Intensive Management Increases Phytolith-Occluded Carbon Sequestration in Moso Bamboo Plantations in Subtropical China

Abstract

Plantation management practices could markedly change the sequestration of phytolith-occluded carbon (PhytOC) in plants and soils. However, for Moso bamboo (Phyllostachys pubescens) plantations, the effect of intensive plantation management (including fertilization, tillage, and removal of understory vegetation) on the accretion rate of PhytOC in the soil-plant system is much less understood than extensive management (without fertilization, tillage, and removal of understory vegetation). The objectives of this study were to investigate the effect of intensive and extensive management practices on the production, accumulation, and runoff of PhytOC and their distribution in physical fractions in Moso bamboo plantations. Our results showed that intensive management (1) increased PhytOC production mainly due to increased forest productivity; (2) increased PhytOC storage in the heavy fraction but decreased its storage in the light fraction of organic matter, resulting in the lack of effect on soil PhytOC storage; (3) increased the rate of dissolution of phytolith and the loss of PhytOC in runoff; and (4) promoted PhytOC sequestration in the soil-plant system, mostly in the plants, due to the greater rate of PhytOC production than the rate of loss. We conclude that intensive bamboo plantation management practices are beneficial to increasing long-term PhytOC sequestration in the soil-plant system.