Maximizing the Utilization of Rainwater for the Agricultural Use

In arid and semi-arid regions, where precipitation is low or infrequent during the dry season, it is necessary to store the maximum amount of rainwater during the wet season for use in the agriculture sector. Rainfall in the Kingdom of Saudi Arabia takes place primarily during winter and spring seasons. The amount of rainfall ranges from 0.1 to 0.2 m in the area extending from north of Riyadh to the vicinity of Hail. The shortage of rainfall, high soil water evaporation and deep-water percolation derived us to give great thought to the present study. One of the methods frequently used in rainwater harvesting is the storage of rainwater in situ. Mulching is the procedure usually used to reduce soil water evaporation. Soil compaction can lead to reduction for the deep-water percolation. Collecting the rainfall in situ, reducing the soil water evaporation and reducing the deep-water percolation simultaneously are our ultimate goals from this study. For achieving this study, several field plots in the Agriculture and Veterinary Faculty FarmAl-Qassim, King Saud University were selected. The dimension of such a plot was 3x5m and 1 m apart. For harvesting the rainfall or the sprinkler irrigation water effectively, a big metal drum with a notch was designed to dig coneholes in the soil surface to 0.1 m depth and 0.10 m I.D. The holes were 0.30 m apart. A single plant of faba bean was planted nearby the holes on 10 of October, 2003 in the winter season. Similarly, the corn and green bean were planted on 6 of April, 2004. To suppress water evaporation from the holes, three patterns were used. The first pattern was filling the hole with grass residue. In the second pattern, the holes were filled with rocks (5-20 mm diameter). The third pattern, the holes were covered with drilled black plastic (winter season) or white plastic (summer season) sheet. In addition to these treatments, planting nearby the holes and in flat plots were used too as treatments. Sprinkler irrigation system was used for irrigation when the rainfall was limited. Three replicates were assigned for each treatment. The growth and yield parameters were monitored during the growing season that lasted till 9 of March, 2004 during the winter season and 20 of July during the summer season. The growth rate of faba bean for the plastic treatment was 0.0095 m/day while it was 0.006 m/day for either the flat or grass residue treatments. The results of the final yield of faba bean followed the order: plastic> rock> grass> hole> flat treatments. The fresh weight of green bean followed the order: rock>plastic>hole>grass>flat treatments. In the corn experiment, all surface treatments gave greater ear yield than the yield of flat treatment. The results of this project validated soil surface management that positively Eleventh International Water Technology Conference, IWTC11 2007 Sharm El-Sheikh, Egypt impact crop yield and water conservation. Therefore, using the designed machine can enhance the soil water storage that lead to great yield of a crop.