Accounting for photodegradation dramatically improves prediction of carbon losses in dryland systems

• DOI: 10.1002/ecs2.1892
• Publication Date: 2017-07-28T15:10:36Z
• Authors: E. Carol Adair; William J. Parton; Jennifer Y. King; Leslie A. Brandt; Yang Lin
• Keywords: Photodegradation; Plant litter

Abstract Traditional models of decomposition fail to capture litter mass loss patterns in dryland systems. This shortcoming has stimulated research into alternative drivers decomposition, including photodegradation. Here, we use aboveground data for (arid) sites from the Long‐term Intersite Decomposition Experiment Team set test hypotheses (models) about mechanisms and impacts Incorporating photodegradation a traditional biotic model substantially improved predictions at these sites, especially after four years. The best accounted effects solar radiation via intermediate cellulosic lignin pools direct inhibition microbial decomposition. Despite concurrent on loss, increased by an average 12% per year compared biotic‐only model. also allowed soil infiltration litterbags reduce shading radiation. Our modeling results did not entirely support popular hypothesis that initial content increases loss; surprisingly, higher decreased rate Importantly, our suggest rates due may be comparable rates: Mass alone resulted losses 6–15% year, while ranged 20% during early‐stage 3% late‐stage Overall, failing account under‐predicted long‐term approximately 26%. Thus, likely large underestimations carbon