Case Study: Cultivated margins

 

Author: Nicholas Watts
Farm: Vine House Farm, Lincolnshire

Aims:

The aim was to create an insect-rich foraging habitat for farmland birds. I farm on fertile peat soils, so effective control of pernicious weeds is essential.

Management:

I started using this option 5 years ago. For the first four years, I cultivated annually in the spring. Blackgrass is hit by spring cultivations and the seed is short-lived, so successive spring cultivations along with lack of fertiliser have virtually eliminated it.

This year, I applied a herbicide in March to control grass weeds instead of cultivating. This has the advantages of providing seed food for birds through the ‘hungry gap’ (January – April inclusive), providing pollen and nectar throughout the spring, and I think that the plant diversity has increased as a result. It has taken me 4 or 5 years to get the margins to produce food in the lean time of year, because of the need for annual spring cultivations to get on top of the blackgrass. If someone has no blackgrass then an early spring food source can be produced in year two or three. In future, I may only cultivate in alternate years and use herbicide in the 2nd year.

Creeping thistle is a major concern with potatoes and sugar beet in the rotation, so I spot spray thistles with a knapsack sprayer. This has reduced the thistle numbers over time. I had to spot-spray some areas to remove couch and field bindweed with a boom sprayer at harvest time, when the annuals were dormant.

Achievements:

The floristic diversity of these margins is unparalleled by any other habitat on the farm. Plant species richness per margin varies from 55 to 70 species, almost an order of magnitude greater than my wild flower margins, and even more impressive compared with my grass margins, ditch banks and hedgerows.

In years when the spring cultivation is not required, it delivers pollen and nectar throughout the year as well as any sown mixture. Red dead-nettle feeds bumblebees in March and a progression of a wide range of flowers take over from then onwards. When spring cultivation is undertaken, these margins provide pollen and nectar from June onwards.

The full range of farmland birds forage for insects in these margins: grey partridges, linnets, reed buntings, corn buntings and even quail. Turtle doves are scarce on the farm now: common sense suggests that they should use them as a source of seed food too, but I have not been able to witness this. I now have ten times the density of linnets feeding on this farm compared with neighbouring farms. I put this down to the availability of seeds in these margins. I think that the accessibility to the ground in combination with the abundance of insects (and seeds in the case of linnets) provides the ideal conditions for foraging birds.

The combination of spring cultivations, use of selective herbicide and spot-spraying have effectively controlled all of the noxious weed problems. Uncropped cultivated margins are more work than grass margins, but less than some of the other arable options, such as wild bird seed mixtures.

http://www.vinehousefarm.co.uk

Case Study: Wild flower margins

Author: Nicholas Watts
Farm: Vine House Farm, Lincolnshire

Aims:

The aim was to boost insect food for farmland birds through the summer. The farm is on peat soils in the Lincolnshire Fens.

Management:

The first margins were established 15 years ago. A wild flower and grass mix was purchased from Emorsgate Seeds. The seed mixture was 20% wild flowers and 80% fine grasses. Wildflowers included yarrow, common knapweed, wild carrot, lady’s bedstraw, self-heal, meadow buttercup, common sorrel and red campion. In addition, some flowering plants that were not in the original seed mix have established from the seed bank.

We cut them for hay in early August, as we have a market for it. Cutting and removing is important to reduce the fertility and maintain the floristic diversity. In addition, I have applied a herbicide in the spring whenever I have considered that coarse grasses were becoming a problem in the previous summer. One margin was sprayed this year for the first time in 7 years. I also pull ragwort and spot-spray thistles with a knapsack sprayer.

Achievements:

Although the floristic diversity of the original mix has declined, they remain as diverse flower margins absolutely humming with insect life. Knapweed has not survived in some of the mixtures on the acid soils. Our 15-year-old margin still retains mallow, sorrel, wild carrot, buttercup, lady’s bedstraw and self-heal. Yarrow has remained particularly dominant. In one margin, we incorporated cowslip and betony, but these did not appear in the sward until 5 years and 8 years after sowing, respectively.

The range of birds that use them has disappointed me. They are used by skylarks, meadow pipits and linnets (which take the sorrel seeds), but apparently not by my corn buntings and other small passerines. It may be that they are too dense for them. As a result, I have tried uncropped cultivated margins as an alternative means of providing an insect-rich foraging habitat for birds.

I feel that they are a significantly better option for wildlife than the standard grass margins.

http://www.vinehousefarm.co.uk/