Showing 1573 results for on
Reza Aminpour, Sayed-Farhad Mousavi,
Volume 1, Issue 1 (4-1997)
Abstract
In order to determine the effects of number of irrigations on stages of development, yield, and yield components of cumin, an experiment was conducted in 1993 - 94 growing season with a randomized complete block design and four replications. The location of the experiment was Isfahan University of Technology Research Station in Shervedan Field. The irrigation treatments were: I1- Irrigation after planting I2- Irrigation after planting and at the stage of full standing of plants I3- Irrigation after planting, full standing of plants, and anthesis and I4- Irrigation after planting, full standing of plants, anthesis, and beginning of grain filling stage. The stages of development (from emergence to anthesis) occurred simultaneously in all treatments. However, the water deficit in I1 and I2 caused the plants to reach their physiological maturity 5 days sooner than the other two treatments. The time intervals between anthesis and physiological maturity in I4 and I3 treatments were 12 days and 5 days longer than those in the other two treatments, respectively. The grain yield of I1 and I2 were approximately 60% of I3 and no significant difference was observed between the grain yields of I1 and I2 treatments, nor between I3 and I4 treatments. The grain yields in I3 and I4 treatments were about 1742 and 1800 Kg/ha, respectively. The number of umbels per plant, the most important grain yield component, was greater in I3 and I4 than the other two irrigation regimes, but the number of seeds per umbel and 1000-seed weight of I3 and I4 were lower than that in I1 and I2 treatments.
Abdolmajid Rezai,
Volume 1, Issue 1 (4-1997)
Abstract
The relation between high molecular weight glutenin subunit alleles and flour quality traits have been studied for 117 recombinant inbred lines (RILs) derived by single seed descend to F7 from a cross of Anza, a low quality cultivar, and Inia, a high quality cultivar, containing different alleles at 3 GLU-1 seed storage protein loci. RILs were classified by SDS-PAGE for the 8 possible combinations of the alleles. The allelic variation at the GLU-D1 locus accounted for most of the variation observed in SDS-sedimentation, mixing time and tolerance, and protein content. The GLU-D1 allele encoding the subunits 5+10 was superior to its allelic counterpart, encoding 2+ 12. All three loci had significant single locus additive effects for SDS-sedimentation volume and mixing tolerance. The additive effects of GLU-D1 locus on mixing time and protein content were also significant. The epistatic additive effects were mostly negative and with the exception of αAB and αAD for SDS-sedimentation volume were not significant.
Rahim Ebadi,
Volume 1, Issue 1 (4-1997)
Abstract
In this study, conducted in Isfahan region over a period of two years, six oilseed sunflower cultivars named Record, Venimek 8931, Chernianka, Zaria, Perdovik and Mehr hybrid were investigated in a split-split plot design. These cultivars were planted on March 29 and April 29, with and without the presence of pollinator insects. The results showed that the yield of different cultivars were significantly different (p<0.01). The planting date of March 29 caused a higher yield than that of April 29. Also the presence of pollinator insects during the bloom increased the amount of yield in all cultivars planted on both dates. Venimek and Record cultivars planted on March 29 with the presence of pollinator insects during the bloom produced the highest, i.e. an average of 3910 and 3821 kilograms of seeds per hectare and Chernianka with an average of 2944 kilograms of seeds per hectare had the lowest amount of seed. In this study, Record and Venimek cultivars in the first place and then Mehr hybrid planted on March 29 with the presence of pollinator insects during the bloom were better than the other cultivars in terms of attractiveness to honeybees, yield per hectare, seed hollowness percent, weight of 1000 seeds, germination percentage, speed of germination and the amount of oil production.
