Residual effect of pig slurry on common carpet grass pasture

Efeito residual de dejeto líquido de suínos em pastagem de grama-tapete comum

ABSTRACT

This study investigated the residual effects of pig slurry (PS) applied to common carpet grass pasture (Axonopus affinis) for two years (September 2008-March 2010) on dry matter yield and forage-nitrogen uptake from October 2010-May 2011. A field experiment was conducted in a randomized complete block design with four replications. The treatments were 102, 204, 306, 408, and 510 m³ ha^-1 pig slurry applied for two years; one mineral nitrogen rate (1,250 kg ha^-1 ammonium nitrate) for two years; and no nitrogen fertilization (control). The pasture was cut at intervals of 48, 34, 43 and 69 days, which corresponded to 266, 300, 343, and 412 days after the last fertilizer application, respectively. Dry matter yield increased by 398 kg ha^-1 for each 100 m³ of PS applied, the equivalent of 317 and 564 kg ha^-1 for each 100 kg ha^-1 of inorganic and organic N applied, respectively. The residual effect of PS on dry matter yield and forage-nitrogen uptake ranged from 11-45% and 8-40%, respectively, indicating a gradual release and availability of N in PS, which can help reduce the amounts of nitrogen applied to pasture.

Key words:
nitrogen uptake; dry matter yield; manure