Soil invertebrate biomass is a key driver of ecosystem processes, however, biomass is rarely measured in soil ecological studies, largely because existing methods are labor-intensive or lack individual-level resolution. We developed a simple, low-tech, image-based method to estimate soil macroinvertebrate biomass. This method uses a desktop CCD scanner to digitize composite samples and open-source software (ImageJ) to extract morphometric descriptors from multiple individuals simultaneously. A total of 1153 individuals, representing 96 species and seven taxonomic classes, were scanned and weighed to develop predictive allometric equations for fresh and dry biomass.Multiple linear regression integrating surface area and perimeter yielded the most robust predictors for biomass. For fresh mass, the general model demonstrated high reliability at both the community level (R2 = 0.98, MAPE = 7.4%) and the individual level (R2 = 0.98, MAPE = 25.8%). Dry mass showed similarly strong performance, with class-specific equations substantially improving predictive accuracy. We further quantified biases introduced by alcohol preservation with strong retraction observed in soft-bodied organisms such as earthworms (e.g., a 34% reduction in surface area in 90% alcohol). We derived correction coefficients to adjust predicted biomass values, effectively reducing errors caused by preservation-induced shrinkage. This method enables rapid and reproducible estimation of biomass at both community and individual levels, the latter providing valuable individual-level data for functional trait analyses. Its accessibility makes it suitable for laboratories with limited resources and for retrospective use on preserved collections.

Aim Macroinvertebrates comprise a highly diverse set of taxa with great potential as indicators of soil quality. Communities were sampled at 3,694 sites distributed world-wide. We aimed to analyse the patterns of abundance, composition and network characteristics and their relationships to latitude, mean annual temperature and rainfall, land cover, soil texture and agricultural practices. Location Sites are distributed in 41 countries, ranging from 55 degrees S to 57 degrees N latitude, from 0 to 4,000 m in elevation, with annual rainfall ranging from 500 to >3,000 mm and mean temperatures of 5-32 degrees C. Time period 1980-2018. Major taxa studied All soil macroinvertebrates: Haplotaxida; Coleoptera; Formicidae; Arachnida; Chilopoda; Diplopoda; Diptera; Isoptera; Isopoda; Homoptera; Hemiptera; Gastropoda; Blattaria; Orthoptera; Lepidoptera; Dermaptera; and "others". Methods Standard ISO 23611-5 sampling protocol was applied at all sites. Data treatment used a set of multivariate analyses, principal components analysis (PCA) on macrofauna data transformed by Hellinger's method, multiple correspondence analysis for environmental data (latitude, elevation, temperature and average annual rainfall, type of vegetation cover) transformed into discrete classes, coinertia analysis to compare these two data sets, and bias-corrected and accelerated bootstrap tests to evaluate the part of the variance of the macrofauna data attributable to each of the environmental factors. Network analysis was performed. Each pairwise association of taxonomic units was tested against a null model considering local and regional scales, in order to avoid spurious correlations. Results Communities were separated into five clusters reflecting their densities and taxonomic richness. They were significantly influenced by climatic conditions, soil texture and vegetation cover. Abundance and diversity, highest in tropical forests (1,895 +/- 234 individuals/m(2)) and savannahs (1,796 +/- 72 individuals/m(2)), progressively decreased in tropical cropping systems (tree-associated crops, 1,358 +/- 120 individuals/m(2); pastures, 1,178 +/- 154 individuals/m(2); and annual crops, 867 +/- 62 individuals/m(2)), temperate grasslands (529 +/- 60 individuals/m(2)), forests (232 +/- 20 individuals/m(2)) and annual crops (231 +/- 24 individuals/m(2)) and temperate dry forests and shrubs (195 +/- 11 individuals/m(2)). Agricultural management decreased overall abundance by <= 54% in tropical areas and 64% in temperate areas. Connectivity varied with taxa, with dominant positive connections in litter transformers and negative connections with ecosystem engineers and Arachnida. Connectivity and modularity were higher in communities with low abundance and taxonomic richness. Main conclusions Soil macroinvertebrate communities respond to climatic, soil and land-cover conditions. All taxa, except termites, are found everywhere, and communities from the five clusters cover a wide range of geographical and environmental conditions. Agricultural practices significantly decrease abundance, although the presence of tree components alleviates this effect.

