Contour hedgerow system has been promoted for soil conservation and soil fertility improvement through the use of prunings for the system as mulch green manure However, decomposition process of organic C in the prunings is a key factor affecting nutrient release of prunings Organic C decomposition of prunings from six species of hedgerows was studied by the litterbag method The results indicated that most of the decomposable organic C decomposed within the first 2 weeks in the prunings from Desmodium rensonii and Leucaena leucocephala, within 4 weeks from Tephrosia candida and Aldizia yunnanensis, and more than 8 weeks from Acacia dealbata and A cacia mearnsii, Organic C of prunings incorporated into soil decomposed faster than that used as mulch Cumulative percentage of decomposed organic C could be fitted well by exponent models C_t=C₀(1-e^-kt) or C_t=C₀₁(1-e^-k₁t)+₀₂(1-e^-k₂t) (where C_t represents organic C by time t, C₀ and C₀₁ represent the decomposable fractions of organic C, C₀₂ is the resistant fraction of organic C in the prunings, and k, k₁ and k₂ are the rate constants of C₀, C₀₁ and C₀₂, respectively), and the latter model seems to be more reasonable. The results also indicated that initial C/N ratio was negatively correlated with percentage of C decomposed during the first 12 weeks. Itwas recommended that half life of prunings organic C could be used as a criterion for their nutrient availability to crops in short period under contour hedgerow intercropping.