Soil improver, erosion control and afforestation
Calliandra is an N-fixing legume that roots abundantly and nodulates readily with Rhizobium bacteria. It yields high amounts of biomass and has been recommended for green manure in areas of low fertility. It can be used in rotation with cash crops like sugarcane or maize (in alley cropping systems). However, the high tannin content of the leaves reduces the microbial breakdown of organic matter in the soil (Palmer et al., 1994). The dense canopy of calliandra provides good cover against sun and rain. Its spreading root system binds soil on steep slopes and cleared forests that are at high risk of erosion (Orwa et al., 2009; Palmer et al., 1994). In mountainous areas of Indonesia, calliandra could be aerially seeded, making possible the afforestation of inaccessible areas (Palmer et al., 1994).
Companion legume, nurse-tree and weed controller
Calliandra is often used as a companion legume in alley cropping systems. It must be pruned regularly so that it does not over-shade other crops (Wiersum et al., 1997). It is a useful nurse tree for partially shade-tolerant timber trees such as Agathis (Orwa et al., 2009). A pioneer species, calliandra may be helpful for the control of alang-alang (Imperata cylindrica) and other species from degraded grasslands of grasses such as Eupatrium and Saccharum (Orwa et al., 2009).
Mitigation of methane emissions by ruminants
Feeding calliandra to ruminants results in lower enteric methane emissions than with grasses or herbaceous legumes: it reduced methane emissions by 24% when replacing a non-tanniferous legume at 30% of the diet (Tiemann et al., 2008a). Lower methane emissions are typical of tannin-rich forages, but, in the case of calliandra, lower emissions may be primarily due to its fibre characteristics and the lower digestibility of the fibre, rather than to tannins (Tiemann et al., 2008b).