Understanding global biodiversity change, its drivers, and the ecosystem consequences requires a better appreciation of both the factors that shape soil macrofauna communities and the ecosystem effects of these organisms. The project “sOilFauna” was funded by the synthesis center sDiv (Germany) to address this major gap by forming a community of soil ecologists, identifying the most pressing research questions and hypotheses, as well as conducting a series of workshops to foster the global synthesis and hypothesis testing of soil macrofauna. The overarching goal is to analyze the most comprehensive soil macrofauna database - the MACROFAUNA database - which collates abundance data of 17 soil invertebrate groups assessed with a standardized method at 7180 sites around the world, and seeks to foster the collection of future data. In a recent kick-off workshop in May 2022, the first research priorities and collaboration guidelines were determined. Here, we summarize the main outcomes of this workshop and highlight the benefits of creating an open global community of soil ecologists providing standardized soil macrofauna data for future research, evaluation of ecosystem health, and nature protection.

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.

Oil palm (Elaeis guineensis Jacq.) is currently cultivated on 19 million ha, and palm oil represents more than one-third of the global vegetable oil market. Addition of nitrogen (N) via legume cover crop and fertilizers is a common practice in industrial oil palm plantations, however, there is a tendency for N loss, thus contributing significantly to environmental effects. To improve the sustainability of palm oil production, it is crucial to determine which management practices minimize N losses. Continuous field measurements would be cost-prohibiting as a monitoring tool, and in the case of oil palm, available models do not account for all the potential nitrogen inputs and losses or management practices. In this context, we developed IN-Palm, a model to help managers and scientists estimate N losses to the environment and identify best management practices. The main challenge was to build the model in a context of knowledge scarcity. Given these objectives and constraints, we developed an agri-environmental indicator, using the INDIGO method and fuzzy decision trees. We validated the N leaching module of IN-Palm against field data from Sumatra, Indonesia. IN-Palm is implemented in an Excel file and uses 21 readily available input variables to compute 17 modules. It estimates annual emissions and scores for each N-loss pathway and provides recommendations to reduce N losses. IN-Palm predictions of N leaching were acceptable according to several statistics, with a tendency to underestimate nitrogen leaching. Thus, we highlighted necessary improvements to increase IN-Palm precision before use in plantations.

The assessment of the impacts of land-use and management on soil organic carbon (SOC) dynamics is a major environmental concern, as the soil carbon cycle underpins key ecosystem services. However, assessments based on short-term SOC dynamics face methodological and experimental difficulties. Hurisso et al. (2016) proposed a method to assess SOC dynamics by coupling two methods: Permanganate Oxidizable Carbon (POXC) and Basal Soil Respiration (BSR). This method has been used in laboratory on dried and re-wetted soil samples from temperate regions mainly. In our study, we adapted this method to the field and proposed a cost-effective in-field indicator combining the POXC and in situ Basal Soil Respiration (SituResp (R) method). We tested the indicator at four study sites (n = 169 points) within various tropical land-use and management contexts based on rubber, soybean and oil palm cropping systems respectively in Thailand, Cambodia and Indonesia. The results demonstrated the relevance, sensitivity and robustness of the POXC-SituResp (R) indicator to characterize the impact of a gradient of disturbance on SOC dynamics. The results also highlighted the potential of conservation agriculture (no-tillage and crops residues) and compost amendments to accumulate SOC. Rock-Eval (R) analysis showed that POXC-SituResp (R) indicator is negatively linked to excess of potentially mineralizable labile carbon. Carbon pools targeted by the POXC were specified by Rock-Eval (R) pyrolysis measurements to be a rather thermal resistant pool of SOC. Our study confirms that the integrated indicator based on POXC and BSR assess a relative carbon stabilization of SOC pools. This indicator can be measured in the field by a rapid and cost-effective method.

Oil palm produces about 38.7% of all vegetable oil (palm oil and palm kernel oil, 2016) and its cultivation area reach in 18.7 million ha worldwide (mature plantations) in 2017. While palm oil demand will increase in the future, leading an increase of global production, an adapted fertilization is needed to increase yield while preserving soil multifunctionality. Organic fertilization, by Empty fruit bunches (EFB) or compost is an alternative to mineral fertilization. The effect of EFB application on soil quality has been investigated, however the effect of compost application on soil functions and soil macrofauna in oil palm plantations is poorly known. To investigate the effect of compost application, we compared soil functions and soil macrofauna of two treatments of an agronomical trial (compost application / mineral fertilization), taking into account the zone around the palm tree (harvesting path, circle and windrow). Soil functions were assessed using the Biofunctool® framework, which is a novel set of in-field, low tech and time-effective indicators to assess main soil functions: soil carbon transformation, nutrient cycling and structure maintenance. Effect of the zone around the palm tree on soil functions and macrofauna, was largest than the effect of the treatment and the compost application slightly improved carbon transformation functions in the circle zone. Soil functions and macrofauna functional groups data showed similar co-structures indicating the link between soil functions and fauna. We highlighted the importance of spatial heterogeneity and discussed the effect of organic matter.

