Landscape Irrigation Audit Guidelines

ƒƒ 1Landscape Irrigation Audit Guidelines Irrigation Water Management (IWM) is applying water according to crop needs in an amount that can be stored in the plant root zone. When to irrigate? • When soil moisture is depleted 30-50%, depending on time of year. How long to irrigate? • Time it takes to refill the root-zone. How much water should be applied? • Generally ¼” – ½” on turf grass, depending on depth of root-zone. How often to irrigate? • 1-2 times per week depending on time of year. (depending on age of planting) • According to long-term behavior of the irrigated turf. Available Water Capacity (AWC) is the portion of water in a soil that can be readily absorbed by plant roots of a crop. Soil moisture depletion is the amount of water required to raise the content of the crop root-zone to field capacity. Field capacity is the amount of water a well drained soil holds after free water has drained because of gravity. • For a coarse textured soil, drainage occurs soon after irrigation (or rain) because of relatively large pores and low soil particle surface tension. • In fine textured soil, drainage takes much longer because of smaller pores. • Major soil properties that affect field capacity are texture, structure, bulk density and strata within the profile that restrict water movement. • Generally fine textured soils can hold more water than course textured soil. • Soils with large amounts of organic matter hold water ...