Levy Paes Barreto

Características físicas e químicas de substratos à base de pó de coco e resíduo de sisal para produção de mudas de sabiá (Mimosa caesalpiniaefolia Benth)

O experimento foi instalado com o objetivo de analisar as caracteristicas fisicas e quimicas ocorridas em substratos com diferentes concentracoes de po de coco (PC), residuo de sisal (RS) e Argissolo Vermelho- Amarelo distrofico (Arg), no crescimento de mudas de sabia (Mimosa caesalpiniaefolia Benth), produzidas em recipientes com capacidade para 2 dm3. O delineamento utilizado foi o inteiramente casualizado, com 13 tratamentos e quatro repeticoes, contendo oito vasos por repeticao, num total de 416 unidades amostrais. Avaliaram-se as caracteristicas fisicas e quimicas, bem como as variaveis da altura total das plantas e do diâmetro do coleto a cada 30 dias, a area foliar, o numero de folhas e a massa seca da parte aerea. Recomenda-se o uso de po de coco como componente para substratos, pois suas propriedades fisicas e quimicas, aliadas a sua estrutura e durabilidade, apresentaram condicoes para a producao de mudas de sabia. Nao se recomenda o uso do residuo de sisal como componente para substratos na producao de mudas de sabia, pois esse residuo revelou valores de condutividade eletrica (CE) e pH inadequados ao cultivo.

Deposição e acúmulo de matéria seca e nutrientes em serapilheira em um bosque de sabiá (Mimosa caesalpiniifolia Benth.)

n Quantification of litter deposition and organic mantle accumulation are important steps on nutrient cycling studies. This study aimed to quantify litter deposition and organic mantle in a sabiAE (Mimosa caesalpiniifolia Benth) woodlot in an experimental farm in the Brazilian northeast region. Twenty 0.50 x 0.50 x 0.15 m wood collectors, to quantify litter deposition, were systematically distributed over the area elevated 30 cm above the soil. Deposited material was collected monthly from October 2000 to September 2001, and separated into leaves, twigs, flowers, pods and mixed portions. Undecomposed organic mantle was randomly sampled nearby collector boxes, to a total of 20 monthly samples, from which a 0.30 x 0.30 m composed sample was collected. The collected material was also hand separated into leaves, twigs, flowers,

Produção e qualidade da serrapilheira de três leguminosas arbóreas nativas do nordeste do Brasil

The objective of this work was to study the production and litter quality of three native trees legumes of northeast of Brazil, the faveira (Parkia platycephala Benth.), the pau-ferro (Caesalpinea ferrea Mart. ex Tul.) and bordao-de-velho (Samanea saman (Jack.) Merr.) aiming the inclusion of these species in silvipastoral systems. Samples were taken from material deposited in collectors installed under the canopy of individuals; the samples were separates in folioles, miscellaneous and pods. The average productions were: bordao-de-velho, 542; faveira, 311 and pau-ferro, 594 g/m2. The three species presented seasonal production, with the bordao-de-velho concen-trating the production in August, the faveira from July to October, and the pau-ferro from April to August. The P contents in the three species had been low, with exceptions for pods of bordao-de-velho (0.21%) and miscellaneus and pods of pau-ferro (0.14 and 0.16%, respectively). The contents of K varied from 0.16%, in miscellaneus of faveira to 0.65% in pods of the bordao-de-velho. The contents of N varied from 0.85%, in miscellaneus of faveira to 2.13% in folioles of bordao-de-velho. The three species showed potential for soil conservation through the deposition of its litter, and for integration in silvipastoral systems.

Exportação de macronutrientes em cultivos comerciais de bambu no tabuleiro costeiro do estado da Paraíba

Samples of soil and bamboo chips (Bambusa vulgaris) 11 months in age (regrowth) were collected at commercial sites, located in the state of Paraiba (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.