MINI REVIEW article

Front. Agron., 23 July 2026

Sec. Plant-Soil Interactions

Volume 8 - 2026 | https://doi.org/10.3389/fagro.2026.1900760

Mulch representation in soil-crop models

  • 1. Plant Sciences Unit, Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Merelbeke-Melle, Belgium

  • 2. Department of Environment – SENSE Group, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium

  • 3. Department of Environment, Unesco Chair in Eremology, Ghent University, Ghent, Belgium

  • 4. Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium

Abstract

Organic mulching is widely used in agriculture to improve soil conditions and enhance crop performance. However, mulch induces complex changes in soil processes, making process-based soil-crop models essential for understanding and predicting these effects. This non-systematic review summarizes the effects of mulch on soil hydrology, fertility, and temperature to evaluate how these processes are integrated into process-based soil-crop models. Current modeling approaches range from simple surface-residue representations that affect evaporation to more integrated frameworks that simulate decomposition and energy-balance feedbacks. Nevertheless, comprehensive and transferable representations of mulch effects remain limited. Future progress will require open-access datasets and modeling frameworks that explicitly represent mulch processes and feedback mechanisms with soil and crops. These improvements would enhance the implementation and optimization of mulch management strategies under varying environmental conditions.

1 What is organic mulching?

In natural ecosystems, plants influence the environment through the accumulation of litter, which stimulates soil life and strengthens ecosystem nutrient cycling (). In agriculture, most plant material is typically harvested, thus limiting the input of organic matter into the agroecosystem. Mimicking natural ecosystems in an agronomical context by applying undecomposed plant material, i.e., mulch, at least partially, compensates for crop residue removal. In this paper, the term ‘mulch’ refers specifically to organic mulching (using undecomposed plant-based litter) as opposed to plastic, inorganic, or living mulches.

Organic mulch is primarily used to improve the crop’s yield and water-use efficiency (WUE) (; ; ). A meta-analysis across 19 countries reported a 20% increase in yield and WUE for wheat and maize under straw mulching, though outcomes vary with environment, crop type, nitrogen and water availability (). Moreover, when matched to crop, management, and climate, mulch has been reported to buffer soil temperatures, support microbial activity and enhance nutrient cycling (; ; ). It has also been reported to reduce residual pesticides, fertilizers, heavy metals, while suppressing weeds (), and enhance disease tolerance (). However, the limited availability of local biomass or its conflict with other uses, and the labor-intensive nature and high transportation costs of its application are challenges to its broader adoption (; ).

A wide variety of organic mulch types have been used in agriculture, each with its own advantages in specific locations. The degree to which these mulches affect the soil quality, defined in this article as the soil’s capacity to function and support plant productivity (), depends on mulch type, thickness, and application method (e.g., full or partial cover and ridge–furrow systems) (; ; ). have provided a broad overview of application methods and mulch types. Readers are referred to this work for more in-depth information.

Although organic mulching is promoted as a valuable management strategy, its mechanisms and representation in soil-crop models remain insufficiently understood. Improving this representation is essential for evaluating mulch management strategies and supporting decision-making under varying environmental conditions. In this non-systematic review paper, we introduce the effects of organic mulching on soil hydrological processes, soil fertility, and soil temperature, focusing on mechanisms represented in process-based soil-crop models (Figure 1). This information is then used to evaluate how commonly process-based soil–crop models represent mulching, and to discuss their limitations and potential.

Figure 1

2 Effects of organic mulching on soil quality

2.1 Effects on soil hydrological processes

Runoff is the first pathway of water loss. Mulch protects the soil surface by dissipating raindrop kinetic energy, reducing particle detachment and flow velocity, and thereby limiting erosion and runoff (; ; ).

Mulches also increase soil water infiltration by limiting crust formation (; ; ) and increasing soil organic matter (SOM), which promotes soil aggregates and soil porosity (; ; ). This improved soil structure further enhances soil water retention capacity (; ; ; ). Although mulches intercept and absorb part of the rainfall (), field studies generally report improved soil water storage ().

Finally, by reducing solar radiation reaching the soil, mulching lowers soil evaporation and helps conserve moisture (; ; ; ). Over time, the application of mulch tends to improve the water budget for crops (; ).

2.2 Effects on soil fertility

Mulch influences soil fertility, defined as the soil’s ability to sustain plant growth by nutrient availability and biological activity (). Its effects on hydrological processes play a primary role, as nutrient transport is linked to transpiration, and drought can limit nutrient uptake despite the availability of nutrients (; ).

