The persistence of tropical grass-legume associations under grazing in Brazil

Abstract

SummaryThe persistence under a close intermittent grazing regime of eight accessions of Stylosanthes guianensis, Stylosanthes macrocephala and Stylosanthes capitata in combination with Andropogon gayanus (cv. Planaltina) and Brachiaria decumbens (cv. Basilisk) was evaluated in small plots on a low fertility acid oxisol in the tropical savannah region of Brazil. Five accessions persisted for four seasons with both grasses, although legume yields were lower in the B. decumbens associations.S. macrocephala CIAT 1582 (CPAC 139), S. capitata CIAT 1019 (CPAC 704) and CIAT 1097 (CPAC 706) were the most productive accessions at the end of the experiment. The three accessions S. guianensis cv. Cook, S. capitata CIAT 1315 (CPAC 707) and CIAT 1405 (CPAC 846), which failed to persist, were destroyed by anthracnose (Colletotrichum gloeosporioides). This disease remains the primary factor limiting the use of Stylosanthes in the region. The value of small-plot grazing experiments is briefly discussed.