NUTRIENT AVAILABILITY AND FOLIAR NUTRIENT STATUS OF SUGAR MAPLE SAPLINGS FOLLOWING FERTILIZATION

Foliar analysis of maple sugar (Acer saccharum Marsh.) saplings having low foliar K (5.4 g kg-1) and P (1.2 g kg-1) was carried out for 3 yr to investigate the effects of a single application of fertilizer P tr iple superphosphate [TSP], K (K2SO4) and Ca [Ca(OH)2]. Also, soil, wat er-saturated soil extract, resin sacks buried in situ, and lysimeter s olution analysis methods were used. Potassium and P additions signific antly increased foliar K (1.81 g kg-1 increase) and P (0.25 g kg-1 inc rease) for the 3 yr that the observations were conducted. Calcium addi tion had no effect on foliar element concentrations. A Diagnosis and R ecommendation Integrated System (DRIS) analysis corroborated the folia r analysis: K indices increased with increased K fertilization (from - 47 to - 23) and P indices increased with increased P fertilization (f rom -25 to -15). Calcium application significantly increased the effec tive cation-exchange capacity (CEC), exchangeable Ca and Mg and water- extractable Ca and decreased the acidity in the rooting zone for a 3-y r period. Conventional soil analysis and resin sacks detected signific ant effects of P and K fertilizers on their respective elements. Howev er, these effects did not last more than 2 yr after fertilizer applica tion in the surface soil horizon (Ah). Lysimeter solution analysis sho wed that K2SO4 fertilizer caused short-term increases in SO4 and Ca le aching. The duration of fertilizer P and K on foliar nutrition and the behavior of soil nutrients suggested that biochemical cycles are impo rtant mechanisms perpetuating fertilizer effects.