Zhang et al. (2025) Evaporation and transpiration processes and changes in their proportional relationships in cotton fields under varying degrees of film biodegradation

Identification

• Journal: Frontiers in Plant Science
• Year: 2025
• Date: 2025-11-26
• Authors: Hao Zhang, Dong Wang, Xun Zhang, Z. Z. Lv, Tao Jia, Haijun Liu, Yifan Wang, Lin Tao, Qiuxiang Tang
• DOI: 10.3389/fpls.2025.1662751

Research Groups

• College of Agriculture, Xinjiang Agricultural University, Xinjiang, China
• Xinjiang Jinfengyuan Seed Industry Co., LTD., Xinjiang, China
• Cotton Research Institute, Xinjiang Uyghur Autonomous Region Academy of Agricultural Sciences, Xinjiang, China
• Xinjiang Cotton Technology Innovation Center, Academy of Agricultural Sciences of the Xinjiang Uyghur Autonomous Region, Xinjiang, China
• Xinjiang Key Laboratory of Cotton Genetic Improvement and Intelligent Productions, Academy of Agricultural Sciences of the Xinjiang Uyghur Autonomous Region, Xinjiang, China
• National Cotton Engineering Technology Research Center, Academy of Agricultural Sciences of the Xinjiang Uyghur Autonomous Region, Xinjiang, China

Short Summary

This study quantified the dynamic changes in evaporation and transpiration in cotton fields under varying biodegradable film degradation and irrigation depths, finding that an optimized irrigation depth of 495 mm can mitigate water stress from film degradation and increase cotton yield by 5.50–14.55%.

Objective

• To accurately investigate the characteristics of evapotranspiration (ET) and changes in its component ratios under the coupled effects of varying biodegradable mulch breakdown areas and irrigation levels in cotton fields.
• To reveal the spatiotemporal characteristics of soil moisture in cotton fields covered with biodegradable mulch under different irrigation depths.
• To quantify the dynamic changes in ET, the proportion of crop transpiration, and the proportion of soil evaporation in these cotton fields.
• To clarify the composition and transformation processes of ET under the coupled conditions of different irrigation depths and different mulch breakdown areas.

Study Configuration

• Spatial Scale: Field experiment conducted in Hailou Town, Shaya County, Aksu Region, Xinjiang, China (41°17’ N, 82°42’ E, 897 m above sea level). Each experimental plot measured 64.98 m² (9.50 m length, 6.84 m width). Soil measurements were taken at 0–80 cm depth.
• Temporal Scale: A 2-year field experiment conducted from 2021 to 2022 during the cotton growth period. Film degradation and soil water content were monitored every 7 days, and soil evaporation was measured daily.

Methodology and Data

• Models used:
  • Film degradation monitoring: Film recognition method based on supervised classifiers (parallelepiped, minimum distance, Mahalanobis distance, maximum likelihood classifiers) using ENVI 5.3 software, with accuracy verification via AutoCAD 2020. Color channel threshold segmentation method.
  • Reference evapotranspiration (ET0): Food and Agriculture Organization-recommended Penman–Monteith formula.
  • Soil water consumption: Agricultural water balance method (simplified due to negligible groundwater recharge, deep percolation, and surface runoff).
  • Statistical analysis: Least significant difference (LSD) method in SPSS v. 22.0.
• Data sources:
  • Field experiment: Randomized block design with four mulch types (traditional polyethylene film (PE), fully biodegradable mulch (B1, B3), thermo-oxygen-biodegradable mulch (B2)) and three irrigation depths (W1: 315 mm (63.6% ET0), W2: 405 mm (81.8% ET0), W3: 495 mm (100% ET0)).
  • Film degradation: Photographic monitoring of biodegradable film rupture area every 7 days (sampling area 0.16 m²).
  • Soil water content: TRIME-PICO-IPH TDR profiling soil water measurement system at 0–80 cm depth in 10-cm intervals, measured every 7 days and after irrigation/rainfall.
  • Soil evaporation: Micro-lysimeters (PVC pipes, 11 cm diameter, 15 cm height) weighed daily.
  • Plant transpiration: Calculated from total ET and soil evaporation.
  • Leaf Area Index (LAI): Monitored throughout the growth period.
  • Yield: Harvest measurements of effective plant density, bolls per plant, and boll weight.
  • Meteorological data: Daily average air temperature, daily precipitation, and daily ET.
  • Soil properties: Fundamental physicochemical properties of the soil (0–80 cm depth) prior to cotton sowing.

