In 1999, the efficacy of the treatments to control raspberry disease differed between the raised and flat beds at Pigman's Farm (Table 1). On raised beds, chicken manure produced the highest yield while on flat beds, horse manure produced the highest yield. Trichoderma produced the second highest yield on both raised and flat beds. Trichoderma appeared to have a beneficial effect in both the raised and flat bed rows, while chicken and horse manure appeared to work well in one or the other, but not both.
In 2000, fruit yield in raised beds was higher than on flat beds at Pigman's Farm, but this difference was not significant. Dairy and horse manure treatments produced the highest yields (significantly) at each site (Table 2). At Vancouver REU, yields in response to dairy manure, Trichoderma, and Gliocladium were comparable to yield in response to Ridomil. Manure + T-22 produced lower yield than manure or T-22 alone at both sites, indicating a possible negative interaction. Benefits of manure may be due to suppression of root rot pathogen and enhancement of beneficial fungi, as well as improved plant nutrition. There were no differences in root rot ratings of fruiting canes due to any of the treatments (Table 3). Fruiting canes at mid-harvest at Vancouver REU were chlorotic as compared to fruiting canes in adjacent conventional plots (Table 4). Plants began to show nitrogen stress symptoms in early June, when hot temperatures caused rapid plant growth.
Nitrogen stress was likely due to the slow release activity of the organic fertilizer (blood meal) under low soil temperatures in the spring. T-22 and G-41 produced the lowest photosynthetic rates in primocanes following harvest while primocanes in adjacent conventional plots had the highest rates.
Raspberry plots at Pigman's Produce are limited due to the overall size of the raspberry planting at this farm. Small plots have led to a lack in replications and we believe this has limited the scientific conclusions of this study at that location. To improve our on-farm experimental design, we will establish new on-farm plots with Sakuma Farms in Skagit County, Sakuma Farms have established 30 acres of 'transition to organic' raspberries and have made a portion of this planting available to us for this study.