Produtividade, exportação de nutrientes, eficiência nutricional e de uso da água em palma forrageira 'Gigante' sob diferentes adubações e espaçamentos

Abstract

The objective of this work was to evaluate the production of green mass, dry matter and water, macro and micronutrient contents, nutrient exportation in forage palm cultivar Opuntia fícus-indica 'Giant' cultivated in chemical, organic and organo mineral fertilizations. The experiment consisted of 72 treatments, involving two types of arrangements in the plots, three spacings in the subplots and 12 types of fertilization in the subplots, arranged in sub-subdivided plots. The experimental design was in a randomized block with three replicates. In the three production cycles, morphometric characteristics and the content and extraction and export of nutrients were evaluated. The yield of the forage palm was also determined. The data were submitted to analysis of variance and comparisons were made between the means of the different spacings by the Tukey test (P<0,05) and the fertilizations by the Scott-Knott criterion (P Ca> N> Mg> S> P for organic, mineral fertilizations with 30 Mg ha-1 year1 of manure and organo mineral with 30 and 60 Mg ha-1 year-1 of manure added with NPK and PK, and changes to K> Ca> N> Mg> P> S in organic manures with 60 and 90 Mg ha-1 of manure and organo mineral with 90 Mg ha-1 plus K. The nutrient balance after three cycles of production is positive for N, P and S, negative for Ca and Mg in all fertilizations, and positive for K in mineral fertilizations with 600 kg ha-1 of K2O and organo mineral with 30, 60 and 90 Mg ha-1 of manure added of 600 kg ha-1 of K2O. The highest recovery rates of K and the lowest of N occur in organic fertilizers, which add the lowest and highest amounts of K and N to the soil compared to mineral and organo mineral fertilizers.