Water Harvesting Induced by Reduction of Both Evaporation and Deep Percolation of Water under Some Growing Crops

In arid and semi-arid regions where precipitation is low or infrequent during the dry season, it is necessary to store a maximum amount of rainwater during the wet season for use during the dry season in the agriculture sector. Rainfall in the northern section of Saudi Arabia ranges from 100 to 200 mm. The shortage of rainfall, the high soil water evaporation and the deep-water percolation are the main problems that face the agriculture in the area under study. So, this study aims to evaluate a new technique of water harvesting depending upon reducing both evaporation and deep percolation of water. Several field plots (3-m wide, 5-m length, and 1 m-apart each) in the Agriculture and Veterinary Faculty Farm, Qassim University, were selected to carry out this study. A big metal cylinder was designed to dig conical pits (0.10-m depth and 0.10-m inside diameter) in the soil surface. These pits were means for collecting the rainfall or the sprinkler irrigation water. The pits were 0.30 m apart. A single plant of faba bean (Vicia faba, L) was planted nearby the pits on October 10, 2003 (winter season). Similarly, corn (Zea mays, L) and green bean (Phaseolus vulgaris, L) plants were sown on April 6, 2004 (summer season). Five treatments were used for rainfall harvesting including flat soil surface (control), empty conical pits, conical pits filled with fresh grass residues, conical pits filled with gravels and conical pits covered after plant emergence by drilled black plastic (winter season) or white plastic (summer season) sheet. Sprinkler irrigation system was used to simulate the rainfall when it was limited. Three replications were assigned for each treatment. The growth and yield parameters were monitored during the growing season that lasted on March 9, 2004 (winter season) and on July 20, 2004 (summer season). The growth rate of faba bean (Vicia faba, L) for the plastic treatment was 9.5 mm/day while it was 5.9 mm/day for either the flat or grass residue treatment. The yield of faba bean (Vicia faba, L) decreased in the order of plastic> gravel> grass> pit> flat treatments. The fresh weight of green bean (Phaseolus vulgaris, L) showed a decrease in the order of gravel> plastic> pit> grass> flat treatments. In the corn (Zea mays, L) experiment, all treatments gave greater yield than that of the flat surface treatment (control). The results of this study validated that the soil surface management positively influences the crop yield and water conservation. Therefore, by using the designed machine, it can be seen the enhance of the soil water storage in situ leading to a great crop yield.