Desempenho agronômico da grama-missioneira-gigante em latossolo com uso de dejeto líquido de suíno

Abstract

The objective of this study was to evaluate the response of giant-missionary grass (Axonopus jesuiticus x A. scoparius) to pig slurry (PS) fertilization. The experiment was carried out on field conditions on a Red Latosol (Typic Haplorthox), in no Centro de Pesquisas da Epagri-Cepaf, Western Santa Catarina region, from 2007 to 2009. The PS were which rates were 100, 200, 300, 400 and 500 kg/ha/year of total nitrogen (N). On the average of these two years, PS was applied to the soil surface at rates of 54.8; 109.6; 164.3; 219.8 and 272.8 m3.ha-1.year-1. These treatments were compared to ammonium nitrate (200 kg. ha-1.year-1 of N) and to a control (no N application). The tested rates were split on four applications per year and applied after the pasture was cut, what was done five times per year. The PS fertilization increased the vegetative and reproductive canopy height, culm diameter, length and width leaf, tillers number, as well the crude protein, K, Zn and Cu content. Dry matter yield did not change between years and linearly increased the dry natter production as function to PS doses, changing from 2,698 kg of DM.ha-1.year-1 (Control) to 11,371 kg of DM.ha-1.year-1 (500 kg of N or 272.8 m3 of PS). The average increment of DM was 32.3 of DM.m-3.ha- or 17.7 kg of DM.N-1.ha-1, respectively. The application of 300 kg of N.ha-1.year- 1 (164.4 m3.ha-1) yield 9,152 kg of DM.ha-1.year-1 and such production did not differ from that found with ammonium nitrate. The highest average daily rate of DM accumulation (66.8 kg.ha-1.day-1) was obtained with the higher dose of PS and occurred between February/2007 and April/2008. The nitrogen utilization efficiency did not change among PS rates, being 19.0 kg of DM.kg-1 of N and this value was lower than that obtained with ammonium nitrate (30.3 kg of DM.kg-1 of N). The PS efficiency index was 0.63 in the year average