Main Results

• Film Degradation: Biodegradable films (B2 and B1) showed initial gap formation earlier (28 and 42 days, respectively) than B3. Degradation rates increased over time, with B2 > B1 > B3. B2 achieved a 76.02% degradation rate at 150 days after sowing in 2021. Increased irrigation depth slowed the rupture speed of biodegradable mulch films.
• Soil Evaporation: For every 1% increase in film area damage compared to PE, the soil evaporation rate increased by 0.34 mm·d⁻¹ (R² = 0.6027, n = 1613, p = 0.028). Soil evaporation significantly increased under biodegradable film coverage compared to PE.
• Soil Moisture Content: Biodegradable films exhibited inferior moisture retention compared to PE. At 60–80 cm depth, soil water content under BEs decreased by 28.5–42.13% from the seedling to the boll-opening stage. Increasing the irrigation depth enhanced the soil moisture content by 5.29–15.37%.
• Canopy Development and Transpiration: Increasing the irrigation depth promoted canopy development, increasing the leaf area index by 15.26–25.14% and plant transpiration by 10.32–17.86%.
• Evapotranspiration Partitioning: As the biodegradable film coverage rate (Fd) decreased, the ratio of soil evaporation to total evapotranspiration (E/ET) decreased following a power function. A deeper irrigation regime diminished the proportion of E to ET.
• Yield: Seed cotton yield under biodegradable mulch cover showed a gradual increase with increasing irrigation depth, reaching a maximum under W3. The highest yields for B1 and B2 (5862–5872 kg·ha⁻¹ in 2021 and 6789–6854 kg·ha⁻¹ in 2022) were not significantly different from those under PE cover. An optimized irrigation regime of 495 mm increased cotton yield by 5.50–14.55%.
• Water Productivity (WPc): WPc consistently decreased with increasing irrigation depth, being lowest when seed cotton yield was highest under B1 and B2.

Contributions

• Developed and validated an accurate, quantitative method (color channel threshold segmentation based on supervised classifiers) for monitoring biodegradable mulch film damage, overcoming the limitations of subjective visual assessment and time-consuming weight loss methods.
• Quantified the direct driving mechanism of degradation processes on water loss, showing that a 1% increase in film damage leads to a 0.34 mm·d⁻¹ increase in soil evaporation.
• Demonstrated that an optimized irrigation regime of 495 mm can effectively compensate for water stress caused by plastic mulch degradation, increasing soil moisture content and significantly elevating the proportion of crop water use dominated by transpiration efficiency.
• Provided a systematic solution combining precise monitoring methods with quantitative irrigation strategies to address the dual challenges of agricultural plastic pollution and efficient water resource utilization in arid and semi-arid regions.
• Established the economic feasibility and environmental sustainability of fully biodegradable mulch films under an optimized irrigation regime, showing they can effectively replace traditional plastic mulch without compromising yield.

Funding

• “Tianshan Talents” Training Program -”Youth Top Talent Project -Youth Scientific and Technological Innovation Talents” (2023TSYCCX0019)
• National Modern Agricultural Industry Technology System -Cotton Industry Technology System Post Scientist (CARS-15-12; CARS-15-13)
• Xinjiang Modern Agricultural Industry Technology System -Cotton Industry Technology System (XIARS-03)
• Xinjiang Tianshan Talent Cultivation Program Cotton Lightweight and Efficient Cultivation Technology Innovation Team (2023TSYCTD004)
• Autonomous Region Graduate Education Innovation Program Research and Innovation Project (XJ2023G130)

Citation

@article{Zhang2025Evaporation,
  author = {Zhang, Hao and Wang, Dong and Zhang, Xun and Lv, Z. Z. and Jia, Tao and Liu, Haijun and Wang, Yifan and Tao, Lin and Tang, Qiuxiang},
  title = {Evaporation and transpiration processes and changes in their proportional relationships in cotton fields under varying degrees of film biodegradation},
  journal = {Frontiers in Plant Science},
  year = {2025},
  doi = {10.3389/fpls.2025.1662751},
  url = {https://doi.org/10.3389/fpls.2025.1662751}
}