An overview of microplastic and nanoplastic pollution in agroecosystems.

https://pure.knaw.nl/ws/files/7087721/6554_Qi.pdf

Macro- and micro- plastics in soil-plant system : Effects of plastic mulch film residues on wheat (Triticum aestivum) growth

The superior effect of nature based solutions in land management for enhancing ecosystem services.

Microplastics are widespread contaminants in terrestrial environments but comparatively little is known about interactions between microplastics and common terrestrial contaminants such as zinc (Zn). In adsorption experiments fragmented HDPE bags c. one mm2 in size showed similar sorption characteristics to soil. However, when present in combination with soil, concentrations of adsorbed Zn on a per mass basis were over an order of magnitude lower on microplastics. Desorption of the Zn was minimal from both microplastics and soil in synthetic soil solution (0.01 M CaCl2), but in synthetic earthworm guts desorption was higher from microplastics (40–60%) than soil (2–15%), suggesting microplastics could increase Zn bioavailability. Individual Lumbricus terrestris earthworms exposed for 28 days in mesocosms of 260 g moist soil containing 0.35 wt % of Zn-bearing microplastic (236–4505 mg kg–1) ingested the microplastics, but there was no evidence of Zn accumulation, mortality, or weight change. Digestion of th...

/pdf/plastic-bag-derived-microplastics-as-a-vector-for-metal-53400nhpo0.pdf

Plastic bag derived-microplastics as a vector for metal exposure in terrestrial invertebrates

To meet the challenge of feeding a growing world population with minimal environmental impact, we need comprehensive and quantitative knowledge of ecological factors affecting crop production. Earthworms are among the most important soil dwelling invertebrates. Their activity affects both biotic and abiotic soil properties, in turn affecting plant growth. Yet, studies on the effect of earthworm presence on crop yields have not been quantitatively synthesized. Here we show, using meta-analysis, that on average earthworm presence in agroecosystems leads to a 25% increase in crop yield and a 23% increase in aboveground biomass. The magnitude of these effects depends on presence of crop residue, earthworm density and type and rate of fertilization. The positive effects of earthworms become larger when more residue is returned to the soil, but disappear when soil nitrogen availability is high. This suggests that earthworms stimulate plant growth predominantly through releasing nitrogen locked away in residue and soil organic matter. Our results therefore imply that earthworms are of crucial importance to decrease the yield gap of farmers who can't -or won't- use nitrogen fertilizer.

/pdf/earthworms-increase-plant-production-a-meta-analysis-c4ejxyl7y6.pdf

Earthworms increase plant production: a meta- analysis

Summary Biodiversity is responsible for the provision of many ecosystem services; human well-being is based on these services, and consequently on biodiversity. In soil, earthworms represent the largest component of the animal biomass and are commonly termed ‘ecosystem engineers’. This review considers the contribution of earthworms to ecosystem services through pedogenesis, development of soil structure, water regulation, nutrient cycling, primary production, climate regulation, pollution remediation and cultural services. Although there has been much research into the role of earthworms in soil ecology, this review demonstrates substantial gaps in our knowledge related in particular to difficulties in identifying the effects of species, land use and climate. The review aims to assist people involved in all aspects of land management, including conservation, agriculture, mining or other industries, to obtain a broad knowledge of earthworms and ecosystem services.

/pdf/a-review-of-earthworm-impact-on-soil-function-and-ecosystem-1kvj0nuth5.pdf

E.A. Delgado

Papers

A review of earthworm impact on soil function and ecosystem services