Soil Moisture Dynamics of St. Augustinegrass Under Varying Irrigation.

Irrigation best management practices are critical for water conservation efforts in urban areas.  Previous research has defined appropriate crop coefficients for use in estimating plant water requirements of St. Augustinegrass (Stenotaphrum secundatum [Walt.] Kuntze).  The effects of irrigating at deficit levels on St. Augustinegrass lawn performance and soil moisture flux has been less well-documented.  Thus, a field study was initiated at the Texas A&M Turfgrass Field Laboratory in College Station, TX, to measure changes in soil moisture and turf quality of St. Augustinegrass as influenced by three levels of irrigation and three levels of nitrogen fertility.  Preliminary findings indicate severe deficit irrigation levels could sustain high quality turf when soils demonstrated high porosity, and water extraction was sustained deep in the soil profile.  High soil bulk density resulted in reduced water extraction rates which partly offset the reduction in plant available water.