Zheng et al. (2026) Toward sustainable Brassica napus production: Optimizing fertilization regimes for yield, water, and nutrient efficiency

Identification

• Journal: Agricultural Water Management
• Year: 2026
• Date: 2026-01-16
• Authors: Qiang Zheng, Peng Song, Xin Wang, Siqi Han, K. Zhang, Peng Hou, Peiling Yang
• DOI: 10.1016/j.agwat.2026.110145

Research Groups

• School of Water Conservancy and Transportation, Zhengzhou University, Zhengzhou, China
• College of Water Resources and Civil Engineering, China Agricultural University, Beijing, China
• China Irrigation and Drainage Development Center, Beijing, China

Short Summary

This study optimized fertilization regimes for edible-shoot Brassica napus, demonstrating that split NPK application via precision drip fertigation significantly improved yield, irrigation water productivity, and nitrogen use efficiency compared to conventional methods. The optimal regime, T3 (three equal splits), was identified using a hybrid AHP-EWM evaluation framework.

Objective

• To elucidate how different water fertilizer regimes regulate soil physicochemical processes, nutrient availability, and crop growth in a multi-cut Brassica napus system.
• To quantify the direct and indirect pathways influencing yield, irrigation water productivity (WPI), and partial factor productivity of N (PFPN) using structural equation modeling.
• To determine the optimal fertigation regime through an integrated AHP-EWM evaluation, identifying strategies that balance productivity, resource-use efficiency, and environmental performance.

Study Configuration

• Spatial Scale: Field experiment conducted in Gusheng Village, Wanchiao Town, Dali City, Dali Bai Autonomous Prefecture, Yunnan Province, China (25°48′55″ N, 100°08′10″ E; elevation 1939.3 m). Individual plots measured 12 m × 4 m (48 m²).
• Temporal Scale: Two consecutive growing seasons (October 2022 to March 2023, and October 2023 to March 2024).

Methodology and Data

• Models used:
  • Structural Equation Modeling (SEM) using AMOS 26.0
  • Analytic Hierarchy Process (AHP)
  • Entropy Weight Method (EWM)
  • Combined AHP-EWM evaluation framework
• Data sources:
  • Field measurements of soil physicochemical properties (moisture content, pH, electrical conductivity, ammonium nitrogen, nitrate nitrogen, available phosphorus, available potassium).
  • Plant growth indicators (plant height, stem diameter, leaf area, dry biomass of roots, stems, leaves, flower buds).
  • Yield components (number of shoots, shoot length, shoot diameter, individual shoot weight, total shoot yield).
  • Calculated irrigation water productivity (WPI) and partial factor productivity of N fertilizer (PFPN).
  • Soil moisture sensors for continuous monitoring.
  • Vernier caliper, measuring tape, electronic balance for plant measurements.
  • Malvern Mastersizer 2000 laser diffraction particle size analyzer for soil texture.
  • Indophenol blue colorimetric method for NH4+-N, UV spectrophotometry for NO3--N, molybdenum blue colorimetric method for available phosphorus.

Main Results

• Drip fertigation significantly improved subsoil moisture (0.4–1.0 m soil layer increased by 1.61 %–31.68 %) and reduced soil electrical conductivity (decreased by 2.07 %–29.91 % compared to T1).
• Treatments T3 and T4 enhanced nitrate nitrogen availability (increased by 7.63 %–58.3 % for T3 and 17.9 %–83.1 % for T4 compared to T1), stem diameter (increased by 1.33 %–45.6 % for T3 and 3.77 %–55.9 % for T4), plant height, and biomass accumulation.
• Compared with conventional treatment (T1), T3 and T4 increased shoot yield by 17.1 % and 9.31 %, irrigation water productivity (WPI) by 17.1 % and 9.17 %, and partial factor productivity of N fertilizer (PFPN) by 1.62 % and 7.63 %, respectively.
• Structural equation modeling identified stem diameter, dry weight, and inflorescence number as key yield drivers, while PFPN was affected by morphological and physiological traits.
• A combined AHP-EWM evaluation framework identified T3 (fertilizer applied in three equal splits) as the optimal fertilization regime, achieving the highest overall performance score.

Contributions

• Developed and evaluated a harvest-synchronized split-fertigation strategy using organic water-soluble fertilizer for multi-cut Brassica napus, addressing a gap in research for high-value multi-cut vegetables.
• Integrated structural equation modeling (SEM) and a hybrid AHP-EWM multi-objective evaluation framework to provide a novel, comprehensive decision-support method for optimizing fertigation strategies, considering soil conditions, crop morphology, yield, and resource-use efficiency simultaneously.
• Demonstrated that harvest-aligned scheduling with organic water-soluble fertilizer produced more balanced nitrate-N availability and stronger regrowth-driven biomass allocation compared to conventional or fixed-phenological stage approaches.
• Provided evidence-based guidance for developing stage-specific fertigation strategies to enhance sustainable intensification in multi-harvest vegetable production systems.

Funding

• National Natural Science Foundation of China (Grant No. 52409074)
• Key R&D and Promotion Special Project of Henan Province (252102321111)
• Key Scientific Research Project of Higher Education Institutions in Henan Province (25A570003)

Citation

@article{Zheng2026Toward,
  author = {Zheng, Qiang and Song, Peng and Wang, Xin and Han, Siqi and Zhang, K. and Hou, Peng and Yang, Peiling},
  title = {Toward sustainable Brassica napus production: Optimizing fertilization regimes for yield, water, and nutrient efficiency},
  journal = {Agricultural Water Management},
  year = {2026},
  doi = {10.1016/j.agwat.2026.110145},
  url = {https://doi.org/10.1016/j.agwat.2026.110145}
}