Effective Use of Sub-Irrigation Water in Sandy Soil Using Barrier of Gravel and Porous-Alpha Layers.

Limited availability of water for irrigation can restrict growth and production in many crop-irrigated areas, and particularly in drylands area. Water supplies that rely solely on precipitation are often limited and erratic. Using barrier of gravel and porous-Alpha can be increasing the capillary and storage water in the root zoon. The objective of this study was to determine the effects of a porous-Alpha (recycled from used glass bottles) and gravel on water holding capacity and crop growth, in sandy soil assessed by growing Japanese Green Mizuna. The experiment was conducted and replicated four times in a sandy soil under a greenhouse condition using underground water irrigation system. Treatments consisted of porous-Alpha of 2 cm thickens and 10 cm thickens of gravel placed in 20 cm depth in the soil. The control soil received no treatment. Irrigation amount was 50 % of small pan evaporation. Water content was measured every 1hr by SM200 (Delta-t Co. Ltd.) at 18 and 25 cm depth. The water content was significantly differences; the average value was 0.12, 0.09, and 0.04 cm3 cm-3 for gravel, porous-Alpha, and control, respectively. Mizuna was grown well under gravel treatment. Fresh Mizuna yield was significantly differences (14.6 g/plant) as compared to other treatment. Thus, results demonstrated that the gravel was significantly difference fallowed by porous-Alpha indicating the possibility of these treatments to increase water capillary barrier and keep more water in root zoon. We also confirmed water movement in root zone with barrier of gravel and porous-Alpha layers using computer simulation.