JOURNAL OF AGRICULTURAL ENGINEERING RESEARCH
Year:2009 | Volume:10 | Issue:2|Papers Count:8

The effects of chemical and physical treatments on the storage life of bitter lemons in Jiroft, Kerman province, were investigated. After harvesting, the lemons were treated by curing, fungicide, waxed paper, shrink wrap or using a combination of these treatments. The samples were stored in standard citrus fruit boxes for three months at 85-90% relative humidity at a temperature of 3oC. Once a month, the percentage of vitamin C, weight decrease, taste, hardness and rate of decay were recorded. It was found that the curing and fungicide treatments significantly reduced penicillium Sp. and aspergillus Sp. in the fruit. The fungicide, fungicide with waxed paper and fungicide with shrink wrap treatments retained the highest percentage of juice (hardness). The treatments of curing with waxed paper, shrink wrap with fungicide and shrink wrap had the highest percentage of vitamin C. Taste and hardness decreased during storage. Shrink wrap with curing, fungicide with shrink wrap and curing were effective in reducing the rate of decay in the lemons. The combined treatment of fungicide with curing and shrink wrap is recommended for the storage of bitter lemons because it not only controlled penicillium Sp. and aspergillus Sp., but also prevented weight loss and was more economical in comparison with the other treatments.

Soil salinity is a serious problem in south Khouzestan province. This study was conducted in Shawoor Agricultural Research Station, north of the city of Ahwaz, on silty-clay soil with 8 dSm-1 salinity during 2006 and 2007. A completely randomized block design arranged in split plots with three replications was used. The plots (planting methods) were: broadcasting + disk harrow (P1), broadcasting + disk harrow + corrugate (P2), seed drilling (P3), seed drilling + corrugate (P4), two rows on the ridge (P5) and three rows on the ridge (P6). Subplots were seed rates of 6, 9, 12 and 15 kg/ha. The results showed significant differences (P≤0.01) between planting methods for fuel consumption, total operation time and field capacity. The lowest fuel consumption with 5.02 lit/ha obtained from P3 and followed by P5 with 6 lit/ha. The highest field capacity (1.7 ha/h) was obtained from P5, an increase of 63%, 156%, 5%, 104% and 8% over P1, P2, P3, P4 and P6, respectively. The lowest total operation time (0.58 h/ha) was obtained from P5, a reduction of 38%, 60%, 13%, 150% and 6% over P1, P2, P3, P4 and P6, respectively. Significant differences were found between planting methods for grain yield, percent of germination, number of plants per m2 and number of packsacks per plant. However, number of seeds per packsack and 1,000 kernel weights were not significant. Differences between seed rates for grain yield, number of plants per m2 and number of seeds per packsack were significant. Duration of germination, percent germinated number of packsacks per plant and 1,000 kernel weights were not significant. Maximum grain yield (2134 kg/ha), percent germinated (86%), number of plants per m2 (99), number of packsacks per plant (78) and number of seeds per packsack (23) were obtained from P5. The results suggest that, for canola Hayola 401 hybrid crops in the slightly saline soil of Khouzestan, treatment P5 (two rows 30 cm apart on the ridge and 60 cm from each other) with a seed rate of 9-12 kg/ha is the best applicable treatment.

The main source of heavy metals in soil is the use of urban and industrial waste water, synthetic phosphate fertilizers, sludge from sewage treatment plants. Most heavy metals accumulate in the top soil and in the long term, their increased concentration in the soil and accumulation in the plants. The quantity or level of absorption in plants, depends not only on the concentration levels of the metals in the physical and chemical composition of the soil, but also varies in different parts of the plant type. Several studies have been conducted on the use of waste water and sewage, carrying heavy metals, for agriculture; however information regarding amount of absorption and accumulation of heavy metals in various parts of different crops and plant types is limited. This study has been conducted with the objective of analyzing the impact of various levels of cadmium concentration in soil on the quantity of its absorption and accumulation in various parts of five different types of cucurbits, commonly used in Iran. The experiments were carried out in a factorial experiment in completely randomized design, with three repetitions. The factors includes Cd concentration in 4 levels (control treatment, without adding Cd, soil with 50 mg kg-1 Cd, soil with 50 mg kg-1 Cd, soil with 50 mg kg-1 Cd and irrigation water with 0.5 molar EDTA). And plants species (five summer crops) at the end of agriculture season, samples from different organs of species have been collected to measure the magnitude of Cadmium accumulated in them. With SPSS software, variance analysis of the collected data was performed, and comparison of means was performed by Duncan multiple range test (P£0.05 and P£0.01). The obtained results indicate a direct relation between Cd accumulation and Cd concentration in root region. Adding 0.5 molar EDTA to irrigation water causes more than 50 percent increase in Cd accumulation in treatment of 50 ppm Cd. Also the results show (except in control treatment) that Cd concentration is in excess of limit for human consumption.

