FORAGE LEGUME ESTABLISHMENT IN RICE SLASH-AND-BURN SYSTEMS

Increasing population pressures combined with government policies exer t considerable pressure on traditional slash-and-burn farmers in north ern Laos to change to other production systems. Replacing the natural fallow vegetation with fodder legumes could increase fodder availabili ty, suppress weeds, and accelerate nutrient cycling. Establishment met hods for potential forage species were evaluated at the Houay Khot sta tion during 1992 and 1993. When broadcast into upland rice immediately after weeding in July, good or excellent establishment was observed f or Stylosanthes guianensis, S. hamata, Macroptilium atropurpureum, Pue raria javanica, P. phaseoloides, Calopogonium mucunoides, C. caeruleum , Leucaena leucocephala, Centrosema pubescens, and C. plumieri, Poor e stablishment was observed for Arachis pintoi, Flemingia congesta, Crot alaria anagyroides, C. juncea, pigeon pea (Cajanus cajan), Tephrosia v ogelii, and Lablab purpureus. July and August sowings resulted in bett er plant densities than June or September sowings. However, early sowi ng of Stylosanthes species reduced rice yield by 20-30% in 1993. Dibbl ing rice mixed (same hill) with leucaena resulted in good establishmen t without detrimental effect on rice yield, while dibbling rice mixed with pigeon pea reduced rice yield by 55-65%.