JOURNAL OF AGRICULTURAL SCIENCE AND SUSTAINABLE PRODUCTION
Year:2006 | Volume:16 | Issue:2|Papers Count:30

Local scour around bridge piers is one of the most destructing factors in bridge failure. Studies have shown that 60 percent of the bridge failure can be related to the local scour around bridge piers or other hydraulic phenomena. Up to now a good deal of research has been carried out on the effect of different factors on the development of the scour depth using physical models. In spite of considerable efforts made to understand the effect of side wall on the scour depth development, a comprehensive study of this phenomenon has yet to be established. The main aim of the present research was to improve knowledge 'of the effect of the side wall on the scour depth. Experimental results showed that, in order to achieve maximum scour depth, the D/W scale should be attained around 0.11. It was also found that scale parameter D/W greater than 0.11 created a reduction of up to 35 percent in the depth of the scour hole.

Local scour around bridge piers is one of the most destructing factors in bridge failure. Studies have shown that 60 percent of the bridge failure can be related to the local scour around bridge piers or other hydraulic phenomena. Up to now a good deal of research has been carried out on the effect of different factors on the development of the scour depth using physical models. In spite of considerable efforts made to understand the effect of side wall on the scour depth development, a comprehensive study of this phenomenon has yet to be established. The main aim of the present research was to improve knowledge of the effect of the side wall on the scour depth. Experimental results showed that, in order to achieve maximum scour depth, the D/W scale should be attained around 0.11. It was also found that scale parameter D/W greater than 0.11 created a reduction of up to 35 percent in the depth of the scour hole.

In this study, the effect of changes in the price of fuel on agricultural employment in Iran between 1971 and 2001 was studied. The existence of a causal relationship between agricultural employment and fuel price changes was established using Granger causality by final prediction error. In addition, the relationship between the change in agricultural employment and the changes in variables including value added, price of fuel, technology and real wage rate was investigated by an econometric model. The time series data was gathered from different sources such as Planning and Development Research Institute. The results indicated that technology and value added had negative effects on agricultural employment, but fuel price had no significant effect on employment.

Agricultural sustainability largely depends on soil quality maintenance. Measuring soil quality is a difficult task, however, it is important for evaluating the economical aspects and helps the agro-environmental policy designs. The objective of this study was to estimate the soil quality index for some selected rainfed wheat soils. For this purpose, the soil texture and depth were selected as soil physical indicators, organic matter content as biological, and pH, K and P as chemical properties. The required data were collected from rainfed wheat farms situated in Charoymagh township in 2003, using three stage random sampling method. The soil quality index, was calculated after the application of multiple regression models. The results indicated that value of the soil quality in this area is between 0.33-1 with the average of 0.64. Any management to increase organic matter of the soils, such as crop rotation, application of organic fertilizers, mulching and soil conservation, will improve the soil quality in the study area.

The development of growing cucumber in greenhouse needs to assess the accessible facilities in Iran. In different countries, various growing media are used in hydroponic systems. Hence, an experiment was conducted to find out the effect of growing media on the growth and quality of cucumber. Various growing media, perlite, vermiculite, rockwool and their mixture were used as treatments. Seeds of cucumber (Cucunis sativus cv Sultan) were planted in hydroponics system and irrigated with nutrient solution. The growing period was 2.5 month and fruits were harvested at two day intervals. The results showed that the highest yield (4.5 kg per plant) was observed for perlite and vermiculite mixture treatment. Leaf number and height of the plant for perlite and vermiculite mixture treatment was 4 leaves and 40 cm higher than that of the other treatments, respectively. Nitrate concentration in the fruits was 50-67 mg/kg which is not hazardous for human health. Increasing of yield and its components were associated with apropriate conditions of the treatment having mixture of perlite and vermiculite, which is able to provide enough water and air to the plant. It can be concluded that the mixture of perlite and vermiculite could be an optimal medium for hydroponics system.

