Earthworm Abundance Research Articles

Spatial patterns and species associations of earthworms in relation to micro-topography and insolation

Despite significant advancements in our understanding of the relationship between soil animal life and environmental gradients, as well as their impact on ecosystem functioning, there is a growing need for quantitative research that considers the spatial and temporal heterogeneity of soil biodiversity. Such research can help to address current knowledge gaps and support the development of legislation and conservation measures aimed at preserving soil biodiversity in the future. Earthworms, one of the most important group of soil animals, show patchy horizontal distribution in response to spatial heterogeneity in soil physico-chemical parameters, food availability and biological interactions at various scales.The aim of this study was to explore whether the spatial and temporal variability and co-occurrence probability of earthworm species and ecological categories (epigeic, endogeic and anecic) can be characterized by exploiting habitat micro-topography and insolation.Field research was carried out in spring and summer at seven locations using a regular grid of 49 sampling points with 5 m inter-sample distance over an altitudinal gradient. The results of Geary's C and Moran's I indices, as well as the semivariograms calculated for each species, season and location confirmed a patchy spatial distribution. The range of semivariograms varied from 3.2 m to 32.8 m in spring, and from 0.3 m to 32.8 m in summer. Overall (all locations and both seasons), the mean range was similar for adult (8.4 m) and juvenile (9.2 m) earthworms. In spring, epigeic species had a larger range than endogeic species. Abundances of juvenile earthworms were negatively correlated with microtopographic elevation in spring (at most locations) and in summer (at all locations). The relationship between adult earthworms and microtopographic elevation could not be interpreted generally within season. Additionally, correlations between earthworm abundance and average monthly insolation were weak. Pairwise analysis of species co-occurrence revealed a random pattern for most species. In the analysis of co-occurrence of ecological categories, endogeics and epigeics had more positive probabilities than other pairs. The obtained results could be useable in soil biodiversity assessments, or creation of monitoring protocols.

Agricultural farming intensification significantly reduced earthworm abundance and diversity in Usangu agro-ecosystems, Tanzania

Earthworms an ecologically important group of invertebrates that are crucial to delivery of many ecosystem services, but also considered ecosystem engineers playing an important role in soil fertility and land productivity. Earthworms facilitate breakdown and decomposition of plant and animal materials releasing plant nutrients. Earthworm burrows allow air and water movement in the soil but also improve soil fertility and drainages. Earthworm population in agricultural soils is influenced by different factors i.e., tillage, farming activities, soil chemistry as well as chemical contaminants. Agricultural (paddy farming) intensification with increased and excessive use of agrochemicals (fertilizers, pesticides, and herbicides) may affect earthworm population in agricultural soils. Recently, there scant studies conducted to characterize earthworm abundance and diversity in Tanzania's agro-ecosystem. Therefore, the present study characterized earthworm population in agricultural soils of contrasting intensification in Usangu agro-ecosystem (UA) to understand influence of current land use on earthworm abundance and their diversity as they have a vital role in agro-ecosystem productivity and sustainability. This study found that current paddy farming and associated activities in UA negatively affect earthworm occurrence, distribution, and diversity. Where only four dominant earthworm species were determined (Apporectodea caliginosa (endogeic), Lumbricus terrestris (Anecic), Pontoscolex corentrurus (endogeic), Fimoscolex sporadochactus (Anecic)) compared to other tropical areas. But also, highly intensified paddy farming areas (i.e., Chimala, Igalako, Ihahi, Kapunga, Mahongole, and Uturo) were observed to have earthworm abundance <25 individuals/m2 an FAO recommended earthworm count/m2 in healthy soils compared to less intensified schemes (25-40 earthworm/m2). The earthworm abundance and biomass determined in UA was below global average of 78 individuals per m2 and 150 g/m2, indicating that UA is in deteriorating quality. Thus, current farming practices creates unfavourable environmental conditions which likely leads to migration of earthworm to other land use or death due to harsh environment created. High earthworm abundance and biomass improve land productivity via nutrient recycling, thus low earthworm counts and diversity in UA likely to threaten agro-ecosystem sustainability. The present study provides baseline information on earthworm abundance and their diversity in UA and Tanzania.

