Erythrina in alley farming

Alley-farming experiments began at CATIE in 1982. A large experiment has been maintained since 1982, comparing Erythrina and Gliricidia alley farming with sole cropping using mulches of the same species. In 1984, a second experiment was initiated combining E. poeppigiana with maize at different spacings. Another experiment, initiated in 1987, focuses on the effects of row orientation on crop yield. In 1990, an experiment was launched to compare different maize and bean varieties under alley farming with E. poeppigiana, Gliricidia sepium, and Calliandra calothyrsus. Finally, a study began in 1990 to assess runoff under alley farming with different row spacings of E. fusca. All of these experiments are still in progress. Problems identified through this work include Erythrina's poor tolerance for pruning at low heights and poor ability to compete with crops for nitrogen. Although bean production was consistently higher under alley farming with E. poeppigiana than under sole cropping, maize production with Erythrina never differed significantly from controls. Except for increases in Olsen extractable K and buildup of inorganic P, application of up to 8 t DM ha-1 yr-1 of Erythrina prunings had surprisingly little effect on soil properties.