Contribución del agua de lluvia en la oferta de nutrientes minerales para Eucalyptus grandis

Abstract

Incident precipitation, throughfall and stemflow under a Eucalyptus grandis stand were collected and their chemical composition was analysed to quantify nutrient accretion to the soi! by precipitation during a 12 month period from November 1992 through October 1993. The stand was stablished in the State of São Paulo, Brazil, in 1991 after applications of pulp residues and ash. Throughfall and stemflow were generally richer in K, Ca, Mg and S04 but very poor in P and N probably due to the direct absorption of the latter by the canopy. The same was observed with K but only in the plot that received no pulp residue or ash. This paper summarizes the results of the present nutrient input study, correlating it with the nutrient requirement of E. grandis. RESUMEN Este trabajo evalúa la contribución de las lluvias en nutrientes minerales en el período de noviembre de 1992 hasta octubre de 1993, en plantaciones de Eucalyptus grandis abonadas con fertilizantes minerales y con residuos de celulosa y de ceniza de cal dera en el Estado de São Paulo, Brasil. Para la captación deI agua de precipitación, fueron instalados colectores en área abierta, sin Eucalyptus, y para la evaluación de la precipitación efectiva, debajo de las copas de los árboles. Se observó que después de la circulación por la copa y tronco de los árboles, el agua de lluvia presentó mayores cantidades de potasio, calcio, magnesio y sulfato. Por otra parte, nitrógeno y fósforo presentaron, por regIa general, menores cantidades, indicando una posible absorción, principalmente deI nitrógeno, directamente en el doseI arbóreo. Para el potasio hay una disminución en su cantidad en el agua de lluvia, después que ésta atraviesa la cubierta forestal, en el tratamiento que recibió menor cantidad de nutrientes en la fertilización.

Evaluation of the throughfall and stemflow nutrient contents in mixed and pure plantations of Acacia mangium, Pseudosamenea guachapele and Eucalyptus grandis

“…In this work, the inputs of calcium from rainfall (6.74 kg.ha -1 .year -1 ) to soil were lower than that found by others authors (GOLLEY et al, 1978;LIMA, 1993;JORDAN, 1982). Similar quantities due to rainfall were detected by Andrade et al (1995) (5.09 kg.ha -1 .year -1 ) in Rio de Janeiro (near the sea).…”

“…Differences in nutrient inputs for each plantation could be attributed to their nutrient status, as considered by Andrade et al (1995). In the present experiment, higher quantities of Ca +2 were added by stemflow in eucalyptus than by other species, and the N-NH 4 + , P and Na + contents in mangium stemflow were higher than from all other species.…”

“…Compared to this work, Andrade et al (1995) in Mogi-Guaçu, São Paulo State, reported N inputs (by rainfall) 1.6 times higher (5.32 kg.ha -1 .year -1 ) and similar quantities of P (1.20 kg.ha -1 .year -1 ) and about 5.3 kg.ha -1 .year -1 of K. The P input found (0.95 kg.ha -1 .year -1 ) is also 1.6 times higher than that reported by Golley et al (1978) (0.6 kg.ha -1 .year -1 ) in a Tropical Humid Forest in Panama.…”

“…Rainfall and throughfall, entering each stand, were collected by nine 15 cm diameter polyethylene funnels (REICHARDT, 1990) connected by tubes to two-liter polyethylene containers. Stemflow samples were collected by a special collector made with polyurethane foam (BALIEIRO et al, 2001) placed at breast height, directing the water to 54-liter polyethylene containers. No biocides were added to the collectors, but they were washed with chloric acid solution 3%, followed by washing with distilled water.…”

“…Several factors such as canopy architecture , leaf area index, density and structure of plantation, rainfall intensity and raindrop size can be responsible for differences in the magnitude of this interaction "rainfallforest" (OPAKUNLE, 1989;LEITE et al, 1999;CALDER, 1998;ARCOVA et al, 2003), whereas geographical location (ANDRADE et al, 1995;LACLAU et al, 2003), proximity to industrial zones, urban centers or marine areas (GOLLEY et al, 1978;LACLAU et al, 2003) and burning occurrence (LIMA, 1979) are the others related to water composition.…”