Mulching cultivation regulates the root-zone microenvironment by modifying the exchange of radiation, heat, water vapor, and gases at the soil–atmosphere interface. Its effectiveness is governed by the selective transport properties of the covering material. As agriculture transitions from conventional polyethylene films—which persist in the environment and cause plastic pollution—to biodegradable alternatives such as polylactic acid, polybutylene adipate terephthalate, plant fiber mulch, and liquid mulch, a critical knowledge gap persists: the heat and mass transfer characteristics of these emerging materials remain poorly quantified. This gap impedes both the rational design of novel materials and the optimization of field application strategies.This review systematically evaluates the heat and mass transfer performance of representative mulch films, focusing on four key parameters: light transmittance, thermal conductivity, oxygen permeability, and water vapor permeability. Substantial differences exist among material types. Polyethylene films offer high transmittance of ranging from 84% to 90%, and moderate water vapor barrier performance, ranging from 0.015 to 0.053 g·mm/(m²·d). Polylactic acid films achieve even higher transmittance—ranging from 88% to 98%—but exhibit significantly elevated water vapor permeability, between 1 and 5 g·mm/(m²·d), which severely compromises moisture retention in dryland farming. Polybutylene adipate terephthalate films provide good flexibility, yet their gas barrier properties are poor, with water vapor permeability ranging from 6 to 15 g·mm/(m²·d), and these properties degrade further upon hydrolysis. Plant fiber films, characterized by porous structures, deliver excellent thermal insulation with thermal conductivity values between 0.04 and 0.07 W/(m·K) and strong weed suppression, but they show very high vapor permeability, reaching 896 to 2489 g·mm/(m²·d). Liquid mulch films, applied as sprayable emulsions, provide moderate moisture retention through the formation of a continuous surface layer. Notably, standardized testing protocols for optical and mass transfer properties are absent across all material categories. Wavelength ranges, weighting functions, and measurement conditions vary considerably among studies, rendering cross-study comparisons largely invalid.In theoretical development, soil heat and mass transfer models have evolved from early static coefficient approaches—built upon Fourier‘s law of heat conduction, Fick’s law of diffusion, and Darcy's law of fluid flow—to dynamic coupled frameworks, most notably the Richards equation for unsaturated flow and the Philip–De Vries model, which unified liquid water and water vapor transport under non-isothermal conditions. Subsequent refinements introduced thermal–hydraulic–mechanical multi-field coupling and advanced numerical techniques including finite element and finite difference methods. However, the majority of existing models still treat the mulch layer as a passive, inert barrier with invariant optical and transport properties. This simplification fails to capture the time-dependent behavior of biodegradable materials, whose transmittance, permeability, and thermal properties evolve markedly over the cropping season as degradation progresses. Although several specialized models have been developed to simulate the sub-film microenvironment—accounting for convective air movement, condensation–evaporation phase changes, and biological activity from roots and soil microorganisms—these efforts remain fragmented and lack a cohesive theoretical foundation.In terms of practical application, current numerical approaches fall into three distinct categories. First, rigorous partial differential equation solvers, exemplified by the HYDRUS series, deliver high physical accuracy and numerical precision, yet require substantial computational resources and extensive parameter calibration. Second, soil–water–atmosphere–plant system models, such as the soil–water–atmosphere–plant model and the Denitrification–Decomposition model, integrate multiple biophysical processes and support scenario-based management analysis, though they represent mulch effects in a highly simplified manner. Third, empirical and semi-empirical models offer computational efficiency and are well-suited for regional-scale assessments, but their extrapolation capability is inherently limited. Case studies illustrate successful applications of each category—from assessing the regional climatic feedback of large-scale mulching, to optimizing nitrogen fertilization under biodegradable film coverage, to establishing simple coverage-to-moisture response relationships for rapid on-farm decision support. Nevertheless, a persistent bottleneck remains: simulation outputs are rarely translated into actionable agronomic guidance, such as site-specific film selection, optimal timing for film application and removal, or integrated water and nutrient management.To overcome these challenges, future research should prioritize three interconnected directions. The first is the establishment of a comprehensive and openly accessible performance database covering all mulch film types—including optical, thermal, mass transfer, and biodegradation metrics—together with standardized testing protocols, with particular emphasis on documenting the dynamic evolution of material properties during field service. The second is the development of multi-field, multi-phase, and multi-scale theoretical models that explicitly integrate degradation-induced changes in film properties and resolve the coupled convection–phase change–biological feedback processes operating within the sub-film microenvironment. The third is the deeper integration of physics-based simulations with data-driven approaches, such as machine learning, to preserve physical interpretability while substantially reducing computational cost, and to translate model predictions into actionable management strategies—specifically, answering which film to select, when to apply it, and when to remove it under given climatic, soil, and cropping conditions. Addressing these interrelated deficiencies will collectively advance film mulching technology toward greater precision, intelligence, and long-term sustainability.

