Crescimento e acumulação de nutrientes em plantas de taro sob níveis de sombreamento artificial

Abstract

An experiment was carried out in pots with soil to evaluate the growth and nutrient accumulation of taro plants (Colacasia esculenta) under artificial shading levels. The experiment consisted of four levels of shading (0, 25, 50 and 75% restriction of light) and nine monthly samples in a split-plot randomized block design with four replications. Shading levels were obtained through cubic metal frames covered with nylon nets. The restriction of light did not change the total biomass of plants, but root:shoot ratio was lower under 50 and 75% light restriction. Under these conditions taro plants showed greater height, number of leaves and leaf area, but lower net assimilation rate. The 75% light restriction delayed cormels formation by 30 days and reduced the final cormels production. The light restriction did not affect the accumulation of macronutrients, and the maximal accumulation was observed at 102 days after planting for N, P and K, and 123 days for Ca and Mg. Intense light restriction induced an initial investment of taro plants in the shoot rather than roots, with subsequent delay in the formation of reserve organs leading to reduced cormels production.