DOI: 10.5061/dryad.6m905qg5r
title: Root litter decomposition is suppressed in species mixtures and in the presence of living roots

description: Plant species diversity and identity can significantly modify litter
 decomposition, but the underlying mechanisms remain elusive, particularly
 for root litter. Here, we aimed to disentangle the mechanisms by which
 plant species diversity alters root litter decomposition We hypothesised
 that 1) interactions between species in mixed communities result in litter
 that decomposes faster than litter produced in monocultures; 2) litter
 decomposition is accelerated in the presence of living plants, especially
 when the litter and living plant identities are matched (known as home
 field advantage). Monocultures and a mixture of four common grassland
 species were established to obtain individual litter and a ‘natural’ root
 litter mixture. An ‘artificial’ mixed litter was created using litter from
 monocultures, mixed in the same proportions as the species composition in
 the natural litter mixtures based on qPCR measurements. These six root
 litter types were incubated in four monocultures, a four-species mixture,
 and an unplanted soil. Root decomposition was strongly affected by root
 litter identity and the presence, but not diversity, of living roots.
 Mixed-species litter decomposed slower than expected based on the
 decomposition of single-species litters. In addition, the presence of
 living roots suppressed decomposition independent of the match between
 litter and living plant identities. Decomposition was not significantly
 different between the ‘natural’ and ‘artificial’ root litter mixtures,
 indicating that root-root interactions in species mixtures did not affect
 root chemical quality. Synthesis: Suppressed decomposition in the presence
 of living roots indicates that interactions between microbial communities
 associated with living roots and root litter control root litter
 decomposition. As we found no support for the importance of home field
 advantage or interspecific root interactions in modifying decomposition,
 suppressed decomposition of mixed-species litter seems to be primarily
 driven by chemical rather than biotic interactions.
description: # Root litter decomposition is suppressed in species mixtures and in the
 presence of living roots
 [https://doi.org/10.5061/dryad.6m905qg5r](https://doi.org/10.5061/dryad.6m905qg5r) There are two spreadsheets that include all data used for the data analysis for our study. The first spreadsheet has all data for the analysis of home-field advantage, priming effect, root litter decomposition, root traits, microbial communities and nutrient contents. The second spreadsheet has the data used to calculate expected and observed root litter decomposition based on the proportions in natural mixtures using qPCR. ## Description of the data and file structure | Variable Abbreviation | Variable Abbreviation meaning | | --------------------- | ----------------------------- | | Ts | Treatment | | Pot | Pot number | | Block | Experimental block | | Litter\_id | Litter organized as per species name and type of mixture<br>Ao= *Anthoxanthum odoratum* <br>Dg= *Dactylis glomerata*<br>Lv= *Leucanthemum vulgare*<br>Ra= *Rumex acetosa*<br>M= Natural mixture <br>Mix\_art= Artificial mixture | | Litter\_type | Litter organized as per monoculture, natural mixture and artificial mixture<br>Mono= monoculture <br>Mix\_nat= Natural mixture<br>Mix\_art= Artificial mixture | | Plant\_community | Plant community organized as per planted species or bare soil. <br>Ao=*Anthoxanthum odoratum*<br>Dg= *Dactylis glomerata*<br>Lv= *Leucanthemum vulgare* <br>Ra= *Rumex acetosa*<br>Mix= Natural mixture <br>So= soil | | Soil | Variable used to calculate priming effect, using "plant" and "soil" to discriminate treatments.<br>plant = living plant community <br>soil= bare soil | | Plant\_community\_type | Plant community type<br>Mono= monoculture<br>Mix= mixture <br>soil= bare soil | | Home\_away | "Home" when litter and plant community were the same. <br>"Away" when litter differed from plant community | | DWAB | Dried weight above biomass (grams) | | FWRB | Fresh weight root biomass (grams) | | DWRB | Dried weight root biomass (grams) | | prop\_remain1 | Root litter proportion remaining in sampling point 1 | | prop\_remain2 | Root litter proportion remaining | | Amo\_H2O | Water extraction of ammonium (mg g<sup>-1</sup> dry soil) | | Ni\_KCL | KCl extraction of nitrate (mg g<sup>-1</sup> dry soil) | | TN\_H20 | Total nitrogen by water extraction (mg g<sup>-1</sup> dry soil) | | K2S04\_Fumigated | Nitrogen extraction with K2S04 solution after soil was fumigated with chloroform (mg g<sup>-1</sup> dry soil) | | K2S04\_Unfumigated | Nitrogen extraction with K2S04 solution from non fumigated soil (mg g<sup>-1</sup> dry soil) | | MBN | Microbial Biomass-Nitrogen (mg g<sup>-1</sup> dry soil) | | MBC | Microbial Biomass -Carbon (mg g<sup>-1</sup> dry soil) | | MBratio | Microbial Biomass ratio calculated using MBN and MBC. | | DOC | Dissolve organic carbon (mg g<sup>-1</sup> dry soil) | | TC | Total Carbon(mg g<sup>-1</sup> dry soil) | | DIC | Dissolve inorganic carbon (mg g<sup>-1</sup> dry soil) | | pH | pH measured in water | | RNC | Root nitrogen content (mg per gram dry soil) | | RCC | Root carbon content (mg per gram dry soil) | | C\_N\_ratio | root Carbon/ Nitrogen ratio | | total\_PLFAs | Total PLFAs (nmol g<sup>-1</sup>) | | total\_fungal | Total Fungi (nmol g<sup>-1</sup>) | | total\_bacteria | Total Bacteria (nmol g<sup>-1</sup>) | | fungal\_bacterial | Ratio fungi / bacteria | | total\_gram\_po | Total of Gram Positive Bacteria (nmol g<sup>-1</sup>) | | total\_gram\_ne | Total of Gram Negative Bacteria (nmol g<sup>-1</sup>) | | gram\_ratio | Gram Bacteria Ratio | **Second sheet** | Variable abbreviation | Variable abbreviation meaning | | --------------------- | ----------------------------- | | Plant\_community | Living plant community where root litter was placed<br>Ao=*Anthoxanthum odoratum*<br>Dg= *Dactylis glomerata*<br>Lv= *Leucanthemum vulgare* <br>Ra= *Rumex acetosa*<br>Mix= Natural mixture <br>So= soil | | Treatment | All experimental unites belong to treatment testing the decomposition of artificial mixed root litters on each plant community.<br>Mix\_art= Artificial mixture | | Block | Experimental block where the pot was placed | | Mix\_ID | Specific artificial mixed root litter placed in each pot. Each mixture was created using the real proportions in natural mixed root litters obtained by qPCR analysis. | | Exp\_prop\_remain1 | Expected proportion of remain litter for sampling point one | | Obs\_prop\_remain1 | Observed proportion of remain litter for sampling point one | | obsexp\_dif1 | Difference between observed and expected remain litter for sampling point one | | Exp\_prop\_remain2 | Expected proportion of remain litter for sampling point two | | Obs\_prop\_remain2 | Observed proportion of remain litter for sampling point two | | obsexp\_dif2 | Difference between observed and expected remain litter for sampling point two |