Decoupling of nitrogen, phosphorus, and carbon release from fine and coarse roots during 7 years of decomposition

Belowground litter decomposition represents an important source of the limiting nutrients nitrogen (N) and phosphorus (P) to forest soils, but roots also immobilize these nutrients during the decomposition process. Despite clear implications for soil fertility, the rates and drivers of nutrient immobilization and release (as the percent of increase and decrease of the initial pool) from root litter remain poorly understood, especially in coarse roots (> 2 mm diameter). To address this gap, we conducted a seven-year field decomposition experiment using roots from three species, across five diameter classes (< 1 mm, 1–2 mm, 2–5 mm, 5–10 mm, and 10–20 mm) in a temperate forest. Nitrogen dynamics were largely decoupled with P and carbon (C) over the course of the experiment, and both varied by species and root diameter. Roots released P to the surrounding soil within the first year of decomposition. In contrast, roots immobilized N for much longer, with the coarsest roots remain..., Root material for incubation from three to five mature individuals of each species was excavated in late May 2012 from the 0–20 cm soil layer, and immediately taken back to the lab for processing. The roots were cleaned with tap water, and dead roots were removed and then divided into five diameter classes: < 1 mm, 1–2 mm, 2–5 mm, 5–10 mm, 10–20 mm, and then mixed for each diameter class and each species to reduce the influence of intra-species variability of roots traits on decomposition. A sample of 2–5 g air-dried roots was placed into each 0.1 mm mesh litter-bag, and the masses were later corrected to oven-dried (65°C) mass using species- and diameter-specific correction factors. The correction factor, i.e., the ratio of the oven-dried (65 °C) mass to the air-dried mass, was determined with another root sample of 5 g for each of the five diameters for the three species. Although the litter-bag method may not accurately estimate root decomposition rate by changing the relationship..., , # Decoupling of nitrogen, phosphorus, and carbon release from fine and coarse roots during 7 years of decomposition ## Description of the data and file structure 1. Root decomposition parameter and initial root quality These datasets contain root decomposition parameter and initial root quality from five root diameter classes of the three tree species * species, the tree species used in the study; * diameter, the root diameter used in the study (mm); * *k*LT, double exponential model long-term average decomposition rate; * *k*2, double exponential model decomposition rate for the slow pool; * *k*2s, single exponential model decomposition rate for the slow pool * *k*a, asymptotic model decomposition rate * LCR, long-term C release; * LNR, long-term N release; * LPR, long-term P release; * *k*1, double exponential model decomposition rate for the fast pool; * *k*1s, single exponential model decomposition rate for t...地下凋落物分解是森林土壤限制性养分氮（N）与磷（P）的重要来源，但根系在分解过程中亦会固持这些养分。 尽管其对土壤肥力具有明确调控作用，但关于根系凋落物的养分固持与释放速率及驱动因子（以初始养分库的增减百分比计），目前仍缺乏深入研究，尤其针对直径＞2毫米的粗根而言。 为填补这一研究空白，我们在温带森林中开展了为期7年的野外分解试验，所用根系取自3个树种，涵盖5个径级（＜1毫米、1~2毫米、2~5毫米、5~10毫米及10~20毫米）。 试验期间，氮动态与磷、碳（C）大体呈解耦状态，且二者均随树种与根系径级发生显著变化。根系在分解的第一年便向周边土壤释放磷。与之相反，根系固持氮的时长要长得多，其中最粗的根系仍…… 2012年5月下旬，我们从0~20厘米土层中挖掘出各树种3~5株成熟个体的培育用根系材料，并立即带回实验室进行预处理。先用自来水冲洗根系，去除死根后将其划分为5个径级：＜1毫米、1~2毫米、2~5毫米、5~10毫米、10~20毫米，随后按每个径级与每个树种进行混合，以降低种内根系性状变异对分解过程的干扰。每份称取2~5克风干根系装入0.1毫米孔径的凋落物袋中，后续通过树种与径级专属校正系数将鲜重换算为65℃烘干干重。校正系数即65℃烘干干重与风干重的比值，我们通过针对3个树种5个径级各取5克根系样品测定得到该系数。尽管凋落物袋法可能通过改变相关关系无法准确估算根系分解速率…… # 7年分解过程中细根与粗根的氮、磷、碳释放解耦效应 ## 数据与文件结构说明 1. 根系分解参数与初始根系品质 本数据集包含3个树种5个根系径级的根系分解参数与初始根系品质数据 * species：本研究所用的树种； * diameter：本研究所用的根系直径（毫米）； * *k*LT：双指数模型长期平均分解速率； * *k*2：双指数模型慢速组分分解速率； * *k*2s：单指数模型慢速组分分解速率； * *k*a：渐近模型分解速率； * LCR：长期碳释放量； * LNR：长期氮释放量； * LPR：长期磷释放量； * *k*1：双指数模型快速组分分解速率； * *k*1s：单指数模型快速组分分解速率； * 原文此处截断为“t...”