Agricultural Engineering
Year:2012 | Volume:34 | Issue:2|Papers Count:8

In order to study the effects of sugar cane harvest machinery traffic on bulk density and cone index variation, a survey was conducted in 10 farms of Deabel Khozaiee sugarcane agro-industrial company, Ahvaz, in 2006. In this experiment, two types of harvesters including wheel half track and tire wheels with 14 tons of weight, versus two types tractor and basket transporters, with 10 and 18 tons of weight, both with two axles were used. Soil bulk density was measured in 3 depths (0-5, 30-35, 60-65 cm) and cone index was determined at 80 cm depth. Results revealed increased soil bulk density at all depths. The highest amount of increase of soil bulk density with 6.69% was measured in 0-5 cm depth. Half track harvester increased bulk density more than wheel type harvester, but at 60- 65 cm depth wheeled harvester with 5.89% increase was higher than half truck harvester. Variation of soil bulk density in both transporters was not significant at any depth. Results showed that cone index measurement was only greater for half truck harvester treatment where soil moisture was near field capacity. Cone index for half truck and 18 ton transporter at 60-80 cm depth was significantly greater (p£5%), but for other treatments and depth variations, it did not show any significant difference. Generally, results showed greater use of harvesters and wheel half trucks and harvest at low soil moisture could reduce sugar cane field compaction problems.

In order to investigate the effect of Sewage Sludge (SS) application on the amount of micro elements in soil and absorption of these elements in plant organs of medical plants mint (MenthaPipperata), an experiment was carried out in split plot based on a complete randomized block design in three replications in the field of the University of Agricultural Sciences and Natural Resources of Sari. Five levels of fertilizer treatments (T1= control, T2= 20 tons per hectare mix SS and 1/2 fertilizer, T3= SS 20 tons per hectare, T4= 40 tons per hectare mix SS and 1/2 fertilizer and T5= SS 40 tons per hectare) and six levels of fertilizer years one year fertilizer (1385), two unconsecutive years fertilizer (1385 and 1387), two consecutive years fertilizer (1385 and 1386), three unconsecutive years fertilizer (1385, 1386, 1388), three consecutive years fertilizer (1385, 1386 and 1387) and four consecutive years fertilizer (1385, 1386, 1387 and 1388) were considered. The fertilizer treatments were carried out before planting in the land. The results of these tests showed that as the level of consumption and Sewage Sludge increased, the amount of absorbent micro-elements in the soil and the concentration of these elements in the mint plant increased. Most of too the micro-dements were observed in the 40 tons/ha treatment of SS in three consecutive years with more consumption compared to others. The interaction between the years of fertilizer consumption and fertilizer treatment on the rate of absorbent micro-elements except Mn in the soil and root of mint were significantly different, where, as, in the plant leaves, the interactions had a significant effect on the amount of Mn, but no significant effect was observed in the absorption rate of Cu, Fe and Zn.

The objective of this research was to design and develop an automatic device for displacing and placing the spherical-shaped fruits in the trays, with minimum damage to flesh. A planar two-degree-of-freedom tray mechanism was designed which placed the tray in the exact position when the gripper released a fruit. Two platforms with two independent linear motions, along perpendicular directions, were used. Finally, an electronic control system was developed to control the motion of the whole system and perform the motions in the pre-defined time sequences. Many tests on gripper, arm and tray performances were performed. In the tests, a spherical-shaped fruit such as apple with three different shapes, namely, oblong, conic and oblate were used. The results showed that the device had the ability to pick and release the oblong apples more effectively.

Nitrogen as one of the main nutrients is important for plant growth and soil fertility. The avaiable soil nitrogen can be changed due to N uptake by plants and microorganisms, leaching, denitrification, and volatilization processes. The application rate of N fertilizers is very important on nitrogen fate in the soil. To study the effects of three different rates of nitrogen fertilizer on nitrate, ammonium, nitrogen mobility through the soil, a split plot in the form of randomized complete block design experiment was conducted with three replications in Agricultural Research Center of Safiabad Dezful. Treatments comprised three nitrogen fertilizer rates including 150, 225 and 300 kg.ha-1. Nitrogen fertilizers were applied in two splits one after planting and the other in 6-8 leaves stages of maize using the fertigation method. Soil samples were taken 8 to 10 days before and after each fertigation from the depths of 0-30, 30-60, 60-90, 90-120 cm. In the soil samples, nitrate and ammonium concentration were measured by distillation of steam water and total N using Kejeldal methods. The results suggested that fertilizer application increased soil nitrate and total nitrogen concentrations through the soil profile. The most concentrations were measured in 300 kgN.ha-1 treatment. Nitrat movement to lower layers of soil was restricted due to soil heavy texture, high bulk density and optimized irrigation. The most nitrate concentration was observed in 0-30 cm layer of soil. Ammonium concentration was not influenced by the rate of fertilizer and its variation along soil profile was irregular.

