مجله کشاورزی دانشگاه تهران
سال دهم شماره 1 (پیاپی 16، بهار 1387)

600 seven day-old Ross broiler chicks were tested in a factorial experiment (2×5) with two levels of oil (three and six percent) and five levels of soybean oil and soapstock (100:0, 75:25, 50:50, 25:75 and 0:100) with four replicates. Rations were isocaloric and isonitrogenus. The chicks of the rations with three percent fat had higher weight gain and lower feed intake and feed: gain ratio (P<0.05) in whole period. In starter and grower periods, the chicks of ration with three percent fat with soybean oil: soapstock ratio of 0: 100 had lower feed intake and better feed: gain ratio. It was concluded that the acidulated soaopstock could be replaced by soybean oil completely in three percent level in all periods.

In calcareous soils with high calcium carbonate contents and pH, the growth and development of plant might undergo nutritional disorders. The process of biological nitrogen fixation in legumes cultivated and plant growth in these soils could be limite. The use of acid-producing materials like sulfur and a reduction in soil pH improves plant growth and increase the biological nitrogen fixation. A 2 × 5 factorial experiment consisting of two soybean cultivars (Sahar and Williams) and six levels of sulfur (0, 1, 2, 5, 10 and 15 ton/ha) arranged in a completely randomized design with three replicates was conducted under greenhouse conditions in Nuclear Center for Agriculture & Medicine Atomic Energy Organization, Iran. Results showed that the accumulation of sulfate resulted from sulfur additions decreased soil pH and increased EC (p<0.01). Sulfur additions up to 5 and 10 ton/ha respectively for Sahar and Williams cultivars increased the plant dry weight. However, further increase of sulfur levels affected the plant dry weights negatively, due most likely to the increase in soil EC values. In spite of the increased soil EC, increasing sulfur levels resulted in enhanced nitrogen fixation, probably due to favorable soil reaction caused by sulfur oxidation.

High quantity of chemical fertilizer use in farms to increase production but low efficiency irrigation leaches part of nitrate and follows groundwater pollution. In this research, extra water below root zone as deep percolation collected with point drains which installed interface of natural drainage zone and agricultural soil in University of Tehran research farms. Then, concentration of nitrate (NO3-N) measured in the water quality laboratory. Results showed nitrate concentration changed between 0.15 to 289 ppm. In this study, nitrate leaching trend to Karaj groundwater and reasons is considered. Finally, initial soil nitrate measuring, usage of modern irrigation methods with high efficiency, prediction of rainfall time and fertilizer management in fields recommended to preventing of groundwater degradation quality trend.

The vase life of cut flowers prolong by some compounds, which can improve their hormonal regulation and water relations or reduce microbial growth in xylem tissu. The effect of chemical treatments on vase life longevity of Rose 'Ilona'. A randomized complete block design with three replications conducted with following the treatments of Control, STS, Nickel sulfate, Cobalt chloride, Aluminum sulfate, Zinc acetate, HQC and sodium hypochlorite. The CoCl2 400 mg.l-1 and Al2(SO4)3 at 800 mg.l-1 extended vase life and STS at 400 mg.l-1 and Al2(SO4)3 at 800 mg.l-1 and maintained flower quality of roses better than other treatments (P< 0.05). The benefit-cost ratio method showed that HQC was the most profitable treatment and CoCl2 600 mg.l-1 had highest value.

A survey-descriptive research methodology conducted 839 Dehyaries, consisted the statistical population of the study. A number of 149 Dehyaries were selected as sample using a multi-stage sampling technique. The questionnaire was approved to be both valid and reliable. To identify factors affect success of Dehyaries, discriminate analysis was applied. The results revealed that organizational collaboration was the most effective component and the extent of accessibility of Dehyaries to equipment and feasibilities, people participation, motivation of Dehyars for development of village, and Dehyar participation in training courses were the most effective factors, respectively.

