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حسن
رحیمی
author
شهرام
باروتکوب
author
text
article
1996
per
Failure of concrete irrigation canal linings in the forms of cracking, rupture , uplifting and opening of joints , causes loss of water and money in many countries. Foliwing appearance of extensive cracking of concrete linings in Shoeybieh Sugar Cane Industries Unit in khoozestan province ,Iran, extensive research programs were conducted to find the main reasons . In this paper the final results of the researches are presented.
The testing program consisted of laboratory as well as field tests, including identification chemical and mechanical tests of soil samples taken from the borrow pits and canal embankments . Dispersivity tests were performed using pin- hole and chemical methods and swelling tests were conducted using ASTM standard and ISSMFE method. The field test includes the measurement of deformations of the concrete lining and embankment of an actual lined canal with a length of 60 m , due to filling by water. The deformations were recorded by surveying of the elevations of steel bars driven to different depths under canal lining and at different points of canal and its embankment sections.
The results of laboratory tests showed that the soil is low to medium plastic with a classification of CL-ML, having less than one percent soluble content, and being nondisperssive. Swelling tests conducted by ASTM and ISSMFE methods showed completely different results. ISSMFE method resulted in high free swell potential ,while ASTM method indicated a low to medium potential,The results of full scale field tests were all in favor of ISSMFE method. The great difference between. the results of two methods was found due to the different compaction methods as well as the moisture content of the soil sample being prepared for swell tests. While in ASTM method, the sample is compacted by dynamic effort , at optimum water content , in ISSMFE method compaction is done using static effort and a low water content near the shrinkage limit. Therefore, two main factors causing discrepancy between the results of the two methods, i.e. the type of compaction and moisture content are responsible for difference in the structures of the samples being tested and finally different behaviour upon water absorption. The fiocculent structure and lower compaction water content of soil sample in ISSMFE method would result to much higher free swell. Similarity between compaction methods used in the field and static effort used in ISSMFE method, as well as very low soil water content of the canal embankments during lining operation, are the main reasons for swelling of the soil and finally cracking of the concrete linings.
The overall results of the field and laboratory experiments showed that even soils of low to medium plasticity have a high swelling potential when dessication and shrinkage occur due to high temprature and aridity , as it is the case for Khoozestan province . Experiments proved that lower relative density (less than 95%) and compaction in the wet side of optimum water content (about 2 to 3 percent) can effectively control the swelling potential . The research has also proved the superiority of ISSMFE method for evalaution of swelling potential in hot - arid zones like Southern parts of Iran.
Iranian Journal of Agriculture Science
پرديس کشاورزي و منابع طبيعي دانشگاه تهران
1
v.
0
no.
1996
https://jijas.ut.ac.ir/article_16072_b0866c7d3b3548da4503cabe1b0e3663.pdf
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مجید
شاهمرادی
author
غلامرضا
قربانی
author
text
article
1996
per
In this study thirty six (36) Ghezel ram and wether at about five months of age were used to determine the effects of zeranol implants on growth and carcass characteristics in a 2x2 factorial arrangements. Lambs were alloted randomly to the following treatments for 63 days 1) non implanted (NI) rams,2) implanted (I) rams, 3) NI wethers, and 4) I wethers. Rams were heavier than wethers at slaughter (P
Iranian Journal of Agriculture Science
پرديس کشاورزي و منابع طبيعي دانشگاه تهران
1
v.
0
no.
1996
https://jijas.ut.ac.ir/article_16073_c9df6b9cb8646bdcb0cd7f0221425b94.pdf
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محمد رضا
احمدی
author
امیر حسن
امیدی
author
text
article
1996
per
The cultivation of winter type safflower is limited by long growth period and low .yild potential . In this investigation some important agronomic characteristies such as yie4d components , grain yield and oil content of 12 type winter and 16 spring type of safflower were compared in a randomized complete block design.
The selections Zargban - 279 and 14-4 showed the highest yield , among the winter and spring types, respectively.
Safflower has a long growth period and needs about 300 days to maturity in some winter type varieties.ln this regard the varieties Arak- 2811 and Zarghan - 279 which showed good adaptibility were chosen to determine the best time of harvesting , in above mentioned experimental trials.
After the end of flowering , 9 harvesting time with one week intervals for winter type and 4 harvesting times for spring type were considered.
Means for each trait were compared by dunken’s multiple- range test. The results of the eperiment indicatied that 21 days after the end of flowering is the best harvest time for both types.
