JWSS - Journal of Water and Soil Science

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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.

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The physiological characteristics of winter wheat(cv. Shiraz) were evaluated in a 2-yrs field study by using a spilit plot design with four replications, at the experimental farm of Shiraz University, College of Agriculture located at Badjgah. Main plots consisted of three sowing dates (November 6^th, December 6^th and January 5^th) and four planting densities (150, 250, 350 and 450 plants/m²) were assigned as sub plots. The results indicated that delay in sowing was associated with a significant reduction in the grain yield. So that the grain yield in sowing date of January 5^th was significantly less than it in sowing dates of November 6^th and December 6^th. Moreover with delay in sowing date the developmental rate of wheat was enhanced and plants reached maturity more rapidly. The trend of the leaf area index changes and the dry weight of the plants were under the effect of experimental treatments, leaf area index was found to be greater at the higher densities and early planting date. Number of stems per m² were decreased with delay in the sowing date, although at the higher densities, the number of stems per m² was greater, despite severe tiller death observed at these densities. The study of trend of dry weight changes during the season indicated that biomass was greater at higher densities and earlier sowings, which resulted in earlier ground cover and higher amount of radiation interception. In conclusion, the results of the present investigation revealed that to achieve a reasonable grain yield, the 6^th of December and 250 plants per m² were the best sowing date and planting density for wheat (cv. Shiraz) under similar agro climatic conditions with the present investigation.

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Fecundity and sex ratio are the important factors in the quality control of parasitoid, Trichogramma. In this research, the effect of the host egg deprivation on these factors in Trichogramma brassicae Bezdenko was evaluated. The experiment was conducted with four treatments, each in five replications in a completely randomized design. Twenty mated females (24 h old) were transferred into the glass tubes (1.5×10 cm) separately and were fed by honey 20% daily. In one treatment, parasitoids were provided with the 150 host eggs (Sitotroga cerealella) in first day, but in other treatments the 150 host eggs were offered after 2, 4 and 6 days. In order to obtain fecundity, black eggs were counted after 3 or 4 days. After emergence, adult parasitoids were recognized as male and female by their antennae and sex ratio was obtained. Results indicated that as parasitoids, Trichogramma sp., were deprived from the host eggs longer, more decrease was observed in fecundity and female ratio. Therefore, parasitoid quality was decreased by the host egg deprivation.

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In Iran, fertilizers are mainly applied directly to soil. In such conditions, the yield and fertilizer use efficiency are usually low. The simultaneous application of fertilizers and irrigation water (fertigation) is an appropriate alternative to increase the efficiency of applied water and fertilizers. The objective of this study was to investigate the effect of various irrigation and fertilizer amounts on efficiency of applied fertilizers when used as fertigation in a Tape irrigation system. A field experiment was carried out with sunflower as a completely randomized design with 20 treatments and 3 replicates. The fertilizers were applied by fertigation. Four levels of the water (60, 80, 100 and 120% treatments I1 to I4) and five rates of the recommended fertilizers (0, 60, 80, 100, and 120% treatments F₀ to F₄) were applied.The recommended amounts consisted of 400 kg CO(NH₂)₂, 50 kg KCl, 30 kg FeSO₄, 30 kg MnSO₄, 50 kg ZnSO₄, 30 kg CuSO₄, and 30 kg H₃BO₃ per ha. Tape irrigation was used for every treatment. The results indicated that in fertigation method, there were significant differences ( P≥0.01) in fertilizer use efficiency (FUE) for the total dry matter and grain yield between treatments. The results showed that by increasing applied water, fertilizer use efficiency was increased and affected by fertilizers treatments. Thus due to higher availability of nutrients, fertilizer use efficiency increased. was Fertilizer use efficiency also decreased by increasing fertilizer rate. The results also demonstrated there were significant differences in all the treatments. The results showed that fertilizer use efficiency of K is higher than N and N is higher than P.

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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.

