We tested a wildlife crop rotation of a grass and legume mix across different soil types, aimed to support bees, butterflies and insect chick-food; generate soil nitrogen; and inhibit noxious weeds.
This was followed by two years of a wild bird seed mix that would provide seed and insect food for birds and cover in winter. The grass legume mix was made up of two grasses (meadow fescue and timothy), four clovers (red, alsike, crimson and white), bird’s-foot trefoil, sainfoin, early English vetch, yellow trefoil and lucerne.
- On the clay soils, little extra soil nitrogen was detected after the two-year legume ley, however on the sandy soils there was on average an extra 65kg of nitrogen per hectare, with a maximum of 188kg of nitrogen per hectare. In one year heavy rainfall destroyed the ley, so in future years we will sow legumes within the wild bird seed mixture, as many legumes leak nitrogen while they grow.
- The diversity and abundance of wild bees was higher in the legume ley compared with nearby wild flower habitats. There was much less variation between plots, so legume leys provided a more reliable source of flowers.
- Long-tongued bees and solitary bees preferred the legume ley compared with wild flower habitats.
- Over 90% of wild bee visits were to just 10 plant species, of which six were in the legume ley and four common wild flowers.
- Hoverflies, whose larvae are voracious aphid predators, preferred to forage on smaller flowers such as black medic and other flowers found in the wild flower habitats.
- The legume ley supported over four times more grey partridge chick-food insects and almost twice as much general farmland bird food and pest natural enemies compared with wildflower or grass-only habitats.
We presented this work at the Game & Wildlife Conservation All-Party Parliamentary Group (APPG) meeting in Westminster this spring.
A vibrant discussion followed with a number of questions from MPs including; Caroline Spellman MP, Angela Smith MP, Richard Benyon MP and Baroness Byford.