Effect of Peat Moss-Based Organic Material Mixtures On Soil pH, Growth and Fruit Quality of Highbush Blueberry Plants

These three consecutive year studies were conducted to evaluate the mixed use of peat moss (PM) with other organic material such as pine needle (PN), rice husk (RH) and sawdust (SD) for blueberry production in Korea, as a way to cut down the production cost due to the relatively expensive PM that is totally imported to Korea. In spring of 2006, two-year old 'Duke' blueberry nursery plants were transplanted into the field soil. In root zone, the following PM-based organic material mixtures were incorporated: 20 L PM only, 10 L PM + 10 L PN, 10 L PM + 10 L RH and 10 L PM + 10 L SD. Before planting, 1000 kg cow manure, 160 kg sulfur and 20 kg compound fertilizer (N-P-K: 30-25-25) per 10a were incorporated into the soil, then rotary-tilled. Soil pH measured right after planting ranged from 5.3 to 5.9 and was lower in PM only and PM + PN than PM + RH and SD treatments. In the third year, the pH lowered to the range of 4.2 to 4.5, with PM only and PM + PN still maintaining lower values. Vegetative growth was maintained better in PM only and PM + PN, and the number of flower cluster and yield were also slightly higher in those treatments while mean fruit weight was similar among all treatments. Fruit quality was unaffected as total soluble solid, titratable acidity and firmness were measured. These results suggest that relatively cheaper organic material such as PN, RH and SD may relieve in part the total dependence of blueberry production in Korea on the PM and thus cut down the production cost.