Root system growth of the common bean, variety IAC-Carioca, under center pivot irrigation in rotation with fallow; corn; black oat; sunn hemp (Crotalaria juncea L.); pigeon pea [Cajanus cajan (L.) Millsp.] and velvet bean (Mucuna aterrima) was evaluated during a non-conventional (Autumn - Winter) cultivation period, from 1993 to 1995, on a typic Haplorthox soil, at an experimental area of the Instituto Agronômico, in Ribeirão Preto, São Paulo, Brazil. The crop sequences of common bean with corn and green manure reduced the soil resistance to penetration into the ploughed layer; maintained the normal contents of the soil organic matter; reduced acidity and increased the base saturation index in depth, in relation to the initial content. The basic infiltration rate was increased with the inclusion of velvet bean, sunn hemp and corn in the crop sequence. Effective root depth (80% of the total) was around 0.35 to 0.40 m.
Phaseolus vulgaris L.; irrigation; roots; green manure