Optimization of a Lower Irrigation Limit for Lettuce Based on Comprehensive Evaluation: A Field Experiment

Area of Science:

• Agricultural Science
• Environmental Science
• Soil Science

Background:

• Optimizing irrigation often prioritizes crop growth over soil gaseous carbon (C) and nitrogen (N) emissions.
• There is a need for irrigation practices that maintain crop yield and quality while minimizing environmental impact.

Purpose of the Study:

• To evaluate the impact of different drip irrigation (DR) methods on lettuce yield, quality, and soil gas emissions.
• To identify an optimal irrigation strategy that balances crop productivity, quality, and environmental sustainability.

Main Methods:

• Open-field experiments using a randomized block design with four irrigation methods: three drip irrigation levels (DR1, DR2, DR3) and furrow irrigation (FI) as control.
• Monitoring of crop growth indicators, lettuce yield, quality parameters (crude fiber, vitamin C, soluble sugar, nitrate), and stem cracking rates.
• Utilizing an entropy model to evaluate the comprehensive benefits of each irrigation method.

Main Results:

• Drip irrigation (DR) treatments generally improved lettuce quality compared to furrow irrigation (FI).
• DR2 irrigation significantly reduced stem cracking rates by nearly half compared to FI.
• The DR2 method achieved the highest comprehensive evaluation value (0.93) in the entropy model, indicating optimal benefits.

Conclusions:

• Drip irrigation, particularly DR2, offers significant advantages over furrow irrigation for lettuce cultivation.
• The DR2 irrigation method effectively balances water conservation, yield enhancement, improved crop quality, and reduced soil emissions.
• This study highlights the importance of considering soil gas emissions in irrigation management for sustainable agriculture.