JWSS - Journal of Water and Soil Science

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Nitrogen is usually the most limiting nutrient for crop production. Thus, N fertilizer is widely used by farmers. Moreover, Mn deficiency in some calcareous soils of Iran with high pH has been reported. Therefore, the addition of nitrogen and manganese to achieve the optimum yield is necessary. The objective of this study was to evaluate the effect of N and Mn applications on the availability of some soil nutrients under wheat (Triticum aestivum L.), corn (Zea mays L.), and spinach (Spinacia oleracea L.) plants in greenhouse conditions. In a factorial test, five levels of N (0, 50, 100, 200 and 400 mg/kg soil as NH₄NO₃) and three levels of Mn (0, 15 and 30 mg/kg soil as MnSO₄) in a completely randomized design with four replication were applied. Corn, wheat and spinach varieties were sc₇₀₄ Falat and Spinacea spp., respectively. After eight weeks, total N content and DTPA-extractable Mn, Fe, Zn and Cu of soil were measured.

 The results indicated that N and Mn applications increased Mn-extractable of soil in three cultures but didn’t affect the soil total N. Nitrogen application in corn increased available Fe in soil. Mn application decreased extractable Zn and Cu of soil in wheat and soil extractable Cu in corn.

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Agricultural insurance is one of the appropriate ways to overcome the risk in agricultural production and to increase farmers’ income security. In this study, the influence of wheat insurance, as personal-free insurance, and sugar beet insurance, as group-forcible insurance, on farmers’ risk attitudes in Fars Province were investigated as a case study. Data were collected using stratified multi-stage cluster sampling method and interviews in the years 1375-1376. The sample included wheat and sugar beet farmers in three different climates including Mediterranean, warm sub-desert and cold mountainous in Fars Province. Results of estimating risk aversion coefficients of farmers, using Safety First Rule (SFR), showed that sugar beet forcible insurance along with giving inputs, mechanization services, lookout of farms by sugar plants led to continuous insurance purchase by farmers in consecutive years. Therefore, sugar beet farmers tended to welcome insurance and the effect of insurance on their risk aversion coefficients was positive. However, discontinuity of insurance purchase by wheat farmers in consecutive years and farmers’ lack of confidence in insurace system caused the influence of insurance on wheat farmers’ risk aversion coefficient to be insignificant. Thus, sugar beet insurance type is closer than wheat insurance type to one of the main aims of agricultural insurance system, which is increasing farmers’ tendency to take risks.

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This experiment was carried out to study the effects of Lactic Acid Bacteria (LAB) and urea on chemical composition, nutritive value and rumen fermentation characteristics of whole-crop barley. In a completely randomized design with cross over arrangement, 4 Suffolk male lambs were used. Whole-crop barley was either treated with LAB solution (35% dry matter) at the rate of 2 L/ton herbage fresh weight or urea (55% dry matter) at the rate of 40 Kg/ton dry matter herbage and ensiled for 60 days. Low dry matter silages had lower pH and higher residual water soluble carbohydrates, ammonia-N, lactic acid and ethanol and higher lactate:acetate ratios. LAB resulted in higher lactic acid content and lactate:acetate ratios. DM (P<0.001), OM (P<0.01), NDF (P<0.05), ADF (P<0.01) and total nitrogen (TN) digestibility increased with additives. Mean rumen ammonia-N concentration and pH significantly (P<0.05) increased with urea-treated silages. Rumen propionate concentration was significantly (P<0.01) higher with LAB-treated silages than with urea-treated ones. The results indicated that the addition of LAB at the rate of 2 L/ton fresh weight to whole-crop barley at 35% dry matter enhanced fermentation and nutritive value.

