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Bowskill, Vicky
(2024).
DOI: https://doi.org/10.21954/ou.ro.00097871
Abstract
Floodplain meadows can provide a sustainable, low-input agricultural crop, whilst simultaneously supporting botanical diversity of some 40 species per square metre. High nutrient inputs from flood-deposited sediments would lead to decreasing botanical diversity through competitive exclusion unless balanced by removal of nutrients via an annual hay crop and this continued management is essential to their survival.
The timing of haymaking can be contentious. Date restrictions under agri-environment schemes introduced in the 1980s delay harvest from midsummer to mid-July, aimed at protecting ground-nesting birds. Advancing seasons and increasingly unpredictable weather make the use of calendar dates for timing of land-management interventions unreliable. This study tests the use of accumulated thermal time as an alternative metric and finds that the relationship between date and thermal time has advanced by two weeks since the 1980s, which may lead to declining botanical diversity due to influences on nutrient cycling. These delayed cutting dates are also perceived to result in a crop of lower nutritional value compared to hay that is cut earlier, devaluing the crop.
Limited data have been available on aboveground nutrient dynamics in floodplain systems to enable informed decision-making. This study provides data on how nutritive value changes during the growing season, demonstrating that floodplain-meadow hay with a balance of graminoids and forbs offers good broad-spectrum nutrition for most livestock. Double-cutting also presents an opportunity for nutrient removal, which can contribute to nutrient-neutrality targets. Nutrition is found to decline more slowly than in intensively produced grass hay and a second harvest in the autumn has comparable nutritive value to a midsummer cut.
A mixed methods design combines experimental field data with land-manager perspectives to ensure recommendations are practical for on-farm use. Study findings can form the basis of a decision-making framework to balance agricultural production with important environmental and socioeconomic considerations.