2002 soil and weed survey conducted on Saskatchewan organic cropland
A soil survey and a weed survey were conducted on 5% of the organic farms in Saskatchewan, in the four major agricultural eco-regions in the 2002. Soil tests were taken in April and May prior to planting. Phosphorus levels were deficient in all regions. Nitrogen and sulphur varied between fields but were lowest over all in the boreal transition eco-region. Potassium was high in all regions. The weed surveys were conducted in July on the same fields as the soil survey. The most abundant species was green foxtail (Setaria virids (L.) Beauv.), wild oats was the fourth most abundant and the seventh most abundant species was Canada thistle (Cirsium arvense (L.) Scop.). Annual broad-leaved weeds were the most common weed group in the survey. Buckwheat (Polygonum convolvulus L.), lamb’s quarters (Chenopodium album L.), stinkweed (Thlaspi arvense L.), and wild mustard (Sinapis arvensis L.) were four of the six most abundant weeds in the organic survey. These results are opposite to the trend seen in conventional production where annual broad-leaves have become less abundant according to the surveys conducted from 1976 to 1995 (Thomas, 1996).
organic farming, weed abundance, soil nutrients
Soils and Crops Workshop