Litter removal increases the plant carbon input to soil in a Pinus massoniana plantation

Plants are the main sources of soil organic carbon in forest ecosystems. Photosynthetic C assimilated by plants enters the soil through litter, root litter, and root exudates. However, it remains unclear how litter changes affect the plant-C input. We aimed to quantify the responses of C inputs via the litter, root litter, and root exudates to litter alteration. We conducted a 2 years litter manipulation (litter removal, litter addition, and control) experiment in a Pinus massoniana plantation and studied its impacts on plant-C inputs via litter, fine root litter, and root exudates. The results show that litter removal significantly increases the litterfall in summer and autumn and reduces root-C exudation rates in spring but has no effect on the C input by fine roots. The annual C inputs by litter, fine roots, and root exudates in the control plots were 348.28, 42.39, and 17.44 g C m −2 , respectively, accounting for 85.34%, 10.39%, and 4.27% of the total C input, respectively. Litter removal increases the plant annual total C input by 24.55% due to the decrease in the root exudate-C input by 30.50% and increase in the litter-C input by 31.12%. In contrast, litter addition insignificantly affects the C input through litter, fine roots, or root exudates. Increasing the litter-C input and decreasing the root exudate-C input by litter removal are a plant strategy based on which forest growth can be maximized in the short term. The increased plant-C input due to litter removal mitigates the effects of litter alteration. This study is of great significance for understanding plant growth strategies.