Vol. 13 Issue 3

Abdulrahman A. Al-Warthan and Hassan M. Al-Swaidan
A rapid and sensitive method for the determination of trace elements (Mn, Pb, Fe, Co, Ni, Cu, Zn and Cd) in the flesh of various date species of Saudi Arabia is described. The optimization of the operating conditions and figures of merit are given. Detection limits are in the range of 0.01-130 ppb. The relative standard deviations range from 0.47% to 4.87% for the flesh in date cultivars. It has been shown that the method has great advantages for the determination of those elements in date cultivars compared to the wet and dry ashing techniques.

Omar Rimawi and Ali El-Naqa
Transmissivity of aquifers is usually calculated by evaluating pumping test data. But due to the difficulty of carrying out such tests in addition to their relatively high costs, it is oftenly estimated from specific capacity data. In this article, an empirical relationship is derived using 116 pairs of transmissivity and specific capacity values which are obtained from pumping test analyses of groundwater wells penetrating a fractured Basalt Aquifer systems in two main groundwater basins in Jordan (Azraq and Zarqa Basins). Linear and logarithmic regression functions have been performed and has been found that the logarithmic relationship predicting transmissivity from specific capacity values data has a better correlation (r= 0.94) than the linear relationship (r=0.85). This relationship can be justified because transmissivity and specific capacity are lognormally distributed. The spatial distribution of transmissivity is affected only by the structural elements dominating the north-eastern part of Jordan as influenced by the rift formation since other hydrogeologic phenomena (such as karstification) similar to fractured carbonate rocks are not usually present in basalt

S.A. Awadalla and S.A. Gutub
Land drainage is a common practice in agricultural areas where excess water is to be drained to maintain the necessary wetting state for healthy plant roots and to prevent rotting. This requires an understanding of the infiltration process. Several researchers have dealt with the situation analytically and numerically. Their methods of solution varied according to their representation of the physical process of water percolation through soil. In this paper, an attempt is made to demonstrate the capability of a numerical model to describe the stratified drainage process. The output from the numerical analysis is compared with the analytical solution utilizing the Green and Ampt approach. The comparison shows good agreement especially during the early-stage of drainage.

A.A. Rokibah, T.M. Shehab El-Din and M.A. El-Meleigi
An experiment was conducted in 1990/91 and repeated in 1991/92 to the study the effects of Fusarium graminearum the causal agent of foot and root rot and N-level on wheat grain yield, yield components, plant height and heading date. Four nitrogen levels; 0, 138, 276 and 414 kg N/ha were applied to soils non infested or infested with the ungus. The presence of F. graminearum caused a remarkable root rot and significantly reduced wheat grain yield, yield components and plant height. On the other hand, heading date was not influenced by the fungal infection. N-level had significant effects on all studied characteristics in both seasons. The third level of N (276 kg/ha) maximized the grain yield. Concerning the interaction between the fungus and N-level, the highest grain yield losses were found when either higher N-level or no nitrogen were applied to wheat plants in the infested soil. The third and second N-levels were optimum in the non infested and infested soils, respectively. Based on these results the common assumption that application of high N-level to overcome wheat grain yield losses caused by foot and root rot disease is not justified.

Hayder A. Abdel Rahman, Salah A. Elias and Greg Baguhin
The effect of two irrigation frequencies (daily and every 3 days) and three water application rates (3, 6 and 9 mm/day) on the growth and yield of tomatoes were investigated under the relatively warm and humid winter conditions of Oman in the Gulf region. The three water application rates were 0.6, 1.2 and 1.8 times the reference evapotranspiration as computed by the Penman modified method, and corresponding to maximum soil moisture tensions of more than 100K Pa, less than 80K Pa and field capacity, respectively. Daily- and every 3-day irrigations did not produce any statistically detected effects on fruit weights, numbers, dry matter content and total yield or on root volume of tomatoes. Significant differences were obtained in total yield and fruit weights when the application rates were increased from 3 mm/day (0.6 ETo) to 6mm/day (1.2 ETo) with no significant increase in yield or fruit weight when further increasing the application rate of 9 mm/day (1.8 ETo). Maintaining less than 80 K Pa soil moisture tensions optimized yield and fruit numbers, whereas maintaining field capacity levels maximized fresh fruit weights. Fruit setting, percent dry matter and root weight and volume of tomatoes were not affected by any of the soil moisture regimes adopted.

