In the arid and semi-arid areas of China, dryland agricultural production faces significant challenges due to scarce and unpredictable precipitation, high evaporation rates, and low rainwater utilization efficiency, leading to low and unstable farmland productivity (Gan et al., 2013; Peng et al., 2020; Yang et al., 2023). Potato (Solanum tuberosum L.), a major economically important crop in the semi-arid areas of Northwest China, plays a critical role in ensuring national food security (Li et al., 2022a; Zou et al., 2020). This region contributes approximately 36% of China’s total potato production, highlighting its importance in the agricultural sector (Hou and Li, 2019; Hou et al., 2020; Qin et al., 2022). However, persistent drought conditions and soil water deficits severely limit the achievement of and a stable potato yield as well as the sustainable development of the potato industry (Li et al., 2021). To address these challenges, it is imperative to develop efficient mulching cultivation techniques and water-saving measures that can effectively reduce soil water evaporation, optimize soil water allocation, and enhance water use efficiency (WUE). Implementing such strategies is essential for improving potato yields and ensuring sustainable agricultural production in this water-scarce region.

Mulching has been widely recognized for its ability to promote plant growth and development, enhance drought tolerance, improve crop yield, and increase WUE (Billman and Campbell, 2023; Fang et al., 2021; Qin et al., 2015; Verhulst et al., 2011; Wang et al., 2018; Zhang et al., 2022). Plastic film mulching and straw mulching have become the main cultivation techniques in Northwest China due to their effectiveness in conserving soil moisture and enhancing soil water storage (Sabet et al., 2022; Singh et al., 2015). Numerous studies have demonstrated the significant benefits of plastic film mulching, including reducing soil water evaporation by 14.5%–29.8% (Gu et al., 2017; Li et al., 2022b; Yang et al., 2023), increasing soil water storage capacity by 13-21% (Zhang et al., 2020a), and optimizing soil water content across different crop growth stages. These improvements have led to substantial increases in potato yield (19.7%–51.6%) and WUE (16.4%–111.7%) (Obour et al., 2022; Xiong et al., 2020; Zhou et al., 2011). Despite these agronomic benefits, long-term reliance on plastic film mulching has been linked to adverse environmental impacts. For instance, residual plastic film in the soil is difficult to reclaim, which can hinder water and nutrient absorption, reduce crop transpiration, and lower the efficiency of soil moisture utilization (Chen et al., 2015; Zhao et al., 2022). Meta-analyses by Zhang et al. (2020a) revealed that prolonged plastic film use decreased soil moisture evapotranspiration capacity by 2%, reduced soil moisture infiltration by 8%, and lowered soil organic matter by 0.8%. In some polluted areas, cotton yields were estimated to decline by 6%-10%, highlighting the adverse impacts on crop productivity and the sustainable development of agriculture (Chen et al., 2015; Zhao et al., 2022). Additionally, for potato cultivation, the high temperature and humidity conditions under black plastic film mulching (PM) can exacerbate the occurrence of late blight, negatively affect tuber expansion and ultimately reduce potato yields. These limitations highlight the urgent need for alternative mulching practices that sustain productivity while minimizing environmental risks.

Straw mulching has been widely adopted in potato production across the semi-arid regions of Northern China due to its effectiveness in optimizing water utilization throughout all growth stages (Dong et al., 2018). By covering the soil surface, straw mulch reduces direct evaporation, promotes greater rainfall infiltration, and enhances soil water storage, thereby ensuring more stable water availability during critical growth stages. Previous studies have shown that straw mulching can enhance maize (Zea mays L.) and wheat (Triticum aestivum L.) yield and WUE (Feng et al., 2019; Li et al., 2013, 2019; Zhang et al., 2020b). The water-saving effects arise primarily from suppressed soil evaporation, which shifts water use toward crop transpiration, thereby improving water-use efficiency. Additionally, it moderates soil temperature by blocking excessive solar radiation (Ma et al., 2022), creating a more favorable environment for potato tuber formation and expansion. As a result, straw mulching has been reported to increase potato yields by 4.5%–34.0% and WUE by 6.8%–21.5% (Hou and Li, 2019; Shafiq and Kaur, 2021). These advantages make straw mulching a sustainable and effective practice for boosting potato productivity in water-scarce regions.