The purpose of this research was to study deterrent factors for entrepreneurship in relation with personality and environmental characteristics for graduates of agriculture. The statistical population of the research is composed of graduates (N=98) have been able to establish a business in the field of agricultural production, in Boushehr Province (one of the southern provinces of Iran). Validity and reliability of the questionnaires, based upen Cronbach's Alfa coefficient was found to be 0.75 and 0.91 for personality and environmental characteristics. Among personality factors, the weak independence spirit, internal locus of control and lack of risk taking, are the most important deterrent factors for entrepreneurship. The quality of practical educations, high risk of investment in the agriculture sector, and legal and administrative restrictions are the most important deterrent environmental factors. This research indicates that regarding personality characteristics, there are significant different between male entrepreneur graduates and female entrepreneurs spirit of opportunity recognition (t=0.02*) and independence (t=0.05*).

A number of 1810 members of the Water User Associations (WUAs) of Jarghouyeh district consisted the statistical population of the study, out of which 150 farmers were selected as sample using proportionate stratified random sampling technique. A questionnaire was developed for gathering the data and information. Content validity and Cronbach Alpha proved both the validity and reliability of the tool of study, respectively. Coefficient of reliability coefficient was more than 0.75 for different parts of the questionnaire. Factor analysis showed that five factors namely, monitoring on water distribution, maintenance and physical development of network, securing farmer's rights, reducing expenditure of water exploitation and conservation and improving farmer's access to input explained about 77% of variance of the areas of improving water user's associations performance in network management. The result of priority-setting showed that sufficient distribution of water and timely water delivery were two important factors affecting the performance of WUAs.

The main purpose of this research was to perform an analysis of the attitude of male and female students towards agrisciences in the College of Agriculture and Natural Resources of the University of Tehran. It was a correlational-descriptive research which was conducted through a survey method. The statistical population of the study consisted of 1677 male and female students, out of which 236 students were selected as sample using proportionate stratified random sampling technique. The content validity of the questionnaire was approved through getting opinions of 14 agricultural extension specialists and experts working in the University of Tehran. The scale of attitude of the questionnaire was proved to be reliable as Cronbach Alpha Coefficients was equal to 0.80. According to the results, the relationship between student's time spent to use computer and their attitude towards agrisciences was negative and significant. Meanwhile, the relationship between the priority given to the selected discipline at the time of exam entrance with their attitude towards agrisciences was negatively significant. The results of factor analysis of attitude of students towards agrisciences showed that the most important factor of attitude formation was the needs for achievement from the view points of male students. The same analysis revealed that from the opinion of female students the potential of agriscienes to secure psychological needs such as enjoyment of studying agriculture and getting useful information in personal life and satisfaction of psychological needs were the most important factors forming their attitude and making it favorable towards agrisciences.

The statistical population of this study consisted of 944 Post-graduate and under graduate Students, who were in their last academic year in the campus of Agricultural and Natural Resources the University of Tehran. A questionnaire was used to collect the data. The content validity of the questionnaire was established by a panel of experts in the field of agriculture in the University of Tehran. A pilot study was conducted to establish the reliability of the instrument via agricultural students. Cronbach alpha's coefficient for the main scale of the questionnaire was higher than 0.75. The results of correlation analysis showed that there was negative significant relationship between quality of agricultural practical training and the diploma average marks of the students. There was positive significant relationship between the dependent variable and their interest to the subject. In order to identify the problems and obstacles of practical training in agriculture, factor analysis was applied. Accordingly, the problems were classified into four factors of quality of installations for practical training at the farm, motivation and experience of students on agriculture, skills and competencies of teachers in practical training and the quality of equipment for practical training in the campus. These four factors explained about 67 percent of variance of the data indicating problems for practical training.

