JOURNAL OF AGRICULTURAL ENGINEERING RESEARCH
Year:2007 | Volume:7 | Issue:29|Papers Count:11

Indicating cropped area based upon available water, especially during drought spells is of great importance. This study was an attempt to fulfill this task, using proper approaches for river flows forecasting and optimization methods. To accomplish this goal, in the first step six-months river flows ahead have been forecasted using artificial neural networks (ANNs). In the next step, the relation between the first and second six-months flows has been analyzed. However, the results showed that it was necessary to use different approaches for wet and dry years. Furthermore, an optimization model was applied to indicate areas of cultivation for the cropping pattern of study area with respect to the forecasted flows. The results indicated that the applied methodology was able to indicate optimum cropped area during water scarcity periods and could be considered as a suitable method for drought mitigation plans.

Agricultural machinery efficiency has to be tested in regards to climatic and regional especial condition. Therefore the effects of five different seedbed preparation methods were investigated on some physical properties and yield in Darab region for two years. This experiment was carried out using Randomized Complete Block Design with four replications and five treatments as follows: Moldboard plow + disk harrow (twice) as evidence; Disk plow + Disk harrow (once) ; Disk plow + Disk harrow (twice); Disk plow + Rotary tiller; Moldboard plow + Rotary tiller In all tillage methods parameters such as mean weight diameter, effective field capacity, number of plant per area unit, yield and yield components were measured. The results showed that plowing practices by moldboard and disk plow had significant effect on mean weight diameter with %95 confidence. Besides, the surveys indicated that there was not significant difference between MWD's of second, third and forth stages of disk operations. The results also noted that plowing practices with disk plow did not show significant difference between mean weight diameter in second, third and fourth stages of disk operations. The minimum mean weight diameter was obtained when secondary tillage practices were done with rotary tiller as compared with twice of disk practices. Maximum grain yield obtained in tillage practices with disk plow and twice disk harrow. Results indicated that increasing number of plant per area unit, decreased number of kernel per eara and kernel weight.

Many irrigation networks over the world suffer from low irrigation performances and there is a need to evaluate the related problems in the corresponding agriculture district. In the present study, the irrigation performance in Doroodzan Irrigation Network was evaluated in Fars province. Some performance indicators such as efficiency, equity, and dependability and delivery performance ratio were measured using the actual and pre-determined irrigated areas. For this purpose, during three irrigation seasons the delivered water in the beginning of tertiary canals was measured. Results showed that the water delivery was not equitable and upstream farmers received more water than the end-users. The difference between actual and pre-determined irrigated areas caused significant changes on the values of performance indicators which could be important for managers.

A relatively large part of the cultivated area in Iran is devoted to cotton production. Due to the problem of residues and the importance of removing cotton stalks after harvesting, a project was conducted to develop and evaluate a cotton stalk puller. A machine is required to remove cotton stalks to reduce pest proliferation after harvesting. Use of two cleated diskes placed on a main chasis was selected for stalk pulling after the investigation of different methods. Tilt angle, disk overlap and rake angle were adjustable in the machine. The project was carried out using the following two steps. Firstly, the required characteristics of cotton field and stalks were determined by performing primary field experiments. The proper estimated values for tilt angle from 25 to 35 degree, rake angle from 17 to 27 degree and disk overlap from 25 to 55 mm were determined using the mentioned characteristics, theoretical calculations and computer software. Design of the machine was consisted of three sections, namely: the way to fix disks and axle mechanism, mechanism for disk connection to chassis and chassis. Chassis of the machine connected to the three-point hitch of the tractor. After completing the prototype construction, machine performance was tested and evaluated in the field. Secondly, the effects of treatments (tilt and rake angles and disk overlap each at 3 levels) on machine efficiency were evaluated with three replications in the field. The experimental design was split plot in a completely randomized block design. In the field experiments, soil moisture content and CI were 8% (d.b.) and 1.55 MPa, respectively. The results revealed that tilt angle of 30 degree with performance of 95.4 %, the rake angle of 17 degree with 94.9% and finally disk overlap treatment at an overlap of 25mm with 94.1% were appropriate factors for the best machine performance resulting in maximum percentage of stalks being removed. These technical parameters and specifications can be used in semi-industrial and mass production of the machine.