Mohammad Reza Vahhabi, Mehdi Bassiri, Jamaleddin Khajeddin,
Volume 1, Issue 1 (4-1997)
Abstract
Short-term changes (5 years) in canopy cover, species composition and forage production were studied under protection from grazing and grazed condition in 19 range sites in Fereydan region, Isfahan province. In this study, density, canopy cover and forage production data were obtained from quadrates inside and outside exclosures in the spring of 1983. These parameters were studied again in 1988 and compared with the previous data. Results indicated that species diversity in these range sites was relatively high up to 212 plant species were identified. Sixteen, 8.5 and 75.5 percent of these species were classified into I, II and III palatability classes respectively. After five years, comparison of inside and outside exclosures indicated an increase in the density of species of I, II and III palatability classes by 138.8, 120.8 and 51.5 percent inside exclosures, respectively. Density of all species had increased by 62 percent as a result of 5-year protection from grazing. Species composition data as canopy cover were used to construct 3 dendrograms to investigate the similarity among range Sites. Assuming 32% similarity as the threshold level, 19 range sites were classified into 10 vegetation types in 1983. After 5 years, these vegetation types decreased to 8 and increased to 11 under protection from grazing and grazed conditions, respectively. The average forage production inside exclosures was almost twice as much as in grazed sites (600 Vs. 315 kg/h). Three groups of range sites were recognized according to the time requirement for rehabilitation by grazing protection. The first group was improved considerably by the end of the 5-year protection Period. The second group improved relatively within five years of grazing exclusion. The third group did not improve by 5-year grazing protection and needed much longer protection period or some other range rehabilitation practices.
Bahram Sharifnabi, Asghar Nekoei,
Volume 1, Issue 2 (10-1997)
Abstract
In order to study fungi associated with seeds of sainfoin, several seed samples of sainfoin were collected from Isfahan, Ardabil, Zanjan and eastern Azerbaijan provinces, Iran. Seed lots, only half of which were surface sterilized, were allowed to grow on PDA, SMA, MA, sterilized wet paper and drenched sands. The dishes containing seeds were incubated at 25°C with alternate cycles of 12-hour fluorescent light. After seven days, fungi growing from the seeds were transferred to the selective media and subjected to morphological studies. Single spore or hyphal tips from these transfers were the basis for all identification procedures. The most prevalent fungi associated with sainfoin seed were Alternaria, Aspergillus, Penicillium and Rhizopus, although Ulocladium, Cladosporium, Fusarium, Mucor, Nigrospora, Stemphylium, Trichothecium and Botrytis were also isolated in low incidence from these seed lots. The isolates of Uromyces and Oidiopsis were also obtained when the seed samples were examined by washing method.
Mohammad Reza Ebadi, Javad Pour Reza, Mohammad Khorvash, Kambiz Nazer Adl, Abbas Almodares,
Volume 1, Issue 2 (10-1997)
Abstract
Sorghum grain is an important cereal to be cultivated in tropical and sub-tropical areas. The extension of its cultivation and application in animal and poultry diets may reduce the need for imported corn. In order to determine the nutritive value of sorghum, 36 sorghum grain (SG) varieties and one type of corn were grown at the same location. The grains were analyzed for their nutrient composition. Results from of proximate analyses showed that the ash, crude protein (CP), phosphorous (P) and acid detergent fiber (ADF) contents of SG were 1.72±0.54, 11.6±1.18, 0.34±0.03 and 8.35±3.93, respectively. The ether extract (EE) of SG was lower than Iranian and imported corns. Iranian corn had higher amounts of CP (10.7%), EE (5.9%) and CF (3.3%) than the imported one (7.8, 4.2 and 2.25). Tannin contents of low and high SG varieties were 0.021% and 0.998%, respectively. The apparent and true metabolizable energies (AME and TME) of SG were decreased due to increasing the tannin contents. The values of TMEn (3853, 3771 and 3213 Kcal/kg) showed significant differences (p < 0.05) among low, medium and high tannin sorghum (LTS, MTS and HTS) varieties. However, in comparison with the SG, the corn had higher amounts of TME (3853, 3771 and 3213 VS. 3947 Kcal/kg). LTS had the highest AME (3453 Kcal/kg) among all the grains, while there were no significant differences (P > 0.05) between MTS (3458 Kcal/kg) and the two corn grains (3406 Kcal/kg).
