ABSTRACT
Annex........................................................................................................................................... 525
References ................................................................................................................................... 527
Maintaining an appropriate level of soil organic matter and biological cycling of nutrients
is crucial to the success of any soil management in the humid tropics. Cover crops,
mulches, compost, or manure additions have been used successfully, supplying nutrients
to crops, supporting rapid nutrient cycling through microbial biomass, and helping
to retain applied mineral fertilizers better (Goyal et al., 1999; Trujillo, 2002). The benefits
of such amendments are, however, often short-lived, especially in the tropics, since
decomposition rates are high (Jenkinson andAyanaba, 1977) and the added organic matter
is usually mineralized to CO
within only a few cropping seasons (Bol et al., 2000). Organic
amendments therefore have to be applied each year to sustain soil productivity.
