Consequences of 33 years of plastic film mulching and nitrogen fertilization on maize growth and soil quality

Authors: DING, FAN - Shenyang Agricultural University; LI, SHUANGYI - Shenyang Agricultural University; LU, JIE - Shenyang Agricultural University; WANG, QING-WEI - Chinese Academy Of Sciences; LIN, GUIGANG - Chinese Academy Of Sciences; SARDANS, JORDI - Consejo Superior De Investigaciones Cientificas (CSIC); PENUELAS, JOSEP - Consejo Superior De Investigaciones Cientificas (CSIC); WANG, JINGKUAN - Shenyang Agricultural University; RILLIG, MATTHIAS - Berlin-Brandenburg Institute Of Advanced Biodiversity Research (BBIB); Penn, Chad

Submitted to: Environmental Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2023
Publication Date: 6/13/2023
Citation: Ding, F., Li, S., Lu, J., Wang, Q., Lin, G., Sardans, J., Penuelas, J., Wang, J., Rillig, M., Penn, C.J. 2023. Consequences of 33 years of plastic film mulching and nitrogen fertilization on maize growth and soil quality. Environmental Science and Technology. https://doi.org/10.1021/acs.est.2c08878.
DOI: https://doi.org/10.1021/acs.est.2c08878

Interpretive Summary: Using sheets of plastic that cover the ground as a mulching material is a widely utilized practice in various agricultural systems. While plastic mulching presents several immediate benefits (e.g. soil temperature and moisture beneficial to crop growth), there are some questions about potential consequences when practiced in the long-term. The purpose of this study was to determine if long-term plastic mulching had negative soil or crop growth impacts on maize such as increased bulk density or decreased grain yield. Thirty-three year old plots of plastic mulching located in China were split and planted with maize as in previous years, and additionally compared to plots that were never mulched. Soil physical and chemical properties were evaluated along with maize production in all plots. Although long-term plastic film mulching did add substantial amounts of film residues and microplastics in soils, it did not leave a net negative legacy on soil properties such as soil structure or subsequent maize growth and yield.

Technical Abstract: Plastic pollution in croplands has the potential to threaten long-term food security. Plastic mulching film is widely used in agricultural ecosystems, and its long-term use may leave a net negative legacy on maize growth and yield, due to deleterious effects of plastic and microplastic accumulation in soil. Here, we stopped covering soil with plastic film in an experimental site that was previously covered for 33 years, and compared soil properties and subsequent maize growth and yield between plots that were previously covered and never covered with plastic film. Plots were located in Shenyang, China, consisting of a temperate monsoon climate with a mean temperature of 7.9 degrees Celsius and Haplic-Udic Alfisol soils. Maize growth and yield were generally similar between previously and never-mulched plots. Maize had an earlier dough stage (6~10 days) in previously mulched compared to never-mulched plots. Although plastic film mulching did add substantial amounts of film residues and microplastic accumulation into soils, it did not leave a net negative legacy (given the positive effects of the mulching practice in the first place) for soil structure, and subsequent maize growth and yield, at least not as an initial effect in our experiment. Our data add long-term information on this important form of plastic pollution in agricultural systems. Future research should determine if there are delayed negative effects of plastic pollution that develop with time after ceasing plastic use, and also address whether the microplastics at this site have potential to become nanoplastics and impact organisms.