Fenologia, disponibilidade de biomassa e valor nutritivo do carquejo (Calliandra depauperata Benth).

Abstract

An experiment was conducted at the Fazenda Pau Preto, Parambú County, Inhamuns sertão, 400km southwest of Fortaleza, Ceará, Brazil. A 900 sq.meter area with the native vegetation dominated by Carquejo (Calliandra depauperata Benth) was protected from the domestic livestock by a barbed wire fence. Eighteen adult carquejo plants were randomly sorted and permanently marked for the phenological observations. At 28 day intervals, 10 other plants were harvested for biomass availability and nutritive value. The study of the root system was made with one randomly sorted plant for each one of the two soil types of the experimental area. The phenophases af the carquejo were markedly afected by the pluvial preciptation. The dormancy characterized by growth paralizatian and drying of the leaves, ocurred on the onset of the dry season, and the gradual leaf fall was observed throughout the period. Low rainfalls resulted on resprauting, even along the dry season. The flowering ocurred simultaneously with the stage of full leafage. The leaf biomass availability varied greatly troughout the year and it showed a pronounced answer to the precipitation. The leaf to stem rate on the adult plants was generally low and comparable to that of other brush species. However, on the new herbaceous branches, it was high and similar to that of the herbaceous plants. The crude protein content in the dry matter of the leaves was high even during the dry season, and showed values substantially higher than those of the herbaceous cover of the thinned out caatinga near by. The linear correlation coefficients between the biomass weight components and the crown dimensions were signicant (P<0,05) for crown volume and area and total and stem weigths.