S. A. Al-Rawahy

Effect of salt stress on dry matter production and nitrogen uptake by tomatoes.

Abstract Dry matter yield and nitrogen (total and 15N) uptake of tomato plants (Lycopersicum esculentum Mill., cv. Columbia) subjected to saline stress by NaCl were studied in a greenhouse. The treatments consisted of low (control), medium (4 bars), and high (8 bars) salinity. The saline treatments were prepared by adding NaCl to culture solutions. The plants were 80 days old at the start of the 15N treatments and each was in a pot containing 1.8 kg of quartz sand. The 15N was provided to plants by adding K15NO3 to the pots and the 15N treatment period continued for 30 days. The plants were harvested at each 5‐day interval during the 15N treatment period. Dry matter production and nitrogen (total and 15N) uptake were significantly lower for the saline treatments as compared with the control. The significant difference in the above factors (dry matter production, total‐N, and 15N content of plants) was first noted on day 15 of the 15N treatment, and this difference continued to the end of the study period....

Impact of Treated Wastewater from Oil Extraction Process on Soil Physical Properties

Abstract Large quantities of water are usually produced in conjunction with oil production in Oman. Because this water is saline and heavily contaminated with oil, it is not suitable for domestic or agricultural uses. A short-duration comparative study on the effects of using treated oily-water and fresh water on soil physical properties has been performed. It was found from this study that the use of treated oily-water caused a sodicity problem, which has adverse effects on the soil physical properties of the soil such as infiltration rate, saturated hydraulic conductivity and pore size distribution. The reduction in the saturated hydraulic conductivity reached up to 43% of the initial value.

Effects of saline nutrient solutions on the growth and accumulation of mineral elements in some tomato cultivars

Abstract Tomato cultivars were grown in a saline nutrient culture system to investigate growth and fruiting responses in relation to the application of 3 mM potassium (K), 1.5 mM phosphorus (P), and 10 mM calcium (Ca). The deleterious effects of salinity on tomato stem growth and fruit yield were ameliorated following the addition of K, P, and Ca to the nutrient solution. Potassium levels in tomato leaves were increased 4‐fold compared to control plants in the presence of applied K. The use of K resulted in an increase in Na content, however, a comparatively low level of sodium (Na) was obtained in treatments receiving K, Ca, and P. Calcium content was greater than sufficiency levels in all treatments, whereas magnesium (Mg) declined with the increase in salinity. The amount of P in tomato leaves was increased 4–5 fold when the nutrient solution was supplemented with 1.5 mM P. Correlation of vegetative parameters, such as stem height and leaf growth to salinity, revealed no significant responses, however ...

Management of Saline Lands in Oman: Learning to Live with Salinity

Low rainfall, high temperature, and the past human activities resulted serious salinity problems in today’s agriculture in the Sultanate of Oman. Secondary soil salinity has increased rapidly due to the persistent use of saline groundwater, and the extent is increasing due to increased pumping in Batinah region. The balance existing between total pumping and annual recharge before the 1990s has been disturbed that has resulted in the reduction of crop yields and gradual abandoning of lands for agriculture. In addition, seawater intrusion due to overpumping also occurs. In the year 2005, about 18.9–36.0 × 106 US

Dry‐matter yield and nitrogen‐15, Na+, Cl‐, and K+ content of tomatoes under sodium chloride stress 1

was lost due to salinity. To tackle salinity problem, a project was undertaken at Sultan Qaboos University to mitigate soil and water salinity. The project focused on four approaches: soil rehabilitation, biosaline agriculture, fodder production, and integration of fish culture into crop production. The project was initiated with the objectives to develop scientifically sound and environment-friendly guidelines for farmers (a) to sustain cost-effective agricultural production in saline agriculture lands irrigated with saline groundwater, (b) to improve food security of Oman, and (c) to combat desertification in agricultural lands to avoid abandonment. The salt-tolerant varieties of tomatoes, barley, sorghum, and pearl millet have shown promising results for successful cultivation in saline soils. Surface mulching with a thin layer of shredded date palm residues resulted in lesser salt accumulation and more crop yield than other methods. The fodder grown in saline soils using saline irrigation water did not affect growth and meat quality of sheep fed with this fodder. The incorporation of aquaculture in saline areas was proven feasible and profitable.