Javad Pour-Reza, Mehdi Mehrshad,
Volume 1, Issue 2 (10-1997)
Abstract
Two experiments were designed and conducted to evaluate the effect of tallow and the nutritional value of millet and the effect of substituting millet for corn on the performance of laying hens. In the first experiment, the nitrogen corrected true metabolizable energy (TMEn) of tallow and millet was determined. Also the digestibility of dry matter (DM), protein, fat and crude fiber of millet was determined using the Sibbald's method. In the second experiment, with a completely randomized design and in a factorial arrangement, the effect of different levels of substitution of corn (0.0, 25, 50 and 75%), introduction of tallow at various amounts of 0, 3 and 6 percent, and also the effect of processing millet (ground and unground) on the diet of HY-Line layers from 26 to 38 weeks of age were studied. The criteria used were egg production rate, egg weight, egg output, feed intake, and feed conversion ratio. The results from the first experiment showed that screening millet increased its true metabolizable energy. Furthermore, crude fiber digestibility increased as a result of introducing fat into the diet (p<0.05). The results from the second experiment revealed that grinding millet had no significant effect on the performance of laying hens, but feed conversion ratio tended to improve in diets containing ground millet. Substitution of any amount of millet for corn significantly improved egg weight, egg output, and feed intake (P<0.05). Introduction of tallow by 6% significantly increased feed intake (P<0.05) too.
Sayed-Farhad Mousavi, Ahmad Mohammad-Zadeh, Ahmad Jalalian, Hossein Samadi-Boroujeni,
Volume 1, Issue 2 (10-1997)
Abstract
One of the most vital problems in the storage and utilization of surface waters for drinking, flood control, hydropower, and agricultural purposes is that of sedimentation in reservoirs and subsequent decline of dam lifetime. The useful lifetime of a dam is defined as the time necessary for approximately 80% of the volume of its initial capacity to be filled by sediments washed in by water. It is a function of the volume of the incoming sediments, specific weight of sediments, and reservoir trap efficiency. Trap efficiency depends on sediment characteristics, life, shape, and rule curves of the reservoir as well as on the capacity-inflow ratio. It is the purpose of the present study to calculate sediment trap efficiency of small dams and also to determine the relationship(s) among the effective parameters in the Chaharmahal and Bakhtiary region. For our purposes, 14 small earth dams (with heights of less than 15 m and capacities of about 1 MCM) were selected around Shahrekord and Borougen. Since no data were available on the erosion and sedimentation for these dams, the MPSIAC empirical model was used to estimate the incoming sediment to the dams' reservoirs. The model considers nine factors effective on erosion and sediment production in each watershed. These factors were analyzed for the watershed of each dam under study and the annual sediment yield was calculated. The amount of sediments retained in the reservoirs as a result of the working life of the dams was estimated by reservoir surveying. The trap efficiency was calculated for all the reservoirs under study. The results obtained revealed that the trap efficiencies for these small dams ranged from 10.4 to 68.9%. New curves were developed and suggested for the trap efficiency of small dams based on these results.
Mohammad Reza Yazdani, Sayed-Farhad Mousavi,
Volume 1, Issue 2 (10-1997)
Abstract
Water requirements of paddy fields in the Gilan Province are provided for by a large irrigation network including Sepidrud reservoir dam, Tarik diversion dam, Fumanat network, Sangar diversion dam, and Sangar right and left canals. Because of the deposition of sediments in the Sepidrud reservoir, its capacity has been reduced profoundly. To overcome this problem, sediments are flushed in the second half of each year. The sediments coming from erodible surfaces of the Sepidrud watershed area out flowing from the dam in the spring, and the deposited sediments in the Sepidrud river in the second half of each year are a great hazard for the irrigation network. The objective of this research is to study the effect of the sediments on Sepidrud network. In this research, sediment data from the hydrometric station near Sepidrud dam were analyzed. Sediment samples were collected by a hand sampler (type DH-48) from Tarik and Sangar diversion dams, upper and lower ends of Sangar desilting basin, BP4 and SP3 canals, and field ditches and drains. Water discharge was measured by a current meter. Deposited materials in irrigation structures were sampled for grading. The results from this study indicate that the Sepidrud river and Tarik diversion dam deposit sediments at low discharges, but at high river discharges these sediments were found to he erodible. Average efficiencies of left and right desilting basins of Sangar diversion dam were 15.3% and 11.2%, respectively. The area located in Fumanat section, which receives water from Tarik diversion dam, requires desilting structures. The irrigation structures of the network are in danger of sediments. The main and the secondary canals, compared with 3rd and 4th order canals, have less settled sediments in them.
