Influence of vertical sand column and supplemental irrigation on barley yield in arid soils affected by surface crust

A field experiment was conducted during the 1996/1997 season at the University of Jordan Research Station near Al-Muwaqqar village to investigate the effects of sand columns, sand column spacing, soil ridges, and supplemental irrigation on soil water storage, redistribution, and barley yields. The experimental site represents a typical Jordanian arid environmental soil suffering from surface crust formation overlaying impermeable material. In the 600-mm-depth soil profile, soil water storage was improved significantly by 59%, 45%, and 38% in the l-m, 2-m, and 3-m sand column spacing treatments, respectively, compared with soil water storage in the control treatment (no sand columns). Sand columns increased the moisture stored in all four soil layers (0-150, 150-300, 300-450, and 450-600 mm). Moisture stored in the 450-600 mm soil layer increased significantly by about 188%, 147%, 88%, and 29% in the I-In, 2-m, 3-m, and 4-m sand column spacing treatments, respectively, compared with moisture stored in the same soil layer of the control treatment. Increasing soil water storage also increased barley consumptive use significantly from 130 mm in the control treatment to an average of about 185 mm in sand column treatments. Without supplemental irrigation, barley grain and straw yields were negligible and almost zero. Barley yields in the control treatment, with 167 mm supplemental irrigation were low, being 0.19 ton/ha and 1.09 ton/ha of barley grain and straw, respectively. Sand columns increased bar ley grain and straw yields significantly compared with the control treatment to a maximum of 0.68 ton/ha and 3.97 ton/ha, respectively, with the l-m sand column spacing. Soil ridges perpendicular to the land slope had no significant effect on increasing soil water storage due to lateral runoff and loss along the ridge. In general, sand col columns minimize surface runoff and evaporation by allowing water to infiltration through the strong surface crust. Sand columns act as a sink for surface water, enhance subsurface lateral water movement, and reduce the possibility of surface crust formation in the vicinity of the sand column opening by preventing surface pending.