Li et al. (2025) Effects of Cover Crops on Water Use Efficiency in Orchard Systems in the Danjiangkou Catchment, Central China

Identification

• Journal: Plants
• Year: 2025
• Date: 2025-12-07
• Authors: Linyang Li, Peng Chen, Xinxin Jing, Chenhao Lyu, Runqin Zhang, Xiaoliang Yuan, Qian Li, Yi Liu, Xiaoquan Zhang, Zhiguo Li
• DOI: 10.3390/plants14243729

Research Groups

• Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
• Danjiangkou Wetland Ecosystem Field Scientific Observation and Research Station, Chinese Academy of Sciences & Hubei Province, Wuhan, China
• Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
• University of Chinese Academy of Sciences, Beijing, China
• The Nature Conservancy, Beijing, China

Short Summary

This two-year field study investigated the effects of legume, gramineae, and mixed cover crops on soil water dynamics, evapotranspiration (ET), and water use efficiency (WUE) in a young cherry orchard in Central China. The study found that while cover crops generally increased total ET, a legume-gramineae mixture effectively buffered drought-induced water loss and significantly improved WUE, particularly during winter and spring.

Objective

• To analyze variations in soil water dynamics and water balance across soil layers under different cover crop treatments.
• To compare aboveground biomass and water use efficiency (WUE) under different cover crop configurations in an orchard system.

Study Configuration

• Spatial Scale: Individual plots of 80 square meters, each containing eight young cherry trees, within an orchard in Xichuan County, Henan Province, China.
• Temporal Scale: Two-year field study (2021–2022), with monthly soil moisture monitoring and seasonal biomass sampling.

Methodology and Data

• Models used: Allometric model for small trees (AGBtree = e^(2.428 * ln(D10) - 3.007) * 1.128) for estimating fruit tree aboveground biomass.
• Data sources:
  • On-site automatic weather station (HMP155A temperature/humidity sensors, TR-525M tipping-bucket rain gauge, anemometers, pyranometers, soil temperature/moisture probes) for meteorological factors.
  • Gravimetric method for soil water content (SWC) from monthly soil core samples.
  • Galvanized steel sheet enclosures (2 m x 2 m) with collection buckets for surface runoff (R).
  • TerraClimate data (4 km resolution) for historical precipitation analysis (1991–2020).
  • Seasonal sampling of cover crop biomass from 1 m x 1 m quadrats.
  • Stem base diameter measurements (D_10) for fruit tree biomass estimation.

Main Results

• Gramineae cover (GG) reduced 0–100 cm soil water storage by 5.99% compared to bare soil (NC), while Legume-Gramineae mixture (MG) effectively buffered drought-induced water loss.
• All cover crop treatments increased total evapotranspiration (ET), with MG showing the highest increase (10.31%) compared to NC, indicating enhanced transpiration compensated for reduced soil evaporation.
• Water use efficiency (WUE) improved under all cover crop treatments, particularly during winter (0.123 t ha⁻¹ mm⁻¹) and spring (0.037 t ha⁻¹ mm⁻¹), when water demand was lower. MG showed the highest WUE in autumn (0.038 t ha⁻¹ mm⁻¹), and Legume grass (LG) performed best in spring (0.064 t ha⁻¹ mm⁻¹).
• Stepwise regression analysis identified rainfall as the strongest positive driver of ET (β = 0.87, p < 0.001) and humidity as a significant positive driver of WUE (β = 0.55, p < 0.001). Conversely, increased rainfall reduced WUE (β = -0.29, p = 0.025).
• Temperature, radiation, and wind speed were identified as key factors influencing SWC dynamics, with temperature having the strongest negative effect (β = -0.67, p < 0.001).

Contributions

• Provides a preliminary understanding of the distinct seasonal and soil-depth-dependent effects of different cover crop types (legume, gramineae, mixture) on orchard water dynamics in the Danjiangkou Catchment, a water-sensitive region.
• Quantifies the trade-offs between increased evapotranspiration and improved water use efficiency under cover cropping, highlighting the potential for cover crops to create a more stable "soil water bank."
• Identifies key climatic drivers (rainfall, humidity, temperature, radiation, wind speed) influencing soil water content, evapotranspiration, and water use efficiency in orchard systems with cover crops.
• Offers practical guidance for sustainable orchard water management, emphasizing the importance of species selection and mowing management based on local environmental conditions.

Funding

• National Natural Science Foundation of China (project no. 32271726, 32171648)
• Natural Science Foundation of Hubei Province of China (project no. 2022CFB030)
• The International Cooperation Project of The Nature Conservancy (no grant number)

Citation

@article{Li2025Effects,
  author = {Li, Linyang and Chen, Peng and Jing, Xinxin and Lyu, Chenhao and Zhang, Runqin and Yuan, Xiaoliang and Li, Qian and Liu, Yi and Zhang, Xiaoquan and Li, Zhiguo},
  title = {Effects of Cover Crops on Water Use Efficiency in Orchard Systems in the Danjiangkou Catchment, Central China},
  journal = {Plants},
  year = {2025},
  doi = {10.3390/plants14243729},
  url = {https://doi.org/10.3390/plants14243729}
}