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The effect of different media including the growth regulators on somatic embryogenesis from Mexican lime was studied. The average embryo formation after 60 days from unfertilized ovules in different media was evaluated at 0 to 33.75%. The most effective hormone to stimulate embryogenesis was GA₃ at 0.01 and 0.1 mg/l concentrations. Malt extract (ME) at 300 mg/l increased embryo formation, whereas at 1000 mg/l, it inhibited embryogenesis but produced embryogenic callus. Banzyl adenine (BA) at 0.1 and 0.01 mg/l concentrations had significant effects on embryogenesis, while embryo formation was inhibited at high concentrations. Embryo development in different media was also studied. The index of mean root length to mean stem length in the MT³ medium supplemented with 0.1 mg/l of GA₃ was observed to be 1.22±0.22, which was regarded a suitable medium for embryo formation, embryo development and plantlet regeneration.

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Phosphorus (P) and iron (Fe) are essential nutrients for plants. Iron availability is low in calcareous soils of Iran due to the excessive amounts of CaCO₃ and high pH. Overfertilization of P fertilizers may also decrease Fe availability. The objective of this study was to evaluate the effect of P and Fe on the growth and chemical composition of corn (Zea mays L.) under greenhouse conditions. Treatments consisted of a factorial arrangement of P rates (0, 40, 80, 120 and 160 mg kg-1 as KH₂PO₄) and Fe rates (0, 2.5, 5 and 10 mg kg^-1 as Fe EDDHA) in a completely randomized design with four replications. Plants were grown for 8 weeks in a loamy soil, calssified as Chitgar series (fine-loamy, carbonatic, thermic, Typic Calcixerepts). Results showd that P application up to 80 mg kg^-1 increased corn top dry matter. Corn P concentration and total uptake increased by P application but decreased by Fe application. Application of Fe up to 5 mg kg^-1 increased dry matter but decreased it at higher rates. Concentration and total uptake of Fe increased by Fe application but decreased by P application. Zinc and copper concentrations decresed significantly when P was added. Manganese concentration increased at 40 mg P kg^-1 but decreased at higher rates. Iron application decreased zinc and manganese concentrations but had no effect on copper.

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An experiment was conducted to determine growth and carcass characteristics of male broilers subjected to early feed restriction. Restricted birds were fed equivalent to 1/5*BW^0.67 Kcal/day/bird between days 7 and 14. On days 0 to 7 and 14 to 56, all chickens received feed ad-libitum. Diets of feed-restricted birds were supplemented with 15% higher methionin and cystine recommended by NRC (1994) during refeeding in starter and grower periods. No significant differences were observed for liver, breast, heart, carcass and liver fat between early restricted birds and ad-libitum control at 56 days of age. Body weight for restricted broilers were significantly (P<0.05) lower than that of controls in 56 days. However, restricted broilers had significantly lower total-feed to gain ratio than the unrestricted control. Restricted broilers that received diets high in total sulfur amino acids in starter and grower periods had singnificantly lower abdominal fat pad than control birds.

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In order to study the effects of different protein feeds on honey bees (Apis mellifera L), experiments were conducted in a completely randomized block design with 15 treatments and 4 replicates. The nutritional effects of different treatments on caged bees were studied through recording half-life time (50% mortality). Pollen substitutes were soybean flour, soybean meal, bread yeast, wheat gluten, soybean flour + soybean meal, soybean flour + bread yeast, soybean flour + wheat gluten, soybean meal + wheat gluten, and wheat gluten + bread yeast. Pollen supplements were wheat gluten + pollen , soybean flour + pollen, soybean meal + pollen, bread yeast + pollen and two controls as pollen and honey. The nutritional effects of different protein sources provided by pollen substitutes and supplements were recorded on the amount of carcass protein and fatbody of honey bee workers in experimental colonies. The wheat gluten supplement and the soybean substitute showed the longest (60.58 days) and the shortest (10.53 days) half-life time of worker bees, respectively. The amount of food consumption in different treatments was not significantly different (P>0.05). The greatest DM of worker bees (dry matter of carcass) was related to soybean (34%) and the least related to yeast supplement (31.54%), which were significantly different (P<0.05). The highest carcass protein belonged to wheat gluten supplement (22.57%) and the lowest was related to yeast supplement (20.01%). The greatest carcass fat was related to soybean supplement (4.75%) and the lowest to wheat gluten supplement (3.84%). Results of the present experiments showed that soybean flour, soybean meal, wheat gluten and bread yeast can be used in pollen supplement and substitute cakes.