An antibacterial mulch film is required for the rapid response to two key meteorological factors (temperature and humidity) in crop diseases during agricultural production. Conventional disease prevention and control measures respond to the dynamic meteorological conditions—for instance, when a sudden rise in field temperature or a surge in humidity can trigger an outbreak of diseases, often fail to adjust prevention and control strategies in a timely manner; Prevention and control can rely mainly on the large-scale pesticide spraying. This "flood-irrigation" style of pesticide application can easily result in low pesticide utilization efficiency, i.e., substantial pesticide loss. In turn, a series of environmental issues can also cause problems, such as soil pollution and water eutrophication. Meanwhile, excessive pesticide residues in agricultural products can also pose a dual threat to the ecological environment and human health. In this study, an antibacterial mulch film with temperature and humidity responsiveness (CW-C-Gel-WFM) was successfully developed using carnauba wax, gelatin, and temperature-sensitive straw fibers as core raw materials. Each component of mulch film also shares the structural functions. Among them, carnauba wax and gelatin acted as temperature-controlled release materials. Their own structural states were adjusted at the environmental temperature, thereby regulating the pesticide release rate; While temperature-sensitive straw fibers served as carriers, due to their unique porous fiber structure. The active ingredients of pesticides were stably loaded in environmental humidity, thus synergistically achieving precise regulation of "on-demand release". The mulch film was synergistically adjusted as the timing of pesticide release using the physical barrier of carnauba wax and the temperature-sensitive responsiveness of gelatin. As such, the pesticide-controlled release was realized with the changes in field temperature and humidity. Pesticide loss caused by blind release was effectively reduced to dynamically optimize the field pesticide concentration, according to the disease risk at different stages of crop growth, significantly enhancing the controllability of the crop growth environment. Furthermore, the thickness of the mulch film's barrier layer had a significant impact on the mechanical properties (e.g., tensile strength and elongation at break) of CW-C-Gel-WFM. The tensile strength of the mulch film showed a trend of firstly decreasing, then increasing, and finally decreasing again, as the thickness of the barrier layer increased. While the elongation at break decreased slightly. The performance of the straw-fiber-based mulch film was attributed to the repeated coating with a coater and the interaction arising from carnauba wax molecules filling the gaps between gelatin molecules. The tests further indicated that the air permeability rate of the mulch film decreased significantly with the increasing thickness of the barrier layer—when the thickness of the barrier layer reached 30 μm, the air permeability rate dropped to 12.03 μm/(Pa·s). The water evaporation was effectively reduced in the area covered by the mulch film. At the same time, the stable soil humidity was maintained to avoid the excessive volatilization of pesticides caused by overly strong air permeability. In addition, the moisture absorption performance of CW-C-Gel-WFM was significantly superior to that of the control mulch film without carnauba wax (C-Gel-WFM), due to the hydrophobicity of the carnauba wax coating. The mulch film from structural collapse was also prevented under excessive moisture absorption, in order to avoid the premature degradation of pesticides caused by excessive contact with water. Pesticide release kinetics analysis was carried out to evaluate the performance of controlled-release mulch films. The results showed that the pesticide release rate slowed down significantly at constant temperature, with the increasing thickness of the carnauba wax barrier layer, and the controlled release time was extended accordingly. When the thickness of the barrier layer reached 30 μm, the maximum controlled release time reached 96, 120, and 168 h, respectively, which was 48-60 h longer than that of C-Gel-WFM. More importantly, the temperature dominated the pesticide release, with 40 ℃ as a critical threshold: Once the environmental temperature was higher than 40 ℃, pesticide release mainly followed the Fickian diffusion—at this time, the high temperature intensified the molecular movement of the carnauba wax barrier layer for the more internal pores. As such, the pesticides were mainly released from the polymer matrix through molecular diffusion; Once the temperature was lower than 40 °C, the pesticide release shifted to the non-Fickian diffusion. The release was controlled by the swelling of gelatin, the relaxation of polymer chains, and the physical diffusion of carbendazim. The mulch film can be expected to flexibly adjust the release mode according to different temperature environments, further improving the precision of pesticide use. The pot experiments and soil microbial analysis also demonstrated that CW-C-Gel-WFM shared a controlled bacteriostatic behavior to promote plant growth.