Irrigation, Drainage and Soil Salinity in Cracking Soils

A field evaluation of the impact of soil cracking on irrigation, drainage and soil salinity was conducted on a heavy clay soil in the Imperial Valley of California. Results of the evaluations identified that water movement within soil cracks controls the water application uniformity, soil profile wetting, salt leaching, and drain system response to irrigation. From observations of a linear advance trajectory of the border irrigated field, crack volume was estimated as 1600 m^/ha. Maximum water contents at depths of approximately 0.7 m immediately following irrigation appeared to correspond with the effective crack depth. Drain response to applied water occurred during the irrigation event despite extremely low permeability of the soil. Soil salinity exceeded drainwater salinity implying occurrence of minimal leaching. Impacts of soil cracking on irrigation-drainage system design are discussed in the context of future research.