Academia.eduAcademia.edu

Figure 1 – uploaded by Jean-François Ponge

See full PDFdownloadDownload figure
FIGURE 8.1 Relationships of earthworms and other soil “ecosystem engineers” with other soil biological components. Earthworms partly influence the occurrence and activity of other soil organisms because they create large structures that may persist over significant periods and affect the environment. (From Lavelle 1997. With permission.) Effects of Earthworms on Soil Organic Matter and Nurient Dynamics

Figure 8 1 Relationships of earthworms and other soil “ecosystem engineers” with other soil biological components. Earthworms partly influence the occurrence and activity of other soil organisms because they create large structures that may persist over significant periods and affect the environment. (From Lavelle 1997. With permission.) Effects of Earthworms on Soil Organic Matter and Nurient Dynamics

Related Figures (7)

FIGURE 8.2 Effects of earthworm activities on soil processes operating at different scales. scale at which SOM dynamics and nutrient cycling are generally studied. One spectacular result of this smaller-scale approach is a huge discrepancy between the great importance that pedobiologists attribute to earthworms as regulators of soil physical structure and SOM dynamics and the absence of any representation of earthworm activities in simulation models that describe SOM dynamics at
FIGURE 8.2 Effects of earthworm activities on soil processes operating at different scales. scale at which SOM dynamics and nutrient cycling are generally studied. One spectacular result of this smaller-scale approach is a huge discrepancy between the great importance that pedobiologists attribute to earthworms as regulators of soil physical structure and SOM dynamics and the absence of any representation of earthworm activities in simulation models that describe SOM dynamics at
FIGURE 8.3 Effects of earthworm activities on SOM dynamics at different scales of time and space.
FIGURE 8.3 Effects of earthworm activities on SOM dynamics at different scales of time and space.
Effects of Inoculation of the Earthworm Millsonia anomala into Cropping Systems on Bulk Density and Aggregation of Soil from 35.4 to 27.4%. Such changes in soil aggregation resulted in a slight increase of bulk density (significant during the first three cropping cycles) and a significant decrease in infiltration rates and sorptivity, the latter decreasing from 0.34 cm sec"! in non-earthworm-inoculated soils to 0.15 cm sec™!? in treatments inoculated with 36 g m~ fresh biomass of earthworms (Alegre et al. 1996). This transformation in soil physical properties resulted in eventual changes in the soil water regime because soil tended to become drier during dry periods and wetter in periods of heavy rainfall than in the non-earthworm-—inoculated treatment.
Effects of Inoculation of the Earthworm Millsonia anomala into Cropping Systems on Bulk Density and Aggregation of Soil from 35.4 to 27.4%. Such changes in soil aggregation resulted in a slight increase of bulk density (significant during the first three cropping cycles) and a significant decrease in infiltration rates and sorptivity, the latter decreasing from 0.34 cm sec"! in non-earthworm-inoculated soils to 0.15 cm sec™!? in treatments inoculated with 36 g m~ fresh biomass of earthworms (Alegre et al. 1996). This transformation in soil physical properties resulted in eventual changes in the soil water regime because soil tended to become drier during dry periods and wetter in periods of heavy rainfall than in the non-earthworm-—inoculated treatment.
FIGURE 8.4 Changes in carbon and nitrogen contents in an ultisol of Peruvian Amazonia submitted to traditional slash-and-burn agriculture in the presence and absence of earthworms (Pontoscolex corethrurus). Pairs of data with different letters are significantly different. (From Pashanasi et al. 1996. With permission.) Earthworm Ecology, Second Edition
FIGURE 8.4 Changes in carbon and nitrogen contents in an ultisol of Peruvian Amazonia submitted to traditional slash-and-burn agriculture in the presence and absence of earthworms (Pontoscolex corethrurus). Pairs of data with different letters are significantly different. (From Pashanasi et al. 1996. With permission.) Earthworm Ecology, Second Edition
FIGURE 8.5 Changes of carbon contents in soils of a grass savanna at Lamto (Céte d’Ivoire) in the presence and absence of endogeic earthworms; results of a simulation using the CENTURY model. (From A. Martin and W.J. Parton unpublished data, 1993.) Effects of Earthworms on Soil Organic Matter and Nurient Dynamics
FIGURE 8.5 Changes of carbon contents in soils of a grass savanna at Lamto (Céte d’Ivoire) in the presence and absence of endogeic earthworms; results of a simulation using the CENTURY model. (From A. Martin and W.J. Parton unpublished data, 1993.) Effects of Earthworms on Soil Organic Matter and Nurient Dynamics
FIGURE 8.6 Changes in the abundance of earthworms of different ecological categories along a succession in an alpine spruce forest. (From Bernier et al. 1993. With permission.)
FIGURE 8.6 Changes in the abundance of earthworms of different ecological categories along a succession in an alpine spruce forest. (From Bernier et al. 1993. With permission.)
FIGURE 8.7 Changes in the abundance of organic matter (OM) bounded to soil minerals and unbounded organic matter along a succession in an alpine spruce forest. (From Bernier et al. 1993. With permission.) Our hypothesis that earthworm activities may develop at a determined stage in plant successions is supported by data from Bernier et al. (1993) in an alpine forest of France located at a 1550-m elevation. In a succession of forest patches from 10 to 190 years old, significant changes in earthworm communities were observed (Figure 8.6). In the early stages, earthworm populations were large with a clear dominance of endogeic species populations. Population densities decreased steadily during the subsequent 20 years, and after 60 years, when the forest was mature, earthworm populations started to increase again, although their population density was low. These population changes coincided with clear changes in the amounts and quality of organic matter stored in the humus layers. The proportion of organic matter that was bound to minerals (i.e., organic matter mixed into the soil by earthworm activities) was greatest after 10 years and then decreased steadily, with bound organic matter almost absent after 60 years (Figure 8.7). In the later stages of succession, bound organic matter began to accumulate again. The pattern of changes of unbound organic matter in time was exactly opposite to that of bound organic matter.
FIGURE 8.7 Changes in the abundance of organic matter (OM) bounded to soil minerals and unbounded organic matter along a succession in an alpine spruce forest. (From Bernier et al. 1993. With permission.) Our hypothesis that earthworm activities may develop at a determined stage in plant successions is supported by data from Bernier et al. (1993) in an alpine forest of France located at a 1550-m elevation. In a succession of forest patches from 10 to 190 years old, significant changes in earthworm communities were observed (Figure 8.6). In the early stages, earthworm populations were large with a clear dominance of endogeic species populations. Population densities decreased steadily during the subsequent 20 years, and after 60 years, when the forest was mature, earthworm populations started to increase again, although their population density was low. These population changes coincided with clear changes in the amounts and quality of organic matter stored in the humus layers. The proportion of organic matter that was bound to minerals (i.e., organic matter mixed into the soil by earthworm activities) was greatest after 10 years and then decreased steadily, with bound organic matter almost absent after 60 years (Figure 8.7). In the later stages of succession, bound organic matter began to accumulate again. The pattern of changes of unbound organic matter in time was exactly opposite to that of bound organic matter.
Related topics:
Soil ScienceSoil DynamicsSoil ProcessesSoil and Forest Ecosystem
580 California St., Suite 400
San Francisco, CA, 94104
© 2025 Academia. All rights reserved