Despite the abundance of cacti in the Sonoran Desert, most research focuses on population dynamics and physiology. Relatively little is known about their decomposition dynamics. A better understanding of cactus decomposition is important, considering the number of threatened and endangered cactus species. We measured mass, water, nutrient, and structural chemistry over one year of decomposition of two common cactus species, Opuntia chlorotica and Cylindropuntia acanthocarpa, in the Sonoran Desert of Arizona, U.S.A. Our results demonstrate the contribution of cactus decomposition to carbon and nutrient recycling, with comparable dynamics to woody and herbaceous leaf litter for most elements. We enumerate, however, the particularly important role in calcium dynamics. Despite initial differences, both cacti released nutrients at a statistically equivalent rate, though with altered timing due to temporary mass gain in cholla. The resources released from decaying cacti have a modest influence on underlying soil CO₂ flux, secondary to a dominant influence of soil microclimate. Our data provide a baseline for understanding the decay dynamics of two common cactus species and suggest that, while there is still a lack of information pertaining to cactus decomposition, the similarities with leaf litter will aid our predictions of the consequences of future cactus population changes.

尽管索诺兰沙漠中有丰富的仙人掌，但大多数研究都集中在种群动态和生理学上。关于它们的分解动力学知之甚少。考虑到受威胁和濒临灭绝的仙人掌物种的数量，更好地了解仙人掌分解很重要。我们测量了两种常见仙人掌物种Opuntia chlorotica和Cylindropuntia acanthocarpa在一年内分解的质量、水分、养分和结构化学, 在美国亚利桑那州的索诺兰沙漠 我们的结果证明了仙人掌分解对碳和养分循环的贡献，大多数元素的动态与木质和草本落叶类似。然而，我们列举了钙动力学中特别重要的作用。尽管最初存在差异，但两种仙人掌以统计上相等的速率释放营养，但由于 cholla 的暂时质量增加而改变了时间。腐烂的仙人掌释放的资源对下伏土壤 CO _{2 的}影响不大通量，次于土壤微气候的主要影响。我们的数据为理解两种常见仙人掌物种的衰变动态提供了基线，并表明，虽然仍然缺乏与仙人掌分解有关的信息，但与落叶的相似性将有助于我们预测未来仙人掌种群变化的后果。