Trying to listen to our land and find ways of enalbing it to sing while providing for us is proving to be difficult. Constant rain, heavy waterlogged but thin soils, stiff clay subsoils, cold temperatures, limited sunshine, strong winds, short growing season and rushes with thick, deep roots explain why the only crop farmers attempt to grow around Bewcastle is grass. And even for that, fertilisers and glyphosate herbicides are systematically used. Nevertheless, here we are at the beginning of June, three weeks from the summer solstice, and the farmers have yet to turn their cattle out of the byres after their winter sojourn – the ground remains sodden and the grass reluctant to grow. More wind and rain is forecast.
Numerous experiments we have attempted in trying to work with the land have ended in a failure to produce any worthwhile crop so far. Apart from second-season willows that were coppiced after their first year, the orchard, the polytunnel and the raised beds remain the only ‘productive’ areas at Greenholme. These, of course, are relatively controlled environments where the land has been heavily modified.
In the summer of our first year here (2013) we built three ponds. One (the largest) was a ‘restoration’ of an ancient flax pond that had become overgrown, the second was dug out of an unproductive slope, and the third was little more than a ‘scrape’ in a permanently wet and boggy corner of a field. None were artificially lined, all utilised the natural clay subsoil as the water-impervious barrier. All are filled naturally, either from rainfall only (wildlife pond), or rainfall plus intercepted field drains. We have no flowing water on site (although the River White Lynne flows along our border), but we do have over 1200mm of rain a year (note that is 1.2m of water over every square metre of land!). All ponds were ‘inoculated’ with water and plants taken from a local natural pond a few miles away, to seed the invertebrate and macrophyte populations. The margins of each were also planted with Phragmites australis (common reed) and Typha latifolia (reedmace) obtained from a northern nursery.
Main pond – 3m at its deepest with an island
Middle or ‘nursery’ pond – up to 2m deep
Wildlife pond looking northwest
The third pond was intended for wildlife. We hoped it would fill to the brim, since the site was permanently wet even through the dry summer of the previous year, and overflow down to the nursery pond. In point of fact it has never filled to a depth of greater than about 12 inches, the limit of the clay. Thus the vertical edge around the pond demonstrates the thickness (thinness) of the soil over the clay. Above this level the water seeps into the surrounding soil.
The pond is at the highest point of our land and has no natural inflow other than a few metres around it and the rain that falls on its surface. However, unlike the other two, it suffered from clay in suspension that has never settled. Turbidity remained so high, even after 18 months, that light could only penetrate the top few inches of water. As a consequence, almost none of the introduced macrophytes have survived.
Perpetual turbidity in the wildlife pond – February 2015
Light only penetrates the top 2 inches or so
Of all the macrophytes introduced, only bog pondweed (Potamogeton polygonifolius) struggles on
This was an inauspicious start for encouraging wildlife! Clay in suspension will never settle out due to the nature of the electrostatic charges on the surface of the clay minerals and their incredibly small size. Most solutions to the problem involve introducing a flocculating agent (usually the sulphate of calcium, magnesium or aluminium) that cancels out the electrostatic charges and enables the clay particles to clump together until they are large enough for the force of gravity to act upon them.
One form of organic treatment is by the introduction of hay. As the hay decays in the water it releases organic acids whose free hydrogen ions are thought to neutralise the negative charges on the surface of the clay particles. This allows them to flocculate naturally since they no longer repel each other. The decomposition of organic matter utilises disolved oxygen (DO) in the water, so the process can be detrimental to active pond life. For this reason it is best undertaken over the winter months when, although decomposition of the hay will be much slower due to the low temperatures, there is little organic demand on DO from aquatic life.
Before adding hay we took a sample of the pond water and applied the vinegar test. This simulates the release of organic acids to see if the hay is likely to have an effect. After two to three days the turbidity had not changed, and no settling out had taken place. In other words, it looked like the hay treatment would not work.
Nevertheless, nothing was to be lost, so in February 2015 an old square bale of hay was divided and distributed around both the nursery and wildlife ponds.
For several months, there was no observable difference. But as the temperature slowly increased, so decomposition gradually accelerated. At last, at the end of May, the effects were clearly visible, and, for the first time since the wildlife pond was built, it’s bottom could be seen!
Slowly decomposing hay, and the pond bottom at last visible.
Newly introduced common water crowfoot (Ranunculus aquatilis) is beginning to thrive in the now clear water.
Common water crowfoot and emerging reedmace (Typha latifolia) cast their shadows on the now visible pond bed.
Newly planted lady’s mantle (Alchemilla mollis) next to floating sweetgrass (Glyceria fluitans), emerging common reed (Phragmites australis) and the bog pondweed (Potomageton polygonifolius).
So now, perhaps, aquatic life will have a chance to establish itself and learn to sing God’s praise in so doing.