Plant Growth and Root Morphology Are Affected by Earthworm-Driven (Eisenia sp.) Changes in Soil Chemico-Physical Properties: a Mesocosm Experiment with Broccoli and Faba Bean

Earthworms are “ecosystem engineers” that improve soil water and nutrient content, soil macroporosity, and aeration, and provide suitable habitats for microbial populations. This study aimed at defining if the presence of epigeic earthworms (Eisenia sp.) affected the growth and development of two plant species (Brassica oleracea and Vicia faba) via the modifications of soil chemico-physical properties. A mesocosm experiment, in which plants were grown outdoors for 4 months with or without earthworms, was performed. The two plant species were selected based on their different habitus and root architecture and morphology. Soil macroporosity (Msoil) and water holding capacity (WHCsoil) were determined. Earthworm-driven bioturbation (Bsoil) was measured by filling mesh bags with artificial soil. Earthworm abundance and biomass, together with plant morphometric parameters (root and leaf morphology by imaging and microscope techniques), were measured at the end of the trial. The presence of earthworms increased Msoil (on average +16%) and WHCsoil (on average +9%) and this was accompanied by a remarkable degree of Bsoil. In most of the cases, earthworms enhanced plant growth in the two plant species studied, with a significant positive influence on the majority of the shoot and root traits. A significant increase of stomatal density (on average +24%) occurred in the leaves of both the plant species in the presence of earthworms. Our results confirmed the hypothesis that bioturbation by Eisenia sp. had a significant positive effect on plant growth, independently from the plant species cultivated, and that these growth-promoting effects were mediated by changes in soil chemico-physical parameters. By taking into account the essential role of earthworms in maintaining healthy soils and the vegetation they support, soils can become more resilient against environmental perturbations and climate change.

Composition and vertical distribution of agricultural soil Macrofauna community after an extreme high temperature event in the summer of 2022

Extreme high temperature (EHT) events are becoming more frequent and prolonged due to global climate change. Predicting the effects of EHT events on agricultural soil fauna remains a major challenge. In order to assess the response of community composition and vertical distribution of soil fauna to EHT events, this study investigated the soil macrofauna communities in facility agricultural farmlands at the end of an EHT event in East China in 2022 and eighteen days after. The results showed that the taxonomic richness and abundances of the soil macrofauna community were reduced eighteen days after the EHT event. However, changes in abundance were taxonomically dependent: individuals of ants (Pheidole indica), centipedes (Himantariidae) and crickets decreased significantly, while Enchytraeidae and earthworms increased. Soil water content was an important factor determining taxonomic richness at the end of the EHT event and the abundance of earthworms eighteen days after the EHT event. The maximum values of taxonomic richness and abundance of the soil macrofauna community were observed in the surface layer (0–10 cm) at the end of the EHT event and eighteen days after. Earthworms burrowed into the deeper layer at the end of the EHT event, but moved to the surface layer eighteen days after the EHT event. These results showed that most soil fauna taxa experienced adverse effects posed by EHT events, while the earthworm and Enchytraeidae had abilities to increase their abundances rapidly by EHT events. This study suggests that soil water content and vertical distribution should be considered when assessing the impact of an EHT event on soil biodiversity.

Assessing soil health following conversion from forestry to pasture in Canterbury

Soil health was assessed across land conversions from forestry (Pinus radiata) to irrigated dairy pasture. Samples were collected and indicators of soil fertility, organic matter, soil physical condition and biological activity assessed. Soil health scores were calculated from the indicators and distance from optimum shown in radar plots. Soil health was improved for pastoral land use following conversion from forestry. The timesince forestry ceased and irrigation commenced had a signification effect on indicators of soil health, although many were not optimum even for the sites longest out of forestry/under irrigation. The main factors contributing to lower scores across all sites were suboptimal fertility,high C:N ratios, high macroporosity, low microbial respiration and low earthworm abundance and diversity. Some aspects (e.g., fertility) could be managed through nutrient application, while other aspects are more difficult to manage (e.g., C:N ratio and biological activity). Management targeting these properties may accelerate the path to a healthy and well-functioning soil. The inclusion of a wider range of indicators can help to better understand and manage soils during the conversion from forestry to pasture. This approach could be useful across all pasture systems to help ensure well-functioning soils.