Crown and root rot of wheat is a major disease in West Azarbaidjan province. It caused heavy losses in commercial fields in 1997- 1998. In order to determine the causal agent of crown and root rot in irrigated and rainfed wheat fields, several samples were taken from various fields in West Azarbaidjan. The symptoms of disease observed on fully developed plants, were leaf blotch, common root rot, black joint, and head& seedling blight. Isolation of fungi was undertaken by plating pieces of discolored root and crown tissues on P.D.A and C.M.A petri plates. The isolated fungi were identified as Bipolaris sorokiniana, B. spicifera, Fusrium acuminatum, F culmorum and F avenaceum. Pathogeni city of each isolate was determined out using seed inoculationas well as mixing of the inoculum (wheat seeds colonized by the isolate) with pasteurized soil techniques. The results showed that Bipolaris spp. were pathogenic on their cultivar seedlings but Fusarilfm spp., which are probably aggravated by moisture stress at seedling stage of wheat due to poor irrigation management, showed symptoms of the disease only after moisture stress. The results also indicated that among all pathogens, B. sorokiniana had larger frequency and it was considered to be main pathogen of crown and root rot of wheat in irrigated fields of West Azarbaidjan province.

Interactions between plant parasitic nematodes and beneficial and detrimental microorganisms are very important. In the present study, impact of interaction between root-knot nematode (Meloidogyne javanica) collected from naturally infected tomato plants in fields of Varamin and Rhizobium leguminosarum bv. phaseoli obtained from kidney bean plants in Ahar-East Azarbaijan on kidney-bean I CV.COS-16 was studied under greenhouse condition. The plants were raised in pots containing 1 kg sterile soil and depending on the treatment, each pot received 2000 J2 of M javanica and/or 2 ml bacterial suspension at concentration of 107 cells/ ml. The treatments were control (no nematode and no bacterium), nematode alone, bacterium alone, inoculation of bacterium 10 days before nematode and inoculation of nematode 10 days before bacterium and simultaneous inoculation of nematode and bacterium. Each treatment had eight replications and for all the experiments, completely randomized design was used. The data collected were subjected to analysis of variance (ANOVA) using SAS software and differences among the treatments were determined by Duncan's multiple range test. The results revealed that the treatment of bacterium alone increased dry root weight, level of nitrogen in roots and shoots over all other treatments. Nematode population (number of root -knots, females, egg masses, eggs, nematodes in soil and multiplication rate (Pf/Pi)) was highest in the treatment that received nematode alone as compared to other treatments. Dry root weight, level of nitrogen and number of bacterial nodules were reduced in treatments that inoculated with nematode alone, simultaneous inoculation of nematode and bacterium, bacterium 10 days after nematode and nematode 10 days after bacterium inoculation. In these treatments, presence of bacterium decreased nematode population over the treatment of nematode alone. These findings can be considered in root knot nematode management on kidney been.

Pyrenophora graminea causal agent of barley leaf stripe produces toxic compound in liquid culture. Infiltration of toxic compound into host leaves causes symptoms similar to barley leaf stripe. In order to use toxic compound to evaluate resistance of barley landraces, toxic compound of two isolates of pyrenophora graminea, Ajabshir 2 Marand 1, were purified according to Haegi and Porta-Puglia method. The purification process consisted of filtration of liquid culture containing the fungus through different filters, dialyzing the samples and loading of samples on sephacryl S-300- HR chromatography column, respectively. Our results showed that the culture filtrates and dialysed samples could be used to screen for the resistance of barley landraces against this pathogen.