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A number of halophytic species as Salicornia europea, Halocnemum strobilaceum, Aeluropus lagopoides, and Aeluropus littoralis were found to occupy a significant portion of the total vegetation of the surrounding area at the Zayande-Roud inlet to Gavkhoony wetland. However, their ecological demands and bioenvironmental factors by which vegetation community composition has been affected is not undestood. A compehensive knowledge of the establishment is essential for future improvements in using the above species on salanized regions. In this paper, using the ordination method. The establishment pattern of  these four species in a range of varied habitats is evaluated based on the recongition of the relative  significance of habitat soil chemical properties and vegetion crown cover to the establishment of the four species. For this purpose, 48 plants meansurements were taken along a transect, having more species variation in term of vegetation cover percentage. Furthermore, 48 soil samples were taken from the plot along the same transect in a one-year period in 1999. The soil samples were analysed for PH, EC, available Na, K, Ca and Mg as well as clay, and silt contents. The ground and field vegetation data were analysed using the Principlas Components Analysis (PCA), and Canonical Correspondence Analysis (CCA) to produce summary vectors (PCA axes) of both the soil chemistry and habitat vegetation structure datasets. The summary of ordination method quantified the degree to which soil variables and species cover were related to variability in ground vegetation composition. variation in community composition (type and percentage) was significantly related to gradient of the aforementioned soil factors. Generally, the vegatation community composition in this experiment could be considered as a key component to expand the growth and development patterns of these species to similar salinised regions. 

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In this study tractive efficiency (TE) of MF285 and U650 tractors during moldboard plowing were evaluated and compared. Field experiments were conducted at the Experimental Station, College of Agriculture, Shiraz University, using a randomized complete block design with a 3*3 factorial. The soil was sandy clay loam with an average moisture content of 18% b.d. from zero to 30 cm depth. Test treatments were combinations of three tractor types or conditions (U650, MF285 liquid ballasted and MF285 with no liquid or weight ballast) and three levels of plowing depth (10-15 cm, 15-20 cm and 20-25 cm). Plowing speed was kept constant at about 4 km/h throughout the experiment. The measured or calculated parameters included: tractor drawbar pull and rolling resistance, drive wheel slip and tractor tractive efficiency. Statistical analysis of the test results showed that the primary difference between the tractor types or conditions was in their wheel slip, such that the average wheel slip of U650 was lowest (12.6%) while that of unballasted MF285 was highest (27%) and was reduced to 17.7% with liquid ballasting. Also, while growth of unballasted MF285 wheel slip with increasing plowing depth was drastically high (11% to 48%), that of U650 was quite moderate (9.7% to 16.5%). Analysis of the calculated values of TE showed that there was no significant changes in the TE of U650 with increasing plowing depth and that with an average of 73.8%, it had a desirable performance. The TE of unballasted MF285 that was over 75% at shallow plowing, dropped to 46% with increasing plowing depth, while water ballasting improved the decreasing trend of TE with plowing depth and raised its minimum value to about 63%. The overall results of this study showed that unballasted MF285 tractors had desirable TE only at shallow plowing and that for medium and deep plowing, U650 or water ballasted MF285 tractors should be used.