Potato chips are one of the main products of deep - fat flying which consumed mostly by children and teenagers. Therefore the production of suitable chips and determination of their quality and shelf-life are important. The aim of this study was the determination of potato chips' shelf-life which were fired at two formulations of oil, i.e. formula 1 or F1 (palmolein and sunflower oils 50:50) and formula 2 or F2 (palmolein, sunflower and cottonseed oils 50:25:25) and were stored at 26°C and 60°C until one of the characteristics (peroxide value, acid value, total polar compound or TPC, or Fritest) reached the discard point for flying oil. Sensory evaluation of potato chips fried in two frying oils and control (frying oil produced by one of the Iranian factories) was carried out by 40 non-trained panelist (Hedonic test 5 scale). Statistical analysis of the results for oils extracted from chips and stored at 26°C and 60°C showed that the shelf-life of potato chips prepared in F1 and F2 was 11 and 9.5 days and 7.5 and 1.5 days, respectively (p < 0.05). There was no significant difference (P=0.123) between overall acceptance of potato chips fried in F1, F2 and control. Ranking was performed taking into account the fry-life of the oils, shelf - life of the produced potato chips, sensory evaluation, nutritional value and economical aspect of producing F1, F2 and control, and the following result found: F1 > F2 > control. Regarding the high trans fatty acid contents (19.83%), lower nutritional value (P/S+T) [0.35 for control compared to 1.35 for F1 and 1.09 for F2], 6 hours difference in fry-life and hydrogenation cost for control, F1 can be substituted to hydrogenated frying oil (control).

The functionality assessment of an irrigation network is an important step to find the shortages and the ways to improve the efficiency of irrigation networks. Recently the application of conventional benchmarking to irrigation and drainage networks has been suggested by International Water Management Institute (IWMI) and in some countries it has been implemented successfully. In conventional benchmarking method, some pre-determined indicators are measured and the values are presented in graphical format in order to be compared with each other. The indicators which carry the best values would be used to improve the functionality of other irrigation networks. In this study, numerical analysis approach has also been added to the conventional benchmarking method. In new benchmarking method in addition to the graphical comparison, the indicators are also valued and their amounts are normalized. For comparison purposes the selected indicators have been categorized in to: managerial, technical, agricultural productivity, financial and environmental groups. Two existing irrigation and drainage networks called Brimvand and Dinevar networks were selected in Kermanshah province in the west of Iran. The proposed benchmarking approach was used to evaluate the value of the selected indicators. The best measured value of indicators was tagged as a benchmark and standard level with allocated quantity of 1 or 100%. The pair wise comparison matrix using some experts' viewpoints was applied and the inter-relation coefficient of indicators and views were determined using analytical hierarchy process method. The application of above mentioned approach to the Brimvand and Dinevar networks showed inter-relation coefficient values of 0.8708 and 0.9054, respectively. Similar comparison for management performance view point in Brimvand and Dinevar networks showed 0.9128 and 0.9074 values, for technical view point 0.7660 and 0.9731, for productivity efficiency 0.8607, 0.8728, for financial view point 0.8613 and 0.9276 and finally for environmental view point 0.8751 and 0.8187, respectively. Based on the analysis of the above mentioned values, the relative importance coefficients have been calculated in order to define the priority of performance improvement among the five category of indicators. Calculations showed that the orders of performance improvement priorities in Brimvand irrigation network are: management view points with quantity of 0.0394, technical 0.0356, productive efficiency 0.0328, financial 0.0133 and environmental 0.008, respectively. Similar orders of performance improvement priorities for Dinavar irrigation network are: the management viewpoint 0.0419, technical 0.0041, productive efficiency 0.0299, financial 0.0328 and environmental 0.008, respectively.

