Soil water uptake efficiency of some irrigated indigenous and exotic forage species under gcc desert climatic conditions

The desert environment of the Gulf countries is characterized by high temperatures and limited water resources. Agriculture is by far the largest water user; most of it is used for production of fodder crops. Exotic fodder species, especially Rhodes grass (Chloris gayana) is the dominant forage plant grown. This species is poorly adapted to the harsh environment and consumes substantial amounts of water. This study was designed to compare indigenous forage species to Rhodes grass with regard to their ability to utilize water from deep soil layers. Four indigenous forage species were tested; these were Cenchrus cilliaris, Panicum turgidum, Lassiurus scindicus and Coelachyrum piercie together with Rhodes grass in a randomized design with 3 replications. The irrigation regimes tested were; application of the full crop requirement; 50% above and 50% below crop requirement. Water extraction was monitored daily in two soil layers (0-30 and 30-60 cm) using Time Domain Refractrometry (TDR). Result indicated that, except under Cenchrus ciliaris, residual soil moisture was high in the subsoil layer indicating poor extraction of water from this layer under limited water conditions. Cenchrus ciliaris however, was significantly different in extracting subsoil moisture, indicating high adaptation to water deficit conditions. There were small differences in water extraction mode when irrigation water is not limited. This study recommended the expansion in indigenous forage species especially Cenchrus ciliaris at the expense of the exotic species under current water resources of the Gulf region.