Energy change during fine roots decomposition of bamboos in coastal sandy sites

Gross caloric value,standing energy and released amounts were investigated during fine roots decomposition of bamboos in coastal sandy sites.The results showed as follows: GCV decreased first and then increased during fine roots decomposition of bamboos,which reached the minimum point after 180 days′ decomposition.The effect of decomposition time on GCV reached extremely significant level.GCV of Dendrocalamus minor was significantly correlated with monthly air temperature and rainfall(P0.05).Except Dendroclamopsis oldhami,standing energy of bamboos in coastal sandy sites fluctuated largely in one year.Acidosasa edulis was the highest,reaching 2.67×103 kJ·m-2.Phyllostachys makinoi was the lowest,which was 1.63×103 kJ·m-2.The change of Dendroclamopsis oldhami was steady relatively,which concentrated a range of 1.72×103 kJ·m-2.The energy lost and released gradually during decomposition of fine roots.The rate of energy loss was above 68% after 300 days′ decomposition.The rate of energy loss of Phyllostachys prominens was the highest,reaching 77.74%.In general,the average rate of energy loss increased as decomposition time prolonged,which was 73.96% when decomposition completed.The diversity of energy loss of bamboos was large in initial stage of decomposition,which became smaller and smaller as decomposition time prolonged.