This study investigated the effectiveness of heat treatment (50oC, 60oC and 70oC for 1 h and 2 h at 75-80% RH) and cold treatment (0oC and-5oC for 24 h and 48 h) in the control of storage pests in Zahedi and Piyarom dates. Before and after each treatment, the number of surviving adults, larvae, pupae and eggs were recorded and the percentage of infestation was calculated. The dates were treated at the selected temperatures in the first stage and then packed and stored in cold storage or at ambient temperatures for six months. The rate of infestation and microbiological and chemical analysis were recorded after two and four months of storage and six months after removal from storage. Plodia interpunctella, tribolium castaneum, lasioderma serricorne, oryzaephilus surinamensis, bartrachedra amydraula. And carpophillus sp. were collected from the infested dates. All treatments significantly decreased the percentage of infestation compared with the control group. Treatments at 70oC for 2 h and -5oC for 48h were the most effective in reducing the infestation. The results showed that treatment at -5oC for 48 h reduced the infestation in the Zahedi and Piyaroum date fruits to 10% during storage. The type of storage and the length of storage interaction on the amount of infestation and percent acidity (as lactic acid) were significant. The rate of infestation and percent acidity in the samples in cold storage decreased significantly during storage. It was concluded that dry and semi-dry dates should be stored in cold storage to prevent the activity of microorganisms and pests.

The influence of lime on the shear strength of soil has been known for centuries. The conventional method to increase the lime content of a soil is to add less than 10% hydrated lime in the form of powder or grout to the soil. This method is convenient for soils to be used as fill material in projects such as road construction, land fill pavements or lime pile; but is not applicable where a large quantity of naturally occurring soil requires treatment, such as on a slope experiencing slippage. In this research, a new method is examined by which a lime-saturated solution of water permeates the soil. A physical laboratory model was designed, built and tested. The results of a 60 day test showed that the pozolanic reaction between soil particles and the dissolved calcium ions developed cementation between soil aggregates, leading to a significant increase in the soil shear strength. The results of a series of direct shear and Atterberg limit tests carried out on treated and untreated samples demonstrated an increase of 300% and 220% in cohesion and the internal friction angle, respectively. It also showed a decrease of 14% in the plasticity index of the soil resulting from the intrusion of hydrated lime equivalent to a mere 0.5% of the soil mass.

The system dynamics technique is an object-oriented approach that studies and manages complex feedback systems. Its merits include the friendly and easy development and improvement of a model. It is also used as a decision tool for engineering problems. In this paper, the system dynamics technique was used to simulate the performance of a subsurface drainage system in an unsteady state. The model was validated using experimental field data collected from sugar cane farms in Khuzestan. The effect of different parameters on daily water table level and drainage discharge was investigated. The standard error (SE) index was calculated to determine the agreement between the observed and simulated values for water table and drainage discharge. The results indicated that the SE for water table and drainage discharge were 10.2 cm and 0.13 cm per day, respectively. In addition, the predicted upward flux in the soil showed that it can compensate for part of the water required during the irrigation season.

Physical characteristics of agricultural products are the most important parameters in the design of grading, conveying, processing and packaging systems. Among these physical characteristics, volume, mass, projected area and center of gravity are the most important for sizing systems. In this study, the segmentation method was used to estimate lemon volume. A total of 50 randomly selected lemons were examined. The mechanized scanning system consisted of two CCD cameras, two capture cards, an appropriate lighting system and a personal computer. The cameras were arranged at right angles to each other to capture perpendicular images of the lemons. The estimated volume using this technique was compared to the actual volume of the lemons, measured by water displacement, using a paired t-test and the Bland-Altman approach. The estimated volume using the mechanized scanning method was not significantly different from that determined by water displacement (p>0.05). The mean difference between water displacement and mechanized scanning was -0.06 cm3. The characterization results of the lemons showed that the computed volume and measured mass parameters were highly correlated, M=0.8894 V+2.2757, with a coefficient of determination of 0.96. In conclusion, the mechanized scanning technique provides a simple and efficient methodology for estimating lemon volume and mass.