Storage and Flux of Nutrients in a Dry Tropical Forest in India

Abstract

Storage and flux of N, P, Ca, K and Na were studied in a dry tropical forest. The nutrient concentrations in different growth forms were in the order: herb > shrub > tree, whereas the standing state of nutrients followed the order: tree > shrub > herb. The total storage (kg ha(-1)) in vegetation amounted to 567 N, 37 P, 278 Ca, 256 K and 46 Na. The share of above-ground parts in vegetation storage was 82% for N, 83% for P, 76% for Ca, 85% for K and 79% for Na. From 56 to 71% of foliar N, P and K was withdrawn during senescence. Nutrient input (kg ha(-1) year(-1)) from the vegetation (above-ground + below-ground) to forest floor amounted to 115 N, 8 P, 62 Ca, 38 K and 10 Na compared to total net annual uptake (kg ha(-1)) of 143 N, 10 P, 78 Ca, 52 K and 12 Na, indicating marginal accumulation in the system. Fine roots were as important a pathway of nutrient return as leaf litter. Turnover rate and turnover time for different nutrients on the forest floor ranged, respectively, between 72 and 83% and 1.2 and 1.39 years.