Seven rotational systems were evaluated for vegetable crops in USA and Uruguay. Rotational systems that include both winter and summer cover crops and vegetable crops were used. Treatments comprised: continuous cropping system, T1; multiple vegetable system, T2; green manure system, T3; chicken manure system, T4; fallow system, T5; strip tillage system, T6; and no-tillage system, T7. The crops used were sweet potato, squash, oat or triticale winter cover crop, sorghum or Sudan grass summer cover crop, sweetcorn, garlic, carrot with chicken manure and fallow. Different insects, diseases and weed infestations were recorded in the systems. The study began in spring 1999 in Uruguay and spring 2000 in North Carolina, USA. This paper reports only results from Uruguay. The yields obtained were good compared to the national average in most cases. The average yield is 7 t/ha for sweet potato and 3.5 t/ha for garlic. T6 had the highest soil macrofauna (70 worms/m 2 compared to 4.2 in T1). Soil biomass was sampled for four times: 13 April, 26 May, 17 August and 08 November 2000. T7 system had greater soil biomass during the period of observation than T1 or T4 systems. T6 and T7 treatments had the lowest nitrate levels in the soil among all treatments. T4 was enough for garlic growth. T6, T7 and T4 systems had less sclerotia (from Sclerotium rolfsii [ Corticium rolfsii]) than T1 and T2 systems.
