No-tillage and crop-livestock with silage production impact little on carbon and nitrogen in the short-term in a subtropical Ferralsol

Abstract

We assessed the short-term (3.5 years) contributions of no-tillage (NT) relative to conventional tillage (CT), and of integrated crop-livestock systems combined with no-tillage (ICL-NT) relative to NT, on soil carbon (C) and nitrogen (N) and their physical fractions (free-light, occluded-light and heavy), in condition of maize silage production. An Umbric Ferralsol (Latossolo Bruno) was cultivated with ryegrass (Lolium multiflorum), for cover-crop in CT and NT, pasture in ICL-NT; and maize for silage. Notillage, relative to CT, improved C and N stocks in 0-5 cm and mainly in the heavy fraction, but not deeper, so that stocks in whole 0-20 cm were (statistically) similar in both systems (~67 Mg C ha-1 and ~4.8 Mg N ha-1). Likewise, the ICL-NT did not affect C and N stocks to 20 cm relative to NT, not even in the top layer or in some physical fraction. The short 3.5-year period, the originally high C and N contents of this Umbric Ferralsol and the removal of silage have possibly limited the effects of NT or ICL-NT. However, the adoption of those two conservation systems have at least no adverse effects on C and N stocks, without detriment to their already known productive and economic benefits.