Ezatollah Karami, Daryoosh Hayati,
Volume 2, Issue 1 (4-1998)
Abstract
Sustainability has become a part of the language of almost all development projects. Although, in many instances it has been overused and misused, attaining sustainability in agricultural development is always one of our concerns. This paper aims (1) to clarify and describe the core beliefs and values underlying the two opposing world views of agriculture, i.e., “conventional agricultural paradigm” and “sustainable agricultural paradigm” (2) to describe an instrument developed to measure the basic beliefs and values assumed to constitute the two competing paradigms (3) to measure the adherence of extensionists and researchers of the Ministry of Agriculture towards sustainable agriculture and (4) to compare the adherence to alternative paradigms against conventional agricultural paradigms of Iranian groups with permaculture groups and agricultural chemical dealers of USA. The instrument was used in a nation wide survey. A two-stage random sample was used. In the first stage, 11 provinces were randomly selected and then in each of the selected provinces a simple random sample of extension agents, extension experts and agricultural researchers were selected for the study. The findings indicated that there is no significant difference among agricultural researchers, extension agents and extension experts in their mean endorsement score of sustainable agriculture. Data from a similar study in the USA were used to provide a means of comparison. Two extreme groups were selected, permaculture group with strong sustainable agricultural score and agricultural chemical dealers with lowest mean scores of sustainable agriculture. The mean scores of sustainable agriculture adherence of three Iranian groups were considerably lower than that of the USA permaculture group. However, there was no significant difference between three Iranian groups and USA agricultural chemical dealers which indicates low adherence of Iranian sample to sustainable agriculture. Considering the challenges Iranian farmers face for food production in the next decade and the role of the Ministry of Agriculture personnel, recommendations are put forth for changing knowledge, attitudes and skills of agricultural researchers and extensionists.
Mohammad Hajian, Vahid Jahanbakhsh,
Volume 2, Issue 1 (4-1998)
Abstract
Seeds of Haloxylon (H. pericae, H. aphyllum, and H. ammmodendron) were collected from Sabzevar and Gonabad regions. The seeds were kept in the refrigerator for isolation of the fungi after determining the germination rate and moisture content. The recommended methods by International Seed Testing Association (I.S.T.A.) for isolation of seedborne fungi were followed throughout this study. The fungi were isolated by agar plate method, standard blotter technique, Hiltner test and seed analysis. In this study 15 genera and 19 species of fungi were identified. Among them Alternaria, Aspergillus, Camarosporium, Fusarium, and Penicillium were dominant among fungal genera isolates.
Gholam Hossein Tahmasebi, Rahim Ebadi, Morteza Esmaili, Jafar Kambousia,
Volume 2, Issue 1 (4-1998)
Abstract
The first step in fundamental breeding of any living organism is the determination of its genetic make-up. To investigate the genetic make-up of the European honeybee (Apis mellifera L.) in Iran, some research attempts were made during the years 1992-1996 in which the bee's relationship with some exotic races were determined through the application of morphological methods. For this purpose 13000 samples of worker bees from 1320 colonies of 212 apiaries in 104 cities at 25 provinces were taken and twelve morphological characters were measured by using the international method (Ruttner, 1978). Furthermore, seven morphological characters of 900 drone samples taken from 403 colonies of 111 apiaries in 42 cities at 10 provinces were studied through the same method. The principle component analysis (PCA) was used for statistical analysis of the data obtained. The results indicated that the existing populations of honeybees under study were of the Iranian honeybee race (Apis mellifera meda) which were completely distinguishable from those of imported races such as A.m. carnica, A.m. ligustica, A.m. caucasica and exotic races such as A.m. anatoliaca, A.m. syriaca A.m. yemenitica and A.m. lamarkii. The imported races had not had great genetic impact on the Iranian race, as the Iranian honeybees have had good consistency and stability. In addition, import of the exotic queens has been ceased in the last decade.
