Effect of proportion of donor soil added on total plant community biomass.

<p>Soil was mixed in a proportion of 1∶1 or 1∶5 donor∶receptor soil. Significance between proportions within donor soil origin: ns = non significant, (*) <i>P</i> = 0.05, ** <i>P</i><0.01, *** <i>P</i><0.001.</p

Total plant community biomass in relation to soil treatments.

<p>Treatments are arable top soil (organic) or soil from the lower layer (mineral) mixed with a 1∶1 (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0021943#pone-0021943-g001" target="_blank">Fig. 1a</a>) or 1∶5 (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0021943#pone-0021943-g001" target="_blank">Fig. 1b</a>) proportion of donor soil from early (E1 and E2), mid (M1 and M2) or late (L1 and L2) successional restoration grasslands or without donor soil (None). Bars are means ±1 SE, N = 6 for donor soils and N = 12 for ‘none’. Bars not sharing the same letter are significant different at <i>P</i><0.05 with capital letters indicating main effect of donor soil, small case letters indicate effect of donor×receptor soil.</p

Codes of field sites, time since abandonment and plant association.

<p>Field age = years since abandonment. Lat. = Latitude (°N), Long. = Longitude (°E).</p>1<p>According to Schaminée <i>et al.</i><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0021943#pone.0021943-Schamine1" target="_blank">[38]</a>.</p

Biotic soil characteristics of unmixed field soils at the start of the experiment.

<p>For nematodes abundances are given for their total and per feeding group (bacterial, plant, fungal feeders, omni- and carnivores).</p

RDA diagram of plant species shoot biomass in relation to initial soil characteristics of the 26 soil treatments (24 mixtures and unmixed mineral and organic arable soil).

<p>Fine dotted arrows are abiotic and coarse dotted arrows are biotic characteristics. <i>Hr</i> = <i>Hypochaeris radicata</i>, <i>Fo</i> = <i>Festuca ovina</i>, <i>Cr</i> = <i>Campanula rotundifolia</i>, <i>Am</i> = <i>Arnica montana</i>, <i>Ns</i> = <i>Nardus stricta</i>, <i>Ad</i> = <i>Antennaria dioica</i>. bf = bacterial feeders, pf = plant+root-hair feeders, hf = fungal feeders, ca/om = carnivores+omnivores, total nema = all nematodes.</p

Soil ergosterol concentration (mg/kg soil dw) at the end of the main experiment in relation to the origin and proportion of donor and receptor soil.

<p>Significant differences of donor soil addition compared to no addition (none) within receptor soil and its proportion are indicated by * (organic 1∶1), ♦(mineral 1∶1) ° (organic 5∶1), + (mineral 5∶1) with significance P<0.01 for double symbols and P<0.001 for triple symbols and P = 0.06 for (*). Horizontal dotted lines indicate the ergosterol concentrations in the receptor soils without added donor soils.</p

Biotic soil characteristics of the soils at the start of the experiment, for nematodes abundances are given for their total and per feeding group (bacterial, plant, fungal feeders, omni- and carnivores).

<p>Biotic soil characteristics of the soils at the start of the experiment, for nematodes abundances are given for their total and per feeding group (bacterial, plant, fungal feeders, omni- and carnivores).</p

Abiotic characteristics of the soils at the start of the experiment.

<p>Abiotic characteristics of the soils at the start of the experiment.</p

<i>Antennaria dioica</i> total dry biomass (mg dw/pot) in relation to soil inoculum from the main experiment.

<p><i>Antennaria dioica</i> total dry biomass (mg dw/pot) in relation to soil inoculum from the main experiment.</p

Simpson's evenness index (SIEI) and plant species proportional shoot biomass in response to soil treatments.

<p>Numbers above the bars are SIEI values. Treatments as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0021943#pone-0021943-g001" target="_blank">Fig. 1a</a>. Bars not sharing the same letter are significantly different for SIEI at <i>P</i><0.05 (donor soil main effect).</p