A field trial was conducted to evaluate the effects of tillage system and fertilizer N applied to the preceding gramineous rotational crop on horse bean ( Vicia faba L. minor) yield and N uptake, chemical composition and nutritive value. The study took place during the periods 2002-2003 and 2004-2005 within the framework of a long-term experiment started in 1990 and involving a 2-year rotation including triticale and horse bean. The experimental layout was a split-plot design with three replicates and four tillage systems in the main plots. Tillage treatments included conventional tillage (CT), two-layer tillage (TT), surface tillage (ST) and minimum tillage (MT). In the subplots, the three N fertilization rates, applied to the preceding triticale crop, were 0 kg ha -1 (N 0), 50 kg ha -1 (N 50) and 100 kg ha -1 (N 100). Over the whole experimental period, tillage system did not significantly influence horse bean seed yield, N uptake, crude protein content and 48-h in vitro true dry matter digestibility. In spite of many significant interactions among experimental variables, there were comparable results under the different tillage systems, in both the less favourable and more productive years. N fertilization, applied to the preceding gramineous crop, did not exert noteworthy effects on horse bean seed quantiqualitative parameters studied. Continuous reduced tillage management, such as two-layer, surface and minimum tillage, would represent a viable alternative to conventional tillage for horse bean production, under rainfed Mediterranean conditions. In addition to their nutritional significance, these results are of economic and environmental importance, given the interest in adopting reduced tillage systems to limit the risk of soil erosion and degradation. The rate of fertilizer N should be optimized as a function of the production and quality of the preceding cereal crop.
