| Trials were conducted over three years to determine the effects of spring applications of compost and a soy and blood meal based organic fertilizer on soil fertility and production of three varieties of primocane fruiting raspberries in multi-bay high tunnels. In the first year, compost and fertilizer were incorporated into the rows at two rates prior to planting. All treatments resulted in initially high levels of total inorganic nitrogen (N) (≥80 mg kg-1), and levels appeared consistent with initial application rates. Soil salinity in the top soil of the high compost treatment was excessive after the first season, with an EC of 1.22 dS m-1 directly beneath the drip irrigation line. Removing the plastic during winter and exposing the soil to precipitation significantly reduced soil salinity. In the second and third seasons, compost and fertilizer were top dressed over the row in spring, about a month before the tunnels were covered with plastic. This resulted in much lower levels of total inorganic-N than in year one when the compost and fertilizer were incorporated. There were significant differences in total soil inorganic-N and leaf nutrient levels between treatments when they were top dressed, with the high rate of organic fertilizer supplying more soil N and increasing leaf N levels. However, berry yields were not affected by treatments, possibly because plants were deficient in other nutrients. Results indicate that top dressing with solid organic fertilizers does not supply adequate nutrition to raspberries in high tunnels since nutrients appear to remain on the surface instead of being leached into the root zone by early-spring precipitation or drip irrigation. |