Nasrollah Mahboobi Soofiani, Fatemeh Shir-Mohammad, Javad Pour-Reza,
Volume 2, Issue 1 (4-1998)
Abstract
A 46-day feeding trial was conducted with rainbow trout (Oncorhynchus mykiss) to examine the effects of partial substitution of plant protein sources with fish meal in diets. Three different sources of plant protein including soybean, sunflower and cottonseed meals were substituted by fish meal at four levels of 10, 20, 30 and 40 percentages. Each diet was assigned to triplicate groups of fish in a completely randomized design as a 3×4 factorial arrangement, with a control diet. Seven hundred and eighty fish were used in this trial. Twenty fish were randomly assigned to each of 39 pens and were acclimated in these pens to the experimental conditions two weeks before treatments began. This substitution caused no significant differences in all the criteria measured with control diet. Fish fed diets of 30 and 40 percent soybean meal substitution showed greater weight gain and better growth performance, lower FCR and higher PER values in comparison with the fish receiving other diets, although the differences were not significant. Irrespective of substitution levels, comparison of fish fed by three different sources of plant protein in their diets showed that the fish fed diet containing sunflower meal had significantly (p<0.0l) lower final mean weight and growth performance, higher FCR and lower PER than the fish receiving soybean and cottonseed meal diets. Relative liver weight of fish receiving soybean meal diets was significantly (p<0.0l) higher than those fed with cottonseed meal diets, but the difference was not significant when compared with the fish fed with the sunflower meal diets. Partial replacement of cottonseed meal resulted in a higher energy availability to fish and also better performance of fish. However, diets containing soybean meal showed not much effects on performance of rainbow trout. These results indicate that cottonseed and soybean meals can be recommended as a suitable and fish meal-sparing ingredient in diets for rainbow trout.
Teymour Sohrabi, Reza Asilmanesh,
Volume 2, Issue 2 (7-1998)
Abstract
Irrigation systems may or may not be well designed and properly used. Therefore, it is necessary to study these systems to provide direction to management in deciding whether to continue existing practices or to improve upon them. The major objective of this study is to determine the evaluation factors of center-pivot irrigation system and factors which usually affect irrigation performance. A solution. for the improvement of irrigation water use will be presented and design and management problems, will also be mentioned. To achieve the objectives of this study, the characteristics of the soil and the growing plant (seed corn) along with design parameters were determined. The system was designed on the basis of soil and the growing plant characteristics in the 500-ha farm of Ministry of Agriculture (located in the North East of Meshkinabad, Karaj) having a silty loam texture. Then, it was examined with respect to the existing conditions. Four radial rows of catch containers spacing 6 meters were set up and then field data for performance evaluation of system were determined. The evaluation factors were calculated on the basis of field data analysis. The results obtained are as follows: During the growing season, the average PELQ, AELQ and DU for the center-pivot system were about 79, 75.8 and 84 percent, respectively. Analysis of evaluation factors indicated that the system is not efficient DU and PELQ values were not high enough for the system because it was not properly designed for the existing conditions. Al the same time, it seems that the difference between PELQ and AELQ values are meaningful which may indicate management difficulties.
