Young secondary vegetation and soil interactions in Izabal, Guatemala

A study of the relationships of soils and vegetation was undertaken in the humid tropical region of Lake Izabal, Guatemala, Central America. Soils and associated 10-month-old secondary growth were analyzed for N, P, K, Ca, and Mg. In addition, organic matter, Al and pH were determined in the soil samples and plant biomass for the secondary growth were calculated. The secondary growth biomass averaged 9,710 kg/ha for the 10-month growth period. Total nutrient content of the vegetation increased linearly with the biomass, except for Mg. The antagonism of Mg on K and Ca nutrition was quite significant when Mg exceeded Ca in the soil under shifting cultivation. Pure stands of Heliconia sp. and Gynerium sp. appeared to be more efficient in accumulating P than stands of mixed vegetation. Chemical composition and dry matter production of native vegetation may provide additional information to evaluate soil fertility in the humid tropics.