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Prediction of watershed responses and simulation of runoff rate and volume are required for design purposes in most water resources projects. For this purpose, different hydrologic methods and events based on continuous hydrologic mathematical models are applied. In this research, a continuous hydrologic model, Stanford Watershed Model-IV (SWM-IV) is used for simulation of annual and monthly volumes and mean daily runoff flow produced in Roodzard representative basin with an area of 896 km2 located in southwest of Iran. The accuracy of the simulation outputs were checked using the sensitivity analysis over reasonable ranges of input sata related to Roodzard watershed. Calibration and verification of the Stanford model were performed using the data of 1976-1977 and those of the four consecutive years (1978- 1981). The output of the SWM-IV model showed that the values of annual and monthly runoff, groundwater, and monthly interflow can be simulated in close agreement and acceptable precision corresponding to the observed data. The model is also capable of combining the hydrologic components of the basin to determine the dominant flow of the study watershed. Actual evapotranspiration and annual runoff coefficients, are two other parameters that have been estimated successfully by the model. However, the coefficient of determination (R²) for the observed and predicted daily flow values ranged from 0.44 to 0.81 for the available data. Therefore, application of the model is recommended for predicting the hydrologic responses of various sizes of watershed in Iran.

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Side channel spillways have a common usage in conveyance and distribution networks, high dams, water and wastewater treatment plants, and surface drainage networks. A side channel carries spatially varied flow with increasing discharge and their water surface profiles is a main feature in the design process. Usually, the bottom width of the channel is flared in the flow direction and an end sill is also installed at the downstream end to provide a control section and to generate an even water surface profile. In this study, the impact of installing an end sill on the flow characteristics in a non-prismatic side channel is presented. Six distinct longitudinal profiles were clearly observed in each run and the difference between the mid points of the maximum and the minimum profiles of each run was used to evaluate the sill effects on the water surface profile and the energy dissipation. The results indicated that the maximum and the minimum differences are, respectively, equal to critical depth and half of it generated at the channel downstream end. Also, based on an envelope of the data, a method was proposed to determine the maximum potential impact of an end sill that might have on the flow depth, which could also be considered as a guideline in the design process.

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Of the many hydraulic structures developed by man, the weir is perhaps the oldest. Weirs are used for the measurement of discharge and regulation of water flow. The most common types of weirs are broad-crested, sharp-crested, circular-crested and cylindrical, and ogee crest weirs. Advantage of the circular-crested and cylindrical weir compared to the other weirs include simplicity of design, stable overflow pattern, larger coefficient of discharge and the associated lower costs. In the present study, potential flow around a circular cylinder are adapted to determine the velocity distribution at the crest section and to develop a model for coefficient of discharge (C_d) for circular-crested weirs. These results were evaluated using present test data for three types of weir models, namely, cylindrical, semicylindrical and semicylindrical with different heights and also Dressler theory. The results of the study showed that the experimental velocity profile agree very well with the theoretical profiles for the range of the study. Also, the prediction of the velocity distribution over the weir crest using Dressler theory is always less than the proposed model and measured data. The predicted values of coefficient of discharge (C_d) based on the proposed model agree well with C_d determined from direct discharge measurements. For the cylindrical model, the coefficient of discharge can be predicted from the proposed model within an error of –7% and for the semicylindrical and semicylindrical with different heights within ± 5%.

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The main objective of the present study is to investigate the production and marketing of fresh figs in Garmsar Region. Semnan Province has the largest area under fresh figs in Iran. About 84 percent of this area is in Garmsar region, hence, it was selected as the study area. Data were collected by random sampling method through interviews with a sample of 70 fresh fig producers in Garmsar region in summer 1999. The production functions of fresh figs were estimated using translog form for the study region. Technical efficiencies for fresh fig producers were estimated using translog stochastic frontier production function. Results of the current study revealed that farmers are not using some of the inputs optimally. Study of technical efficiency of fresh fig producers did not show the possibility of increasing production by increasing farmers’ technical efficiencies. The average of retail, wholesale and marketing margins of one kilogram of fresh figs were estimated to be 900, 550 and 1450 Rials, respectively. Also, marketing efficiency was calculated as 151%.

