Département de Biologie, Université de Sherbrooke, Sherbrooke, Québec J1K2R1, Canada.
Ann Bot. 2012 Jan;109(1):287-97. doi: 10.1093/aob/mcr259. Epub 2011 Oct 16.
We quantitatively relate in situ root decomposition rates of a wide range of trees and herbs used in agroforestry to root chemical and morphological traits in order to better describe carbon fluxes from roots to the soil carbon pool across a diverse group of plant species.
In situ root decomposition rates were measured over an entire year by an intact core method on ten tree and seven herb species typical of agroforestry systems and were quantified using decay constants (k values) from Olson's single exponential model. Decay constants were related to root chemical (total carbon, nitrogen, soluble carbon, cellulose, hemicellulose, lignin) and morphological (specific root length, specific root length) traits. Traits were measured for both absorbing and non-absorbing roots.
From 61 to 77 % of the variation in the different root traits and 63 % of that in root decomposition rates was interspecific. N was positively correlated, but total carbon and lignin were negatively correlated with k values. Initial root traits accounted for 75 % of the variation in interspecific decomposition rates using partial least squares regressions; partial slopes attributed to each trait were consistent with functional ecology expectations.
Easily measured initial root traits can be used to predict rates of root decomposition in soils in an interspecific context.
我们定量地将农业林业中广泛使用的树木和草本植物的原位根系分解速率与根系的化学和形态特征联系起来，以便更好地描述不同植物物种的根系向土壤碳库的碳通量。
采用完整芯法在整个一年的时间内对 10 种树木和 7 种草本植物进行原位根系分解速率的测量，这些植物是农业林业系统的典型代表，并使用 Olson 单指数模型的衰减常数（k 值）进行量化。衰减常数与根系的化学特性（总碳、氮、可溶性碳、纤维素、半纤维素、木质素）和形态特征（比根长、比根长）有关。吸收根和非吸收根都进行了特性测量。
不同根系特性的变化中有 61%到 77%是种间差异，根系分解速率的变化中有 63%是种间差异。氮与 k 值呈正相关，但总碳和木质素与 k 值呈负相关。使用偏最小二乘回归，初始根系特性可以解释种间分解速率变化的 75%；每个特性的部分斜率与功能生态学的预期一致。
在种间背景下，可通过测量易于获得的初始根系特性来预测根系在土壤中的分解速率。