Development of soil health benchmarks for managed and semi-natural landscapes

Efforts to improve soil health require that target values of key soil properties are established. No agreed targets exist but providing population data as benchmarks is a useful step to standardise soil health comparison between landscapes. We exploited nationally representative topsoil (0–15 cm) measurements to derive soil health benchmarks for managed and semi-natural environments across Great Britain. In total, 4587 soil organic matter (SOM), 3860 pH, 2908 bulk density (BD), and 465 earthworm abundance (EA) datapoints were used. As soil properties are sensitive to site-specific characteristics, data were stratified by habitat, soil type, and mean annual precipitation, with benchmarks defined as the middle 80 % of values in each distribution – yielding 135 benchmarks. BD and pH decreased with land management intensity (agriculture > semi-natural grasslands > woodlands > heathlands > wetlands), and vice versa for SOM and EA. Normalising benchmark ranges by medians revealed soil health indicator benchmark widths increased in the order: pH < BD < SOM < EA, while width increased with decreasing land management intensity. Arable and horticulture and improved grassland exhibited narrow benchmarks for SOM, pH and BD, yet the widest EA benchmark, suggesting additional drivers impact EA patterns. Upland wetlands had the widest BD benchmarks, important when determining carbon stocks. East Anglia currently possesses the largest proportions of atypical soils, including below typical SOM (19.2 %), above typical BD (17.4 %) and pH (39.1 %), and the smallest proportions of above typical SOM (2.4 %), and below typical BD (5.8 %) and pH (2.3 %). This is found even after land use, soil type and rainfall have been considered, underscoring how urgently soil health should be addressed here. Our benchmarking framework allows landowners to compare where their measured soil health indicators fall within expected ranges and is applicable to other biomes, national and multinational contexts.

Field fodder conversion using electricity – Negative effects on earthworms and changes in labile carbon fractions

The development and use of innovative, conservative methods for weed control and field fodder conversion are urgently required to reduce herbicide use and to overcome drawbacks of mechanical methods. Recently, electrical methods are introduced into market. Although these methods seem to allow promising results concerning mortification of undesired plants, side-effects have not been assessed so far. As electricity is known to harm organisms in biological, physical, and chemical ways, this poses the risk of undesired effects on soil organisms. With the present study we aimed to gain insights into the largely unresearched topic of the effects of electrical field fodder conversion or electrical weed control on soil microbial properties and earthworms, as well as on soil chemical parameters. The results were compared to those obtained by common methods. Plots of a field fodder trial were treated either electrically, mechanically, or chemically for conversion and compared to a control without treatment, each with four field replicates. Soil sampling and earthworm extraction were done at three consecutive dates to observe short and mid-term effects of the different methods. Earthworm abundances and biomasses, and amounts of extractable carbon as well as microbial biomass and activity parameters were determined. The efficiency of the electrical treatment for field fodder conversion was rather low compared to the chemical variant that killed nearly all plants. Two weeks after the treatment, the amounts of hot water extractable carbon were 6% and 9% higher in the electrical variant compared to the control and chemical variant, respectively. In the electrical variant, endogeic earthworm biomass was significantly reduced from 28 g m−2 compared to 44 g m−2 in the control (p < 0.05). To summarize, our results show that the electrical treatment had significant impacts on soil and more research is necessary prior to introducing the systems to the market.

Evaluation of Physico-chemical Parameters of Soil in Different Cropping Systems and their Co-relation with Earthworm Diversity

Aim: The present study is an attempt to evaluate the impact of earthworm diversity on physico-chemical parameters of soil in different cropping systems (i.e. basmati-wheat, basmati-chickpea, soybean-wheat, moong-wheat) under organic and conventional farming systems.&#x0D; Place and Duration of Study: The study was conducted at the School of Organic Farming, Punjab Agricultural University, Ludhiana, Punjab, India from June, 2020 to March 2021.&#x0D; Methodology: The four earthworm species found during the study period are Metaphire posthuma, Lampito mauritti, Amynthas morissia and Travoscolides chengannure, which belong to two families i.e. Megascolicidae and Octochateidae. Out of these Travoscolides chengannure was reported for the first time in Punjab.&#x0D; Results: The results indicate that richer earthworm diversity was found in the organic farming systems as compared to the conventional farming systems. The correlation analysis of earthworm abundance with the physicochemical parameters of soil in different farming systems revealed that the abundance of earthworms in organic farming system shows positive but non-significant correlation with pH, nitrogen and potassium levels. In conventional farming system, significant positive correlation (p=0.01) was found for organic carbon, electric conductivity and nitrogen.&#x0D; Conclusion: The findings of this encourage switching from conventional to organic farming practices. These practices not only increase earthworm diversity, but enrich the soil with many major and micro-nutrients. The agriculture practices which are earthworm-friendly should be adopted for long-term soil productivity.