Northwest China is rich in maize straw resources, but most of them are not fully used. Traditional full straw mulching is regarded as one of the best ways to conserve soil moisture in Northern China by increasing the rainwater infiltration capacity and improving the utilization efficiency of corn straw (Qin et al., 2021). However, traditional straw mulching practices have been shown to not only delay crop by reducing soil temperature growth (Zhao et al., 2019b), particularly in cooler climates, but also to increase mechanical difficulties and farming costs. This highlights the need to develop innovative straw mulching techniques that balance the dual objectives of conserving soil moisture and mitigating the negative impact of reduced soil temperature. Additionally, these new methods must be compatible with mechanized tillage systems to ensure practicality and scalability in the semi-arid areas of Northern China (Gao et al., 2022a).

To address these challenges, the straw strip mulching system (SM) technique is introduced as an alternative to straw-mulched strips with bare planting strips. This innovative approach has demonstrated several advantages: it significantly reduces total water consumption during the potato reproductive period by 6.1%-13.2%, increases potato yield by 10.5%–34.2%, and enhances WUE by 8.9%–29.8% (Chen et al., 2019a). In addition, SM promotes nutrient return through straw decomposition, improves soil fertility, and enhances soil water storage (Chang et al., 2020; Song et al., 2024). While straw degradation can initially increase nitrogen demand and lead to temporary competition with the crop, this effect is mitigated over time as decomposed straw contributes to soil organic matter and nutrient release, maintaining nutrient balance in the longer term (Ninkuu et al., 2025). Previous studies have also shown that straw mulching enhances soil enzyme activity (Song et al., 2024) and improves soil structure in potato farmlands (Ma et al., 2024), creating favorable conditions for potato growth and development, as a result, and thus increases potato yield. The straw strip mulching system is considered a promising and sustainable approach for enhancing agroecosystem productivity in the arid and semi-arid agricultural areas of Northwest China (Chai et al., 2022b).

Although both plastic film and straw strip mulching have been studied, limited knowledge exists on how straw strip mulching (SM) regulates water consumption dynamics across different potato growth stages in semi-arid environments. Most existing research has focused on either full plastic film or whole-field straw mulching, with few studies systematically comparing the stage-specific soil water partitioning and water-saving mechanisms between straw strip mulching systems and conventional plastic film mulching (PM). Moreover, the optimal timing for mulching application (fall vs. spring) remains unexplored for potato production under water-limited conditions. To address this gap, we conducted a two-year field experiment (2018–2019) in the semi-arid area of Northwest China to investigate the effects of various mulching practices and stages on potato water consumption and yield. The study compared SM applied in fall and spring, large ridges and small furrows, with only ridges covered by PM in fall and spring, and traditional bare-land planting without mulching. The objectives were to: (a) quantify the effects of SM on soil water partitioning during key potato growth phases; (b) compare water-saving mechanisms between SM and PM systems; and (c) determine the optimal mulching timing for maximizing water-use efficiency and yield. This research aims to provide valuable insights into optimizing mulching techniques to enhance water conservation, crop productivity, and agricultural sustainability in water-scarce environments.

In semi-arid rainfed areas of China, soil water and precipitation are the primary sources of water for potato growth (Chang et al., 2020). Mulching practices, such as straw mulch and plastic mulch, play a crucial role in enhancing soil water retention and improving the utilization efficiency of precipitation. These practices inhibit soil evaporation, optimize the soil–water environment, and significantly promote potato growth (Dong et al., 2022; Sabet et al., 2022; Singh et al., 2015). In this study, In this study, both enhanced the soil water supply capability and increased soil water storage in rainfed agricultural areas. This improvement ensured more soil water was available for potato growth throughout the root zone. The effectiveness of mulching can be attributed to its ability to enhance precipitation infiltration, prevent soil water evaporation, and facilitate the utilization of water stored in deeper soil layers (Chen et al., 2019b; Yang et al., 2019).

