Soil organisms provide crucial ecosystem services that support human life. However, little is known about their diversity, distribution, and the threats affecting them. Here, we compiled a global dataset of 60 sampled earthworm communities from over 7000 sites in 56 countries to predict patterns in earthworm diversity, abundance, and biomass. We identify the environmental drivers shaping these patterns. Local species richness and abundance typically peaked at higher latitudes, while biomass peaked in the tropics, patterns opposite to those observed in aboveground organisms. Similar to many aboveground taxa, climate variables were more important in shaping earthworm communities than soil properties or habitat 65 cover. These findings highlight that, while the environmental drivers are similar, conservation strategies to conserve aboveground biodiversity might not be appropriate for earthworm diversity, especially in a changing climate.

Organic agriculture can and should play an important role in solving future challenges in producing food. The low level of external inputs combined with knowledge on sustainablity minimizes environmental contamination and can help to produce more food for more people without negatively impacting our

Earthworms are an important soil taxon as ecosystem engineers, providing a variety of crucial ecosystem functions and services. Little is known about their diversity and distribution at large spatial scales, despite the availability of considerable amounts of local-scale data. Earthworm diversity data, obtained from the primary literature or provided directly by authors, were collated with information on site locations, including coordinates, habitat cover, and soil properties. Datasets were required, at a minimum, to include abundance or biomass of earthworms at a site. Where possible, site-level species lists were included, as well as the abundance and biomass of individual species and ecological groups. This global dataset contains 10,840 sites, with 184 species, from 60 countries and all continents except Antarctica. The data were obtained from 182 published articles, published between 1973 and 2017, and 17 unpublished datasets. Amalgamating data into a single global database will assist researchers in investigating and answering a wide variety of pressing questions, for example, jointly assessing aboveground and belowground biodiversity distributions and drivers of biodiversity change.

In organic farming, phosphorus (P) can be imported in mineral form with rock phosphate, feedstuff for livestock or suitable organic fertilizers. Many organic farmers, however, rely on biological activation of soil P reserves and tolerate P deficits, not knowing when soil reserves will be depleted. We hypothesized that under conditions of a long-term negative P budget in organic farming, the decline in readily available soil P pools would be less pronounced in dairy systems (arable land and grassland) than in stockless systems (arable land), due to higher shares of forage legumes in crop rotations, longer plant soil coverage, and manure backflow. From 2001 to 2013, we analyzed those systems on one site in North Germany. We assessed topsoil for plant-available soil P concentration [P(CAL)], mineral soil P fractions (Hedley), organic P, acid and alkaline phosphatase, and microbial activity (dehydrogenase). We measured P(CAL) each year on all fields of the crop rotations and grassland. The other soil characteristics were determined only in selected fields in 2001, 2009, and 2013. We observed that in grassland, all mineral P fractions, organic P contents, and microbial activity were considerably higher than in arable fields. On average, soil P(CAL) content decreased significantly in all systems (stockless arable −1.71, dairy arable −1.41, grassland −3.18 mg P kg −1 year −1), but the soil threshold value deemed to be sufficient for P supply (>44 mg kg −1) was preserved. The readily available inorganic P fractions (H 2 O-P, NaHCO 3-P) were also lower in 2013 than in 2001. Our data does not support a different development in either arable system. We could show that higher shares of forage legumes and manure recycling in an organic mixed arable dairy crop rotation and grassland do not necessarily mitigate decreases of plant-available P contents in soil as compared to a stockless system.

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