Soil tillage although have prominent and beneficial effects, but in some cases may have negative results. Applying suitable tillage methods can decrease the damage. This study was conducted to identify the effect of various tillage methods on rice yield and its components in summer 2003 on a clay soil in Shawoor Agricultural Research Station, north of Ahwaz. Experiment was conducted as split plots and Randomized Complete Blokes Design in three replications. Main plots were conventional tillage (Tl), reduced tillage which consisted of two passes of heavy disc harrow (T2), two passes of low disc harrow (T3), one pass of cultivator in depth 10 cm (T4), one pass of cultivator in depth 15cm (T5), one pass of rotivator in depth 5cm (T6) and no-tillage method (T7). Subplots were two rice cultivars Anboory (VI) and LD183 (V2). The results showed that there was a significant difference among tillage methods for yield, panicles and plants per square meter. Howeven, the difference was not significant for .number of seed per panicle, thousand kernel weight (T.K.W) and harvesting index. Difference among conventional tillage and reduced tillage (T2-T6) with no-tillage method was also significant for yield, although there was no significant difference between conventional tillage and reduced tillage methods. Also, difference among varieties was significant for yield and yield components and V2 was better than VI. Interaction between tillage methods and variety cultivar treatments for all indicators was not significant. Results from regression analysis for all tillage methods showed that the number of panicle per square meter was most important component of yield. Consequently, suggestion for rice direct seeding in Shawoor and similar regions, based on working times and machine types, can be proposed for one of the reduced tillage methods, particularly rotary tiller, replacing conventional tillage method.

Reduction of NO3-N contamination and increasing crop production hinges upon proper management of applied water and nitrogen fertilizer. In order to practice such management, it is necessary to evaluate all the effective parameters involve in the cycle of nitrogen in the soil. Such as amount, time, and method of nitrogen and irrigation water application. The objective of this study was to evaluate the effects of various level of water and nitrogen application via a sprinkler irrigation system on corn silage yield and nitrate leaching. The filed experiment included four levels of irrigation water, (1.13ETc (W1) , 1.0ETc (W2), 0.85ETc (W3), and 0.7ETc (W4)), and three levels of nitrogen application (200 Kg N ha-1 (N200),150 Kg N ha-1(N150),and 0.0 Kg N ha-1 (N0)), with three replications. Soil moisture extracts were taken for the depths 30 and 60 cm by soil moisture samplers 24 hours after each irrigation and rainfall from all the treatment plots. Nitrate concentration of soil moisture extracts were measured to quantity the amount of NO3-N leaching below root zone. The NO3-N content of the soil up to the depth of 30 and 60 cm at planting and harvesting times and the total crop nitrogen uptake were measured. The amount of NO3-N leached below the depth of 60 cm in W1, W2, and W4 treatments with 200 Kg nitrogen applied were 6.92, 6.58, and 0.0 Kg ha-1 and with 150 Kg nitrogen applied were 5.03, 4.47, and 0.0 Kg ha-1, respectively. No nitrate ieaching occurred from W3 and W4 plots. The major portion of applied fertilizer to W3 and W4 plots remained unused in the soil, a little was absorbed by the crop, and the rest was volatilized. Increasing the amount of applied fertilizer resulted in improving plant nitrogen uptake, but reduced the ratio of plant uptake to total nitrogen applied. The amount of nitrate leaching significantly increased in response to over irrigation in W1 plots. Results indicate that the amount of NO3-N leaching during the growing season depends on many factors such as soil initial nitrogen content, amount of applied nitrogen fertilizer, crop growth condition, crop nitrogen uptake, and irrigation-fertilizer management.

Physical properties of Canola seed are necessary to design appropriate equipments for handling, transporting, processing and storage. In this study, some physical properties of Canola seeds were determined and evaluated. Samples (Licord Variety) at 3 levels of moisture content wet basis (w.b) were taken to determine parameters of axial dimensions, geometric mean diameter, area, projected area, volume, sphericity and aspect ratio. Analysis of variance of data showed that, moisture content (w.b) significantly affected all parameters (p£0.01). Relationship between the physical properties and moisture content was then expressed by regression relations. Comparison of means with Duncan's method indicated that axial dimensions, geometric mean diameter, area, projected area and volume increased with increasing in moisture content, but sphericity and aspect ratio decreased.

The meal of rapeseed is a good source of protein as food and feed. Rapeseedmeal as a by - product of oil extraction process, contains up to 43% protein with reasonable balanced amino acids profile. Processes for isolate of rapeseed protein are based on dissolving of meal in an alkalin and subsequent recovery of the protein as isolated by precipitation. Suitable conditions for the extraction and precipitation of protein from rapeseed meals were determined using alkalin extraction at pH (10, 11, 12) and precipitation at acidic pH (4.5, 5.5 and 6.5). The results showed that the highest protein yield was obtained by alkaline extraction at pH=12 and precipitation at pH=5.5 in which the isolate consisted about 88.1% of protein. It also contained 0.4% phytic acid and also the glucoseinolate content of all isolates was low and non detectabel.