Best irrigation management practice

MODULE 2: BEST MANAGEMENT PRACTICES FOR NUTRIENT MANAGEMENT OF TURF Irrigation Management to Prevent Nutrient Transport with Runoff and Leaching   Over-irrigation may be the most important factor that results in excessive N leaching and more P runoff from turf during the growing season. Irrigation should be managed to keep the soil dry to moist (not wet) so that water will infiltrate and be stored in the soil rather than runoff or leach through the root zone. Turf areas that are irrigated to maintain relatively wet topsoil requires less rain to generate runoff or leaching. Conversely, a drier topsoil absorbs more rain, which reduces runoff and leaching. Thus, irrigation should be managed so that the soil is capable of infiltrating water and storing low to moderate intensity rainfall. If light to moderate rain routinely generate runoff from an irrigated turf, too much water is being applied through irrigation. The run time and/or frequency of irrigation should be reduced. Moreover, irrigation itself should not generate runoff or ponding of water. Use hand-held irrigation methods whenever feasible to manage small, localized dryness in turf rather than automatic irrigation systems to avoid over-application of water. Irrigate turf as needed based on weather (evapotranspiration) and soil water availability and not on a calendar/clock schedule.If access to data from a weather station is not feasible, the Northeast Climate Center summarizes weather data for New Jersey and other states, which can be used to estimate the need for irrigation. Estimates will be better if you have data from a local rain gauge to refine the estimated need for irrigation. Irrigation controller technology should be optimized to ensure efficient application of irrigation water. Rainfall sensors on shutoff valves should be used with irrigation systems to avoid excessive application of water that would result in runoff or leaching. Avoid irrigation during times of high humidity and early evening hours (before turf wets with dew) to discourage the incidence of turf disease. Avoid automatic irrigation during dry, windy conditions to limit evaporation losses and non-uniform irrigation coverage. After fertilization: Irrigate lightly (< ½ inch) after fertilizer is applied to wash it into the soil and promote nutrient uptake by turf. Irrigation intensity should be low enough to allow infiltration and not produce ponding or runoff. When feasible, direct surface water runoff to catch basins or ponds that recycle water back to irrigation holding ponds, rain gardens, or bioretention basins. More detailed descriptions of irrigation management are available in Rutgers Cooperative Extension publications, FS555, Best Management Practices for Watering Lawns and E278, Best Management Practices for Irrigating Golf Course Turf.