ِahmad Sobati, Abolhassan Hashemi Dezfuli,
Volume 2, Issue 2 (7-1998)
Abstract
Growth and grain yield of irrigated barley cultivars (Valfajr, Binam and Raihaneh) was investigated at 4 sowing dates (6, 22 Oct. and 14, 20 Nov.) in Karaj region. The effect of sowing date, genotype and their interaction on grain yield were statistically significant. Early and late sowing enhanced cold damage. However, the damage was more in late sowings. It was estimated that the optimum sowing date would be about 50 days (600 GDD) prior to freeze-up and maximum cold damage would occur when sowing was delayed until some 22 days (230 GDD) before freeze-up but any more delay in sowing would cause less damage. Highest grain yield was obtained from Raihaneh at 22 Oct. sowing. Binam showed good yield stability and relatively high yield, especially in unfavorable sowing dates. In the relatively favorable sowing dates (6 and 22 Oct.), grain weight showed positive correlation with linear grain filling rate, storage and translocation of reserves. LAI, LAR, RGR, CGR and LAD of each cultivar were higher in the second sowing date compared to the first one. The “ratio of post anthesis growth to maximum TDM” showed a high correlation with the harvest index. Raihaneh was the highest cultivar in resistance to lodging, harvest index, storage and retranslocation of assimilates, and linear grain filling rate. It is suggested that at favorable sowing dates, Valfajr and Binam had source limitation or disturbed translocation and Raihaneh had sink limitation.
Mohammad Rajab Zadeh, Aghafakhr Mirlohi,
Volume 2, Issue 2 (7-1998)
Abstract
Optimum rice population densities and the response of rice yield and yield components to population densities and planting pattern are important factors helping rice producers and researchers to achieve maximum productivity. For this reason, a randomized complete block design experiment was conducted during the summer of 1995 at Isfahan University of Technology Research Farm located at Lavark, Najafabad. Zayandeh-rood cultivar was transplanted with three seedlings per hill at row spacing of 15, 25 and 35 cm and hill spacing of 10, 15 and 20 cm under flooded conditions. Row spacing influenced the plant height significantly at heading and anthesis stages. Wider row spacing, enhanced days to 50% heading and anthesis and consequently grain filling duration and ripening stage coincided with unfavorable conditions at the end of the season, which decreased the percentage of maturity. Although number of tillers per unit area increased, tillers per plant decreased as row spacing was reduced. Narrow row spacing limited vegetative growth after anthesis and thereby growth rate of panicle increased. With reduction of row spacing, without any change in the percentage of full grains per panicle and grain weight, number of panicle per unit area increased but number of grains per panicle decreased. At greater row spacing, grain yield per unit area decreased although grain yield per plant and harvest index increased. Although, effects of hill spacing were similar to those of row spacing, hill spacing usually did not influence plant characters, yield components and grain yield significantly. Stepwise regression and path-coefficient analysis revealed that number of panicle per unit area is the most important yield components. It also showed that indirect effects of panicle per unit area on yield through its association with grain per panicle prevented real effects of grain per panicle on yield. Fifteen × 15 cm spacing produced maximum yield which is probably recommendable for rice production in Isfahan.
Masoud Ezzat-Ahmadi, Hamdollah Kazemi, Mohammad Reza Shakiba, Mostafa Valizadeh,
Volume 2, Issue 2 (7-1998)
Abstract
Effect of different times and levels of nitrogen fertilizer application on growth and grain yield of spring wheat cultivar “Ghods” was studied during 1993-1994 growing season at Karkadj, Agricultural Experiment Station, College of Agriculture, University of Tabriz, using a split plot design with three replications. Main plots were assigned to five levels of N fertilizers (0, 40, 80, 120 and 160 kg/ha) and subplots to five times of applications [all of N fertilizer at planting (T0) 1/2 at planting + 1/2 during tillering stage (T1), 1/2 at planting + 1/2 during heading stage (T2), 1/3 at planting + 1/3 during tillering and 1/3 at heading stages (T3) and 1/4 at planting + 1/4 at tillering + 1/4 at stem elongation and 1/4 at heading (T4)]. Results showed that different levels of N applications affected grain yield and biological yield significantly, while the effect of split application and also N levels × times of application interaction on these two traits were non-significant. Growth stages of wheat were not significantly affected by different N Levels and times of application. Dry matter accumulation, leaf area index, and crop growth rate, in response to growing degree days during growing season, increased when higher levels of N fertilizer were applied. Leaf area index and crop growth rate initially increased up to anthesis and then decreased. Crop growth rate decreased to zero level at soft dough stage and then became negative. Variations in relative growth rate and net assimilation rate, in relation to growing degree days, decreased when different levels of N fertilizer were applied at early part of growing season it was maximum while at later growth stages decreased and finally became negative, Times of N application and level × time interaction during growing season did not affect the growth indices significantly.
