Introduction: Snowmelt water as recharge water has a significant effect on plant growth, but quantitative evidence to support this issue is lacking. We selected four control water sources, including rainwater, groundwater, river water, and tap water, and comparatively analyzed the quantitative effects of snowmelt water on typical plants by setting up replicated experiments.We also explored the mechanisms of snowmelt water effects on plant growth. Methods: Four plant species—Cosmos bipinnatus, Lactuca sativa L., Solanum lycopersicum L. and Poa pratensis L. were selected for a controlled experiment in which they were irrigated throughout their entire growth cycle using meltwater and four other water sources (rainwater, groundwater, river water and tap water). The results were analysed comparatively to provide scientific evidence of the quantitative beneficial effects of meltwater on plant growth. Results: (1) Under controlled conditions, meltwater significantly promoted the growth of all tested plant species, as evidenced by increases in plant height, root length, stem diameter and fresh weight. (2) Snowmelt water promoted plant growth about 46.58% more than plants irrigated with rainfall, groundwater, Songhua River water, and tap water. The most significant effect on the length of the plant root system could be increased by approximately 2.37 times compared with rainfall and approximately 4.11 times compared with tap water. The boosting effect of snowmelt water on plants was most pronounced during their growth spurt. (3) Mechanistic analysis showed that the mechanism by which snowmelt water significantly promoted plant growth was primarily because of a significant reduction in the content of toxicological indicators in snowmelt water. Discussion: These findings quantify the role of meltwater in promoting plant growth. They confirm the differences in the effects of meltwater and other water sources on plant growth, and the conclusions support efforts to improve the utilisation of meltwater resources. However, the underlying mechanisms by which meltwater influences plant growth require further elucidation and investigation.

Microplastics have become a ubiquitous environmental pollutant, widely distributed across various media within natural ecosystems and human living environments. Currently, scholars have primarily focused on the characteristics of microplastics in natural environments, while research into microplastics within snow cover in agricultural areas remains scarce. This study focuses on the Songnen Plain in Northeast China, where 25 sampling points were selected in February 2023. Through laboratory analysis and modelling techniques, it examines the spatial distribution characteristics and potential sources of microplastics within snow cover on agricultural fields. Results indicate the following: (1) The average abundance of microplastics in snow cover on the Songnen Plain was 1451.07 N·L⁻¹. Fragment-type microplastics predominated, with over 86.38 ± 6.62% of particles concentrated within the 20–50 μm size range. A total of 27 types of microplastic polymers were detected, with polyamide (PA) being the predominant polymer type, while polyethylene (PE), polytetrafluoroethylene (PTFE), and polylactic acid (PLA) were the secondary predominant polymer types. Potential sources of microplastics in snow cover on the Songnen Plain encompass agricultural production activities, emissions from industrial buildings, domestic waste inputs, road traffic sources, and textiles and wastewater. (2) Microplastic abundance in agricultural areas is 1–4 orders of magnitude higher than in natural areas, and comparable to or 1 order of magnitude higher than in urban snow. The particle size of microplastics in farmland snow cover is comparable to that in natural areas, being slightly smaller than that in urban snow. The morphology of microplastics in snow cover farmland is essentially identical between natural and urban areas. The composition of microplastics in snow cover farmland differs from that in natural areas, with polyamide (PA) being the most prevalent component, whereas polyethylene terephthalate (PET) dominates in natural areas. Compared to urban areas, the proportion of polytetrafluoroethylene (PTFE) and polylactic acid (PLA) in snow microplastics is higher in agricultural regions.