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This research was conducted in Kooshkak Farm Research Station of Shiraz University in 1997 and 1998 in order to determine crop coefficient and water requirements of rice, using lysimeter. The variety used was Champa-Kamfiroozi which is an early mature variety and is grown by most farmers in the area. Results showed that potential evapotranspiration varied from 3.76 to 9.34 mm/day. Penman FAO method was used in calculating reference evapotranspiration. Crop coefficient was 0.97 in the initial growth stage, 1.25 in the mid-season growth stage, and 1.09 at the time of harvest. Total crop evapotranspiration rates in 1996 and 1997 were 560 and 757 mm, respectively. Average deep percolation rates in the growing season was 3.4 and 3.5 mm/day in 1996 and 1997, respectively. Finally the total water requirements of rice in 1996 and 1997 were 1983 and 2361 mm, respectively.

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For the study of field wind erosion and the design and evaluation of wind erosion control techniques, detailed observations of soil particle transport and vertical destribution of eroded soil particles are needed. The objectives of this study were: 1) To describe one device for soil transport particle measurement, i. e. the BSNE sediment catcher and 2) To assess vertical distribution of wind–eroded sediment with height in eastern Isfahan. The BSNE sediment catcher is a wind erosion sampler that traps eroded material at seven heights of 0.24, 0.60, 1.08, 2.00, 3.00, and 4.00 m above the soil surface. Each trap consists of a steel container with an inlet and outlet, mounted on a wind vane that rotates about a central pole. Before using the sampler in the field, it was tested and calibrated in the wind tunnel. The results showed that the average trapping efficiency with speeds ranging from 5.2 to 7.2 m sec^-1 for 4 different wind–eroded sediments was 0.44 to 0.68. However the trapping efficiency depended on wind speed, particle size distribution, particle density and type of sediment. The sampler had the lowest efficiency for particles < 44 μm. A BSNE sediment catcher was installed in Babaii Air Base. After a sampling period, the sediment in each trap was collected and weighed. The trapped materials were a mixture of saltation and suspension particles. Vertical distribution of wind–eroded sediment showed that the amount of soil collected decreased with increased height and the percentage of fine particles (<63μm) increased with height. The amount of trapped materials for each cm2 frontal intake with increased height were 12.00, 3.42, 1.44, 1.56, 0.75, 0.21, and 0.39 g cm-2, respectively, for the one sampling period.

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Evaluation of uric acid contents of poultry excreta was examined for use in the estimation of apparent protein digestibility. Uric acid was determined either by high-performance liquid chromatography or by spectrophotometric method. A high-pressure liquid chromatographic assay was used with absorbance measured at 285 nm. The method used a reverse-phase system with a C18-bonded column (250*4.6 mm, i.d.). The mobile phase was distilled deionized water. Injection volume was 20 l with a flow rate of 1 ml/min. Correlation (r) between the two methods for uric acid content of excreta from birds fed diets with different methionine levels was 0.976. The uric acid values were then used to determine apparent protein digestibility. The apparent protein digestibility values, when corrected for uric acid nitrogen, were comparable with those calculated from amino acid analysis.

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Effect of supplemental phytase on phosphorus and protein utilization and performance of broiler chickens fed on eight different wheat varieties were evaluated. The phytate contents of wheat varieties were determined. In a completely randomized design with a 8*3 factorial arrangement, 384 day-old commercial male brioler chicks (HubbardPeterson) were divided into 96 groups, four chicks per group. Each of the 24 experimental diets (eight varieties) and three levels of phytase (zero, 500 and 1000 FTU/Kg) were given to four replicates for a period of 21 days. At 21 days of age, chickens of each replicate were weighed and killed by cervical dislocation. Ileal contents were collected and analyzed for P, N, phytate and chromic oxide. Left tibia of two birds in each replicate were removed, pooled and stored at -20^oC for bone ash determination. There was a significant (P<0.03) difference in phytate contents between different wheat varieties. Effect of wheat varieties on body weight, feed conversion ratio and bone ash was significant (P<0.05). Added phytase improved body weight, feed consumption, feed conversion ratio and bone ash significantly (P<0.05). Phytase added at 500 FTU/Kg, improved protein digestibility significantly (P<0.01), but increasing the supplement to 1000 FTU/Kg had no further effect. Difference between enzyme levels (500 and 1000 FTU/Kg) was not significant regarding body weight, feed consumption, feed conversion ratio and bone ash. Overall addition of phytase to the diets containing wheat caused an improvement in performance, protein digestibility, and phytase phosphorus utilization in broiler chickens, and can, therefore, be used in diets to reduce feed cost and environmental problems.

