Exporta??o de macronutrientes em cultivos comerciais de bambu no tabuleiro costeiro do estado da Paraíba

摘要

Samples of soil and bamboo chips (Bambusa vulgaris) 11 months in age (regrowth) were collected at commercial sites, located in the state of Paraíba (Brazil), aiming to evaluate the stem and branch biomass production, and the content and export of nutrients. The soil was analyzed for fertility and chips had analytical determinations made of mineral nutrients. The export quantity of each nutrient was calculated by multiplying the amount contained in the chip, by the chip productivity of each plot. The chip productivity, in tons per hectare was estimated by multiplying the measured yield of each plot, by the conversion factor derived from the relationship between the area of one hectare and the area of each plot. The soil of the Mamoaba farm showed Na, K, P, Fe, Zn and Mn content higher than the soil from the Garapu farm. The content of organic matter in the soil followed this order: Garapu 2 > Garapu 1 > Mamoaba. The Garapu farm had higher productivity than the Mamoaba farm, probably due to the higher rainfall at Garapu farm. The analyzed chips exported roughly twice as much K than N. P and S were the macronutrients less exported by bamboo. The macronutrient contents and exportations followed the same ratio for all sites studied: K>N>Ca>Mg>P>S. The fertilization programs for the studied species of bamboo have to prioritize the supply of nitrogen, potassium and calcium.