Nutrient Uptake in Fertilized Plantations of American Sycamore1
- R. F. Wittwer,
- M. J. Immel and
- F. R. Ellingsworth2
Annual applications of ammonium nitrate (169 kg/ha elemental N), alone and in combination with concentrated superphosphate (112 kg/ha elemental P), increased biomass of 4- and 5-year-old American sycamore (Platanus occidentalis L.) by approximately 45 and 205% on a bottomland and a terrace site, respectively, in the Ohio River Valley region of western Kentucky. Growth response and nutrient contents of trees fertilized with N and P were not significantly different from those receiving N only. After 5 years, N fertilization has increased elemental content of aboveground tree components by 189% for N, 48% for P, 90% for K, 93% for Ca, and 106% for Mg. Initial spacing of the seedlings in these closely-spaced (0.3 by 0.9 m, 0.9 by 0.9 m, 1.8 by 0.9 m) trials did not have a significant effect on nutrient contents. Recovery of added N, as indicated by increased above ground tree contents after 5 years, represented 11 and 14% of the quantity added in fertilizer applications on the bottomland and terrace, respectively. After 5 years, levels of available P in soils receiving annual P fertilization had increased by 140 kg/ha, representing about 25% of the total P added. After 5 years exchangeable Ca had decreased in the bottomland soils and exchangeable K, Ca, and Mg had decreased in the less fertile terrace soil.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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