ISO 23517:2021 pdf free download – Plastics一Soil biodegradable materials for mulch films for use in agriculture and horticulture一 Requirements and test methods regarding biodegradation, ecotoxicity and control of constituents.
Biodegradable mulch films are used worldwide in agriculture and horticulture for many years. They enhance growing conditions and contribute to increased yields and improved crop quality by, for example:
— inhibiting the development of weeds;
— reducing significantly the consumption of water and other resources;
— control of soil temperature;
— reduction in leaching of mineral elements and other fertilizer;
— reduction in soil compaction;
— protecting the crops from soil.
Biodegradable mulch films are not designed to be recovered from soil at the end of the intended service life. Therefore, it is no longer necessary for farmers to retrieve the biodegradable mulch film from the field for disposal or recycling after the harvest. Farmers can simply plow it under along with what remains from the plants so that it is incorporated into soil.
This document defines the standard specification to be met for biodegradable mulch films to be used in agriculture and horticulture. It is suited to characterize both the plastic materials which are used to manufacture mulch films and the mulch films itself with respect to characteristics such as biodegradation, adverse effects on terrestrial organisms and control of constituents.
The purpose of this test is to evaluate adverse effects of materials on the reproduction of earthworms. The effects of mulch films incorporated in soil following the chronic toxicity earthworm test shall be determined in accordance with Iso 11268-2 with the modifications specified in Annex E. Alternatively, the acute toxicity earthworm test given in 5.3.4.2 may be conducted.
The effects on reproduction of adult earthworms (species Eisenia fetida or Eisenia andrei) exposed to mulch films samples incorporated in soil are compared to those observed for samples exposed to blank soil. In addition, observations on growth and survival of adult earthworms are determined.
The survival and the biomass of the surviving adult earthworms in the soil exposed to the test material shall be more than 90 % of those from the corresponding blank soil not exposed to the test material after an incubation period of 28 days.
The observed number of offspring in soil exposed to the test material shall be more than 90 % of those from the corresponding blank soil not exposed to the test material after an incubation time of 56 days.
If the survival and the biomass of the surviving adult earthworms after an incubation period of 28 days, or if the counted number of offspring after an incubation period of 56 days grown in the soil exposed to the test material as well as in the soil exposed to the reference material (e.g. microcrystalline-cellulose) is less than 90 % of those from the corresponding blank soil not exposed to any material, then this could be considered as an indication that a transient phytotoxicity caused by the biodegradation of the high amount of biodegradable materials added to the soil is present and affecting the test. The test is to be considered as not valid and to be repeated after a further maturation of the soil.
The validity criteria as stated in ISO 11268-2 shall be fulfilled in blank soil samples.
Test items that have been already assessed for chronic toxicity to earthworms following EN 17033W] or equivalent standard specifications and fulfilled the pass level for long-term toxicity to earthworm laid down in the respective standard specification do not need to be retested.
5.3.5 Nitrification inhibition test with soil microorganisms
The effects of materials on the microbial nitrification activity in soil shall be determined following Iso 15685 with the modifications specified in Annex F.