Some Whitefly’s species show host correlated morphological variation. Cotton whitefly is a famous one that has a wide variation in its populations and biotypes. This study was conducted to evaluate these variations in Varamin area during 2005-6. For this purpose, infested leaves of tomato, cucumber, egg plant and cotton collected from fields. Pupal cases mounted in microscopic slides. Then their main external morphological characters identified with taxonomical keys. Result showed that it has four host-correlated morphological variations. Description of these variation and their relationships are discussed in this study.

Breakeven analysis is one of the most important existent tools for decision-making in agriculture. This technique used for analysis of different budget components about irrigated wheat crop in Marvdasht township. The required data and information were collected via 154 questionnaires and using the stratified random sampling method during 2004-2005. Results show that farmer's profit (Rls. 479.8 per Kg. of crop) is about thirty percent of the cost price of crop (Rls. 1570.2). The breakeven analysis for factor prices, show the levels of factor prices in existent conditions were much lower than breakeven prices (especially in the case of the factors of insecticides, phosphate fertilizer and urea fertilizer) in such a way that the ratio of mentioned factor prices in existent conditions to their breakeven prices was 0.02, 0.07 and 0.09 respectively. This has caused non-optimal and very much usage of factors in many cases.

The comparative advantage of Iran kiwi production and the effects of governmental applied policies on the production process of kiwi fruit investigated over the period 1998-2003 by using policy analysis matrix. Iran has had comparative advantage in the production of this crop, but the profitability of this crop has been decreased in 1998-2003. The amount of domestic resource cost index has increased from 0.39 in 1998 to 0.92 in 2003. So governmental applied policies in sale market was not in direction of export extension of kiwi and its money-gaining. The incrase in the amount of the index of nominal protection coefficient of input from 0.67 to 1.2 and also the increase in the amount of nominal protection coefficient index from 0.51 to 1.3 reveal that despite the lack of the factor support of this crop, the support in crop sale market has existed and in general, the effects of government intervention in the crop production process have been in favor of producers in domestic market and the amount of effective protection coefficient index has increased from 0.5 to 1.31.

To determine the factors affecting the acceptation of rice insurance in Sari township a number of 90 farmers (45 assured and 45 not assured) were sampled. The information consisted of personal (age, size of family, activity experiment, damage experiment, and non-farm income); social (studies level, agrarian regimes, locality); and geography (farm size, distance between farm to insurance broker). This information was evalyated by estimating the logit model. The locality had the most effect on insurance acceptation. The insurance acceptation in this township have mostly followed on zone factor to personal factor whatever some zone showed more tendency toward insurance than other zone. To have knowledge was an effective variable. The increase of knowledge about insurance was more important. The Age and experience of damage are other effective factors to increase demand for insurance.

This paper presents design and construction of an automatic moldboard profilograph by substituting an optical sensor and a control system together with its evaluation. The modified profilograph is an electro mechanical apparatus in which a micro switch and a DC motor was replaced with an optical sensor and a control system for revolution of a DC motor. Thereby, the considered surface is measured using a non – contact sensor. This apparatus has the capability of drawing the profilograms of a 3-D object as a 2-D drawing in the same contour lines. The profilograms drawn by this apparatus can be useful in moldboard design and its surface modeling. In the end, drawn profilograms before and after modification were compared. Then, to verifying apparatus performance, the horizontal and vertical profilograms of a cylindroidal moldboard was drawn.

A field study was conducted to evaluate the possibility of using water table control techniques in the semi arid region of Iran with special attention to its salinity management. The WTM consisted of three subirrigation treatments with water table controls set at 0.3, 0.5 and 0.7 m from the soil surface and a free drainage (FD) treatment. The electrical conductivity (EC) of water was 1.5 dS/m. The crop cultivated in lysimeters was annual alfalfa (Medicago scutellata). The results indicated that CWT methods can be used in semi arid condition. In all the treatments the soil ECe was not reached to the crop threshold level. The evidence was the higher yield of CWT treatments than FD treatment. The total yield of CWT0.3 and CWT0.5 were 73 and 94% more than FD respectively.