Comparing cover crops
COVER crops are one way to increase diversity on farm and potentially have multiple benefits both above and below ground according to plant and soil scientist Dr Tracy Valentine.
Research at the James Hutton Institute has shown the benefits include adding carbon and nitrogen to the soil, improving soil structure, capturing nutrients and passing them to the next crop, and reducing weed burden, depending on the specific cover crop species or mixture grown.
Dr Valentine said: “Climate change projections of Scotland’s weather include an increase in average temperature across all seasons, with warmer and drier summers and
milder and wetter winters. However, there is still significant local variability in both temperatures and rainfall event patterns.
“These variations could have several impacts on cover crop implementation. For example, while projections suggest that central eastern areas of Scotland will become warmer, it also projects it to be much drier in the AugustSeptember cover crop sowing window, potentially affecting germination rates.
“Further north, the projections become much more uncertain, but the issue of quickly fading light for plant growth will still remain whatever the weather brings.
“There are also farm management interactions.
So far, data has been collated on multiple species of cover crops, from both the literature, a multiple species plot trial and from Grieves House Tillage Trial .”
In the 2022-2023 growing season, the cover crop biomass was measured in March.
The results showed 50% less biomass in the no-till plots than in the inversion plough plots for both the radish and rye cover crops sown.
“Cover crops within no-till systems are key approaches to climate change mitigation, through reduced fuel and attempts to increase carbon sequestration.
“So while biomass is only an indicator of cover crop success, reduced effectiveness in these systems of particular cover crops species is important information.
“Data gathered on responses to management will be combined with seed germination metrics, plant temperature and light growth data in models.
“These will link to climate change projections for different regions in Scotland, to help assist the uptake of cover crops.”