The amount and mineral nutrient content of freshly fallen leaf litter in the hardwood forests of central New York

The amount of dry matter deposited annually by hardwood forest tree leaf litter in closed, second-growth stands in central New York ranged from 2,425 to 3,020 pounds per acre. The more productive soils judged from agricultural crop yields tended to produce somewhat more leaf litter. The differences were not large, however, the maximum between the lowest and highest soil type being only 236 pounds per acre. The nitrogen and calcium content of the leaves on a percentage basis was not significantly different on the more productive and less productive soil types. The magnesium content was higher, while the phosphorus and potassium contents were lower on the more productive soils. Species whose leaf litter was high in nitrogen content are basswood, hop hornbeam, aspen, American elm, sweet cherry, and black birch. Sugar maple and red maple had a low nitrogen content. The highest phosphorus content was exhibited by cucumber tree, black cherry, basswood and white ash while aspen hop hornbeam beech, red maple, and red oak were rather low in this respect. The potassium content of the leaf litter was the least consistent by species, the content apparently being determined more by soil type. However, tulip poplar sweet cherry, cucumber tree, black cherry, and red oak seemed to be rather high in potassium content. The calcium content of the litter was high in the case of the bitternut hickory basswood, black cherry, tulip poplar, white ash, and aspen. The lowest calcium content was found in beech, white oak, red oak, and red maple. The magnesium content proved to be highest in the case of bitternut hickory, basswood, black cherry, and tulip popular. The lowest magnesium contents occurred in beech, white oak, aspen and sugar maple. Some rather distinct differences in species composition existed on the various soil types. The more calcareous and fertile Ontario Dunkirk, and Lansing soils were higher in the proportion of basswood present, while the acid Lordstown soils had very large amounts of sugar maple, red oak and beech with few basswood. The differences in the average mineral nutrient content of the leaf litter falling on a given area were caused more by the inherent differences in the normal nutrient content of the litter of the various individual species than by the influence of the soil type upon the mineral nutrient content of a given species. Potassium proved to be a partial exception to this statement. The average calcium content of the litter was closely correlated with the pH of the surface soil. This, again was caused by differences in proportion of tree species present rather than by any one species absorbing more calcium on the high-calcium soils. It was demonstrated in the case of the sugar maple, however, that if the pH of the surface soil is below 4.5, there may be a direct relationship between soil pH and calcium content of foliage. The actual amount of the essential nutrients returned to the soil was calculated. The average figures expressed as pounds per acre of the elements are as follows: Nitrogen, 16.6 pounds; phosphorus, 3.3 pounds; potassium, 13.5 pounds; calcium, 65.6 pounds; and magnesium, 9.2 pounds.