Collation of a century of soil invertebrate abundance data suggests long-term declines in earthworms but not tipulids.

Large-scale declines in terrestrial insects have been reported over much of Europe and across the world, however, population change assessments of other key invertebrate groups, such as soil invertebrates, have been largely neglected through a lack of available monitoring data. This study collates historic data from previously published studies to assess whether it is possible to infer previously undocumented long-term changes in soil invertebrate abundance. Earthworm and tipulid data were collated from over 100 studies across the UK, spanning almost 100 years. Analyses suggested long-term declines in earthworm abundance of between 1.6 to 2.1% per annum, equivalent to a 33% to 41% decline over 25 years. These appeared greatest in broadleaved woodlands and farmland habitats, and were greater in pasture than arable farmland. Significant differences in earthworm abundance between habitats varied between models but appeared to be highest in urban greenspaces and agricultural pasture. More limited data were available on tipulid abundance, which showed no significant change over time or variation between enclosed farmland and unenclosed habitats. Declines in earthworm populations could be contributing to overall declines in ecosystem function and biodiversity as they are vital for a range of ecosystem services and are keystone prey for many vertebrate species. If robust, our results identify a previously undetected biodiversity decline that would be a significant conservation and economic issue in the UK, and if replicated elsewhere, internationally. We highlight the need for long-term and large-scale soil invertebrate monitoring, which potentially could be carried out by citizen/community scientists.

Acidification of previously limed upland pastures – An overlooked flood risk factor?

In low-lying land, the impact of agriculture on flooding has focussed on soil compaction, whilst in the uplands there has been more interest in the influence of afforestation. The potential effect of acidification of previously limed upland grassland soils on this risk has been overlooked. The marginal economics of upland farms has led to inadequate lime application on these grasslands. In Wales, UK, agronomic improvement of upland acid grasslands with liming was widespread in the last century. The extent and topographical distribution of this land use in Wales was estimated and these characteristics were mapped in four catchments studied in more detail. Then 41 sites on improved pastures within the catchments were sampled, where lime had not been applied for periods of between two and 30 years; unimproved acid pastures adjacent to five of these sites were also sampled. Soil pH, organic matter, infiltration rates and earthworm populations were recorded. Grasslands at risk of acidification without maintenance liming were estimated to cover almost 20 % of upland Wales. The majority of these grasslands were located on steeper slopes (gradients >7o) where any reduction in infiltration would promote surface runoff and limit rainwater retention. The extent of these pastures varied markedly between the four study catchments. There was a 6-fold reduction in infiltration rates between high and low pH soils, and this trend was correlated with reductions in anecic earthworm abundance. The vertical burrows of these earthworms are important for infiltration and no such earthworms were present in the most acidic soils. Recently limed soils had infiltration rates similar to those of unimproved acid pastures. Soil acidification has the potential to exacerbate flood risk but further research is needed to assess the extent of any impact. Modelling of catchment specific flood risk should include the extent of upland soil acidification as an additional land use factor.

