aghilinategh A. Hemmat ahemmat@cc.iut.ac.ir M. Sadeghi One important parameter in determining the allowable stress to prevent soil compaction is pre‌compaction stress (σpc). If the stress induced into the soil due to agricultural machinery traffic is lower than the σpc, the possibility of the irreversible (plastic) deformation is low. In this study, plate sinkage test (PST) and confined compression test (CCT) were used to determine the σpc of the disturbed soil samples obtained from the topsoil of a long-term organic amendment experiment. In the organic amendment experiment, organic manures (sewage sludgeو compost, farmyard manure) at three rates (25, 50 and 100 t ha-1) and one inorganic fertilizer combination (250 kg urea ha-1 and 250 kg ammonium phosphate ha-1) were added to a silty clay loam soil for seven years under wheat-corn rotation. The effect of organic and inorganic fertilizers and gravimetrical water contents (17.1 and 20.9% db) on the σpc values was determined using two statistical designs: 1) factorial design and 2) orthogonal contrasts in a completely randomized design with three replications. The σpc values were estimated by the following methods: 1) Casagrande, 2) maximum curvature and 3) intercept of virgin compression line (VCL) with the x-axis at zero strain. The results showed that in both tests, the σpc values for treatments amended with organic manures had over-estimations and the values of the over-estimation were increased as the manure application rate increased. The values of the over-estimations for CCT were higher than for PST. Therefore, it can be concluded that the results of the PST are more reliable. The σpc values estimated by any of the three procedures depend on the manure treatment as well as the initial water content of the soil. For determining the stress at the threshold of the compaction for the un-manure soils (control and inorganic fertilizer) or the treatments amended with low application rate (25 t ha-1) of the organic manures, the PST and the Casagrande procedure can be recommended. In contrast, for the soils amended with high application rates (50 and 100 t ha-1), the PST and the maximum curvature procedure can be used. Soil compaction; Confined compression test; Plate sinkage test; Pre-compaction stress; Organic manures. 2011 4 01 183 199 http://jstnar.iut.ac.ir/article-1-1554-en.pdf
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JWSS - Isfahan University of Technology jwss 2476-3594 2476-5554 10.47176/jwss 2011 15 55 Effects of Water Stress, Nitrogen Levels and Application Times on Yield and Yield Components of Sunflower at Different Growth Stages GH. Omidi Ardali gha_omidi@yahoo.com M. J. Bahrani The optimum levels of soil moisture and nitrogen are important to obtain higher yields. To investigate the effects of water stress, nitrogen levels and application times on yield and yield components of sunflower (Helianthus annuus L.), the cultivar Euroflor at different growth stages, a two year study (2006-007) was conducted at Research Fields of College of Agriculture, Shiraz University (Badjgah) using a split factorial design with four replications. Treatments were water stress at three levels, (non-stress and stress at flowering and seed formation) as main plot and three N levels (0, 70, 140 kg ha-1) and N application times (split application at planting and stem elongation, planting and heading, and stem elongation and heading) as subplot. Number of seed per head, 1000-seed weight, seed yield, Oil yield and HI were measured. Results showed that the effects of water stress and N rates on yield and yield components were significant, but the effects of N application times and interaction between water stress, nitrogen rates and application times were insignificant. Overall, the crop showed more sensitivity to drought stress at flowering time, and 70 kg N ha-1 is recommended for the region. Water stress 1000-seed weight Seed yield Oil yield. 2011 4 01 199 207 http://jstnar.iut.ac.ir/article-1-1556-en.pdf
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JWSS - Isfahan University of Technology jwss 2476-3594 2476-5554 10.47176/jwss 2011 15 55 Effects of Wheat Residue and Nitrogen Fertilizer Rate on Some Soil Properties in Common Bean Cultivation F. Salehi foroud_salehi@yahoo.com M. J. Bahrani S. A. Kazemaini H. Pakniyat N. A. Karimian Crop residues are beneficial substances that can bring about important changes in soil biological, chemical and physical properties and can also increase or stabilize crops yield. A field experiment was carried out at Research Station of College of Agriculture, Shiraz University, Shiraz, Iran, to determine the effects of wheat (Triticum aestivum L.) residue rates in combination with N levels on some soil properties in common bean (Phaseolus vulgaris L.) cultivation for two years (2008-2009). The experiment was conducted as split split-plot arranged in a completely randomized blocks design with three replications. Treatments were two red bean cultivars as main plots, N levels (0, 34.5, 69, and 103.5 kg ha-1) as sub-plots and residue rates (0, 25, 50 and 75%) as sub sub-plots. The results showed that application of crop residues significantly increased soil organic carbon, N, K, and P contents. Heavy crop residue (75%) application had no effects on these soil properties. Thus, retaining 50% crop residue was optimum for proper soil quality. Increased N application increased soil N, decreased P and K contents, and had no effects on organic carbon. Common bean Wheat residue Soil properties. 2011 4 01 209 218 http://jstnar.iut.ac.ir/article-1-1557-en.pdf