Growth and productivity of forage grasses under phosphorus sources of different solubilities

Resumo

The objective of this study was to evaluate the growth and productivity of BRS Capiaçu and BRS Kurumi cultivars in function of phosphorus sources in the semiarid region of Piauí. The work was conducted in the experimental area of the State University of Piauí, in Picos-PI. The completely randomized design was adopted, in a factorial scheme (4x2), formed by three sources of phosphorus (rock powder, single superphosphate and triple superphosphate) and the witness and two cultivars of elephant grass (BRS Capiaçu and BRS Kurumi), with four replicates, making up 32 experimental units. The planting occurred by means of vegetative propagation. Three cuts were made: the first, of standardization, and the others, of evaluation. After the cuts, evaluation of the variables was performed: plant height, stem diameter, number of tillers, number of leaves per tiller, total number of leaves, green leaf mass, green stem mass, green shoot mass, dry leaf mass, dry stem mass, aerial dry mass and productivity. Phosphate fertilization provided positive results in growth and productivity of the BRS Capiaçu and BRS Kurumi cultivars. Simple superphosphate fertilization is recommended for the production of first cut grass. The positive result in the second cut with the use of rock powder indicates residual effect of this fertilizer, being the same recommended in this study. It is recommended to produce the cultivar BRS Capiaçu under study conditions.