Comparison of carbon sequestration between multiple-crop, single-crop and monoculture agroforestry systems of Melaleuca IN JAVA, INDONESIA

We compared aboveground c accumulation and c cycling of three types of cajuput (melaleuca leucadendron) agroforestry plantations producing cajuput oil in java, indonesia. in the study site in east java, where cajuput trees were planted with cassava and maize in a multiple-crop agroforestry system, cassava was the largest component of aboveground total c accumulation in the plantation. in the site in west java, where trees are planted with rice in a single-crop agroforestry system, both cajuput and rice contributed similar amounts to aboveground total c accumulation. aboveground net c accumulation was highest in the multiple-crop system, where it averaged 18.5 and 7.1 mg c ha-1 year-1 in the 7- and 25-year old stands respectively. in the plantations, relative amounts of harvested (leaf–twigs and branches of cajuput and edible crop biomass) and returned (non-edible crop biomass) c were similar and did not change with stand age. this indicated that although crop harvesting removed large amounts of c from the system, an almost equal amount of organic waste was returned, thus, establishing a dynamic c cycle. the c:n ratio of returned waste was high, suggesting that decomposition rate was slow and that c accumulated in the soil. compared with more complex agroforestry systems, carbon sequestration of cajuput plantations was low. our results, however, suggested that c accumulation may be increased and a sustainable c cycle established by returning more biomass waste and maintaining multiple crop systems.