Vol. 4 Issue 2
S. N. A. Younis
In Saudi Arabian agriculture the selection and determination of the optimum size, power and quantity of machinery do not obey established rules and principles. This study aims at setting a scientific basis for selecting the proper size of the tractor which suits the local agricultural characteristics and the related resources of production. Experimental work included testing the performance of a 30 kW tractor during the execution of three typical agricultural operations namely the primary tillage, the secondary tillage and planting. The obtained data were used to select the appropriate tractor for an objective function which was the overall rate of energy conversion. The analysis of the experimental and mathematically obtained data revealed that the 50 kW tractor was the optimum tractor for the conditions of Saudi agriculture. The decrease in the degree of mechanization of Saudi agriculture was found to be 0.393 kW/ha. The required number of the recommended power level tractors to achieve full mechanization was determined to be 3870 tractors.
Abdulilah M. Al-Ani and Daryl G. Richardson
Experiments were conducted on 60 years old 'Anjou' pear trees under orchard conditions to study the absorption of 45Ca by the fruit skin during the growing season, the mobility of 45 Ca between the shoots and the fruits.
When 45 Ca (Carrier Free) was injected into the branch, 20 cm below the attachment of the fruit spur, the second week of the August, 2%of the torla 45Ca moved into the fruit within 40 days in both the sun side and the shaded side of the tree. When 45Ca was injected in the branch of 'Bartlett' pear on June 25, after removing the terminal meristem about 28% of the total Ca moved out of the application zone during the three days compared with only 17.5% of the total 45Ca moved out of the application zone if the growing point was left intact. Within three days the activity of 45Ca in the fruits on branches with the growing point removed was three times higher than in fruits on branches with the growing point left intact.
When 45Ca was injected in the fruit flesh or in the carpel cavity, only a negligible amount moved out of the fruit, while the 41% of the total 45Ca absorbed by the fruit from painting on the fruit surface, moved out of the fruit to the adjacent leaves and stems within 40 days.
M.F. Soliman
A greenhouse experiment was conducted on clay loam soil of pH 7.8 to evaluate the effect of P and N fertilization and foliar applied Mn on yield and nutrient concentration in leaves and seeds of soybean. A significant yield increase was obtained for each added increment of P fertilizer up to 30 kg P2O5/acre. At application rates of 0, 15, 30 and 45 kg P2O5/acre, the seed yield was subsequently 27.8, 65.8, 84.8 and 83.6% of the maximum yield obtained at the maximum calculated P level. The yield increases were 14.2 and 10.2% due to N and Mn applications. In all cases, in which P was combined with N, the seed yield was relatively higher than with P or N applied alone.
Phosphorus, N and Mn concentration in leaves and seeds were positively correlated with the applied nutrient fertilizers. At any given level of applied P and Mn, the P concentrations were significantly higher in +N treatment than -N treatment. Phosphorus concentration in leaves and seeds decreased by Mn application. While P and Mn applications affected the Mn content of both leaves and seeds, they did not influence the N%
S.O. Elhiweris
The effects of nitrogen fertilizers on the growth of Sorghum vulgare (Pers) and Striga hermonthica (Benth) were investigated in relation to parasitism. Addition of nitrogen fertilizers resulted in an increase in the growth of both infected and non-infected Sorghum plants. Application of either complete nutrient solutions or ammonium sulphate solutions to plants with split-root systems resulted in an increase in the growth of the root system which received high concentrations of the fertilizers compared to the other half or the root system which received only water. The shoot weights of the plants increased whether the fertilizer solution was added to one half of the root system or shared between the two halves, and also with or without infection. The number of Striga plants that emerged per pot was substantially reduced with increase of fertilizer especially by early application.
Measurements of the plant growth promoting substances as "gibberellic acid or kinetin equivalents" in the xylem exudates of Sorghum vulgare revealed an increase in the concentration of both growth substances whether the plant was infected or non-infected with Striga hermonthica. These findings together with the more vigorous growth of Sorghum plants and the suppression of the growth of the Striga plants with the addition of nitrogen fertilizers are discussed and the usefulness of nitrogen fertilizers for control of Striga hermonthica parasitism confirmed
M.A. Abouheif, S.M. Basmaeil and M.N. Bakkar
Daata on 227 Najdi male camels Camelus dromedarius were used to determine the relative value of body measurements in predicting body and carcass weights. Seven body measurements were obtained for each camel; length of neck, length of arm, length of body, chest girth, hump girth and hip girth. The correlations of carcass weight with body measurements were higher than the observed correlations between body weight and body measurements. Correlations of body weight and carcass weight with chest girth, hump girth and hip girth were the highest among all the studied body measurements. Predictions equations were developed by a maximum R2
procedure. The most efficient equations for estimating body or carcass weights were:
Body weight= 1.02 (length of neck, cm) + 0.72 (chest girth, cm) + 1.59 (hump girth, cm) + 1.95 (hip girth, cm) - 385.5
Carcass weight= 0.57 (length of neck, cm) + 0.56 (chest girth, cm) + 0.85 (hump girth, cm) + 0.41 (length of body, cm) + 1.04 (hip girth, cm) - 274.6
Halil A. Semerci and Yavuz Yorulmaz
Heavy petroleum fractions can be mixed with neutrals to give blends having somewhat higher viscosity index than the arithmetical mean of the initial stocks. But the use of polymeric materials so-called viscosity index improves yields far higher viscosity index values. In this study, it was observed that polymethacrylate is more effective as an oil viscosity index improver than ethylene-propylene copolymer. Alkylated polystyrene is also suitable for use as a viscosity index improver for lubricating oils. As the degree of alkylation increases, the polymer becomes more soluble in oil, consequently the viscosity index improving performance of the polymer increases.
Adnan A. Al-Samawi
A time series model is presented for use in generating missing river flow data. A 14-year record average monthly flows of the river Khabur at Zakho (Iraq) is used as a case-study. The time series model of monthly river flows consists of a deterministic component and stochastic component. The deterministic component is presented by a periodic model, while the stochastic component is fitted to a third-order-autoregressive AR(3) model using the Box-Jenkins approach of time series analysis. The model explains more than 87% of the total variance of the original series. The model is then used in generating a sequence of missing data.