The alimentary canal (gut) of the stripped bug, Graphosoma lineatum (L.), was studied. The results showed that it consists of three distinct regions: foregut, midgut and hindgut, so that fore- and hindguts are very short but midgut is differentiated into four distinct portions. Of these, the 1st ventriculus is a wide elongated sac, the 2nd ventriculus is tubular and narrower than the  1st . The 3rd ventriculus is a short dilated region, and the 4th ventriculus is a short tubular region, much narrower than the r. The midgut comprises more than 86.54% or 6/7 of the length of the entire alimentary canal. There are two pairs of Malpighian tubules at the junction of the mid- and the hindgut. The stripped bug, G. lineatum, was classified as Pentatomomorpha with respect to the external structure of its salivary gland. Regarding the external structure of the salivary gland of the bug, no essential difference could be discerned among the different stages except for its size. In the 2ndto 5th instar nymphs, the mean length of right and left salivary glands were 1.21 and 1.19, 1.61 and 1.63, 2.05 and 2.05, and 3.02 and 3.02 mm, respectively. Mean length of the salivarygl and of newly emerged male and female adults were 2.5 and 3.5, of 10 days old were 3.25 and 3.9, and that of 30 days old were 3.75 and 4.25 mm, respectively. In each stage, gland size grows larger, whereas the ratio of its length to the body length decreases. The mean width of right and left salivary gland in 2nd to 5th instar nymphs were 60.27 and 58.11, 98.63 and 98.81, 108.96 and 111.62, and 139.11 and 136.17mm, respectively; in newly emerged male and female adults were 139.1 and 144.11, and 141.13 and 139.19, respectively, in 10 days old males and females were 159.96 and 158.43, and 173.87 and 170.14mm, respectively, and in 30 days old male and female adults were 167.71 and 171.52, and 179.01 and 181.28 mm, respectively, There were no significant differences between means of right and left salivary glands of the body but the effects of sexuality and adults life span were significant at P =0.001. In two adult females, three salivary glands were observed and with respect to literature review, it is the first report of this phenomenon.

It has been reported that phytophagous insects and many phytozoophagous and zoophytophagous insects have a-amylase in their salivary gland and/or in the gut. The nature of the amylases from various insects also has been studied by several investigators. In the present study, salivary and gut aamylase activities (u/mg protein) were studied in the stripped bug, Graphosoma lineatum (L.) and compared with that of some insect amylases known at present. Amylases from the stripped bug's salivary gland complex (SGC), foregut (pG), first to fourth midguts (MGI-MG4), and hindgut (HG) were studied at 405 nm in an autoanalizer (Alcyon 300Ò) at 37°C and ethylidene-p-nitrophenyl maltoheptaoside (EPS-G7) used as substrate. a-amylase activity was observed both in the gut and salivary gland of the stripped bug. There was no enzyme activity in the foregut of the male and female adults and 5th instar-nymphs. Enzyme activity in the hindgut (1.726) was only observed in the 5thinstar nymphs. a-amylase activity in the salivary gland (9.494) was higher than the gut (4.344) and midgut (5.286) (2.185 and 1.80 times, respectively). Amylase activity was higher in the third midgut (15.563) as compared to the salivary gland (9.494), but there were no significant differences between them. The results showed that the posterior lobe of the salivary gland with 75.56% of total enzyme activity was the major source of a-amylase production in this organ. It was revealed that the enzyme activity of salivary gland luminal contents (4.410) was higher than that of the tissue contents (1.118) (nearly 3.74 times). Comparing our results with those of other researchers indicated that the activity and distribution of a-amylase in different parts of the gut, and also in different parts and contents of the salivary gland of the stripped bug is similar to other hyteropterans.

In order to compare different stability statistics in studying GxE interaction on short- term yield trials in rapeseed, rank-correlation coefficients were used. Set 1 (T1) had 22 spring cultivars with Sarigol as the check genotype grown in eight environments, set 2 (T2) had 21 spring cultivars, plus the same check variety, in 16 environments and set 3 (T3) had 23 winter type cultivars, using SLM046 as a check genotype, in 18 environments. The relationship between CVi and bi was significant and positive. The rank-correlation coefficient between W2i and s2i  was very high. Thus using one of them, preferably s2i, is sufficient. Also a high rank-correlation coefficient was estimated among s2i  and S2di. In all of the sets, only positive and significant rank-correlation coefficient between YSi and mean yield was detected. It is indicated that using YSi criterion will result in the selection of stable and high yielding cultivars.

Improving water productivity is vital to sustain and raise crop production. In order to investigate the effect of water and nitrogen rates on wheat, a field experiment was conducted as split plot arranged in arandomized complete block design (RCBD) with three replications, during 2000-2002 at Maragheh. Rainfed Research Station, The treatments included four levels of deficit irrigation (rainfed, %33 F.I., %66F . I, and Full Irrigation (F.I)) and five nitrogen rates (N0, N30, N60,N90, and N120kg.ha-1).Yields of rainfed conditions varied with seasonal rainfall and its distribution, with all main factors having significant effects on it. With irrigation, yield response to N application was generally significant up to 90kgNha-1. Optimum level of deficit irrigation was realized with %66 of full irrigation treatment (%27.3 decreases in full irrigation) which led to maximum irrigation water productivity and with 4467kg.ha-1 grain yield. Water productivity based on irrigation water alone (WPI) and both irrigation - plus rainfall (WPI+p) at 90 kg.N.ha-1 over the two seasons were 9.58 and 27.92kg mm-1, respectively.

