Effects of different factors on leaf litter decomposition in rubber plantations in Danzhou, South China

Litter decomposition influences the nutrient cycle and the availability of soil nutrient resources in rubber plantation ecosystem. This study aimed to analyze effects of different factors such as soil layer depths, root accessibility and soil fertility levels on dynamic decomposition of leaf litter in rubber plantations, as well as physico-chemical properties and microbiological parameters of the soil. We performed decomposition experiments to analyze the effect of these factors on leaf litter decomposition in a rubber plantation in Danzhou, South China. The results showed that the rubber leaf litter decomposition activity increased with the depth of the soil layer. The fertility level of soil affected the decomposition process, with higher soil fertility level restraining litter decomposition. The litter decomposition was affected by the root accessibility, but the roots turned out to not be decisive factors in the decomposition process. The microorganism abundance differed seasonally in the above-ground and underground soil layers during the rubber leaf litter decomposition. The number of actinomycetes, bacteria and fungi changed most dramatically between March and May. The fastest rate of rubber leaf litter decomposition also occurred during this period. The microorganisms played a key role in the rubber litter decomposition underground. Enzymes sucrase, urease, polyphenol oxidase and cellulase contributed in regulating the decomposition of rubber leaf litter. These results may provide further insight into the potential of using leaf litter resources in tropical plantations. This study also provides valuable information about the decomposition mechanism of leaf litter as part of the nutrient cycle.