Abstract. Litter decomposition is an important factor affecting local and global C cycles. It is known that decomposition through soil microbial activity in ecosystems is mainly influenced by soil type and climatic conditions. However, for agroecosystems, there remains a need for a better understanding of how management practices influence litter decomposition. This study examined the effect of different management practices on decomposition at 29 sites with long-term (mean duration of 38 years) field experiments (LTEs) using the Tea Bag Index (TBI) protocol with standard litter (rooibos and green tea) developed by Keuskamp et al. (2013). The objective was to determine if the TBI decomposition rate (k) and stabilization factor (S) are sensitive enough to detect differences in litter decomposition between management practices as well as how they interact with edaphic factors, crop type and local climatic conditions. Tea bags were buried and collected after ∼90 d at 16 Austrian and 13 Swedish sites. The treatments in the Austrian LTEs focused on mineral and organic fertilizer application, tillage systems and crop residue management, whereas those in Sweden addressed cropping systems, mineral fertilizer application and tillage systems. The results for Austria showed that the incorporation of crop residue and high-N fertilizer application increased k, compared with crop residue removal and low or no N application, respectively. Minimum tillage had significantly higher k compared with reduced and conventional tillage. In Sweden, fertilized plots showed higher S than non-fertilized plots and high-N fertilizer had the highest k. Growing spring cereal led to higher k than forage crops. Random forest regressions for Austria and Sweden jointly showed that k and S were mainly governed by climatic conditions, which explained more than 70 % of their variation. However, under similar climatic conditions, management practices strongly influenced decomposition dynamics. It would be appropriate to apply the TBI approach to a more large-scale network using LTEs for agroecosystems, in order to improve the index's usefulness as an indicator of the effect of management practices on litter decomposition dynamics, particularly linking it with the potential for C storage.

中文翻译：

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使用奥地利和瑞典的长期田间实验评估农业生态系统中不同管理实践的茶袋指数方法


摘要。凋落物分解是影响局部和全局C循环的重要因素。众所周知，生态系统中土壤微生物活动的分解主要受土壤类型和气候条件的影响。然而，对于农业生态系统，仍然需要更好地了解管理实践如何影响垃圾分解。本研究通过长期（平均持续时间为 38 年）现场实验 (LTE)，研究了不同管理实践对 29 个地点分解的影响，使用茶袋索引 (TBI) 协议和由科斯坎普等人。 （2013）。目的是确定 TBI 分解率 (k) 和稳定因子 (S) 是否足够敏感，能够检测管​​理实践之间凋落物分解的差异，以及它们如何与土壤因素、作物类型和当地气候条件相互作用。约 90 天后，茶叶袋在 16 个奥地利和 13 个瑞典地点被掩埋和收集。奥地利 LTE 的处理重点是矿物和有机肥料的施用、耕作系统和农作物残留物管理，而瑞典的处理则侧重于种植系统、矿物肥料的施用和耕作系统。奥地利的结果表明，与去除作物残茬和施用低氮或不施氮相比，施用作物残茬和施用高氮肥分别增加了 k。与少耕和常规耕作相比，少耕的 k 值显着更高。在瑞典，施肥地块的硫含量高于未施肥地块，高氮肥的钾含量最高。种植春季谷物的钾含量高于饲料作物。 奥地利和瑞典的随机森林回归联合表明，k 和 S 主要受气候条件影响，这解释了 70% 以上的变化。然而，在相似的气候条件下，管理实践强烈影响分解动态。将 TBI 方法应用于农业生态系统使用 LTE 的更大规模网络是适当的，以提高该指数作为管理实践对凋落物分解动态影响的指标的有用性，特别是将其与 C 的潜力联系起来。贮存。