Under the ridge-furrow system with full plastic film mulching, rainwater harvesting efficiency is significantly improved, soil moisture consumption is reduced, and soil water storage is substantially increased in the semi-arid areas of Northwest China (Jiang and Li, 2015; Xie et al., 2020). In this study, both SM and PM increased soil water storage in the 0–200 cm soil layer during both growing seasons. However, fall mulching demonstrated greater benefits compared to spring mulching. This is likely because the fall mulching effectively increases the precipitation utilization efficiency (the proportion of rainfall converted to plant-available soil water), reduces soil water evaporation during the fall and winter resting stages, and ensures more adequate soil water availability for potato emergence (Qin et al., 2022).

In the rainfed semi-arid regions of Northwest China, relying solely on natural rainfall often fails to meet the water demands of crops during critical growth stages. Therefore, optimizing water consumption patterns through mulching practices is essential to ensure sufficient soil moisture and mitigate the risks of extreme drought (Chai et al., 2022a; Chen et al., 2019a). Numerous studies have demonstrated that mulching significantly improves water consumption structure effectively by reducing evaporation and enhancing WUE (Hou and Li, 2019; Zhao et al., 2019b; Zhao et al., 2014). In this study, both straw mulch and plastic mulch significantly modulated the soil water consumption pattern across the two growing seasons. A key finding was that spring-applied mulches (SSM and SPM) consistently reduced soil water consumption during the early growth stage, while fall-applied mulches (FSM and FPM), which had already conserved winter precipitation, sometimes led to higher early-season soil water consumption due to more available water. Crucially, all mulching treatments tended to support higher soil water consumption during the critical middle and later stages compared to CK. Consistent with our results presented in section 3.1, the PM system generally led to a greater increase in soil water storage than the SM system. However, the improvements under SM were also significant and contributed to the enhanced yield. Fall mulching outperformed spring mulching overall. This is primarily because fall mulching effectively retains precipitation and reduces soil evaporation during the spring, leading to better soil moisture conservation compared to spring mulching (Tao et al., 2015).

Mulching practices effectively modify the crop growth environment in rainfed agriculture (Zheng et al., 2021). For instance, while ridge and furrow mulching systems reduce water consumption (WC) during the early growth stages, they increase it in the mid-stage, with no clear pattern observed later. Study has also shown that combining plastic film mulching on ridges with straw mulching in furrows significantly restrained soil evaporation, remarkably enhanced plant transpiration (Zhang et al., 2020c). These practices improve effective soil water storage by 12.4-34.1%, increase potato yields by 1.0-27.4%, and boost WUE by 12.9-207.5% compared to non-mulched treatments (Amare and Desta, 2021; Chen et al., 2019a; Qi et al., 2020; Singh et al., 2021). Similar results were observed in the present study, SM and PM increased dry potato yield by 12.0% and 22.3%, and WUE by 9.2 and 14.3%, respectively. These improvements were achieved by enhancing water consumption during the critical period from tuber bulking to starch accumulation stages (by 7.7% and 16.7% for SM and PM, respectively), which was supported by an overall increase in seasonal soil water storage. Additionally, mulching significantly reduced WCI before the budding and increased it after the tuber expansion stage, easing water demand during the late growth stage (Li et al., 2018). Similar results were observed in this study, probably because in arid and semi-arid areas, mulching helps to reduce soil surface evaporation and conserve soil moisture resulting in a lower water consumption intensity in the early stages of growth. As the crop grows, its water demand increases. However, mulch can moderate the increase in water consumption intensity during the later stages by regulating soil condition in the two growing seasons, specifically, SSM and SPM increased the WCI 0.3 mm·d^-1 and 0.4 mm·d^-1 during the period from budding to tuber expansion stages respectively, while decreased WCI by 0.2 mm·d^-1 and 0.2 mm·d^-1 during the period from planting to budding stages. The mechanism behind this yield improvement is clearly explained by our correlation analysis ( Figure 6 ). We found that potato yield and WUE were most strongly and positively correlated with water consumption during the period from budding to tuber expansion stages (BD-TE) and the tuber expansion to maturity stages (TE-MT). This indicates that the primary benefit of both SM and PM systems was not just in saving water, but in shifting the water supply to these most critical growth phases, thereby promoting tuber bulking and increasing single tuber weight and commodity rate (Chen et al., 2019a), as shown in our results (Section 3.4).

