EFFECTS OF INTENSIVE POTATO PRODUCTION ON SOIL QUALITY AND YIELD AT ABENCHMARK SITE IN NEW-BRUNSWICK

The cumulative extent of soil redistribution by erosion and tillage wa s measured by comparing the Cs-137 content of a soil under intensive p otato production with that of an undisturbed forest soil. Soil redistr ibution rates estimated from Cs-137 contents for the cultivated site v aried from a loss of as high as 19.0 kg m-2 year-1 (190 t ha-1 year-1) to a gain of as much as 4.3 kg m-2 year-1 (43 t ha-1 year-1), with an average of 5.3 kg m-2 year-1 (53 t ha-1 year-1) soil loss. Measured s oit Cs-137 content and calculated soil loss (and deposition) were both found to be correlated with total potato yield (P<0.01), and with tub er specific gravity (P<0.05), in the two years of yield measurements ( 1991 and 1992). These years had near normal growing season precipitati on, but contrasting distribution patterns of precipitation during the growing season. Estimated soil loss and gain were also correlated (P<0 .01) with soil organic carbon and soil phosphorus contents. It is conc luded that soil redistribution within the site, caused by either water erosion or tillage, or a combination of both these processes, had a m arked effect on soil productivity.