Características agronômicas da mamoneira influenciados pela fertilização orgânica e densidade global do solo: um enfoque de sustentabilidade.

Abstract

The castor bean plant (Ricinus communis L.) found in the semiarid region of Northeast Brazil resources and natural conditions for its development and it is an important alternative to generate income and jobs in the field, becoming thus a major factor in the environmental sustainability. This work consisted of two experiments, which aimed to evaluate the growth, development and production of castor oil, depending on the use of organic fertilizers (castor bean cake and made up of organic waste) and mineral (macro and micro) in different doses in soil artificially compressed into different levels of density. The experiments were conducted in a greenhouse of the National Center for Research in Cotton (CNPA / Cotton Embrapa), in the city of Campina Grande, PB. In experiment I, the experimental design in randomized blocks was used, in a factor analysis (4 x 4), with 3 replications, and the factors: four levels of density of soil (1.4, 1.6, 1.8 and 2.0 kg dm-3) and four doses of castor bean cake (0.0, 2.0, 4.0 and 6.0 t ha -1). In experiment II, the experimental design in a randomized block design with four replications was used, totaling 11 treatments, which are derived from doses of castor bean cake and composed of organic waste (four doses of each) and three witnesses (witness absolute (soil without fertilizers), witness for 1 (NPK - nitrogen, phosphorus and potassium), witness for 2 (NPK + micronutrients - boron (B), copper (Cu), iron (Fe), manganese (Mg) and zinc (Zn )), with subsequent study of orthogonal contrasts. The "cultivar" (cultivate) used for this study was the Paraguaçu BRS, which was planted in pots of 60 L and the variables in the two experiments were related to growth and development, production, the physiology and biochemistry of castor beans and some variables related to the chemical (fertility) and soil physics. The results of certain variables were subjected to analysis of variance by the SAS statistical software (Statistical Analysis SISTEM), and the level of significance was analyzed through the test "F ". The averages were compared among themselves by Tukey test at 1% probability. The results show that the highest densities of soil, contributed significantly to reducing the growth and development of castor bean plants, whose effect was, in some way, softened by adding cake of castor oil to the ground. The cake of castor oil has a significant effect on levels of N, MO, P, P2O5 and K2O present in the leaf of castor bean and carbon contents of organic matter and nitrogen to soil, which highlights its importance as an excellent organic fertilizer, whereas the organic waste compost added to soil at different doses did not affect the components of growth, development and production of plants, the constituents of the leaf and soil nutrients, and it is an organic fertilizer with low production efficiency for the cultivation of castor beans.