Effect of Phosphorus-Containing Polymers on the Shoot Dry Weight Yield and Nutritive Value of Mavuno Grass

Abstract

In an effort to improve fertility, recover degraded areas and increase support for the capacity of livestock on pasture, new forms of fertilizer are being developed. Polymer-coated monoammonium phosphate (MAP) is an innovative source of phosphorus (P) for maintaining forage grass productivity. The aim this study was to evaluate the agronomic efficiency of P rates with the presence and absence of the polymer on the productivity, development and nutritional value of hybrid signalgrass (Urochloa spp.) cv. Mavuno. The field research was conducted on a dystrophic Ultisol. The experiment was arranged in a randomized complete block design with four replications and treatments applied in a factorial scheme (2 × 4) + 1. The treatments included two P sources (uncoated MAP and polymers-coated MAP) at four rates (20, 40, 80 and 160 kg ha−1 of P2O5), and the control received no P fertilization. The measured variables showed no differences between sources with or without polymer. The maximum production of accumulated shoot dry weight yield (SDWY) of the ‘Mavuno’ grass was 20.2 Mg ha−1 with the dose of 114 kg ha−1 of P2O5. The value of crude protein and in vitro dry matter digestibility showed a quadratic response with maximum production of 76.5% and 15.9% for the P2O5 rates of 37.2 and 91.1 kg ha−1, respectively, while the acid detergent insoluble fiber showed a linear increase up to the rate of 80 kg ha−1 of P2O5. No differences were observed in plant height, number of tillers, or the relative chlorophyll content between treatments.

Keywords

• forage
• nutritive value
• <i>Urochloa</i>
• tropical grass