In this study the effects of irrigation method, variety, and planting date on the production of true potato seed (TPS) were investigated in Golgeh Rokh Agricultural Station in Khorasan Province. Statistical design was a strip split plot with three replications. The irrigation methods (Drip, Farrow and Sprinkler irrigation), arranged in vertical blocks, varieties (Picaso, Famoza and Granola) in horizontal blocks and planting dates (May 26, June 10 and June 25) as complete blocks in subplots. The study, Furrow irrigation had the highest amount of TPS but it was not significantly- different from the trickle irrigation. Water consumption was also lower in trickle irrigation. Among the varieties, Picaso had the highest and Granola the second highest yield of TPS. The second planting date showed the highest TPS production than other planting dates (25 Jun. and 26 May). In conclusion picaso produced highest TPS (27.72 kg/ha) under furrow irrigation and planting date of June 20.  

A split plot design with randomized complete blocks with three replications was conducted in Zanjan Agricultural Research Center in 2003, to investigate the effects of full irrigation, irrigation until flowering, irrigation at flowering and no irrigation on phenology and yield of three chickpea Cultivars (Jam, Hashem and Pirouz). Days until flowering, days until pod formation, days until maturity, plant height, number of axillary branches, number o( pods per plant, number of grains per plant, number of grains per pod, 100 grain weight, biomass and grain yield were significantly higher under full irrigation, compared with the other irrigations regimes. However, number of grains per pod was not significantly affected by irrigation treatments. There were significant differences among chickpea cultivars for all traits except for number of axillary branches. The mean 100 grain weight and grain yield in Jam were significantly higher than Hashem and those of Hashem was higher than Pirouz. However, the difference between Hashem and Pirouz for grain yield was not significant. More grains per pod and higher mean grain weight were the main reasons for yield superiority of Jam, compared with Hashem and Pirouz. Yield reduction due to water shortage was higher in Jam and Hashem than in Pirouz. This indicates that Pirouz as a desi-type cultivar is more tolerant to water deficit than other two kabuli-type cultivars. Chickpea grain yield under irrigation until flowering was higher than the treatment without irrigation. However, there was no significant difference between irrigation until flowering and irrigation at flowering in terms of grain yield. Since water use efficiency under irrigation at flowering was significantly higher than irrigation until flowering, therefore, when water availability is limited, chickpea yield reductions could be prevented by irrigation at flowering.

This study was conducted to determine the effect of pruning of head (no pruning, pruning of head after formation of 10 and 14 nodes) and nitrogen levels (0, 50, 100 and 200 kg/ha) on seed oil and fatty acids content of pumpkin seeds (Cucurbita pepo L.) using a factorial experiment with randomized complete block design with three replicates during 2003 and 2004 at Gorgan. The results showed that pruning of head and nitrogen levels had significant effect on the seed oil content, the percentage of linoleic and oleic acids. The maximum oil content of the seeds (46.868%) and the percentage of linoleic acid (54.192%) were obtained by pruning of head after formation of 14 nodes. There was significant difference between control (no pruning) and pruning of head after formation of 10 nodes. Among the nitrogen levels, the maximum oil content of the seeds (45.56%) and the percentage of linoleic acid (55.120%) were obtained at nitrogen level of 100 kg/ha. Significant difference was observed between control (0) and two other levels (50 and 200 kg/ha). Interaction of pruning by nitrogen was no significant for all of the studied characters.

