Management of green-manure nitrogen on Oxisols at Manaus, Brazil.

Abstract

Studies on Oxisols in the Cerrado of Brazil have shown that mucuna, a common green manure, can provide much of the nitrogen required by a succeeding food crop. Such green manures, if effectively managed, appear to hold promise as a supplement or an alternative for fertilizer nitrogen in the Cerrado. This experirnent, established as a companion study to the work in the Cerrado, sought to test similar greenmanure management techniques for their suitability to soil and climate conditions in the Manaus region. The objectives were 1) to quamify the N supplied by green manures to com and rice, and 2) to evaluate the importance and availability of green-manure N to crops. This study contained two experiments with treatments described in Table 1. Both experiments were planted to com in October, 1984, followed by rice in February, 1985. Treatrnents were established only