In central Florida, blueberries are raised in 30-cm high pine bark beds over native sandy soil. Despite having a high C:N ratio (300:1), pine bark continually degrades to less than 15 cm in less than 5 years. This degradation is due to high doses of nitrogen fertilizer and high summer temperatures coupled with frequent irrigations and summer rainfall. A constant irrigation schedule over five years is not helpful as blueberry root-zone depth decreases continually reducing plant available water.
In a paper recently published in Soil Science Society of America Journal, researches reported how physical and hydraulic properties dynamically changed as pine bark degraded over 5-years in two blueberry farms representing two soil drainage classes in central Florida and the role of soil water sensors in determining these changes reliably.
Field capacity water content (θfc) increased from 7 to 21% in 2 years. After which θfc remained constant, attributed to the lack of change in capillary size porosity as pine bark progressively degraded.
Knowledge of these processes is imperative to reduce excessive irrigations and minimize nitrate leaching to ground water as the main source of drinking water comes from aquifers.
Read the full paper in SSSAJ. Free preview March 30 - April 6