During its decomposition, mulch serves as a nutrient source, primarily for nitrogen (N). Overall, it improves crop N use efficiency () and reduces N and phosphate loss (; ; ; ). However, benefits depend on the synchronization of nutrient release with crop demand (). In this context, mulch quality in terms of C:N ratio is a key determinant of mineralization rate and the associated immobilization of soil nutrients (; ). Low C:N ratio mulches (e.g, leguminous residues) decompose faster, stimulate microbial mineralization, and enhance soil N availability, whereas high C:N ratio mulches (e.g, woody residues) immobilize N and reduce crop production (; ; ; ). The form of organic C also matters. Labile compounds, such as glucose cause stronger immobilization than more stable forms such as cellulose or tannins ().

By buffering moisture and providing carbon and nutrients, mulch stimulates microbial activity and accelerates residue turnover, enhancing nutrient cycling (; ; ; ) and improving SOM content (; ).

In summary, mulch can improve fertility by supplying nutrients and carbon and by maintaining soil moisture that supports microbial activity. The net outcome depends on mulch quality (e.g., C:N ratio and carbon form) and on how decomposition-driven nutrient release aligns with crop demand. Projected climate change will accelerate decomposition (), underscoring the importance of mulching on soil fertility.

2.3 Effects on soil temperature

Soil temperature is correlated with air temperature and surface cover () and governs the rate of various physical, chemical, and biological processes such as microbial activity, seed germination, plant development, pesticide degradation, and organic matter decomposition (; ). Mulch-driven changes in soil temperature have been observed to affect shoot growth, root development, biomass allocation, and nutrient uptake ().

Primarily, mulch alters surface energy fluxes by reflecting and absorbing shortwave radiation (; ; ; ), and by changing how energy is partitioned between latent and sensible heat during wetting and drying cycles (; ; ). In addition, a mulch layer acts as a thermal conductivity barrier, reducing the soil’s heat loss (; ; ). As a result, mulching buffers daily soil temperature fluctuations, cooling soils in summer and keeping them warm in winter, though outcomes depend on mulch thickness, mulch type, soil type, and climate (; ; ; ; ).

The effects of mulch-induced soil temperature changes on crop development depend on local climate, vary seasonally (), and are governed by crop-specific thermal requirements (; ). While a buffered soil temperature can improve and accelerate plant development under certain circumstances (; ), it can reduce yields or delay plant development under other circumstances (; ; ; ).

3 Representation of mulching in process-based soil-crop models

Mulching affects multiple interacting processes (Figure 1), making its impacts context-dependent. Process-based soil–crop models address this by representing soil–crop dynamics and interactions to simulate complex outcomes such as yield and soil water balance (). These models are widely used for decision support in crop management, studying genotype–environment interactions, and climate impact analysis. Consequently, process-based models can assess the effects of mulch when key processes are represented (). However, many models lack explicit mulch modules or have not been tested for this purpose.

3.1 General simulated soil processes

Models can be categorized into four distinct types according to the processes they represent. In this model, mulch is typically represented as an additional interacting component with specific properties.

Type 1 models only include the direct hydraulic impact of a mulch layer. Most commonly, this effect is implemented by reducing soil evaporation and runoff. For example, a mulch layer can reduce soil evaporation by acting as a sponge. It absorbs water and evaporates the intercepted water before the soil water is depleted (). Surface runoff, on the other hand, can be reduced by increasing simulated surface roughness, which promotes temporary ponding and enhances the infiltration rate (; ). These processes are often simplified using a “bucket” approach, in which mulch is represented as an intercepting reservoir with a fixed storage capacity (; ). Overall, this representation improves simulated plant water availability.

Type 2 models expand on Type 1 by incorporating mulch effects on the soil nutrient transformation and transport processes. Soil nutrient dynamics are generally represented by mass-balance equations. In these equations, nutrient pools change according to process-based rates influenced by soil temperature, soil moisture, and soil pH (; ). Therefore, mulch is represented via the mass balances and process rates governing the simulated system (; ). Nutrient availability influences root uptake, crop growth, and, indirectly, transpiration and soil water dynamics through feedbacks between biomass production and water demand ().

Type 3 models also build on Type 1 by incorporating the effect of mulch on the system’s energy balance rather than on the nutrient cycle. Soil temperature is commonly simulated using a heat-transport equation (; ), with mulch effects implemented through modified surface energy balance terms ().

