AGROFORESTRY IN THE BOLIVIAN ALTIPLANO - EVALUATION OF TREE SPECIES AND GREENHOUSE GROWTH OF WHEAT ON SOILS TREATED WITH TREE LEAVES

Severe environmental problems encountered in the highlands of Bolivia may be remedied through the adoption of agroforestry systems, never be fore studied adequately in this region. As a first step, seven tree sp ecies were tested for growth, survival and health at two elevations in the Bolivian altiplano. Species responded variably with Buddleja cori acea Remy., Pinus radiata D. Don. and Eucalyptus globulus Labill. (at the higher elevation) and E. globulus, Baccharis spp., Robinia pseudoa cacia L. and B. coriacea (at the lower elevation), displaying high sur vival, growth and health. In a related greenhouse study, grain yields of wheat planted in soils amended with incorporated foliage of B. cori acea, P. radiata and E. globulus increased three-fold (similar to 0.3 g.plant(-1) to > 1.0 g.plant(-1)) over grain yields in unamended soils (B. coriacea > P. radiata = E. globulus). Grain nitrogen (mg.plant(-1 )) increased equally in soils amended with P. radiata and B. coriacea foliage (similar to 18 mg N.plant(-1) to similar to 20 mg.plant(-1)) b ut decreased in soils amended with foliage of E. globulus (similar to 18 g.plant(-1) to similar to 9 g.plant(-1)).