Ferula ovina Boiss. is one of forage species that belongs to Apiaceae. According to ISTA reports, seeds of Ferula ovina have shown dormancy that causes reduction in seed germination of this species Therefore in this research, a factorial experiment using a randomized complete block design with 3 replications performed for, evaluation of effects of cold with two levels (with and without prechilling), alternating- temperature regime with three levels (constant temperature 20/20 and alternating , temperature 15/25, 20/30 °c) and nitrogenous compounds with three levels (control, thiourea and potassium nitrate). The results showed that effects of three factors on germination of Ferula are significant. Alternating temperature regimes stimulated seed' germination better than constant temperature. In the constant temperature and under the condition of no prechilding, effect of nitrogenous compounds was not significant but under alternating temperature regime, nitrogenous compounds (thiourea and potassium nitrate) helped to promote germination. In non-prechilled seeds, potassium nitrate in alternating temperature of 20/30°C, showed the highest influence on seed germination percentage. For prechilled seeds, nitrogenous treatments did not have significant effect. Perhaps prechilling was able to induce total effects of nitrogenous compounds. Interaction between cold and alternating temperature showed that effects of these two factors is additive and highest seed germination percentage obtained using prechilled seeds in alternating temperature of 20/30°C. It was concluded that seed dormancy of Ferula ovina presumably is a type of physiological end dormancy that could be broken by prechilling and alternating temperature.

In order to study the effect of salinity stress on morpho-physiological traits of wheat genotypes, two experiments were carried out at the two locations (Ece=1.5, Ece=10 dS/m) of Miandoab Agricultural Research Station, north-west of Iran, using 10 genotypes. The experimental design was randomized complete block with five replications. The result of combined analysis of variance revealed significant differences between the two experimental conditions (saline and non saline) and among genotypes for all the studied characters except potassium content of the flag leaf under two conditions. Under salinity stress, total dry matter, grain yield and its components, K/Na ratio as well as potassium accumulation decreased, whereas Na ion accumulation, soluble sugars and proline content increased. Arvand and Kavir cultivars were high yielding genotypes under salinity and normal conditions, respectively. In contrast, Roshan and Shole produced lowest grain yield under both conditions. Arvand cultivar with minimum salinity susceptibility index had also the least accumulation of Na ion, medium amount of K ion and maximum K/Na ratio. In contrast, Falat cultivar showed the lowest amount of K ion, medium accumulation of Na and minimum K/Na ratio under salinity condition. Overall, Arvand and Falat genotypes had maximum and minimum accumulation of compatible solutes (proline and soluble sugars), respectively. Among yield components, maximum reduction under salinity condition belonged to the number of spikes per square meter.

Four abomasal canulated multiparous lactating Sannen dairy goats in midlactation with mean milk production and days in milk. of 1.7±0.62 kg and 110±4 days, respectively, were used in a 4x4 Latin square design with two weeks of adaptation to basal diet in all treatments and 7-d experimental periods to determine effects of the abomasal infusion of cottonseed oil and wheat starch on milk yield and composition. Goats were fed with basal diet included 0% alfalfa hay and 60% concentrate. Treatments were abomasal infusion of 1) water (control), 2) cottonseed oil (45 g/d ), 3) wheat starch (100 g/d) and 4) a mixture of cottonseed oil and wheat starch (22.5 and 50 g/d, respectively). Infusion of cottonseed oil decreased dry matter intake and increased content of milk fat and total solids. There were no significant differences between treatments for milk yield, percentage and yield of total protein, true protein, casein, NPN, lactose, SNF and whey of milk between treatments. Cholestrol and triglyceride of plasma increased by infusion of cottonseed oil or mixture of starch and cottonseed oil. However, infusion of starch with cottonseed oil only increased plasma glucose concentration. The total tract digestibilities of dry matter, organic matter, crude protein, neutral detergent fiber and acid detergent fiber were not different among treatments. It was concluded that supplying of more energy as starch or oil in postruminally in midlactation had no substantial effect on performance, and infusion of oil increased only the content of milk fat.

Apple pomace (AP) is the by-product which obtained in juice industry. It can be used as animal feedstuff. An experiment was conducted to evaluate the effects of different levels of AP (ensiled AP (EAP) and dried AP (DAP) on milk yield and its components in Holstein dairy cows. A balanced change-over design with ten cows, five rations (1-5), five periods (21 days/period), and two blocks were employed. Experimental diets contained no AP (control), 15% EAP, 30%EAP, 15% DAP and 30% DAP, respectively. The mean corrected milk yield for 4% fat for the cows using diets 1 to 5 was 19, 20.4, 20.2, 20.4 and 19.4 kg/day, respectively. The differences among the treatments were not significant. The mean dry matter intakes for treatments were 24.1, 28.4, 30.3 and 23.1 kg/day, respectively. The differences among them were significant (P<0.05). Dry matter intakes for 4% corrected milk were 1.28, 1.41, 1.51, 1.24 and 1.21 kg, respectively. The differences among them were significant (P<0.05). The concentrations of the milk fat, protein and lactose were not affected by the experimental diets. Feeding the AP influenced the feed cost per unit of milk yield in the experimental cows. The minimum cost of the milk production was observed in the diet containing 30% DAP.