Natural farming improves crop yield in SE India when compared to conventional or organic systems by enhancing soil quality

Zero Budget Natural Farming (ZBNF) is a grassroot agrarian movement and a state backed extension in Andhra Pradesh, and has been claimed to potentially meet the twin goals of global food security and environmental conservation. However, there is a lack of statistically evaluated data to support assertions of yield benefits of ZBNF compared to organic or conventional alternatives, or to mechanistically account for them. In order to fill this gap, controlled field experiments were established in twenty-eight farms across six districts, spanning over 800 km, over three cropping seasons. In these experiments, we compared ZBNF (no synthetic pesticides or fertilisers, home-made inputs comprising desi cow dung and urine with mulch) to conventional (synthetic fertilisers and pesticides) and organic (no synthetic pesticides or fertilisers, no mulch, purchased organic inputs, e.g. farmyard manure and vermicompost) treatments, all with no tillage. Comparisons were made in terms of yield, soil pH, temperature, moisture content, nutrient content and earthworm abundance. Our data shows that yield was significantly higher in the ZBNF treatment (z score = 0.58 ± 0.08), than the organic (z= −0.34 ± 0.06) or conventional (−0.24 ± 0.07) treatment when all farm experiments were analysed together. However, the efficacy of the ZBNF treatment was context specific and varied according to district and the crop in question. The ZBNF yield benefit is likely attributed to mulching, generating a cooler soil, with a higher moisture content and a larger earthworm population. There were no significant differences between ZBNF and the conventional treatment in the majority of nutrients. This is a particularly important observation, as intensive use of synthetic pesticides and fertilisers comes with a number of associated risks to farmers’ finances, human health, greenhouse gas emissions, biodiversity loss and environmental pollution. However, long-term field and landscape scale trials are needed to corroborate these initial observations.

Earthworm communities in long-term no-tillage systems and secondary forest fragments in Paraná, Southern Brazil.

The area destined for agricultural production in Paraná state in Brazil is ~6 million hectares, of which 79% are under no-tillage systems (NTS) that can positively affect earthworm populations. Furthermore, earthworm abundance and richness can be valuable soil quality. This study assessed earthworm communities in long-term no-tillage sites (NTS) and nearby secondary Atlantic Forest (SF) fragments. Sampling was performed in June 2018 and May 2019 using the quantitative Tropical Soil Biology and Fertility handsorting method (ISO-TSBF), complemented by qualitative sampling in three municipalities: Faxinal, Mauá da Serra and Palmeira, in NTS and SF. Eleven earthworm species, belonging to five families (Benhamiidae, Glossoscolecidae, Megascolecidae, Ocnerodrilidae, and Rhinodrilidae) were found along with seven native species (Glossoscolex sp.22, Glossoscolex sp.23, Fimoscolex sp.21, Fimoscolex sp.24, Fimoscolex sp.42, Andiorrhinus duseni and Urobenus brasiliensis) and four exotic or cosmopolitan species (Dichogaster gracilis, Amynthas gracilis, Metaphire californica and Pontoscolex corethrurus). The cosmopolitan P. corethrurus dominated Faxinal and Mauá da Serra, while in Palmeira Fimoscolex and Glossoscolex were the most abundant. Six species belonging to Glossoscolex and Fimoscolex were new to science and must be described. Overall, 239 individuals were found. In 2018 126 individuals were found (76 in NTS and 50 in SF) and in 2019, only 112 individuals were found (45 in NTS and 67 in SF). The highest earthworm abundance was in Faxinal (123 individuals), with 76 individuals in NTS and 47 in SF. In Mauá da Serra the same pattern was observed (SF>NTS), while in Palmeira in overall, fewer individuals (38) were collected (24 in NTS and 14 in SF). The NTS at Faxinal and SF Mauá da Serra in 2019 had only/more exotic/cosmopolitan species, while at the other dates and sites >50% of the specimens sampled were native species. Overall, forests had more native species than exotics: in 2018, natives represented > 75% of all specimens, but in 2019 both Faxinal and Mauá da Serra had more exotic species (> 65%), while at Palmeira, they represented 50% of the individuals. Earthworm total biomass for forest sites was higher in Faxinal (3.2 g) and NTS in Mauá da Serra (1.7 g) in 2019. Overall, the total biomass was higher in SF sites than NTS. Using a classification available for earthworm populations in no-tillage systems, all three sites were considered to have poor quality in terms of abundance (ind m-2), while for species richness, they were considered to have moderate (Faxinal and Mauá da Serra) and good quality (Palmeira).