Pesticides application can be leached to ground water or throughout runoff reach to water surface. The adsorption behavior of the river sediment with the pesticides has a significant influence On the environmental quality of a river. The objective of this research was to study the sorption isotherms of lindane pesticide on sediments of Ahvaz fifth bridge, Darkhoin and Khorramshahr hydrometric stations in two low water and high water seasons. Also, the effect of some chemical and physical properties on adsorption capability of sediments was investigated. The water and sediment samples used in this research were collected from downstream of the Karoon River. The results showed the salinity of water and sediments of the river in both seasons increased from Ahvaz to Khorramshahr. The highest percentages of OM and clay were 2.45 and 30.8, respectively, for Darkhoin and the lowest were 0.49 and 2.1 for Ahvaz fifth bridge station. The kf value of Lindane for Darkhoin sediments (195.5 mg/kg) was found to be highest and the lowest kf value (81.5 mg/kg) was observed in Ahvaz fifth bridge station. Langmuir b value for lindane was found to be 340 and 140 mg/kg for Darkhoin and Ahvaz fifth bridge station, respectively. Significant correlation was found between clay and organic matter percentage of sediments and amount of lindane adsorption.

To study the effects of irrigation water salinity, nitrogen, and foliar application of calcium chloride on yield and growth indices of pepper, a factorial pot experiment was carried out in Znajan Agricultural Research Center in 2010 using a completely randomized design and three replications. In this experiment, four levels of nitrogen (0, 75, 150 and 300 mg/kg), four levels of salinity (0.7, 1.5, 3 and 6 dS/m) and two levels of foliar spray (with and without spray) were used. Analysis of variance showed that the effects of salinity were significant on yield, number of fruit, length and diameter of fruit, dry weights of root, plant height and dry weights of leaf and fruit, and these parameters decreased as the salinity levels increased. Yield and growth indices of pepper plant increased as the nitrogen levels increased, but fruit length and diameter were not affected by nitrogen application. Foliar application of calcium chloride was not effective on growth indices of pepper under saline conditions. But interactive effects of salinity and nitrogen was significant on plant yield. When the salinity levels of treatments were 0.7 or 1.5 dS/m, the plant yield increased as the nitrogen levels increased. However under the salinity levels of 3 dS/m, the plant yield increased when the nitrogen levels did notexceed 150 mg/kg. At higher salinity level (6 dS/m), application of nitrogen decreased the plant yield as compared to control.

In order to determine the efficiency and appropriate levels of two biofertilizers including municipal solid waste compost and vermicompost on improving nutrient availability, growth and yield of canola under drought stress conditions, an experiment was conducted as factorial arrangement based on randomized complete block design with four replications. Treatments consisted of three levels of drought stress, including no stress, mild stress and severe stress conditions, and biofertilizer combination in five levels including control, application of municipal solid waste compost at two and four percent levels and application of vermicompost at two and four percent. Results showed that the effect of stress and biofertilizer levels on nutrient uptake, growth, and yield was significant. The interaction of drought stress and biofertilizer had significantly affected all traits except nitrogen and zinc percent. The results of mean comparison indicated that the mild and severe stress significantly reduced nitrogen, phosphorous, iron percentage and grain yield of canola and increased potassium and sodium percentage in shoot in comparison with the control group. Application of four percent vermicompost resulted in an increase in biomass, yield and nutrient uptake except zinc, under no stress, mild and severe drought stress compared to other biofertilizer treatments. Overall, it could be concluded that biofertilizers, especially vermicompost, positively affected plant growth under drought stress conditions.

In the present research, the performance characteristics of a four-cylinder spark ignition engine were investigated using bioethanol - gasoline blends. The experiments were performed in factorial tests with a randomized complete block design with three replications. Factors of experiments were six bioethanol- gasoline blends (E0, E10, E20, E30, E40 and E50) and six engine speeds (2000, 2500. 3000, 3500, 4000 and 4500 rpm). Engine performance characteristics for fuel blends were compared with gasoline. The results of the engine test showed that bioethanol addition to gasoline significantly increased the torque, brake power, and brake thermal efficiency while the brake specific fuel consumption decreased in ElO and increased in E50. Results showed that in all engine speeds, 10 vol.% ethanol in fuel blend gave the best results for torque, brake power and brake specific fuel consumption.