Plastic materials such as mulch films are widely used in agri- cultural applications to contribute toward food security for the growing world population. Global interest in the use of biodegrad- able instead of non-biodegradable polymers in agriculture has increased in recent decades due to the potential reduction in the accumulation of plastics in the environment. After usage, biodegradable mulch films are intended to be composted or tilled into the soil to decompose into carbon dioxide (CO2) and water or be incorporated into microbial biomass. Applying biomass- derived biodegradable mulch film not only reduces waste and saves labour, but also reduces greenhouse gas emissions in the agricultural sector, leading to a circular economy (Figure 1). To be more widely adopted, biodegradable mulch films must have the same advantages as conventional plastic mulch films, i.e., increased soil temperature, reduced weed pressure, water reten- tion, reduction of certain pests, increased yields, and more effi- cient use of soil nutrients. This topical collection of the Italian Journal of Agronomy entitled ‘Use of biodegradable plastic films in agriculture and their fate in soil’ consists of five articles, providing scientific evi- dence on the performance and microbial biodegradation processes of mulch film in agricultural soils. It also provides a thorough dis- cussion on the need to couple direct and indirect methods of to access biodegradation and the overall sustainability of biodegrad- able plastic mulch films. Di Mola et al. (2022) showed that the impact of biodegradable mulch in terms of yield quantity and quality was comparable to conventional low-density polyethylene (LDPE) films under let- tuce production trials in Italy. The authors recommended biodegradable mulch films as they reduce the economic and envi- ronmental costs of removing and disposing of LDPE films. Sintim et al. (2022) compared the modulation of gas exchange and soil microclimate under biodegradable plastic mulch to those under polyethylene (PE) and paper mulches. Gas exchange under biodegradable plastic mulch was lower than PE mulch in terms of CO2 accumulation and oxygen reduction in the soil, although this did not affect sweet corn growth. PE mulch conserved soil mois- ture and inhibited light penetration more effectively than biodegradable plastic mulch. These findings by Sintim et al. (2022) demonstrate differences in gas exchange and soil microcli- mate dynamics between biodegradable plastic mulch and PE, highlighting the need to improve on current industrial products. Francioni et al. (2022) provided a review of the methods used to estimate the biodegradation of biodegradable plastics in the soil, under both laboratory-controlled and open-field conditions. From the review, it emerged that many articles do not report soil characteristics. Moreover, indicators such as mass loss or visual assessment can be useful in open-field experiments as long as they are used on materials already certified as ‘soil-biodegradable’ fol- lowing international standards. This is because mass loss or visual assessment indicates degradation and not necessarily biodegrada- tion that requires the mediation of microorganisms. The authors also highlight that there is an urgent need for a shared methodolo- gy to make results comparable among different experiments. Tsuboi et al. (2022) evaluated the degradation of three differ- ent biodegradable films using the mesh bag method by analyzing the loss of weight and visual area in a cultivated field in Japan over seven months. Among five p-nitrophenyl (pNP) fatty acid substrates investigated to evaluate esterase activity in the soils, three pNP substrates with shorter acyl chains (pNP–C2, –C4, and –C6) indicated an increase in hydrolytic activity with film degra- dation. In particular, pNP–C4 hydrolytic activity can aid in the detection of the microbial activity associated with the biodegrada- tion of polyester-based biodegradable mulch films in cultivated field soils. Bianchini et al. (2022) conducted open-field experiments where they evaluated the effects of soil refinement on the degra- dation rates of three different commercial soil-biodegradable mulch films after their incorporation into the soil. Their results show that soil refinement significantly accelerated the degradation of the tested films. Although this appears to be the first study to evaluate the effect of different soil management under open-field conditions, future studies are needed to quantify the biodegrada- tion of polymers over time following international standards. The articles published in this topical collection highlight sev- eral aspects of the use and biodegradation of soil-biodegradable plastics in agriculture. We expect that this collection will act as a stimulus to advance research and development in biodegradable Correspondence: Ayaka Wenhong Kishimoto-Mo, Institute for Agro- Environmental Sciences, National Agriculture and Food Research Organization, 3-1-3 Kannondai, Tsukuba, Ibaraki 305-8604, Japan. E-mail: mow@affrc.go.jp © Copyright: the Author(s), 2022 Licensee PAGEPress, Italy Italian Journal of Agronomy 2022; 17:2155 doi:10.4081/ija.2022.2155 This article is distributed under the terms of the Creative Commons Attribution Noncommercial License (by-nc 4.0) which permits any non- commercial use, distribution, and reproduction in any medium, provid- ed the original author(s) and source are credited. Publisher's note: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organiza- tions, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its man- ufacturer is not guaranteed or endorsed by the publisher. Use of biodegradable plastic films in agriculture and their fate in soil Ayaka Wenhong Kishimoto-Mo, 1 Henry Y. Sintim, 2 Luigi Ledda 3 1 Institute for Agro-Environmental Sciences, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan; 2 Department of Crop & Soil Sciences, University of Georgia, Athens and Tifton, GA, USA; 3 Department of Agricultural, Food and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy [Italian Journal of Agronomy 2022; 17:2155] [page 181] Italian Journal of Agronomy 2022; volume 17:2155 Non-commercial use only