Decoupling of nitrogen and phosphorus release from fine and coarse roots during seven 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 and P dynamics were largely decoupled 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 remaining a net N sink..., 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 and phosphorus release from fine and coarse roots during seven years of decomposition

[https://doi.org/10.5061/dryad.sj3tx96b8](https://doi.org/10.5061/dryad.sj3tx96b8)

## 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...