Beyond Cereal Rye: Evaluating Soil, Crop, and Water Quality Synergies with Legumes and Brassica Cover Crops


Dr. Giovani Preza Fontes, Assistant Professor, Dept. of Crop Sciences
Dr. Maria Villamil, Professor, Dept. of Crop Sciences
Dr. Rabin Bhattarai, Associate Professor, Dept. of Agricultural and Biological Engineering
Kristin Greer, Senior Research Specialist, Dept. of Crop Sciences


Nutrient Loss Reduction Strategies in the upper Midwest (MN, IA, and IL) identify cover cropping as the most effective in-field conservation practice to achieve nutrient loss reduction goals. Cereal rye is the most commonly grown cover crop in this region because it overwinters and produces considerable biomass in the spring, but it may also reduce the yield of the following cash crop. Addressing the yield gap of cash crops following cereal rye is essential to increase the adoption of cover crops by farmers in Illinois, a trend that is expected to continue considering the Illinois Nutrient Loss Reduction goals.

Cover crop species beyond cereal rye can be an alternative to minimize potential yield losses. Historically, legume cover crops have been used as a source of N to the following cash crop. They can symbiotically fix atmospheric N and have biomass with a low C/N ratio, which means that its residue will decompose quickly, allowing for quick nutrient cycling that can benefit the following cash crops. Brassicas alone or mixed with other species are also used for weed suppression and breaking up soil compaction. If legume or mixture cover crops can provide the needed tile-drainage nitrate-N loss reduction and soil health benefits without compromising the yield of the following cash crops, they would be a great alternative to cereal rye.

This DSynergy project seeks to complement current water quality research at the Dudley Smith Farm by quantifying the soil-crop N dynamics and crop yields under different cover crop species. Our team will conduct a litterbag decomposition study at the Dudley Smith Farm in 2023 and 2024 to address the following objectives:

  1. Determine the composition and nutrient release of different cover crop species currently used at the Dudley Smith Farm (e.g., grass, legume, and legume/brassica blend)
  2. Evaluate the effect of cover crop species on soil N availability, crop N uptake and N use efficiency, and crop yield
  3. Assess whether short-term soil health benefits can be detected with cover cropping

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