DOI: 10.5061/dryad.v41ns1s1s
title: Data from: Rhizodeposition through root senescence and root exudation of atmospheric C and N by legumes is controlled by traits indicative of resource acquisition and root development

description: Legume crop production has many benefits for agricultural systems. Through
 the rhizodeposition process, they release a significant amount of C and N
 into the soil, increasing soil organic C and reducing the use of N
 fertilizer. Rhizodeposition is known as a dynamic process influenced by
 many factors. The aim of this study was to study the contribution of root
 exudation and root senescence to the rhizodeposition of atmospheric C and
 N during vegetative and reproductive growth in annual and perennial
 legumes and to understand how this is linked to the fixation capacities of
 C and N and root functional traits. An original approach that combined
 13CO2 labeling and the 15N dilution method was developed to measure the
 rhizodeposition of atmospheric C and N throughout plant growth by two
 annual grain legumes (pea and faba bean) and two perennial forage legumes
 (white and crimson clovers). C rhizodeposition was found to increase
 proportionally with N rhizodeposition during reproductive development and
 the differences observed between species were related to the C and N
 fixation abilities. The use of root traits such as specific root length,
 root tissue density, and root dry matter content suggests a strong
 contribution of root exudation to C rhizodeposition at vegetative growth
 and a strong contribution of root senescence to both C and N
 rhizodeposition during reproductive growth. Synthesis: Both C and
 N rhizodeposition appeared to be controlled by traits indicative of
 resource acquisition and root development.
description: Two annual grain legumes and
 two perennial forage legumes were grown and labeled with
 <sup>13</sup>CO<sub>2</sub> to measure fixation
 (Total fixed C, g/m<sup>2</sup>) and rhizodeposition (CdfR,
 g/m<sup>2</sup>) of photosynthetically fixed C. The
 <sup>15</sup>N dilution method was used to measure biological
 N fixation (Ndfa, g/m<sup>2</sup>) and transfer of N (NdfR,
 g/m<sup>2</sup>) from the atmosphere to the soil. Root traits
 were also measured with the winrhizo method: (1) total shoot and root dry biomass (g), (2)
 root mass ratio (RMR ;  g/g), the ratio of root dry mass to total plant
 dry mass, (3) root dry matter content (RDMC; mg/g), the ratio of total
 root dry biomass to total root fresh biomass, (4) root tissue density (RTD
 ; mg/cm<sup>3</sup>), the ratio of root dry biomass to total
 root volume, (5) root diameter corresponding to the mean diameter of the
 total root system, (6) specific root length (SRL; m/g), the ratio between
 total root length and dry biomass, (7) root C content (RCC ; mg/g), the
 ratio of amount of root C to root dry mass, (8) root N content (RNC ;
 mg/g), the ratio of root N amount to root dry mass, (9) shoot and root C:N
 ratio, (10) root mass density (RMD ; mg/cm<sup>3</sup>), the
 ratio of root dry mass to the cultivation pot volume (2L), (11) root
 length density (RLD ; cm/cm<sup>3</sup>), the ratio of total
 root length to the cultivation pot volume. Root samples were also used to
 determine the contents of root soluble C and root soluble N.
  Root samples were also used to determine the
 contents of root soluble C and root soluble N. Extractions were carried
 out by successive treatment of dry root tissue powders with 50 % ethanol
 and ultrapure water.
description: All data are expressed here in a csv format