Mulching cultivation is a widely adopted practice in the rainfed semi-arid regions of Northwest China, proven to enhance crop yields and water use efficiency (WUE) by improving soil moisture conservation and utilization under limited rainfall (Dong et al., 2018; Duan et al., 2021; Xiao et al., 2019). Consistent with previous findings on ridge and furrow systems (Qin et al., 2014; Liang et al., 2018), our study confirmed that both plastic film (PM) and straw strip mulching (SM) create stable moisture conditions, promoting seedling emergence, growth, and ultimately increasing tuber weight and yield. This demonstrates that mulching facilitates the effective collection and utilization of precipitation, raises soil moisture content, and ensures water supply during key reproductive periods, thereby supporting potato growth and yield enhancement. Long-term research on maize aligns with this, showing that mulching boosts yield and WUE by improving soil water retention and precipitation use efficiency (Zhang et al., 2022). Similarly, studies on potato confirm that PM and SM enhance total water consumption by reducing soil evaporation and promoting crop transpiration, ultimately improving yield and WUE in semi-arid areas (Chang et al., 2020). However, some studies have reported that SM has a greater effect than PM on increasing potato tuber yield and WUE under dry conditions, particularly when combined with fall ploughing after the autumn harvest (Hou et al., 2020). This contrasts with the findings of this study, likely because PM offers greater advantages in soil water conservation, evaporation reduction, and rainwater harvesting under conditions of relatively sufficient rainfall. Mulching periods and mulching methods together determine potato yield and WUE. The generally superior performance of the PM system over the SM system in this study can be attributed to the integrated ridge-furrow design, which more effectively harvests rainwater and the impermeable film that provides a robust physical barrier against evaporation. The increase in fresh potato yield, dry potato yield, and WUE under PM treatments was higher than that under SM treatments. It is worth noting that the effectiveness of straw strip mulching (SM) in this study may be affected by the continuous use of the same batch of straw. It has been shown that repeated use of the previous year’s straw can lead to a decrease in the mulching effect (e.g., weakened moisture retention capacity, reduced stability of the mulch layer, etc.) due to its partial decay and decomposition (Zhao et al., 2019a). This factor may partly explain why the SM treatment was less effective than the PM treatment in increasing yields. In contrast, PM does not suffer from material degradation and can maintain a more stable cover. Although PM performed better in this trial, the sustainability advantage of SM should not be overlooked. By returning straw to the field, SM can release soil nutrients, thus saving fertilizer costs (Gao et al., 2022b); at the same time, it avoids mulch contamination, and replacing mulch also saves mulch costs, which is expected to save about 214 USD per hectare. Although SM temporarily lagged behind PM in terms of yield increase in the specific data of this study, its comprehensive benefits in terms of environmental friendliness and resource recycling were significant. In addition, some studies have found that straw mulching may increase the occurrence of pests and diseases (McNee et al., 2022), which was not confirmed in this experiment, and straw strip mulching did not cause pest and disease problems in Northwest China. Therefore, the choice between these two mulching systems represents a trade-off. The PM system offered higher immediate yield benefits, whereas the SM system provides a sustainable and cost-effective alternative with significant environmental benefits. Taken together, fall straw strip mulching is expected to be an alternative to mulching with the potential to be economical, green, and yield-enhancing at the same time.

Both straw strip mulching and plastic film mulching can optimize the water consumption structure by reducing the water consumption during the early growth stages of potato and increasing it during the middle and later stages. Additionally, fall mulching is more advantageous in improving potato yield and water use efficiency. However, compared with plastic film mulching, straw strip mulching not only reduces production costs, but also avoids the problem of plastic film residue pollution. Straw strip mulching did not significantly increase the risk of pests, diseases and weeds in the practice of rainfed agriculture in the Northwest. Therefore, considering yield, cost and environmental sustainability, straw strip mulching is a productive, practical and environmentally friendly mulching method for potato production in this region.