Palma forrageira ‘gigante’ submetida a diferentes reposições hídricas com água salobra e densidades de plantio

Abstract

The forage cactus pear (Opuntia ficus-indica) is a xerophytes highly adapted to adverse conditions found the semi-arid, thereby making its cultivation one the best options to produce forage in this region. As a forage crop, it is more stable over time than most crops, even reaching high yields of biomass per unit area. The objective of this study was to evaluate the growth of „Gigante‟ forage cactus pear subjected to different irrigation intervals, planting densities and irrigation depths with saline water. A randomized block design (RBD) was used as treatments were arranged in split-split plots. Two irrigation intervals were assigned to the plots (seven and 15 days), four different planting densities to the split plots (20, 40, 60 and 80 thousand plants per hectare), and four irrigation depths to the split-split plots (0, 11, 22 and 33% id ETo), that is, 32 treatments with three replications, totaling 96 experimental units. The following evaluations were made: electrical conductivity of the saturated soil-paste; irrigation system efficiency; plant height and plant width; number of cladodes; cladode area index; biomass yield; and water use efficiency. Irrigation with saline water (2.91 dS m-1 ) applied to forage cactus pear does not cause salinization of a red-yellow LATOSOL after a production cycle and rainy season. The inline drip irrigation system using saline water increases plant width, plant height, cladode area index, biomass yield. When applying saline water with 22% of ETo, water use efficiency increases, which is, from a sustainability standpoint, of utmost importance. 80 thousand plants ha-1 results in higher cladode area index, yield and water use efficiency.