Earthworms in various agricultural and forest ecosystems in São Carlos—SP, Brazil

Integrated agricultural systems have been greatly expanding in Brazil and currently cover over 30 million hectares. Although these land use systems help soil and environmental quality, little is known of their impacts on earthworm communities. In the present study we evaluated earthworm abundance, biomass and species richness in various integrated and conventional agricultural production systems (pasture, crops), as well as native forest and Eucalyptus plantations. The research was carried out at Fazenda Canchim (Embrapa Livestock Southeast) and at the neighboring campus of the University de São Carlos (UFSCar), in São Carlos municipality in São Paulo state, Brazil. Two earthworm sampling methods, i.e., quantitative (25 x 25 x 20 cm deep monoliths) and qualitative (holes of similar size and niche sampling), were used in three integrated production systems, three conventional systems and two forest systems, totaling 232 quantitative samples and over 160 qualitative samples. Earthworms were counted and identified using available keys. Eight earthworm species of five families (Rhinodrilidae, Ocnerodrilidae, Megascolecidae, Benhamiidae and Glossoscolecidae) were found, with most of the 2,145 individuals being exotic or peregrine species, particularly Pontoscolex corethrurus (88% of total) and various Dichogaster spp. (8% of total). Two native species were encountered in low abundance (55 individuals), both of which are new to science (Fimoscolex n.sp.7 and Glossoscolex n.sp.9) and must still be formally described. The new species were found in the agricultural systems, but not in the native forest and the Eucalyptus plantation, where P. corethrurus and Megascolecids predominated. One unidentified Ocnerodrilid sp. was found only in the intensive pasture. Species richness was highest in the intensive pasture (7 spp.), followed by the agrosilvopastoral and agropastoral systems, highlighting the importance of integrated and pastoral systems in preserving earthworm richness and native species.

Tree-distance and tree-species effects on soil biota in a temperate agroforestry system

AimsCropland agroforestry systems are land-use systems with numerous environmental advantages over monoculture croplands including promotion of soil life. This study aimed to investigate tree-species and tree-distance effects on soil biota in a temperate agroforestry system.MethodsOur study was conducted at a paired alley-cropping and monoculture cropland system. The tree rows of the agroforestry system comprised of blocks of poplar Fritzi Pauley, poplar Max 1 or black locust. Within the agroforestry system, soil microbial and earthworm communities were collected along transects spanning from the center of the tree rows into the crop rows. Archaea, bacteria, and fungi were quantified using real-time PCR. The community composition of fungi and earthworms was deciphered using amplicon sequencing and morphological identification, respectively.ResultsTree rows promoted the abundance of bacteria and earthworms, which we attribute mainly to tree litter input and the absence of tillage. Fungal community composition was altered by the tree rows, resulting in an increased proportion of ectomycorrhizal fungi in the tree-row associated mycobiome. The proportion of Blumeria graminis, the causal agent of powdery mildew, increased with increasing distance from the trees. We suggest that enhanced microbial antagonism, increased earthworm densities and/or altered microclimate contributed to the suppression of B. graminis in vicinity of the trees. Tree-species effect had a minor influence on the abundance and composition of soil communities at our study site.ConclusionsIn comparison to monoculture cropland, agroforestry benefits the abundance, diversity, and function of soil biota and may enhance soil suppressiveness.

Effects of organic and inorganic fertilizers on soil properties related to the regeneration of ecosystem services in peat grasslands

Worldwide, agricultural grasslands on drained peat contribute to CO2 emission but provide also provisioning and supporting ecosystem services that are managed by farmers. This paper evaluates the performance of organic and inorganic fertilizers in relation to soil biotic and abiotic properties linked to soil ecosystem services of peat grasslands with biodiversity goals. Effects of cattle slurry, compost, farmyard manure, solid fraction of cattle slurry and inorganic nitrogen (N) fertilizer with and without added sawdust were compared to those of an unfertilized control in a three-year field experiment. Total N input was targeted at 120 kg N ha−1 year−1; total carbon (C) input was variable due to different C:N ratios of source materials. The abundance of earthworms in spring was increased with solid fraction (+35 % as compared to the control), which had the largest C input, and was reduced with inorganic N (−24 %). Combining inorganic N with sawdust did not affect earthworm abundance. Bacteria (determined by phospholipid fatty acid analysis) were increased following inorganic N fertilizer application with (+65 %) or without (+52 %) sawdust. Arbuscular mycorrhizal fungi were reduced by all fertilizers (−40 to −88 %), but less so by those with large C input (solid fraction) or with lignin-rich C input (sawdust + inorganic N fertilizer). Physical and chemical soil properties related to water infiltration and soil organic matter (SOM) decomposition were marginally influenced by fertilizers. The measured changes in soil pH, P availability and (micro)biology may affect SOM dynamics in the longer term. Grass dry matter yield was similarly increased by all fertilizers (+7 to 11 %) whereas grass N yield was increased by fertilizers only when the applied N was in mineral form (+16 to 20 %). From our results, we propose that the moderate use of organic fertilizers with a high and non-humified organic matter content such as solid fraction of cattle slurry can be part of a regeneration strategy in peat grasslands with biodiversity goals.

