Evaluating subclover as a living mulch companion crop for durum wheat

Overview

This research collaboration opportunity investigates the use of subterranean clover (subclover) as a living mulch companion crop for durum wheat in Mediterranean farming systems. The study addresses a critical gap in intercropping research by examining how different spatial arrangements between durum wheat and subclover rows affect crop competitiveness, weed suppression, and subclover reseeding potential. The goal is to identify an optimal planting pattern that delivers high wheat grain yield while ensuring sufficient subclover regeneration after harvest, offering an environmentally sustainable alternative to conventional cropping practices.

Subclover is particularly well-suited as a living mulch because it fixes atmospheric nitrogen, reducing competition with cereals for this nutrient. Its prostrate growth habit minimizes competition for light, and its buried seed production enables natural regeneration after autumn rainfall. These characteristics make subclover a promising candidate for sustainable Mediterranean agriculture, where reducing chemical inputs while maintaining productivity is a growing priority.

Technical specifications

The field experiment will test five treatments:

• Durum wheat monoculture
• Subclover monoculture
• Three durum wheat/subclover intercropping patterns with varying spatial arrangements

Two nitrogen fertilization levels will be applied (zero and conventional farmer practice of 100 kg/ha), along with two weed management regimes (weed-free and weedy), to evaluate how planting patterns interact with fertilization and weed pressure.

Key measurements will include:

• Wheat yield components: plant height, fertile spikes, kernels per spike, thousand grain weight, and harvest index
• Grain quality characteristics
• Aboveground biomass of wheat, subclover, and weeds at physiological maturity
• Photosynthetically active radiation (PAR) at ground level using a linear ceptometer
• Chlorophyll content and NDVI readings using MC-100 and RapidScan tools
• Competitive indices to assess crop-weed and crop-subclover interactions

Wheat will be sown at 400 seeds/m² and subclover at 600 seeds/m² in pure stands or 300 seeds/m² in intercropped treatments, creating a semi-additive series design.

Technology readiness level

This is an active field research proposal at the experimental validation stage. The study design includes detailed protocols for soil preparation, sowing, fertilization, weed management, and data collection across the full growing season. Competitive indices and resource use measurements (light, nutrients, water) will provide quantitative validation of how spatial arrangements influence system performance. The research is positioned to generate actionable findings for Mediterranean cereal-legume intercropping systems, with potential applications in sustainable wheat production and integrated weed management.