Note to readers, attached is the complete final report for FNE96-142
Phytophthora root rot is a common disease of cranberries, as of many other crops. The Phytophthora fungus thrives in moist soils; consequently a sensible way to fight this disease is to improve drainage. Mr. Lee, along with Dr. Peter Oudemans of the Rutgers Blueberry and Cranberry Research Station, devised an experiment to compare the efficacy of several methods of improving soil drainage.
They laid out twenty plots, each measuring 15 feet by 15 feet, in a portion of Mr. Lee’s cranberry bog that had been observed to retain standing water for several hours following rainfall or irrigation. The following treatments were applied, 1) ditches 6 inches wide and 15 feet long were dug across five of the plots, 2) 15 feet of perforated pipe was buried at a depth of 14 inches under each of five other plots, and 3) three ditches, each 15 feet long, 6 inches wide, and 4 feet deep were dug across five other plots and refilled, thus breaking up the soil horizonation and homogenizing the material. All ditches and pipes emptied into a system of buried pipes which drained water from the plots. Five plots received no treatment.
The amount of standing water on the plots was assessed visually, following several irrigation events. An aerial infrared photograph of the plots was taken following one such event. The visual assessments showed that homogenization was by far the best treatment; this conclusion is quite dramatically borne out by the aerial photograph. The comparison is somewhat flawed, however, because the homogenization involved three deep ditches, totaling 45 linear feet per plot, while the other plots received only a single ditch or pipe 15 feet in length, and did not go nearly as deep.
Mr. Lee concludes that at a cost of approximately 25¢ per foot, deep homogenization is an economically feasible means of improving drainage on cranberry bogs.