Fischer Christine, Roscher Christiane, Jensen Britta, Eisenhauer Nico, Baade Jussi, Attinger Sabine, Scheu Stefan, Weisser Wolfgang W, Schumacher Jens, Hildebrandt Anke
Institute of Geosciences, Friedrich-Schiller-University Jena, Jena, Germany; Max Planck Institute for Biogeochemistry, Jena, Germany.
UFZ, Helmholtz Centre for Environmental Research, Department of Community Ecology, Halle, Germany.
PLoS One. 2014 Jun 11;9(2):e98987. doi: 10.1371/journal.pone.0098987. eCollection 2014.
Infiltration is a key process in determining the water balance, but so far effects of earthworms, soil texture, plant species diversity and their interaction on infiltration capacity have not been studied.
METHODOLOGY/PRINCIPAL FINDINGS: We measured infiltration capacity in subplots with ambient and reduced earthworm density nested in plots of different plant species (1, 4, and 16 species) and plant functional group richness and composition (1 to 4 groups; legumes, grasses, small herbs, tall herbs). In summer, earthworm presence significantly increased infiltration, whereas in fall effects of grasses and legumes on infiltration were due to plant-mediated changes in earthworm biomass. Effects of grasses and legumes on infiltration even reversed effects of texture. We propose two pathways: (i) direct, probably by modifying the pore spectrum and (ii) indirect, by enhancing or suppressing earthworm biomass, which in turn influenced infiltration capacity due to change in burrowing activity of earthworms.
CONCLUSIONS/SIGNIFICANCE: Overall, the results suggest that spatial and temporal variations in soil hydraulic properties can be explained by biotic processes, especially the presence of certain plant functional groups affecting earthworm biomass, while soil texture had no significant effect. Therefore biotic parameters should be taken into account in hydrological applications.
入渗是决定水分平衡的关键过程，但迄今为止，蚯蚓、土壤质地、植物物种多样性及其相互作用对入渗能力的影响尚未得到研究。
方法/主要发现：我们在嵌套于不同植物物种（1、4和16种）以及植物功能群丰富度和组成（1至4个功能群；豆科植物、禾本科植物、小型草本植物、大型草本植物）样地中的、蚯蚓密度为自然密度和降低密度的亚样地中测量了入渗能力。在夏季，蚯蚓的存在显著增加了入渗，而在秋季，禾本科植物和豆科植物对入渗的影响归因于植物介导的蚯蚓生物量变化。禾本科植物和豆科植物对入渗的影响甚至逆转了质地的影响。我们提出了两条途径：（i）直接途径，可能是通过改变孔隙谱；（ii）间接途径，通过增强或抑制蚯蚓生物量，这反过来又由于蚯蚓挖掘活动的变化而影响入渗能力。
结论/意义：总体而言，结果表明土壤水力性质的时空变化可以由生物过程来解释，特别是某些影响蚯蚓生物量的植物功能群的存在，而土壤质地没有显著影响。因此，在水文应用中应考虑生物参数。
