Productivity and nutrient concentration in spineless cactus under different fertilizations and plant densities

Abstract

The objective was to evaluate the productivity and nutrient concentration in spineless cactus ‘Miuda’ (Nopalea cochenillifera Salm Dyck) under levels of nitrogen (N) fertilization (0, 150, 450 and 600 kg N ha-1 year-1), P fertilization (0 and 150 kg P2O5 ha-1 year-1), plant densities (5,000 and 40,000 plants ha-1) in two sites (Caruaru and Sao Bento do Una). The productivity was greater in plots with 40,000 plants ha-1, regardless of the site, with average of 16.8 and 7.2 t DM ha-1 two years-1, for 40,000 and 5,000 plants ha-1, respectively. In plots with 5,000 plants ha-1, nitrogen fertilization did not affect productivity, however, there was a linear increase in plots with 40,000 ha-1 plants. The plant N concentration increased with nitrogen fertilization and ranged from 7.3 to 9.9 g kg-1. The plant phosphorus (P) concentration was influenced by the interaction between all the factors evaluated and reduced until estimated fertilization of 322 kg N ha-1 in plots with 40,000 plants ha-1 and 150 kg P ha-1 and only in Sao Bento do Una, with P concentration of 1.19 g kg-1. Nitrogen fertilization increased N concentration in cladodes and productivity when using high plant density. The increase in planting density increases productivity and reduces the concentration of most nutrients, except sulphur (S).