Large-scale ecologically-based farming systems foster earthworm communities and their contribution to ecosystem processes

In the Pampean region of Argentina, large-scale ecologically-based farming systems (EBS) are proposed as a more sustainable alternative to the conventional systems (CS). EBS rely on soil biological functioning, where earthworms are essential by their contribution to ecosystem processes such as nutrient cycling and soil aggregation. Our aim was to assess the effect of EBS, compared to CS and undisturbed grasslands (GS), on earthworm communities and their contribution to the process of soil structure formation, evaluated through direct sorting and quantification of earthworm casts. EBS and GS had similar earthworm richness and abundance, in both cases significantly higher than in CS. Earthworm biomass was higher in GS than in both farming systems and higher in EBS than in CS. Cast production was higher in EBS compared to CS, and similar in EBS and GS. Cast production was linearly related to earthworm abundance and to a greater extent to earthworm biomass. We conclude, in the first direct assessment of earthworm contribution to soil structure formation in EBS of the Pampean region, that this farming system provides better conditions for earthworm development compared to CS, enhancing their role in the soil ecosystem processes. Thus, we confirmed the ability of EBS to increase soil biological fertility replacing chemical inputs by ecosystem processes thus achieving more resilient and sustainable farming systems.

Earthworms are not just “earth” worms: Multiple drivers to large diversity in deadwood

Earthworms are ecosystem engineers associated with important soil functions. Despite the large amount of literature on earthworm ecology, relatively few studies have examined earthworms in deadwood or quantified their importance in this habitat. We investigated earthworm communities in decaying deadwood and disentangled how their community dynamics are influenced by variation in tree species, wood decomposition stage, and forest environment. Decaying logs (of standardised size) of ten common, temperate tree species were laid out to decay on the soil surface for four years. The experiment was carried out in the “tree cemetery” experiment LOGLIFE, in two contrasting temperate forests in the central Netherlands. The decaying logs yielded surprisingly rich earthworm populations, with on average 19 individuals per meter of log and in total belonging to 12 different species. Our findings highlighted that earthworm communities in deadwood in terms of composition and abundance were influenced by tree species, wood decomposition stage and forest type with different soil properties, as well as their interactions. After one and two years of decay, earthworm abundance was higher in the logs of Picea abies and relatively fast decomposing Populus spp. than in other trees, while this pattern changed after four years with higher earthworm abundance observed in the other tree species. Overall, Populus spp. supported the highest earthworm abundance, followed by Picea abies and Quercus robur. The earthworm community composition in the logs in the two forest sites had broadly similar dynamic trends of first becoming very dissimilar between one and two years, then relatively more similar from two to four years of decay, although the community composition differed between sites. The interacting influences of tree species, wood decay stage and forest environment on earthworm communities strongly suggest that diversity in deadwood resources contributes to earthworm diversity in forests. Thus, by mixing different tree species and logging gradually through the years, forest managers could enhance the diversity of this abundant and understudied component of deadwood invertebrate diversity. Further research should study the feedback loop between earthworm communities and decomposition of deadwood.

