Where have all the Flowers Gone…?

From Nigel Spring –

This is part 3 of a four-part article.  Since 2012 a team of volunteers and contractors working through EuCAN Community Interest Company and Butterfly Conservation has been working on the chalk downland sites between Lyons Gate and Godmanstone to remove the invading bushes and trees that are threatening to destroy the last vestiges of this incredibly biodiverse habitat in this area of Dorset. The plumes of smoke from the hillsides on Thursdays between September and March cannot have gone unnoticed…..

We are very fortunate to have a number of well-known and highly regarded chalk downland sites in this area of Dorset – good examples are Black Hill, Yelcombe and Giant Hill above Cerne Abbas; Lankham Bottom Butterfly Reserve above Cattistock and Hogcliff National Nature Reserve above Frampton and Maiden Newton.

But look at a map of Dorset and the UK and you will see that the chalk stretches from west Dorset at its SW corner to Yorkshire and Norfolk at the northern end and into Kent to the east. So why is this habitat such a rare commodity? In centuries past, the downs were grazed by large numbers of roving sheep flocks, while only steep flinty, less productive slopes would have been maintained as woodland (some of these ancient coppices still remain). Hawthorn, gorse and bramble would have been far less abundant, some it cropped as furze for fires, but most of it nipped off by the flocks as they passed through.

Hawthorn

hawthorn

Our ancestors would have cultivated some of the hilltops and the slopes but on a very small scale as the human populations were so low. You can still see relics of the celtic field systems in the Cerne, Sydling and Frome valleys, many of them pre-Roman. Chalk grassland and the butterflies and other wildlife it supports would have flourished from east Devon to Kent to Yorkshire.

gorse

gorse

 

Previously open stretches of chalk countryside were divided up by the 18th century enclosures but it was after the end of the second world war that the widespread arable cultivation of downland took  place, with the government encouraging farmers to ensure that we would never again be vulnerable to being starved into submission.

bramble-flowers1

Bramble

The scale of these operations has accelerated enormously during the last fifty years with the help of advances in technology which have not only given the farming industry larger more powerful machines to work on the steeper slopes, but also the chemicals to ensure that rivals for their growing space like insects and weeds (aka wildflowers) have become reduced to a minimum. Chalk soils drain very freely so fertilisers tend to get leached out of the ground by the rain. The free drainage and lack of organic matter in the soil mean that arable crops have to be treated continuously with fertilisers as well as pesticides and weedkillers.

The consequence of this arable revolution that began at the beginning of the 50’s is that chalk downland habitats have become reduced in Britain by over 90% , with the remaining sites now being restricted to steep slopes. Very few flat downland sites are to be found now – Martin Down on the Dorset/Hampshire border and large parts of Salisbury Plain still survive thanks to the involvement of the military.

Further information can be found on the EuCAN website http://www.eucan.org.uk/uk/dorset/cerne-valley-project/

What’s Growing in that Field? part 1 Dairy Farming and Cereals

By mid-January a lot of the forage brassica crops, described in my post of 18th December about feeding cattle outdoors, will have been eaten, but also the young sprouts of next year’s crops are visible in many fields. Further fields are lying fallow.  Obviously the type of farming engaged by a particular farm will have a significant bearing on what is grown.  In the words of the dairy farmer I was talking to last night, the main objective is to get back to grass as soon as possible.  At the same time, however, other crops need to be grown to provide supplementation and food for the winter:  these are planted in rotation.

As well as grass, cereals are planted.  These comprise winter wheat, winter barley, spring wheat, and spring barley.  The winter cereals are sown after the harvest in September/October.  The spring cereals are sown in about March.

winter wheatWheat is favoured because it has higher yields.  The downside is that it needs a deeper soil so can only be sown in the ‘better’ fields.  Barley is better in poorer soils such as those found on slopes because the soil is thinner over the chalk.  Wheat is also particularly susceptible to disease buildup in the soil.  The dreaded ‘Take All’ fungus can reduce the crop yield by as much as 20%!

Competition is a fact of life.  Humans create a fantastic opportunity for other organisms through ploughing, creating square miles of virgin soil ripe for seed germination, and fields of monoculture crops, creating a seemingly endless food source for fungi and other microorganisms as well as insects and larger animals like birds and mammals.  Modern farming uses chemicals to redress the balance so that other species do not take too much of the food we are growing for ourselves and our animals.  Herbicides kill the plants (‘weeds’) that lust after the freshly ploughed soil and pesticides kill the insects and microbes that see our crops as an easy food source.

Rotation is an ancient form of land management which also reduces the buildup of weeds and microbes (which cause diseases).  The agricultural pest ‘Black Grass’ is now resistant to selective herbicides and is becoming a more serious pest.  It is partly for this reason that increasingly cereal crops are not sown until the spring.  Instead the field is roughly cultivated in the autumn in order to ‘chit’ the weed seeds (encourage them to grow).  Once they have been tricked into growth, the field is sprayed with Roundup (glyphosate), a herbicide which kills plants by interfering with biochemical pathways unique to plants.

Black Grass rearing its heads above Barley Maccheek at the English language Wikipedia  CC-BY-SA-3.0 http://creativecommons.org/licenses/by-sa/3.0/)%5D, from Wikimedia Commons

I once knew a farmer in Herefordshire who was totally unembarrassed about using chemicals.  “Jane”, he said, “when you’ve spent your youth hoeing the weeds from 50 acre fields of potatoes, you KNOW what the alternative is!”