Silvicultural practices applied in managed forest plantations may help counteract the effects of climate change by influencing soil surface CO2 efflux (F-s). Understanding the effects of silvicultural practices on F-s will provide unbiased estimates of carbon fluxes and allow better silvicultural decisions for carbon sequestration. Therefore, we assessed how F-s differed seasonally across silvicultural practices (i.e., stocking levels, clone, fertilization and weed control treatments) and evaluated the effects of soil temperature (T-s) and soil volumetric water content (theta(v)) on F-s across these practices for a mid-rotation (14 year-old) Pinus radiata plantation in the Canterbury region of New Zealand. There were significant differences in F-s (p < 0.05) over the four seasons, three levels of stocking, and five clones. The effects of fertilization and weed control applied 12 years previously on F-s were insignificant. Annual estimate of F-s (mean +/- 1 standard deviation) from the study site was 22.7 +/- 7.1 t ha(-1) a(-1) in the form of CO2 (6.2 +/- 2.1 t ha(-1) a(-1) in the form of C). F-s values were consistently higher in plots with 1250 stems ha(-1) compared to 2500 stems ha(-1), which may be related to a strong soil resource limitation because of the close spacing in the latter plantation. Significant differences in F-s across clones suggest that variations in carbon partitioning might explain their growth performance. Silvicultural treatments influenced F-s response to soil temperature (p < 0.05), resulting in models explaining 28-49% of the total variance in F-s. These findings provide insights into how silvicultural management decisions may impact F-s in mid-rotation radiata pine plantations, contributing towards developing more precise and unbiased plantation carbon budgets.