LAUSR

Litter production and litter decomposition influence the availability of nutrients in the soil. The investigation aimed at characterizing the dynamics of leaf litter decomposition, and soil physico-chemical and biological parameters in rubber plantations of different ages. During a 12-months’ period, field studies were done in 7-, 12-, and 25-year-old rubber plantations. For measuring of litter decomposition and input from aboveground, 324 litter bags and 27 litter traps (1 m × 1 m) were placed in 3 sampling areas per age class of rubber plantations. The soil parameters were also characterized. The results showed that the annual litter production and the amounts of organic carbon in leaves increased with the aging of the plantations. The annual decomposition constant (k) ranged from 0.0381 ± 0.0040 year−1 in the 25-year-old plantations to 0.0767 ± 0.0111 year−1 in the 7-year-old plantations. The annually decomposed litter mass varied between 2.7 ± 0.3 t ha−1 year−1 in the 12-year-old plantations to 4.2 ± 0.3 t ha−1 year−1 in the 25-year-old plantations. The soil of the 25-year-old plantations showed higher values of most physico-chemical and biological variables as compared to the 7-year-old plantations: annual litter production (+ 32%), annual litter mass decomposed (+ 11%), annual carbon (+ 15%) and nitrogen (+ 11%) inputs, soil organic carbon (+ 52%), total nitrogen (+ 32%), soil organic matter (+ 52%), soil water content (+ 74%), and the total density of soil invertebrates (+ 121%). The results indicate an improvement of soil properties with the aging of the rubber plantations and the importance of this agricultural system for carbon sequestration.