JOURNAL OF AGRICULTURAL ENGINEERING RESEARCH
Year:2004 | Volume:4 | Issue:17|Papers Count:6

The first step for suitable planning in order to decreasing of potato wastes during the storage is determining the forcible factors on wastes and economical damages. The present study evaluated the impact of storage condition on the potato losses in Hamedan province (2000-2001). For this purpose, by using of random sampling method 11 depots from different kinds of potato stores in the two main areas of potato plantation of Hamedan was selected. For determining the effect of temperature, humidity, kind of storage, variety of potatoes and total days of storage on the weight loss, percentage of reduced sugar and changes of microbial infection and diseases of tubers, the necessary samples were collected from the selected stores. The analysis of results by SPSS software and regression models showed that Marfona variety is more sensitive than the Agria in unsuitable condition of storage. Among the different factors of storage, temperature is the most effective factor on the quantitative and qualitative losses of potato tubers than the others. The value of wastes in Agria and Marfona varieties which was stored in traditional stores increased 152% and 199% versus to technical stores respectively. The maximum and minimum wastes for Agria and Marfona varieties occurred in traditional stores (45.04% and 47.55%) and in technical ones (15.06% and 18.86%) respectively. The range of average potato loss in the Hamedan storage rooms was estimated between 18.31% to 40.17% for Agria and 25.07% to 48.35% for Marfona varieties.  

The semi-empirical model proposed by Schwartzman and Zur for estimating width and depth of the wetted soil volume under a single emitter was tested by field observations. As the model was developed from data resulted from only two emitter discharges in two soil types, field experiments were conducted in six different soil types and twenty two emitter discharges. A linear regression with zero intercept was performed to verify the validity of the model. The slope of the line of best fit and its coefficient of determination were 0.99 and 0.98, respectively. Relative error and root of mean squared errors (RMSE) were used to check the discrepancies between observed and estimated values of the maximum diameter of the resulting wetted bulbs. The amount of RMSE, maximum and minimum values of relative errors were 10 cm, 30%, and 0%, respectively. Regarding the statistical results, the validity of the model is confirmed.  

Every year the degradation of agricultural soils are increasing due to improper tillage operations. The main objective of this study was evaluation and comparison of shallow and conventional tillage methods and their effects on wheat yield and its components. The study was conducted in three consecutive years with two treatments and four replications. Conventional tillage method comprised of: moldboard plowing at the depth of 20-25 cm, disk harrowing at the depth of 12-15 cm, leveling, following by chemical fertilizer and planting with grain drill. Shallow tillage method was included: disk harrowing in the depth of 6-8 cm after removing residue, disk harrowing in the depth of 12-15 cm in fall, spike tooth harrowing, following by chemical fertilizer and planting with grain drill. The treatments were arranged in a complete randomize block design. The analysis of data indicated that conventional tillage is better than shallow tillage as far as grain yield, number of heads in unit area, number of grain in the head, weight of 1000 seeds, weight of straw and harvesting' index are concerned. Significant differences were observed between treatments in some areas. The average wheat yield by conventional tillage was 315 kg more than that of by shallow tillage. This difference might be due to higher plowing depth and better residual burying with moldboard plow. The grain yield in surface tillage was 90% of the yield in conventional tillage. Conventional tillage consumes more energy compared to shallow tillage, takes more time, causes more depreciation of the implements and therefore increases costs. This necessitates more study to obtained correct results. Considering that the farmers often cultivate two times a year, and the time for cultivation is short, and also no significant differences in the yield by the two methods, the shallow tillage can be therefore recommended in irrigated wheat in Iran.  

Improving an integrated model on performance assessment of Irrigation systems is subjected to uncertainty of natural parameters, and vagueness or fuzziness characteristics of operation and maintenance parameters. Application of these linguistic-expression parameters usually is impossible, and a fuzzy approach is recommended. The main issue of this method is to provide indicators, based on subjective judgments, and applied linguistic-expression beside the Technical, Economical, and Environmental indicators. In this method assessment is based on the judgments of Water users and Managers separately. The assessment of Irrigation system also is possible by defined seven expression indicators of Water users' judgment. Initial indicators define initial condition of the system, and fuzzy rules are defined for interaction-influence of indicators. The Mamdani and Sugeno fuzzy inference is conducted. The selection of the defuzzification methods; center of area (COA) or Mean of Maximum (MOM) is not important in this model (r2 >- 0.98); the difference between two methods is less than 7%. Results comparison to Standard Method indicates that, COA gives the better result. The model tested in Moghan Irrigation system, and is compared with Ghazvin irrigation system. 27% lower management performance assessment result on Ghazvin Irrigation system is not because of shortage of Irrigation water only, but it is subjected to similarity( <16%) or diversity (>44%) of water users and service agency's judgments in Moghan and Ghazvin  respectively. It is happened because of differences of social-management conditions of two systems.  

The irrigation management and water productivity of Abshar Right Bank irrigation district in  Esfahan was evaluated by using remote sensing data and computing various irrigation management indicators such as volume of water supply and demand, relative water supply, water productivity and economic water productivity. In order to obtain the required data, it was attempted to upscale the accuracy of NOAA satellite images by using Landsat images. From a time series of NOAA images during the one growing season, the relationship between actual irrigated areas in each of the irrigation sub-districts with the Esfahan district was derived. Based on this relationship the actual irrigated area in the Abshar Right Bank irrigation district for each one of the ten growing seasons (1370-1380) were calculated. The irrigation water requirement of the Abshar sub-district was estimated by calculating the water use of nine major crops from the 40 different crops that are grown in the sub-district. The water requirement of one growing season, for each crop was calculated by Cropwat program during the ten years period of the study. The total water requirement of the sub-district was computed from the estimates of the crop water use by the Cropwat model and area under cultivation of each crop. Results indicated that most of the time the volume of water delivered exceeds the volume of water required by the sub-district. The relative water supply index was found to be greater than 1 for most of the growing seasons except during the dry years. The average of relative water supply during the ten-year period studied was 1.3. The average water productivity for all entire crops during the ten-years period, except for the two dry years was 0.8-1.4 and during the entire ten-years period was about 1.3kg/m3.The economic water productivity during the ten-years except for the two dry-years was 0.05-0.19 and during the whole ten-years period was 0.1 $/m3. The world average w ater productivity is however about 0.25$/m3.