No abstract

Al-Ahsa Oasis is one of the main and oldest agricultural centers in Saudi Arabia and one of the largest natural oases in the world. It is the largest irrigated agricultural oasis worldwide. The cultivated area is about 12,000 hectares in the region of Al-Ahsa. Groundwater was considered the main water source, if not the only source, for the different purposes of Al-Ahsa Oasis. However, due to groundwater depletion from these aquifers, treated wastewater is currently used to meet the shortage of irrigation water at Al-Ahsa Oasis. Today, several problems affect the agricultural productivity at Al-Ahsa Oasis, and modern geophysical techniques could contribute effectively to solving these problems; such problems are increasing soil salinity and the existence of a hardpan layer in some parts of the Al-Ahsa oasis. The soil texture is considered a critical factor to be taken into consideration. Therefore, the objectives of this study were to evaluate the effectiveness of modern geophysical techniques to study the agricultural aspects of Al-Ahsa oasis. Ten profiles of 2-D electrical tomography using SuperSting R8/IP 8 channel multielectrode resistivity and IP imaging system with 112 electrodes at one-meter spacing were implemented. Moreover, twenty electrical conductivity profiles were measured of 2240 points using EM38-MK2 at vertical mode with transmitter–receiver coils of 0.5 and one meter spacing. The results indicated that the salinity variation along the measured profiles was changed vertically and laterally due to the changes in the soil type, texture, moisture content, sabkha, and the whole oasis. Analysis and interpretation of the interpreted resistively tomograms of the ten 2-D profiles indicate remarkably the different geoelectric units of different hydrogeological conditions and soil texture across the oasis. These results will be of good utility for farmers, development sectors, and research institutions, especially in agriculture development studies, at Al-Ahsa Oasis, to ensure the sustainability of agriculture in this important historical Oasis.

Three irrigation water regimes for wheat cv Bro bread, viz. 100%, 80% and 60% ETc were used over three successive seasons (2009/10, 2010/11 and 2011/12) at the Agricultural and Veterinary Research Station of King Faisal University using a randomized complete block design with three replicates. Data were collected on different parameters pertaining to crop agronomic and yield attributes viz. plant population and height, number of tillers, leaf area index (LAI), number of spikelets and grains/spike, 1000-grains weight, harvest index (HI) and total grain yield; as well as water use efficiency (WUE). Obtained results revealed that, watering regime of 60% ETc was statistically (P  0.05) inferior in terms of almost all the prescribed parameters. 100% and 80% ETc watering regimes were statistically similar in comparison to their corresponding treatments in all seasons. In addition, the obtained results showed that averaged of watering regime viz. 100, 80 and 60% ETc were 2.90, 2.73 and 2.03 t/ha, respectively. WUE was recorded the highest values (0.42) at 80% ETc watering regime, whereas the lowest (0.36) at 100% ETc.

No abstract

No abstract