Abdol-Hossain Samie, Javad Pour-Reza,
Volume 2, Issue 2 (7-1998)
Abstract
A total of adult leghorn roosters and 360 day-old broiler chicks were used in two completely randomized experiment to evaluate metabolizable energy (ME) and feeding value of faba beans in broiler rations. In a factorial arrangement with 10 treatments and 3 replicates chicks were fed isonitrogenous rations containing either 0, 10, 20 or 30 percent of raw, cooked or dehulled faba beans for 8 weeks. Data from sibbald procedure showed cooking had no significant effect on energy value of beans, while dehulled beans had a significantly (p < 0.05) higher energy value. Final body weights at 8th week of age were unaffected due to processing of beans. No significant differences were observed in liver weight, abdominal fat or feed efficiency ratio due to processing and/or percentage of beans in the ration. Raw, whole beans significantly (p < 0.05) increased percentage and weight of pancreas compared to those that had consumed dehulled beans. This indicates that trypsin inhibitor is located in hulls. Cooked beans reduced pancreas size to normal, indicating destruction of inhibitor due to cooking. One interesting point is that the control group which consumed more soybean meal had a pancreas weight of 4.67 grams comparable to 4.83 grams of pancreas weights of chicks consuming raw, whole beans. This last fact indicates that soybean meals might not have received enough heat treatments during processing, which requires further investigation.
Davar Khalili, Abolghassem Yousefi,
Volume 2, Issue 3 (10-1998)
Abstract
Physiographic characteristics of Atrak Watershed described by a number of parameters were used in regression models to estimate maximum daily discharges. These parameters were sub-watershed area, main waterway length, mean waterway slope, mean watershed elevation and mean watershed slope. Based on the results of correlation between the above parameters and their suitability for discharge estimation, three regression models were developed for further analysis. Model 1 applied area as the independent variable to estimate maximum daily discharge. In model 2 area and mean watershed elevation were the independent variables. Model 3 used area and mean waterway slope as the independent variables. Even though the results of testing did identified all three models as appropriate for application, further testing selected model 1 as the most appropriate. Recommendations were made for model application to similar watersheds lacking the necessary data.
Behrouz Mostafazadeh, Sayed-Farhad Mousavi, Mohammad Hossain Sharif-Bayanolhagh,
Volume 2, Issue 3 (10-1998)
Abstract
To determine the effects of field slope, emitter discharge, irrigation water volume and soil texture on soil moisture profile and soil surface wetted shape from a point source, field data were collected on three different soil types, three emitter discharges (4, 8, and 12 lph), four slopes (0, 2, 5, and 10%), and five irrigation water volumes (10, 20, 30, 40, and 50 liters) with three replications. The results showed that the surface-wetted area increases as the emitter discharge increases. The surface-wetted area decreased with a corresponding increase in emitter discharge in experimental fields with light-textured soils. In experimental fields with heavy textured soils and slopes greater than 5%, the changes in surface-wetted area due to the emitter discharge increases, were higher compared to slopes of less than 5%. Since, a higher emitter discharge would result in higher surface-wetted area, the results showed that for an equal volume of irrigation water, the soil moisture profile was deeper for lower emitter discharge. In general, the volume of wetted zone was higher for greater emitter discharges. It was found that as the volume of irrigation water increased, the volume of wetted zone would increase correspondingly. This effect is more prominent than that of emitter discharge. In general, the depth of wetting front was lower and the wetted surface area was greater for heavy textured soils as compared to the light textured soils. The wetted-surface area and the shape of wetting front in the direction of slope were affected by the soil infiltration, emitter discharge and volume of irrigation water where these effects were more critical in higher sloping lands.
