干旱区生态环境知识资源中心

Atmospheric nitrogen input of about 1 622 g, m(-2) year(-1) is a major source of nitrogen for plants in the foredunes of Lake Huron at Pinery Provincial Park. The concentration of total nitrogen and nitrate nitrogen in the soil increased from the beach to the first and the second dune ridges. The south slopes of dune ridges contained greater available soil nitrogen Phosphorous from atmospheric deposition (0 016 g m(-2) year(-1)) was too low to meet the demands of grasses on both the first and second dune ridges. The source of phosphorous in sand dunes was primarily from the weathering of parent material in the soil pool. The total phosphorous pool in the soil did not change from the first to the second dune ridge primarily because of sand movement, erosion, and sand accretion. No relationship was found between decay rates and age of sand dune ridges After eight months of decay the loss of above- and below-ground biomass ranged from 27 to 39% in five habitats. The length of time for complete decomposition of above- and below-ground biomass ranged between 495 to 855 days. Nitrogen leaching loss was higher from the soil on the second dune ridge, while phosphorous leaching loss was higher on the first dune ridge. Proportionately less nitrogen was lost in leaching than phosphorous Even though nitrogen and phosphorous were present in low quantities, the plant species did not show any symptoms of deficiency.