The Effect of Mulching on the Biological and Physical Properties of Soil in Maize

To study the effect of different mulching levels on the physical and biological properties of the soil. A field experiment was conducted in Gödöllő Szárítópuszta of the Hungarian University of Agriculture and Life Sciences experimental farm (Pest county). The experiment was laid down in a random block design with five treatments, namely M0%= control, M25%= 25%, M50%= 50%, M75%= 75%, and M100%= 100% level of mulch cover. Soil moisture content (SMC), soil penetration resistance (SPR) and earthworm abundance were measured. SMC, SPR and earthworm abundance were taken at 15-day intervals unless the weather prevented sampling. The experiment was set up from May 2019 until September 2019. The statistical data was carried out using one-way variance analysis with Tukey HSD (Honestly Significant Difference) multiple comparisons post hoc tests. The significance level used in the statistical studies was 5%. Mulch treatments improved water significantly in the first two months (June and July) of crop growth at 10 and 20 cm, however, moisture was not conserved for too long. Mulch treatment did not affect penetration resistance in all treatments. SPR was high after July in all the treatments due to low SMC. The measured SPR reached 5.3 MPa in August in M25%. The highest earthworm abundance was measured at M100% in August while the lowest was measured in control treatments. The grain yield was highest at M50% (1704 kg/ha) compared to the control. Mulch treatments were assessed based on factors such as soil moisture content, biological activity and penetration resistance and mulch was partially found to be advantageous.

The Assessment of Soil Quality in Contrasting Land-Use and Tillage Systems on Farm Fields with Stagnic Luvisol Soil in Estonia

Soil quality indicates the soil’s ability to provide ecosystem services. Reducing the tillage intensity has been suggested as an alternative to conventional tillage for sustaining soil quality. This study aimed to evaluate the effect of soil tillage systems on individual soil quality indicators in comparison to those on grassland with Stagnic Luvisol soil in Estonia. Four soil management systems were compared: no-tillage (NT), minimum tillage (MT), conventional tillage (CT) and grassland (G) as a reference. Soil quality indicators included physical (bulk density, water-stable aggregates, porosity, air-filled pores, moisture content, water-holding capacity, penetration resistance and water permeability), chemical (total N, total soil organic C, permanganate oxidisable C, pH, P, K, Ca and Mg) and biological (earthworm abundance) parameters. CT soils had a significantly lower aggregate stability compared to MT and G soils. The higher penetration resistance of CT under an arable layer suggested the presence of a plough pan. NT improved the soil’s physical quality at 5–10 cm, which was indicated by higher moisture content, water-holding capacity and porosity and a lower bulk density, whereas penetration resistance exceeded 2 MPa in the lower part of the topsoil. NT also had significantly lower total soil organic C and total N compared to MT and G. The absence of tillage in the NT and G systems may have improved the soil’s resistance to moisture loss under dry conditions, which, in turn, improved the soil habitability for earthworms a despite higher density. In general, NT or MT stabilised or increased the soil quality compared to CT.

Application of organic additives as voltage enhancers for vermicompost-derived bio-battery

A bio-battery which is powered by organic compounds provides a clean alternative renewable power source. Huge amount of green wastes around Universiti Teknologi PETRONAS (UTP) campus such as fallen leaves and grass clippings provides an opportunity for waste conversion into value-added products using an eco-friendly composting method called vermicomposting where locally abundant earthworms are added to speed up the breakdown the organic wastes into vermicompost. Recent studies revealed the potential of vermicompost to be used as green electrolyte of bio-battery instead of being solely used as fertilizer. However, the voltage produced from bio-battery is found typically lower and less stable than conventional batteries. The main goal of this research work is therefore to enhance the voltage generation of bio-battery derived from UTP vermicomposts. As a start, good quality vermicompost was produced from available green wastes in UTP compound at optimum carbon-to-nitrogen (C:N) ratio of 30. Next, the humic acid and fulvic acid were be extracted from the vermicompost to be used as the bio-battery’s electrolytes. Different organic additives were added into the electrolyte to determine their suitability as voltage enhancers via voltage profiling. Compost quality was established by final C:N ratio, humic and fulvic acid yield and moisture content analysis in comparison to commercial vermicompost. Key highlights of the project include vermicompost reached maturation on day 41, mass reduction of 18%, and humic and fulvic acid yields at 3.41% and 0.38%. The highest voltage recorded was 0.62 V for humic acid electrolyte with fruit enzyme additive. This approach has multi-fold benefits of cutting down labour requirement, promoting eco-friendly waste management and generating value-added products from waste.