Nutrient Content of Canopy Throughfall in Three Minnesota Forests

Calcium, magnesium, nitrogen and phosphorus were measured in throughfall of an oak, marginal fen, and white cedar swamp forest in east-central Minnesota, U. S.A. Annual totals of calcium in throughfall of the oak, fen and swamp forest were 7.6, 10.5, and 10.7 kg/ha respectively. Totals for magnesium were 3.1, 3.8 and 3.7; for ammonia and organic-nitrogen, 5.5, 5.5, and 6.0; and for phosphorus, 0.7, 0.6, and 0.5 kg/ha. These totals were comparable with data in the literature. Calcium depositions in throughfall as per cents of the sum of throughfall and litter fall were 13, 10, and 10 per cent in the oak, fen and swamp forests respectively. Similar percentages for magnesium were 23, 22, and 23; for nitrogen, 11, 10, and 12; and for phosphorus, 11, 8, and 7.