Type 4 models combine all three major connections of Type 1, 2, and 3 models: (i) the effect on water relations, (ii) the nutrient cycle, and (iii) the energy balance. These models simultaneously simulate water, nutrient, and energy balances and their effects on crop growth, including interactions such as the influence of soil temperature on water and nutrient availability (). While this is a common feature in soil-crop models, and Type 4 can be used to model all connections between mulch and the soil-crop ecosystem (e.g., ), in practice, Type 4 is rarely tested due to its complex parametrization and the limited availability of datasets for model evaluation (; ; ; ; ; ; ; ; ; ; ) (Table 1).

Table 1

ModelWater reationsNutrient cycleEnergy balance
APSIM – type 4
x
xx
xx
AquaCrop – type 1
x
x
x
DSSAT – type 4
xx
xx
x
HYDRUS 1D/SWAP–WOFOST – type 4
xx
xx
x
STICS – type 4
xx
xx
xxx

Five common soil–crop models, their type classification, and representative publications on mulch-effect representation.

The three categories water relations, nutrient cycling, and energy balance are marked with an “x” when the publication accounts for direct mulch-induced modifications. Model can in theory represent more than what they’ve been tested for.

In addition, soil biotic processes are not well represented in soil-crop models, even though they play an important role in soil quality (see section 2.2).

3.2 Common process-based soil-crop models

Numerous process-based soil-crop models have been developed over time, but their ability to simulate the effects of mulch varies. Here, we discuss six commonly used soil-crop models and their ability to represent mulching. These models are categorized according to the classification described above. APSIM, Aquacrop, DSSAT-CSM, HYDRUS 1-D, SWAP-WOFOST, and STICS. Table 1 summarizes the main characteristics and mulch-related functionalities. It is important to note that this list is not exhaustive, and other models can also be adapted to represent mulch as well, e.g., ARMOSA (), PASTIS (), RothC (), and nameless models ().

APSIM (Agricultural Production Systems Simulator) () can simulate systems for a diverse range of plant, animal, soil, climate, and management interactions, including organic mulch. The SurfaceOM module calculates the addition and decomposition of organic material at the soil surface, influencing soil evaporation and runoff. Carbon and nitrogen cycling are represented by complementary modules: SoilN simulates belowground transformations, while RESIDUE describes aboveground residue dynamics. Indirect effects of mulch, such as increased biomass production and associated changes in transpiration, are incorporated through SoilN processes (). However, APSIM can not reproduce temperature-induced delays in crop phenology, because it does not account for canopy temperature or mulch-driven soil temperature effects on crop growth (, ; ). To address this limitation, modified the temperature-time representation in the model.

AquaCrop simulates crop yield responses to water and is specifically developed where water is a major limiting factor for productivity (). The model is designed to be simple, robust, and accurate, requiring relatively few parameters and input variables. In AquaCrop, mulch only affects soil evaporation through two characteristics: soil cover fraction (0-100%) and mulch type. While this simplicity enables rapid assessment of mulch effects on soil–crop water relations, the model does not account for nutrient and energy balances or their interactions. Therefore, AquaCrop is useful when these processes are negligible or outside the research scope, while avoiding overparameterization (; ; ). However, while all models are simplifications of reality, in real-world applications, the nutrient and energy balance can rarely be neglected. As such, the use of AquaCrop to model mulch effects should be done with caution and careful consideration of the limitations of the model.

DSSAT (Decision Support System for Agrotechnology Transfer) simulates growth, development, and yield for a range of crops from coupled soil-plant-atmosphere processes (). Adding a mulch layer in DSSAT has a dual effect on soil evaporation: it stores and evaporates intercepted water, and buffers soil evaporation by meeting evaporative demand first. Furthermore, mulch representation promotes temporary ponding and increases infiltration, the latter represented by modified runoff coefficients and water storage limits (). Soil temperature is computed with a solar radiation and albedo-based module (), which can potentially capture mulch effects. With regard to nutrient dynamics, the CENTURY module () incorporates the effects of decomposing surface organic residue layers on soil organic matter and nutrient cycling. This decomposition is influenced by soil temperature and soil water content ().

Hydrus–1D () and SWAP () are finite element models capable of simulating water flow, as well as heat and solute transport. SWAP () can be coupled with WOFOST () to simulate complex crop growth (). Neither model includes a built-in option for a simulated mulch layer (). Mulch effects can nevertheless be represented by (i) adding an explicit surface layer with parametrized hydraulic and thermal properties (; ; ), or (ii) using simplified boundary-condition approaches (). While mulching effects on nutrient dynamics could, in theory, be captured by calibrating solute-transport parameters in the two aforementioned models, to the best of our knowledge, no studies to date have applied this adaptation.

