Nitrogen use of Panicum and brachiaria cultivars vary with nitrogen supply: II nitrogen use efficiency rankings and partition

Abstract

An improved N use in grasses is necessary to increase the nutrient use efficiency and the species persistence in the production systems. However, it is not known if the same grass cultivars should be used in high or low N situations to achieve high nitrogen use efficiency (NUE). This study aimed to analyze whether Brachiaria brizantha cv. Marandu, B. brizantha cv. Xaraés, B. brizantha cv. Piatã, B. decumbens cv. Basilisk, Panicum maximum cv. Mombaça, P. maximum cv. Tanzania, P. maximum cv. Aruana and P. maximum x P. infestum cv. Massai grasses modify the N partition to an improved nutrient use efficiency when growing in an environment with low and high N availability. The experiment was carried out in a greenhouse with an Entisol collected in a degraded pasture area. The experiment was set up with 8 cultivars (four cultivars each of Brachiaria spp. and Panicum spp.) x 2 N rates in a complete randomized block design, with four replications. The studied grasses modified the N partition and the nitrate and ammonium concentrations in shoots and roots at high and low N supplied rates. These differences reflect the higher NUE by Mombaça and Tanzania compared with the other six cultivars.