12 September 2013

In the aftermath of summer

After the summer hay cut, the meadows quickly green up and begin to grow again - putting on 'aftermath' growth.
In most years, it helps site condition to late summer or autumn sheep graze this aftermath.
The timing of  grazing varies from site to site and season to season, but generally the first meadow to be aftermath grazed is Fox Fritillary meadow.  The meadow is on relatively fertile floodplain alluvial soils and so quickly 'springs' back into growth after the haysling.
We delivered a flock of SWT Hebridean sheep to this meadow in mid August.  At first their task looked like a daunting one, but they soon set about nibbling back and revealing the fence lines, as well as tackling the tall herbs along the edge of the ditch and any docks or thistles that try to creep into the sward.
The sheep do an excellent job in encouraging the grass to 'tiller', which tightens the sward and helps prevent bare patches where undesirable  plants like ragwort, creeping and spear thistle might otherwise establish.
Although the sheep do generate a certain amount of nutrients as dung, the overall effect of aftermath grazing is a second harvest of the meadow. There is net movement of nutrients off the meadow in the form of nutrients that have been assimilated into the fabric of the sheep -  so when the sheep leave the meadows so do the nutrients!
The sheep dung is also a useful source of organic matter and can  be important for soil and dung invertebrates.
The grazing means that the sward is low at the beginning of the next growing season. This tends to favour wildflowers that are intolerant of shading and competition from taller grasses. The snake's head fritillary pushes up its delicate leaves before the taller grasses get going, giving it a head start in the photosynthesising stakes. Low growing plants like adder's tongue, bugle and cowslip which would soon be engulfed by large grasses also take advantage of this early window.