Iranian Journal of Agriculture Science
پرديس کشاورزي و منابع طبيعي دانشگاه تهران
1
v.
0
no.
1996
https://jijas.ut.ac.ir/article_16074_992f9d7fd32908658618f160e5be0c82.pdf
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محمود
تورچی
author
عبدالحمید
رضائی
author
text
article
1996
per
To evaluate the general combining ability of male—sterile lines of sorghum for grain yield and some related traits in a genetically broad base population of sorghum [Sorghum bicolor (L) Moench], in 1990, nineteen randomly selected male-sterile lines (A-line) were top crossed to a broad genetic base tester (a mixture of equal amount of seed from 120 fertility restorer(R—lines) and 19 top crosses were produced. Genotypes, consisting of 19 top crosses, 19 male—fertile lines (B—lines) and tester were grown in 1991 at the Isfahan University of Technology Research Farm located in Najaf-Abad. Genotypes were evaluated in two favorable and unfavorable environments in a split—split plot design with complete randomized block arrangment in 3 replications. The main plots were two planting dates, 1st and 16 May. Two within rows plant spacings (10 and 20 cm) considered as the sub plots. Differences between means of top crosses and their respective B—lines, that indicates heterosis and superiority relative to the female parent, were statistically different from zero, for most of the traits studied. Heterosis led to an increase in grain yield, test weight, panicle lenght, plant height, panicle weight and earliness.
Grain yield and test weight had the smallest heritability estimates, based on variance components and regression of top crosses on female parents. The highest estimate of heritability based on variance component and regression belonged to plant height and panicle lenght. Due to high genetic variability and unadequate number of environments studied, the heritability estimates were high for most of the traits. The stimates of heritability for most of the traits in unfavorable environmental conditions were lower than those in favorable conditions. Howevere, the high estimates of heritabilites indicated the efficiency of selection for superior genotypes based on these traits. Therefore, it is possible to increase the mean of these traits by selection.
In favorable environment A22 and A23 had Significant general combining ability (GCA) effects for all of the traits,e.g. grain yield, and can be used as better parent in hybrid production. A12 had only a better performances for most of the traits in favorable environmental conditions. A22 showed a good performance in both environments, and its GCA effects for all of the traits, except plant height and test weight were positive and significant. Therefore, it can be used as a potential parent in hybrid seed production for a wide range of environments.
Iranian Journal of Agriculture Science
پرديس کشاورزي و منابع طبيعي دانشگاه تهران
1
v.
0
no.
1996
https://jijas.ut.ac.ir/article_16075_767c6074770e6fe0f516a377246d1d76.pdf
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عباس
همت
author
text
article
1996
per
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Iranian Journal of Agriculture Science
پرديس کشاورزي و منابع طبيعي دانشگاه تهران
1
v.
0
no.
1996
https://jijas.ut.ac.ir/article_16076_72d3d923cb73a9c571421572917753a0.pdf
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مریم
شهبازی
author
زرین تاج محقق
دوست
author
text
article
1996
per
In plants which are exposed to salinity , There is a specific relationship between composition of cellular inorganic ion contents and proline and soluble sugars accumulation Two wheat cultivar seedlings were treated with 0,50,100, 175 mM sodium chloride in Hogland nutrient solution and accumulation of the compounds were studied. proline and solbule sugars accumulated and growth reduced significantly at 175 mM. The study of 10 wheat cultivars at this treatment showed that the relative growth rate had a positive and significant correlation (
Iranian Journal of Agriculture Science
پرديس کشاورزي و منابع طبيعي دانشگاه تهران
1
v.
0
no.
1996
https://jijas.ut.ac.ir/article_16077_b5174000dfb709afcef83c8e9f224504.pdf
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علی
محرری
author
ابوالقاسم
گلیان
author
علی
نیکخواه
author
text
article
1996
per
Urea dilution method was validated as an estimator of body composition . In this study urea space method was determined in 29 male growing Holstein cattle, although total body composition of 10 of them were determined through slaughtering. Chemical composition was also measured by using 12th and 9-10-11th ribs from each carcass. Urea space measured 12 minutes following urea infusion in jugular vein. Urea space was also evaluated as a biological entity using the composition indicated by the regression equations relating urea space to body composition. The regression equations relating total body composition. To The regression equation relating total body composition to the ribs composition showed that , the ribs composition Showed that, the ribs composition may be used for estimation of carcass composition . In both approaches., the observed urea dilution results agreed with the predicted values. It was concluded that urea space measurement can be used as a practical estimator of carcass composition of live growing Holstein cattle
Iranian Journal of Agriculture Science
پرديس کشاورزي و منابع طبيعي دانشگاه تهران
1
v.