The assessment of soil quality is a scientific issue that has been widely debated in the literature for the last twenty years. We developed the Biofunctool (R) framework to assess soil quality based on an integrative approach that accounts for the link between the physico-chemical properties and the biological activity of soils. Biofunctool (R) consists in a set of twelve in-field, time- and cost-effective indicators to assess three main soil functions: carbon transformation, nutrient cycling and structure maintenance. The indicators were applied in a network of mostly rubber plantations compared with three other land uses in Thailand. We collected 1952 indicators values in 180 sampling points over a wide range of pedo-climatic and agronomic contexts in order to assess the validity of the indicators. A reliability, redundancy and sensitivity analysis was performed to validate the capacity of the set of indicators to assess the impact of land management on soil quality. The results showed the relevance and consistence of each of the twelve indicators to assess the soil functioning. Improvements are finally discussed to guide further implementation of the indicators in various contexts and build a soil quality index.

Soil organisms, including earthworms, are a key component of terrestrial ecosystems. However, little is known about their diversity, their distribution, and the threats affecting them. We compiled a global dataset of sampled earthworm communities from 6928 sites in 57 countries as a basis for predicting patterns in earthworm diversity, abundance, and biomass. We found that local species richness and abundance typically peaked at higher latitudes, displaying patterns opposite to those observed in aboveground organisms. However, high species dissimilarity across tropical locations may cause diversity across the entirety of the tropics to be higher than elsewhere. Climate variables were found to be more important in shaping earthworm communities than soil properties or habitat cover. These findings suggest that climate change may have serious implications for earthworm communities and for the functions they provide.

Oil palm cultivation produces a massive amount of biomass (e.g., empty fruit bunches (EFB), frond and trunk) which could be recycled directly in the plantation to maintain/improve the quality of soils. The impact of this biomass recycling, i.e., EFB and frond, - in term of chemical, physical and biological characteristics, will be analyzed. The fresh application of the EFB could alternate most of the soil parameters in line with the kinetics of the decomposition of the EFB and the release of nutrients. For example, the pH of the soil after the EFB application was higher during more than 18 months compared to the initial situation. Soil exchangeable potassium increased dramatically within a few days after EFB spreading. Frond recycling, at harvesting and pruning, modifies the chemical and physical characteristics of soils whether they were applied on heaps between palms in dedicated inter-rows, or spread on harvesting paths where they could reduce run-off and erosion. The systematic distribution of fronds in inter-rows reduced rainwater run-off by more than 30%, even on 5% gentle slopes. Subsequently, soil loss through erosion was reduced by 65% depending on the slope intensity of the terrain. Consequently, the loss of nutrients was considerably reduced, resulting in higher fertilizer efficiency. Similar measurements have been done when applying fresh EFB to the soil. The impact on soil physical fertility, i.e., rainwater infiltration rate and subsequently soil humidity are improved. We have also recorded a reduction of the soil resistance to penetration, as well as an improvement of the soil aggregate stability. Several representative parameters of soil biological activity, i.e., soil fauna feeding activity using bait-lamina test system and earthworm’ population showed the positive impact of EFB applications as well as frond spreading in inter-rows.

Assessing how much management of agricultural landscapes, in addition to protected areas, can offset biodiversity erosion in the tropics is a central issue for conservation that still requires cross-taxonomic and landscape-scale studies. We measured the effects of Amazonia deforestation and subsequent land-use intensification in 6 agricultural areas (landscape scale), where we sampled plants and 4 animal groups (birds, earthworms, fruit flies, and moths). We assessed land-use intensification with a synthetic index based on landscape metrics (total area and relative percentages of land uses, edge density, mean patch density and diversity, and fractal structures at 5 dates from 1990 to 2007). Species richness decreased consistently as agricultural intensification increased despite slight differences in the responses of sampled groups. Globally, in moderately deforested landscapes species richness was relatively stable, and there was a clear threshold in biodiversity loss midway along the intensification gradient, mainly linked to a drop in forest cover and quality. Our results suggest anthropogenic landscapes with high-quality forest covering >40 % of the surface area may prevent biodiversity loss in Amazonia.