Two experiments were conducted to study the effect of reducing dietary protein level in corn-soy diet as compared to a positive control diet with 23% CP on Ross male broilers performance, efficiency of energy and protein utilization during the starter period. Amino acid composition was determined for corn and soybean meal, before starting the experiments. The diets in the first (9 to 16 days of age) and second (6 to 16 days of age) experiments contained 17, 19, 21 and 18, 19, 20% CP, respectively. A positive control diet with 23% CP was used as an index in both experiments. All diets were isocalloric (3200 kcal MEn/kg) and supplemented with appropriate levels of synthetic essential amino acids to match the NRC recommendations. In the first experiment, reducing the crude protein up to 19% did not have a significant effect on broiler performance as compared to birds fed with the control diet, but lowering the crude protein diet to 17% significantly (p<0.05) reduced weight gain (41 g), feed intake (26g), protein intake (20g) and increased feed conversion (0.024 unit). In the 2nd experiment, broilers had significantly lower weight gain (46g), protein intake (15g) and higher feed conversion (0.34 unit) when fed 18% CP diet as compared to 23% CP diet. The performance of broilers fed with other diets was not different as compared to the control. The results of these experiments indicate that lowering protein diet more than 19% reduce broilers performance and efficiency of energy utilization even the diet supplemented with appropriate amounts of essential amino acids.

The effect of four different levels of dietary L-Carnitine on performance and immune system of broiler chickes was studied. One hundred and twelve chicks (Ross hybrid 308) were distributed randomly in four groups of 28 with four replicates of 7 chicks. A randomized complete block design (RCB) was employed. L- Carnitine levels used in this experiment were 0, 25, 75 and 100 ppm. The characters measured included body weight gain, feed intake, feed convertion rate, bursa, spleenand thymus weight. The anti SRBC (Sheep Red Blood Cells) and anti Newcastle virus (NDV) antibodies were also measured. No significant effect was noted using L-Carnitine on performance. Supplemented diet with 100 ppm L- Carnitine had significant effect on SRBC antibody (P<0.05) and anti Newcastle virus (NDV) antibody (P<0.01) compared with other groups. Bursa, spleen (P<0.05) and thymus weight (P<0.01) were largely higher with 100 ppm L-Carnitine than others.

This research program was conducted as a 2x4 factorial experiment to study the effects of xylanase enzyme (without enzyme or with enzyme [0.5 gr/Kg]) and fat type (tallow fat [50 gr/Kg], soybean oil [50 gr/Kg], fat blends [tallow 12.5gr, soybean oil 37.5gr] or [tallow 37.5 gr, soybean oil 12.5gr]) on performance, intestinal viscosity and some blood parameters of broilers fed soybean meal-wheat based diets from 7 to 42 days. Enzyme supplementation significantly improved body weight gain, feed conversion ratio (p< 0.05) and decreased (p<0.01) intestinal viscosity (6.65 vs 4.76 centi pose). Triglyceride value was lowest with enzyme supplementation (p<0.01). Body weight gain, feed intake and intestinal viscosity was not affected by different fat sources and replacement of soybean oil with tallow increased blood triglyceride (p<0.05) but concentration of blood cholesterol and glucose were not affected by fat type. The results of this experiment showed that enzyme decrease of intestinal viscosity could eliminate the negative effects of nonstarch polysaccharid on performance of broilers fed with wheat, based diets. The results did not show any interaction between enzyme and fat sources.

