Iran Agricultural Research
Volume:30 Issue: 1, Winter and Spring 2011

This study was carried out on olive trees cv. Amygdalifolia, to investigate the effect of spraying potassium nitrate (KNO3) and zinc sulfate (ZnSO4) on the fruit weight, dimension and volume. The plants were sprayed with 0, 0.5, 1.0 and 1.5% KNO3 and 0, 0.25, 0.50 and 0.75% ZnSO4 and their combinations in August about halfway through the fruit growth period. The highest fruit weight was observed using 0.5% ZnSO4 + 0.5% KNO3. Fruit length and diameter were affected significantly using different ZnSO4 concentrations especially in combination with KNO3. The fruit, pulp and pulp/pit volume increased by increasing ZnSO4 concentrations. The highest fruit, pulp and pulp/pit volume were also obtained from trees treated with 0.5% ZnSO4 + 0.5% KNO3. Our results emphasize the importance of an appropriate fertilization management, particularly for table olives, in which fruit size, and pulp/pit ratio are important characteristics.

fully instrumented air conditioning laboratory unit capable of controlling drying air temperature and humidity integrated with an instantaneous weighing thin layer drying system was used to investigate the thin layer drying behavior and desorption equilibrium moisture content of canola (Brassica napus L.).To this aim, freshly harvested canola samples with moisture content of about 12±0.5% (d.b.) were dried at temperature levels of 40, 45, 50, 55 °C and absolute air humidity levels of 0.005, 0.01, 0.015, and 0.02 Kg/Kg. The instantaneous grain moisture content was measured by weighing the sample periodically. Drying was continued until canola kernels reached a constant weight to obtain the hygroscopic equilibrium moisture for different combinations of drying air temperature and absolute humidity. To select a suitable model for describing the thin layer drying of canola, experimental drying data were fitted with three thin layer drying models,namely, Page, Modified Page and Two-Term Exponential models. Furthermore,four widely used desorption isotherm models including Chung-Pfost, Modified Chung–Pfost, Modified Oswin, and Modified Smith were used to fit the experimental data of equilibrium moisture content. Finally, non-linear regression analyses were run and based on the highest value for R2 and the lowest value for 2, mean bias error (MBE) and root mean square error (RMSE), the most suitable models for thin layer drying and equilibrium moisture content were determined to be Two-Term Exponential and Modified Smith, respectively.

Lack of sewage collection systems, percolation of surface waters,and seepage of wells have raised the groundwater table in Shiraz area in the south of Iran. The growing population generates environmental pollution resulting in the degradation of the quality of surface and groundwaters used for agriculture.Inorganic and organic pollutants have been traced in Shiraz water resources.Heavy metals, As+2, Cd2+, Cr2+, Fe2+, Hg2+, and Pb2+ have been reported as potential pollutants of both surface and groundwaters. The safety of groundwater supplies in Shiraz was studied with respect to heavy metal concentrations. From 50 semi deep wells, which supply water for agricultural production, three water samples per well were examined to determin the physical and chemical characteristics of the water. The results of the study indicated that the concentration of Cd2+, Cr2+, Fe2+, Mn2+, and Pb2+ exceed permissible values for crop production. A network of gallery systems was proposed for wastewater collection and the disposal of Shiraz groundwater, to increase the water table depth in urban areas. It is estimated that about 100M m3 wastewater could be drained annually through the proposed gallery system which could be used for agricultural production. It is believed that mixing the drained waters from the proposed network of galleries with the agricultural water supplies will help control concentrations of heavy metals so they do not have serious acute impacts on agricultural production. The chronic effects of the impacts of water quality on agricultural production should be monitored temporarilly.