0
no.
1996
https://jijas.ut.ac.ir/article_16078_580a7dd85d1fb212d14d64c95314753e.pdf
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فرزاد
کرمپور
author
محمود
اخوت
author
عباس شریفی
تهرانی
author
text
article
1996
per
The effect of 6 concentrations of Benomyl and Rovral Ts(35% Iprodione & 15% Carbendazime) fungicides were investigated on growth rate of Fusasrium solani in PDA culture with 3 replications . The means of colony diameter of the fungus in 3ppm of Benomyl , Rovrat and control treatments were 21.66,21. 33 and 85.5 respectively . These two fungicides reduced growth of the pathogen up to 75.25 and 75.05% respectively. Benomyl and Rovral decreased the germination of the spores at rate 63.5 and6&04 percent in vitro. 100 ppm concentration of the fungicides were used in infested soil in a randomized completely design with three replications. Results indicated that benomyl and Rovral decreased black root rot up to 62 and 69% respectively. The use of these fungicides in (infected) soil increased height and fresh weight of chickpea shoots comparing with those of infested soil with the pathogen , but in healthy control these fig were greater than other treaments.
Iranian Journal of Agriculture Science
پرديس کشاورزي و منابع طبيعي دانشگاه تهران
1
v.
0
no.
1996
https://jijas.ut.ac.ir/article_16079_44d585e0f16e670e00cf0ee5c9197cab.pdf
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جواد
ترکمانی
author
text
article
1996
per
The importance of risk in efficiency analysis is acknowledged. Then ,considering the risky nature of agiculture, a procedure to determine the levels, of economic efficiency and its allocative and technical components, in the mathematical risk programming framework, is presented. Various type of risk programming methods were. evaluated . Direct expected mathematical model was then adopted for the current study. The programming models were then solved by using the General Algebraic Modeling System (GAMS/MINOS) non-linear maximization option. The results indicated that it would be feasible tosubstantially increase farm product and farmer’s total net revenue by increasing their economic efficiency.,
The ELCE interview technique with imaginaty payoffs and the triangular distribution method were used to elicit the utility functions and subjective probability distribution of crop yields and of prices from sample farmers, respectively.. The analysis of the results classifiled all the sample farmers as risk averse. Thus understanding of this aversion is an important factor in proposing policies by the planning agencies.
Iranian Journal of Agriculture Science
پرديس کشاورزي و منابع طبيعي دانشگاه تهران
1
v.
0
no.
1996
https://jijas.ut.ac.ir/article_16080_c4cf10d5af6372c32565e81998cc17a8.pdf
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جعفر
آقایی
author
سیروس عبد
میشانی
author
ناصر
خدابنده
author
text
article
1996
per
It s long been recognized that the gluten protein fraction is the main determination of the quality property of pesta and the viscoelastic property of dough made from wheat flours. To study the diversity of II MW-glutenin and LM W-glutenin in Iranian Durum wheat collection, 513 lines selected from landraces of 58 Iranian cities were used. We used S1)S-PAGE procedure for fragmenting the glutenin and found 3 alletes in GLIJ-A1 and 10 alleles in GLU-Bi Loci. The LMW-glutenin sub units and well scored by SC)S-PAGE and confirmed by I
• gliadines. We found that 85% of the lines had LMW-2 Genetic Identity calculated by alletic frequency in each city and the data from the cities and geographical regions were clustered in 4 groups by using cluster analysis. This study showed that the geographical regions diversity is followed with genetic variation. Also to determine the relationship between HMW and LMW
-glutenin alleles and pesta quality, we used SDS-scdimentation test on 100 lines that had all the different HMW-glutenin and LMW-glutenin alleles. Then by one-way analysis of variances and regression analysis we found that 1 and 2* alletes from GLU-Al, 14 - 15 from GUJ-B1 locus and LMW-2 had a positive effects on SDS-sedimentation test values.
Iranian Journal of Agriculture Science
پرديس کشاورزي و منابع طبيعي دانشگاه تهران
1
v.
0
no.
1996
https://jijas.ut.ac.ir/article_16081_2a082dd1cb5ab454b6b987e7a2aa6fb4.pdf