Overview of the LegacyNet experiment
LegacyNet investigates the potential for multi-species grassland leys to support sustainable crop production. Specifically, LegacyNet investigates the design of multi-species grassland leys to optimise both forage production and legacy effects for following cereal crops (with the option to use an annual grass as replacement) in crop rotations.
The continuous monoculture cropping of crops is associated with several negative externalities, including greenhouse gas emissions, eutrophication, soil nutrient and organic matter depletion, reduction in carbon stocks, weed invasion and reductions in biodiversity. Compared to monocultures, benefits from multi-species grassland leys can include yield increases, reduction of nitrogen fertilizer requirements, resilience and resistance towards environmental stresses, weed and pest suppression, increased soil health, higher carbon sequestration rates and increased animal health and productivity. When included in a crop rotation, these benefits can provide legacy effects for the following crop that include nitrogen provision and improved soil health for the following crop. But how do we design multi-species mixtures to maximize their grassland performance and their legacy effects? What is the optimal number of species and/or functional groups? And are these legacy effects affected by environmental conditions or soil types, and if so, by how much?
LegacyNet investigates multi-species grassland leys as a practical farm management strategy to improve i) the quantity and quality of forage yield, ii) the resource use efficiency and ecosystem services from grassland leys, and iii) the legacy effects of such leys within crop rotation systems. We use an innovative experimental design with 40 systematically varying combinations of six forage species to test a range of multi-species mixtures (1-6 species) with complementary traits (two grasses, two legumes and two herbs), and to design species' combinations (and proportions) that optimize forage production, forage quality and legacy effects. Relatively few experiments have been conducted that examine the impact of grassland leys in crop rotations with comparable methods across several countries; this is a key strength of LegacyNet.
With crop rotations and mixed farming systems so far being predominantly used in organic agriculture, we are particularly interested in a large array of production systems to be represented in LegacyNet. This research will be relevant for most farmers, independent of their current production system, but shall also identify tools to reduce environmental impact of food or forage production without impairing the productivity of the system.
Further details on the LegacyNet experiment are available via several documents on our Details (and protocol) page.