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

Cranberries (Vaccinium macrocarpon Ait.) historically have been establ ished 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 ra nge of these characteristics which have resulted from management pract ices. Soil bulk densities ranged from 0.16 to 1.40 Mg/m3, particle den sities 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 regula rly 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 bo gs from the other areas had higher average bulk and particle density l evels, approximately 1 and 1.7 Mg/m3, respectively. content. Soil bulk density was generally highest for NT at planting, however, the bulk d ensity for CP and MP increased later in the season attaining values co mparable to those of NT treatment. Chiseling and moldboard plowing red uced soil aggregate stability. Soil temperature at planting was lower for no-tillage compared to the moldboard plowed system. Effects of til lage on pore size distribution, for the first two years of the experim ent, were significant only at planting. Total porosity was higher for MP than CP and NT in both years. At midseason, 1991, total porosity wa s 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 s eed bed and root bed conditions following soybean (third year) than so d (first year) and better weed control. Initial crop yield advantages of MP over the conservation tillage systems (NT and CP) deteriorated o ver time, resulting in decreased soil aggregation, total porosity and soil productivity.