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Downslope soil movement along riverbanks is a significant erosion process. Plant roots, particularly of woody vegetation, apparently stabilize soil on slopes because in most areas where the vegetation is removed, frequent bank failure occurs. Plant roots increase soil-shearing resistance both directly by mechanical reinforcement and indirectly through removal of pore water by transpiration. In this study, the effects of two plant species on the stability of the Karoon River has been investigated. To determine the In-situ shear strength of soil, a special device was designed and manufactured. This device is capable of measuring the shear strength of soil blocks as large as two cubic meters. In this study, twelve soil blocks, four blocks with roots of each tree and four blocks of root permitted were measured. Comparison of the soil shear strength with roots and root permitted soil shows that tree roots can significantly increase the shear strength of the soil. The amount of increase depends on the type of plant, the age of plant, the diameter of the roots and the percentage of roots in the block. In this study, the amount of increase varied between 20-66%. From the analysis of the data, two equations were developed to determine the increased shear strength.

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This study utilized a descriptive-correlational surveying approach to examine some economic factors involved in the adoption of an integrated campaign to control rice stem borer (Chilo suppressalis) in Isfahan Province. The population consisted of farmers living in the vilages where Biological Control Plan was conducted (N=6000). The population frame was obtained from Isfahan Agricultural Organization. The sample was obtained using the cluster random sampling method (n=361). Questionnaire and interview were used for data collection in this study. Face and content validity of the instrument was established using a panel of experts consisting of senior faculty members in agricultural extension and education at Tarbiat Modaress University. Further, the agricultural officer of Isfahan Province validated the questionnaire. A reliability analysis was conducted and Cronbach alpha value was reported to be 83 percent. The results showed that the rate of adoption of Integrated Campaign to Control Rice Stem Borer among the farmers was moderate. Among the economic characteristics, there was a significant relationship between adoption of integrated campaign and area of land, amount of area under cultivation, degree of family cooperation in the agricultural activities, access to agricultural inputs, access to financial resources, and yield of rice per hectare.

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The objective of this research was to evaluate bromide leaching in a field under corn, wheat and alfalfa. Potassium bromide (300 kg/ha) was uniformly applied and 15 mm of water was sprinkled over the plots in the first and second years. Plots were leached 8 times during the first year and 9 times in the second year (each time with 100 mm of water). Soil samples were collected at 0-30, 30-60, 60-90 and 90-120 cm depths two days after each leaching practice. Bromide concentration in soil samples was measured using an ion selective electrode. Moisture content in each plot was measured using a neutron meter to a depth of 120 cm and after calculation of evaporation from soil surface, the net water applied was determined. CXTFIT software and Regional Stochastic Model (RSM) were used to simulate leaching under field conditions. The results showed that flow velocity and dispersivity of treatmens were not significantly different from the control in the first year, indicating that treatments had no effect on preferential flow. Control treatments were not significantly different in the first and second years. In the second year, flow velocity in wheat, corn and alfalfa treatments were 1.54, 1.86 and 2.21 times higher than flow velocity in the control, respectively. Dispersivity in alfalfa and corn treatments were 4.30 and 5.30 times higher as compared to the control. The increase in flow velocity and dispersivity is caused by an increase of preferential flow in the second year. The root channels remaining in soil at the end of the first year may also have increased preferential flow. After adding 25 cm of water, 30% of bromide leached from the top 50 cm soil in all plots in the first year and control plots in the second year but the values in the second year were 47, 67 and 70% of bromide leaching from the top 50 cm soil in wheat, corn and alfalfa plots, respectively.