Speaker
Description
In intensive vegetable production systems, cover crops are usually incorporated into the soil by disking prior to the subsequent crop. In recent years, silage tarps have gained popularity amongst farmers in Quebec as a suitable tool for no-till cropping systems. Termination of cover crops by roller-crimping is another strategy used by organic farmers. However, these practices have not been studied extensively in vegetable cropping systems in Eastern Canada. Our main objective was to assess the impact of cover crop termination with or without tillage on soil health indicators.
A 2-year field experiment (2022-2023) was conducted on a clay loam at a research site in Saint-Augustin-de-Desmaures, QC, Canada. An annual spring-seeded cover crop mixture was terminated in mid-July, followed by a vegetable crop in both years. In 2022, a mixture of field peas and oats was seeded, while in 2023, the cover crop mixture consisted of field peas and faba beans. Treatments were arranged in a split-plot design with four blocks. Cover crop termination methods were ascribed to main plots. They consisted of 1) roller-crimping, 2) flail-mowing and tarping, 3) flail-mowing and incorporation by disking, and 4) a fallow control with no-cover crop. The subplot factor was the fertilization rate of vegetable crops based on provincial nitrogen recommendations (0%, 50%, and 100%). After the termination of cover crops, broccoli and beetroot were transplanted in 2022 and 2023, respectively. At harvest time, soil samples were collected at a 0-10 cm depth, and soil health indicators were measured using soil-based lab tests.
The use of spring cover crops resulted in a higher proportion of water-stable aggregates (>2mm) and a larger mean-weight diameter of stable aggregates compared to the no-cover crop control. Soil respiration values were higher in the treatments with cover crop than in the no-cover crop control, and soil bulk density was higher in the roller-crimped cover crop treatment than in the other treatments. Broccoli and beetroot yields were lower in the roller-crimped treatment compared to the other treatments. Surprisingly, yields were similar between the no-cover crop control and cover crops incorporated by disking. Nonetheless, our results showed that establishing spring-seeded cover crops into organic vegetable production systems offers some soil health benefits in the short-term.
| Keywords | Organic farming; No-till vegetables; Spring cover crops; Aggregate stability; Microbial respiration |
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