Fontes e doses de adubação orgânica no cultivo da mamoneira irrigada com e sem cobertura morta.

Abstract

The Castor bean (Ricinus communis L.) is a very important oil production plant; its seeds produce an oil of excellent properties. Plant resistant to water deficit and exigent in fertility, requiring significant amounts of nutrients for grain production and oil and protein synthesis. The objective of the present work was to evaluate the castor bean behavior (BRS Energy cultivar) when submitted to two organic matter sources (castor bean pie and cow manure) with and without mulching. The experiment was conducted in a green house at the Federal University of Campina Grande on a 2x4x4 confounded random block factorial statistical scheme with three replicates totalizing 36 experimental units. The first factor was the two organic matter sources applied on soils without mulching and the second factor four doses o f organic nitrogen applied on soils without mulching (200, 400, 600 e 800 kg N ha"1). The additional factor was the organic matter applied on two doses (200 e 600 kg N ha"1) on covered soils. The analyzed variables were plant height, steam diameter and their absolute growing rates, leaf area, phytomass of the aerial part, fruit and seeds production, oil content of the seeds and consumptive and irrigation water use efficiency. The organic matter sources promoted signifícant positive effects on the growth, development and production o f the castor bean, with the castor bean pie offering the best results. Also the irrigation water use efficiency of the plants fertilized with castor bean pie was higher than the efficiency obtained when used cow manure