Earthworms, as ecosystem engineers, help to mineralize soil organic matter, construct and maintain soil structure, and often stimulate plant growth and protect plants from pests. The aim of this study was (i) to determine the connection between earthworm traits and indicators of soil ecosystem services and (ii) to identify earthworm "response" traits, which are selected by the landscape or changes in the soil, and "effect" traits, which contribute to soil processes. In the southern portion of the state of Para (eastern Brazilian Amazonia), we sampled earthworms at 135 points distributed among 3 locations, 9 sub locations and 27 farms (5 sampling points per farm). At each point, three 25 cm x 25 cm soil samples were hand-sorted for earthworms. We measured eight functional traits in 1148 individuals: relative gizzard size, type of typhlosole, length and type of caudal setae, pigmentation, overall length, thickness of septa and musculature in anterior segments. We found a significant, although relatively low, relationship between landscape classes and trait proportions. Earthworm trait proportions significantly covaried with soil parameters and indicators of soil ecosystem services. We did not find significant covariation between earthworm morphospecies and soil ecosystem services. We identified earthworm "response" traits that had been selected and assessed consequences of these changes on effects of earthworm communities (via their "effect" traits) on soil processes and ecosystem services. Typhlosole type, gizzard size and septa thickness were identified as "response" traits selected by soil and landscape conditions. These traits were also identified as "effect" traits for their influence on soil structure. Results indicated a connection between earthworm traits and landscape degradation and soil services, which is a new step toward conceptualizing earthworm ecological studies that go beyond the species level. (C) 2017 Elsevier Masson SAS. All rights reserved.

Palm oil is nowadays the first vegetable oil consumed worldwide. Given the world population growth and the increasing demand in fat for food and fuel, the increase in oil palm production is expected to continue. It is thus important to find ways of reducing the ecological impact of oil palm plantations at both the agroecosystem and the mill supply area levels, by improving agricultural practices and land uses. This is where agroecology can play a very critical role. The present article gathers short stories on agroecological practices currently taking place in oil palm plantations in South-East Asia. Such stories notably highlight the importance of the various palm co-products and how appropriate recycling strategies can allow for reducing external inputs to both the field and the mill. Besides limiting environmental impacts thanks to such savings, several co-products used as organic amendments can even help to maintain or enhance soil quality. Other stories explored agroecological practices developed for biological controls. Although integrated pest management has been applied in palm plantations for a long time, the underlying mechanisms are still not fully deciphered and practices still need to be improved. More knowledge is needed in order to better account for the holistic role of biodiversity and arbitrate trade-offs between practices and ecosystem services, at both plantation and landscape levels.

Soils containing archaeological black earth (ABE) are formed by the continuous deposition of organic residue, and maintain their high fertility even after years of cultivation. The aim of this study was to characterise and quantify the forms of organic phosphorus in areas of archaeological black earth (ABE), with a view to understanding the dynamics of the element and contributing to the development of sustainable practices of land use. Samples of 10 profiles were used from Latosols, Argisols and Gleysols located in the eastern Amazon with an anthropogenic A-horizon (ABE), using adjacent, non-anthropogenic soils as reference. The samples relative to the A, transitional and B-horizons, were subjected to sequential fractionation of P in an acid base extraction, and to further physicochemical characterisation. The acid-extracted P fraction in the A1 and B-horizons predominated over the basic-extractant labile and soluble fractions in all areas, displaying the highest percentages for the inorganic form. An increase in the labile organic phosphorus content (Pol) was found in the A1-horizon, with a reduction between the A and B-horizons of 97.6%. The amount of total phosphorus (TP) was significantly higher (6,778 mg dm-3) in the A-horizons of the ABE in comparison with the soil in the reference area (168 mg dm-3). The predominance of inorganic phosphorus over organic phosphorus was found for the total fraction, while the opposite occurred with the labile fractions. Most of the total labile P is therefore accumulated in the organic fractions of the soil, and represents an active means of supplying the nutrient to plants as it mineralises.

Nitrogen (N) losses in agroecosystems are a major environmental and economic issue. This issue is particularly pronounced in oil palm cultivation because oil palm production area is expected to increase to 12 Mha by 2050. N fertilization in oil palm plantations is mainly provided by mineral fertilizers, palm oil mill by-products, and biological fixation using legume cover crops. N loss has a major environmental impact during cultivation. For instance, 48.7 % of the greenhouse gases emitted to produce 1 t of palm oil fruit are due to N fertilization. Actually, there is little comprehensive knowledge on how to calculate N budgets in oil palm plantation in order to optimize fertilization, taking into account N leaching and N gases emissions. Here we modeled knowledge about all N fluxes in an oil palm field following standard management practices of industrial plantations, on a mineral soil, from planting to felling after a 25-year-growth cycle. The largest fluxes are internal fluxes, such as oil palm uptake, with 40–380 kg N ha −1 year −1 , and the decomposition of felled palms at the end of the cycle, with 465–642 kg N ha −1 . The largest losses are emissions of NH 3 and leaching of NO 3 − , corresponding to 0.1–42 % and 1–34 % of mineral N applied, respectively. The most uncertain and least documented fluxes are N losses such as N 2 O, NO x , N 2 emissions, leaching, NH 3 volatilization, and runoff. The most critical conditions for N losses occur during the immature phase when young palms uptake is low and during the mature phase in areas with sparse soil cover or receiving high amounts of fertilizers. Data is lacking about the effects of management practices on NO 3 − leaching and N 2 O/NO x emissions in those critical conditions.