STICS (Simulateur mulTIdisciplinaire pour les Cultures Standard) simulates the dynamic interactions among crops, soil, climate, and agricultural management modules () and provides one of the most integrated mulch implementations among the models discussed. A mulch layer directly affects soil evaporation by intercepting precipitation () and reducing surface runoff. Water intercepted by the layer evaporates (), adding moisture to the atmosphere, reducing crop transpiration, and impacting soil temperature. Soil evaporation is further reduced through the energy balance via the interception of solar radiation by the mulch layer (). Surface runoff is affected by mulch through the presence of soil surface obstacles (). As such, a mulch layer reduced runoff in proportion to the amount of mulch (t ha-1) that is applied to the soil, using a threshold of mulch presence above which no runoff occurred (; ). In addition, STICS computes mulch decomposition rates that depend on the type of plant residue. Decay of the mulch, in turn, affects the nutrient cycle by altering soil nitrogen availability ().

4 Challenges and opportunities in mulch modeling

Organic mulches improve soil quality and stabilize crop performance, but their effects are context-dependent and vary with soil type, plant species, mulch type, mulching method, and local climate. Therefore, understanding and predicting mulch effects under varying environmental conditions requires process-based soil–crop models that simulate coupled soil–plant processes and their feedback mechanisms (Figure 1).

While a wide range of models exists, explicit representation of mulch remains limited or absent.

In hard-coded models, mulch is often represented by modelers as an additional surface or adapted soil layer based on field and laboratory measurements (; ). The development of more flexible and modular open-source modeling frameworks facilitates the integration of a mulch module, as demonstrated by .

A major challenge remains the development of robust and transferable parameterizations of the mulch model. Mainly due to the extended range of mulch effects, contrasting environmental conditions, multiple management strategies, and different model representations. Progress in this area will require well-documented experimental datasets to support parameter estimation, calibration, sensitivity analysis, and independent model validation.

Model selection should also remain consistent and be guided by data availability and study objectives: simpler approaches, such as AquaCrop, may be adequate under limited-data conditions, whereas more complex models, such as STICS, require extensive calibration to reliably represent mulch-driven processes.

Future advances in mulch representation will improve the predictive capacity of soil–crop models and support the implementation and optimization of mulching as a sustainable agricultural management strategy. In particular, improved process representation could help quantify how long mulch-induced changes in nutrient availability persist, how different mulch types modify soil temperature, and how mulching alters crop resilience to drought in terms of timing, duration, and severity. Ultimately, such developments would support the optimization of mulch management strategies for specific crops and environmental conditions.

Statements

Author contributions

RW: Investigation, Writing – original draft, Writing – review & editing, Conceptualization. TD: Conceptualization, Investigation, Writing – review & editing, Writing – original draft. SG: Writing – review & editing. WC: Writing – review & editing. MD: Writing – original draft, Conceptualization, Investigation, Writing – review & editing. JS: Supervision, Investigation, Conceptualization, Writing – review & editing, Writing – original draft.

Funding

The author(s) declared that financial support was received for this work and/or its publication. This research is funded by the Agency for Agriculture and Fisheries of the Flemish government of Flanders, Belgium and is part of the Relance Plan ‘Vlaamse Veerkracht’ 2021.

Acknowledgments

We would like to thank the Agency for Agriculture and Fisheries of the Flemish government for funding the SoilStruct Project, under which this review was initiated.

Conflict of interest

The author(s) declared that this work was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Generative AI statement

The author(s) declared that generative AI was used in the creation of this manuscript. Generative AI was used for language editing, sentence rephrasing, grammar checking and improving the clarity of the manuscript.

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All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, 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 manufacturer, is not guaranteed or endorsed by the publisher.

References

Summary

Keywords

crop production, organic mulching, process-based soil-crop model, soil fertility, soil hydrological processes, soil temperature

Citation

Willemet R, De Swaef T, Garré S, Cornelis WM, De Boever M and Schreel JDM (2026) Mulch representation in soil-crop models. Front. Agron. 8:1900760. doi: 10.3389/fagro.2026.1900760

Received

05 June 2026

Revised

04 July 2026

Accepted

07 July 2026

Published

23 July 2026

Volume

8 - 2026

Edited by

Indra Jeet Chaudhary, Savitribai Phule Pune University, India

Reviewed by

Khuram Shehzad Khan, China Agricultural University, China

Pengliang Tian, Gansu Agricultural University, China

Updates

Copyright

*Correspondence: Rémy Willemet,

Disclaimer

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, 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 manufacturer is not guaranteed or endorsed by the publisher.

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