In order to find a generalized mathematical model for predicting the draft force of an oblique blade subsoiler with a completely submerged blade, four simulated models, developed by Duriraj and Kumar (4) Perumpral et al. (14) Godwin and Spoor (6) and Mckyes and Ali (13), were compared with the results of this experiment. Field experiments were conducted to evaluate draft force of the oblique blade subsoiler in the Fars Agricultural Research Center in Zaighan, with rake angle at four levels (7.5, 15, 22.5 and 30 degrees) and working depth at three levels (250, 350 and 450 mm) in a dry soil. The results showed that Duriraj and Kumar, Godwin and Spoor, Perumpral et. al. and Mckyes and Ali models, having the largest R-square and minimum standard deviation of squares, respectively, could be used reasonablely to predict the draft force and were in good agreement with the experimental data.

In order to increase the efficiency of solar energy and decrease the contamination of raisin and ultimately increase product quality, boxes were made from wood and set up on inclined floors made up of brick and concrete .The floor of the frames inclined at 20° from horizontal and was oriented towards south. The walls of boxes were made in two heights (12 and 17 cm) and for entrance and exit of air to the boxes two openings in three height sizes (0.2, 0.5 and 0.6 of wall height) were prepared. In the ceiling of the boxes, glass was employed. Before starting the experiments, the grapes were pretreated with K3CO3 solution. The experiment was carried out in a split-split design based on randomized complete blocks with three replications. The type, height and opening dimensions of the boxes were considered as main, sub and sub-sub plots, respectively. The results revealed that drying rate of the Sultana cultivars in the boxes was about two times faster than in the control sample, and product quality and color was better than that the control. Regarding the drying time, a box with brick floor, 12 cm wall height, and with the opening size of 0.2 was considered as the best box.

In direct cut combining of crops, two factors are involved: grain losses and harvesting velocity which are significant in field harvesting. Omitting the cuterbar of combine’s head and designing of a new head for separation of canola’s pod from it’s stem needs basic information and data about the amount of force for stability of canola plant’s roots in the soil. During past years, there has not been much work done on mechanical properties of this plant. Past year, in harvesting time, when the moisture of seeds were 9% and moisture content of plants 56/6%,the diameter of stem was measured in 3 replications. Three level of diameter size were determined which named: thin, medium and thick stem (11.3, 21.6, 25.6 mm). Required canola uprooting force was obtained by using uprooting machine. Data were processed by japanies analyzer (TC-31K), then uprooting curves (force-time) were drawn. Uprooting machine operated with, 0.01 m/sec., constant velocity. Results showed the required forces that were between 15/6 to 46/7 Kgf. In other word, in design of harvesting machine, the maximum requiring force for pod separation from it,s stem, should not be more than 15.6 kgf. In the research, the maximum power for a single canola plant uprooting was calculated between 1.53 to 5.3 watt (jole/sec.). The results showed that canola,s uprooting forces increases with increasing the stem diameter and decreases with increasing the uprooting time. For future needs ,an experiment were carried out on determination of uprooting force for flowering and seeding stage ,having respectively 81% and 75% moisture on wet basies. The uprooting forces for these two stages were more than those which required for harvesting stage. In the flowering and seed setting stages, under applied forces, crushing in stems happened, but in harvesting no stem was crushed and increasing the force, result fracturing.

New combines have a high performance. The combine performance characteristics are related to threshing ability, minimum amount of loss and fuel consumption. Loss is divided into preharvest loss, head loss, threshing loss, separating loss and quality loss (In this paper, the sum of threshing, separating and cleaning losses are called as rear loss). Describing different processes by mathematical models is the first step in identification and minimization of combine losses. Two important factors which affect combine field capacity are: the through put (feed rate) which is the function of combine speed and crop yield, and the thresher speed which is function of thresher drum rpm and its dimensions. The experiment was carried out as factorial, using randomized complete block design with three replications. The experiments consisted of two factors (each in three levels): grain flow rate and thresher speed. During the test, rear loss was measured. Results indicated that the effect of both factors on rear loss were significant at 1% probability levels. Using of multiple-nonlinear regression, the fallowing model was evaluated in terms of grain flow rate and threshing speed. Loss% = a1,+a2a3e xa2+ya2 where a1=3.053, a2=-0.036, a3=0.199 were constant coefficients and x and y are grain flow rate and thresher drum speed, respectively. Regression analysis of variance showed that this model mas significant at 5% probability level.