A SURVEY OF SEVERAL SOIL PHYSICAL CHARACTERISTICS OF CULTIVATED CRANBERRY BOG SOILS IN NORTH-AMERICA

Cranberries (Vaccinium macrocarpon Ait.) historically have been established on peat based soils and, in most cases, are treated every three to five years with a 1-4 cm layer of sand. A total of 46 soil samples from cranberry bogs in five states [Massachusetts (MA), New Jersey (NJ), Oregon (OR), Washington (WA), and Wisconsin (WI)] and one Canadian province [British Columbia (BC)] were collected and analyzed for bulk density, particle density, and percent organic carbon to assess the range of these characteristics which have resulted from management practices. Soil bulk densities ranged from 0.16 to 1.40 Mg/m3, particle densities from 0.71 to 2.45 Mg/m3, and organic carbon from 1.3 to 95. 2%. The wide ranges reflect the differences between non-sanded and regularly sanded bogs. The low end of density and high end of organic C were found in the non-sanded bogs, which were located in WA and BC. The bogs from the other areas had higher average bulk and particle density levels, approximately 1 and 1.7 Mg/m3, respectively. content. Soil bulk density was generally highest for NT at planting, however, the bulk density for CP and MP increased later in the season attaining values comparable to those of NT treatment. Chiseling and moldboard plowing reduced soil aggregate stability. Soil temperature at planting was lower for no-tillage compared to the moldboard plowed system. Effects of tillage on pore size distribution, for the first two years of the experiment, were significant only at planting. Total porosity was higher for MP than CP and NT in both years. At midseason, 1991, total porosity was lower with MP than with NT and CP. The improved NT crop performance relative to the CP and MP treatments could also be related to better seed bed and root bed conditions following soybean (third year) than sod (first year) and better weed control. Initial crop yield advantages of MP over the conservation tillage systems (NT and CP) deteriorated over time, resulting in decreased soil aggregation, total porosity and soil productivity.