The extensive use of pesticides in agriculture is compromising soil and water quality. One major concern is protecting water resources from contamination.The main objective of this research was measuring 2,4- D in a silty clay soil and simulating temporal transportation of this herbicide in soil using a LEACHP model, in a corn root zone field. 2,4- D was applied at 3.5 kg a.i./ha, followed by two irrigation treatments in a completely randomized design with three replications. 2,4- D concentrations were measured during the growing season by obtaining soil samples from each plot through a 1 m depth. The measured data showed a temporal reduction of 2,4-D concentrations in the soil down to a maximum depth of 40 cm for both irrigation treatments. Total concentration of 2,4 -D in the soil profile 8, 13, 23, 30, 37,and 57 days after application for normal irrigation were 18.5, 16.36, 11.67, 10.47,8.47 and 3.2 mg kg 1, respectively and deficit irrigation showed 20.2, 16.7, 11.22,10.05, 8.8 and 7.3 mg kg 1, respectively for the same dates and soil depth. Accordingto our study region, the half life of 2,4- D for 0 10 cm and 10 20 cm of soil depths in a normal irrigation level were 7 and 33 days and in a deficit irrigation level were 9 and 34.65 days, respectively. The statistical parameters including RMSE, CRM and d were used to compare simulated with measured data. These parameters were 0.67, 0.5 and 0.87 for normal irrigation and 0.8, 0.61 and 0.88 for deficit irrigation. The LEACHP model simulations were in agreement with actual observations.

The present pot experiment was undertaken to investigate the phytoremediation potential of corn and oat in soil. Treatments consisted of four cadmium (Cd) levels (0, 5, 10 and 20 mg l 1) and three irrigation intervals (1, 3 and 7 days), arranged in the form of a complete randomized design with three replications. Corn and oat were harvested after 75 and 90 days, respectively.Transpiration rates, shoot dry weight and shoot Cd concentration of both plants were measured. Cadmium uptake, Cd bioconcentration factor (BCF), the apparent recovery of Cd and water use efficiency were also calculated. Cadmium had negative, and in some cases stimulating effects on plant growth. Furthermore, the phytoremediation capacities of both plants were higher at the 1 day irrigation frequency. The BCF values for both plants were less than unity, indicating that the phytoremediation potentials of oat and corn were low in this study. Overall, oat was more efficient than corn in phytoremediation of Cd as it accumulated 52, 169 and 132% more Cd than corn at 1, 3 and 7 day irrigation intervals, respectively.On the average, oat also took up soil Cd about 80% more than corn. From the results reported herein, it is recommended to conduct additional experiments with different Cd levels and more irrigation intervals using different types of agronomic and horticultural crops.

The functional response of Aphidius ervi to different Sitobion avenae densities on two wheat cultivars (Sardary and Alvand) was examined in laboratory conditions. Experiments were carried out in test tubes on an F2 lab generation without wheat clusters and also on F2 and F5 generations in pots using wheat clusters. In the tubes, female wasps were exposed to aphid densities of 2,4, 7, 14, 28, 32, 42 and 56 for one hour, but on the potted plants, to the same densities of aphids for 24 hours. Results obtained from the logistic regression indicated types II (Holling’s model) and III (Roger’s model) in all 3 experiments on Alvand as a resistant cultivar and Sardary as a sensitive cultivar, respectively.The type II model of functional response fitted on data obtained on the Alvandcultivar indicates a negative bottom top impact of the resistant cultivar on the parasitoid. The model parameters estimated for F2 and F5 wasps were not significantly different for the Sardary cultivar. However, the area of discovery and handling time in the F5 generation on the Alvand cultivar were higher than that of F2.

The aim of this study was to determine the factors affecting stillbirth and the consequences of stillbirth on longevity, production, and reproductive performance in Holstein cows of Iran. Calving records from March 2000 to April 2009 comprising of 220,043 calvings on 102,199 cows in 33 herds were used. The results showed that 4.06% of the newborn calves died within 48 h of birth. The stillbirth rate was significantly higher for first parity cows (P<0.01). Calving difficulty significantly increased the risk of stillbirths (P<0.01). The frequency of stillbirth was lower for female calves than for males and was higher for twins than for singletons (P<0.01). Stillbirth significantly (P<0.01) reduced 305 d milk, fat and protein yield by 222 (±31), 8 (±1.12), and 6 (±1.01) kg per cow per lactation,respectively. Milk protein percentage, but not fat percentage, was affected by stillbirth (P<0.01). The mean calving interval for cows experiencing stillbirth was significantly longer than for those with live calves [410.3 (±1.17) vs. 405.5 (±1.05) d (P<0.01), respectively]. The overall mean longevity was affected by stillbirth while the shortest lifetime was observed for cows with stillbirth at their first parity (P<0.01).