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Discrete Models of Spatial Variability (DMSV) have limitations for soil identification in traditional soil maps. New approaches, generally called digital soil mapping (DSM), using continuous methods (CMSV), try to predict soil classes or soil properties based on easily-available environmental variables. The objective of this study was to map the soil classes of the Borujen area, Chaharmahal-va-Bakhtiari province, using digital elevation model (DEM) and its attributes and Soil-Land Inference Model (SoLIM). To do this, eighteen terrain attributes were derived from the DEM of the area. The primary analysis showed seven attributes are the most important derivatives. These derivatives as well as three dominant soil subgroups and seven soil families of the region (41 profiles from 125 profiles) were used to construct the input data matrix of the model. Then, output fuzzy soil maps of SoLIM were converted to polygonal soil map, using ArcGIS. Results showed that different combinations of DEM attributes have different accuracy rates for soil prediction. The accuracy of the interpolation was twice that of the extrapolation. Although SoLIM had an acceptable accuracy for soil nomination, and identification of soil map units’ types, it did not have enough accuracy for the location of soil classes. It seems that using other data like parent material and geomorphic surface maps will increase the accuracy of the model prediction.

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Magnetic susceptibility measurement is a simple and quick technique for characterizing soils and sediments and describing soil-forming processes. The interpretation of soil magnetic susceptibility data needs sufficient knowledge about the factors affecting this parameter. To identify the effects of parent material, gypsum and calcium carbonate equivalent, 42 samples were taken from horizons of soils developed on loessial, alluvial, granitic and marly materials in southern Mashhad. Gypsum and carbonates of soil samples were removed by successive washing with distilled water and diluted HCl, respectively. Magnetic susceptibility of bulk samples (lfbulk), gypsum free samples (lfGf), gypsum and carbonates free samples (lfGCf) and gypsum, carbonates and sand free samples (lfGCSf) was measured. The results revealed a strong 1:1 correlation between the measured and calculated lfGf and lfGCf. Despite the high amounts of gypsum and carbonates in soils developed on marls, their lfbulk was much more than that of the other soils and reached up to 121.8×10-8m3 kg-1. In contrast, the lfbulk values of saprolitic granite were less than 10.4×10-8m3 kg-1. The lfbulk values of loessial and alluvial soils were less than those of marly soils but higher than those of soils developed on saprolitic granite. lfbulk values were negatively correlated with the amount of sand. However, reduction in magnetic susceptibility values of marly soils after removing sand reflects the different nature of this soil. The correlation between lfbulk and amount of silt and clay is positive, but the magnetic susceptibility values are more sensitive to clay percentage, indicating the more important contribution of clay to magnetic susceptibility values. The results of this study highlight the role of parent materials, gypsum and carbonates in the soil magnetic susceptibility values that should be considered.

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The aim of this study was to investigate the effect of parent materials and pedogenic processes on distribution of Pb, Zn, Cu, and Ni in the residual soils derived from different parent materials in the Binaloud zone, western Mashhad. Two soil profiles on the summit of granitic, ultrabasic and metamorphic rocks were described and sampled from their genetic horizons. Pseudototal concentrations of selected heavy metals and fractions of these metals were determined using aqua-regia and sequential extraction methods, respectively. 178.1-419.7 mg kg-1of Ni in ultrabasic soil versus 0.7-27.5 mg kg-1 in the granitic soil make the Ni a distinctive element in the studied area. Cu with the average contents of 60 and 56.3 mg kg-1 in the ultrabasic and metamorphic soils respectively showed more concentration in comparison to granitic soils with 12.1 mg kg-1. The amount of Zn was not significantly different among the soils, although the average of this element in the granitic soil (55 mg kg-1) is slightly more than the other soils. Pb was only detectable in the surface layers of all pedons reaching up to 6 mg kg-1. Residual fraction except Ni and Cu in granitic soil was the main fraction for all of the studied heavy elements that was expectable according to the low weathering intensity of the soils. The eolain addition of gypsum and carbonates have influenced heavy metals concentration, especially in surface horizons. In conclusion, the amount of heavy metals was significantly affected by parent materials and the eolian deposition must be considered as the secondary influencing factor.