Fouad S. Soliman
The efficiency of four herbicides, viz, isoproturon (arelone), methabenzthiazuron (tribunil), fenoxaprop-ethyl (puma) and a ready mix formulation of mecoprop/dichlorprop/MCPA (duplosan super) and some of their combinations in controlling weeds in wheat fields as well as their effect on grain yield and its components were studied at the Agricultural Research and Experimental Station of Dierab in seasons 1991 and 1992 in two different sites. The experimental sites were of loamy sand soil and were under sprinkler and central pivot irrigation system. The results of the study revealed that, Malva spp (common mallow) and Lolium rigidum (ryegrass) were the predominant weeds in the experimental area. Treatments of duplosan super at 3.5 and 2.5 L/ha; combinations of duplosan super (2.5 L/ha) with either tribunil (0.75 kg/ha), arelone (0.75 L/ha) or puma (2.5 L/ha); tribunil (1.5 kg/ha) showed to be most efficient in controlling broad-leaved weeds. Arelone (1.5 and 0.75 L/ha) and puma (3.5 and 2.5 L/ha), on the other hand, gave slight control of the grassy weed Lolium rigidum. The results also showed that duplosan super and its combinations as well as tribunil had significantly increased grain yield in wheat in the first site. On the other hand, duplosan super 2.5 L +puma 2.5 L/ha was the only treatment that significantly increased grain yield in wheat in the second season in the second site

Adnan Husain, Zainab Baroon, Sherif Al-Khalafawi, Tareq Al-Ati and Wajih Sawaya
The exploding and burning of Kuwait's oil fields resulted in significant environmental pollution. To assess the impact of this pollution on locally grown food, samples of fruits and vegetables were collected from local fields and home gardens 6-7 months after the start of the oil well fires. These foods were analyzed or their inorganic pollutant content (Ni, V, Pb, Cd) either by an atomic absorption spectrophotometer with a graphite furnace or by the cold vapor technique (Hg). Results showed that toxic metals were detected in a number of samples, but contamination did not exceed the maximum permissible concentration of metals in fresh fruits and vegetables as recommended by the FAO/WHO except for higher Hg, Cd, and Pb levels in the tissues of a few fruit and vegetables samples

Ibrahim B. Abou-Deya
The effect of irrigation intervals; 10, 20, 30 days and N fertilizer levels; 70, 140 and 210 kg N/ha on vegetative growth of Acacia cyclops A. Cunn. during 1990-1993 were studied at South-Sinai, Egypt. Salinity concentration in irrigation well water and the experimental soil were 6.8 and 9.7 mmhos/cm, respectively. Results revealed that irrigating plants by saline water every 10 days, significantly increased plant weight before full establishment. However, older plants (over 2 years age) produced the highest dry weight by expanding irrigation interval to 20 days. Gradual increasing in salt accumulation hindered growth development. Adding 210 kg N/ha in the form of ammonium sulphate, significantly enhanced plant height, foliage diameter and both fresh and dry weight of individual shrub.

F.Y. Al-Yamani and A.M. Fahmi
We present new records of ellobiopsid parasites (Ellobiopsis chattoni and Thalassomyces sp.) on 18 species of copepods from the Arabian Gulf. These constitute new host records for the copepod species, as well as new geographical records of the parasites. The parasites were observed and identified during a post oil-spill zooplankton survey of the northwestern waters of the Arabian Gulf. The monthly plankton survey covered 13 stations in Kuwaiti coastal waters in the period September 1991 through February 1992. Intensity of parasitism varied both temporally and spatially during our survey. The highest incidence of parasitism was noted during October 1991. Parasite preference regarding either host size or sex was not observed. Although the occurrence of the parasites cannot be directly linked to the oil spill, their presence might be an indication of environment stress.

Ali A. Al-Helal and I. Al-Hubashi
The effect of constant temperatures (20, 25, 30, 35 and 40°C) on the rate of seed germination was studied. Seed germination percentage was high at 20, 25, 30 and 35°C and was significantly reduced at 40°C. The rate of germination appeared to be best at 30 and 35°C. NaCl at 0.001 and 0.01 M had no effect on germination at the temperatures studied (25, 30 and 35°C). Seed germination tolerance to a higher salt concentration was temperature-dependent. 0.1 M had no effect at 25 and 30°C but inhibited germination significantly at 35°C. 0.2 M inhibited germination significantly at 30 and 35°C. 0.3 M inhibited germination significantly at all temperatures studied.