Nutrient concentration in spineless cactus under different planting densities and harvesting management

Abstract

Spineless cactus ‘Orelha de Elefante Mexicana’ (Opuntia spp.) has high productivity and resistance to the carmine cochineal. This research was carried out at the experimental research station of the Instituto Agronomico de Pernambuco located in Arcoverde, Pernambuco, Brazil, from June 2011 to June 2013. The effect of planting density (55,556, 27,778, 13,889, and 6944 plants ha(-1)), harvest frequency (annual and biennial), and harvest intensity (preserving the mother cladode or primary cladodes) on nutrient concentration of spineless cactus ‘Orelha de Elefante Mexicana’ was investigated. The treatments were allocated in a randomized complete block design, with split-split plot arrangement and four replications. Fertilization was performed with 200 kg N ha(-1) year(-1) using urea and 20 t organic matter ha(-1) year(-1) from cattle manure. Response variables included plant N, P, and K concentrations. The N and P concentrations were affected by interaction between harvest frequency and harvest intensity. Plants harvested annually had higher N and P concentrations when the mother cladode was preserved; in biennially harvested plants, there was no effect of harvest intensity. For the plants harvested preserving mother and primary cladodes at annual and biennial frequency, N concentrations obtained were 11.0, 8.9, 6.1, and 6.8 g kg(-1) and P concentrations were 3.4, 2.2, 2.3, and 2.3 g kg(-1), respectively. Planting density also affected plant P concentration, with a quadratic response, increasing from 1.59 to 3.01 g kg(-1) at 6944 and 41,646 plants ha(-1) density, respectively. Plant K concentration was affected only by harvest frequency, with superior K concentrations in plants harvested annually. The combination of harvesting frequency and intensity can affect cactus ‘Orelha de Elefante Mexicana’ N and P concentrations.