Central Florida Blueberries: Management Of Water In Pine-Bark Amended Soil.

Saturated hydraulic conductivity (K_sat) of central Florida sandy ridge soil is about 90 cm h^-1.  When amended with coarse pine bark, the K_sat can increase by two to five folds.  Efficiency of irrigation in blueberry produced in this region, denoted as a ratio of the sum of water used in irrigation and effective rainfall to reference evapotranspiration under drip irrigation, was between 4 and 6.  A ratio of 1.0 to 1.5 may indicate irrigations are efficient.  The reasons for the excessive use of water are a) very frequent irrigations to keep the soil consistently moist, b) continuous overnight irrigation with a large quantity of water during freezing nights, and c) less effective use of heavy rainfall.  The water holding capacity of the sandy native soil and the amended soil is very low. During the wet season (June to end of October), growers irrigated 9 to 14 mm d^-1 (2 to 6 irrigation pulses of 12 to 20-min duration).  The bulk of the water from freeze protection irrigation, heavy rainfalls, and excessive regular irrigations can move below the root zone very quickly because of the very high K_sat and the low water holding capacity. Agrochemicals are therefore vulnerable to leaching and may end up in the groundwater. About 90% of Florida’s drinking water comes from groundwater.