Advertisements

Rainy walk sees serious soil run-off for farmers

Richard Hollingum sizes up the puddles…

Rain, Rain, Rain. According to northamptonweather.org.uk, the county had received 75.2mm, or nearly three inches of rain in the month of March.

This figure is almost half of the rain that has fallen in the year so far. We all know that the weather patterns appear to be changing: the temperature fluctuated considerably as well as it being very wet. It may be that the extremes are not so apparent, not many really hot periods and not many really cold periods, but are we getting wetter?

Looking at the fields, I would say yes. The ditches and the streams have been running at levels which I have only seen once before in the past ten years or so, but the difference here is that it appears sustained. And what I do know is that it seems to be raining every time I take the dog out!

submerged trees

One of our more frequent walks with the dog takes in three fields at the start before heading out to the next village. The first field is a steepish climb and is known in the family as Snow Angel. It got its name from the heavy snows of six or seven years ago when people found that the snow at the top of this field was deep enough and soft enough to fall back into and flap their arms.

The next field is Puddocks, so called because every agricultural area has to have a field called Puddocks, as, I believe, there is in Ambridge of Archers fame. I have only recently discovered that a puddock is a frog or toad, so a field full of them would sensibly be called such. The path in Puddocks goes down the hill and into Thunder Field, given its name after we temporarily stored a metal drink container in the hedge when a thunder storm brewed up quickly and we felt vulnerable with the canister in the back pack.

sinkhole

Going up Snow Angel this month has been quite a challenge as a result of the consistent and persistent rain, and the associated mud. The bottom of the field has been very soggy but as you squelch your way up, it gets a tad firmer. Towards the end of March, yet another day of incessant, heavy, rain, I turned the corner into Puddocks and spotted what looked like swans on the field near the bottom. As I walked down the path I could see that these white birds were on an impromptu stream from an old clay pit in the centre of the field, to the ditch in the next field. This stream was running quite slowly but was certainly running. As I got lower down the field I could clearly make out the swans. Except that they were not swans. They were not even white ducks. They were large mounds of white and brown-white spume; a froth whipped up by the force of the water running across the soil, finding the path of least resistance to the ditch and hence on to the main stream.

Crossing into Thunder Field, the ditch was full and was itself moving at a fast rate. The ditch had been recently cleared out and was quite deep in places relative to the surrounding land. Further along, as it neared its junction with the local stream, its passage was blocked and the water dammed. The dam was not a solid structure but a pile of brush wood collected from the flailing of the boundary hedge in February, and scooped along the ditch to form a porous barrier. The water can still get through but the speed and the volume have been restricted at this point. The result is that the ditch empties into the stream at a much reduced rate. On this day, there was slight flooding of this corner of the field, and in an interesting phenomenon of water running into a small sinkhole that had opened in the clay at the edge of the ploughed land.

Standing Water on field

The issues of flooding of agricultural land are not new but the growing concern about the loss of soil and the double hit of reduced soil on the land and unwelcome soil in the river system, has become a major priority for agriculture and for the environment. The Allerton Project (www.gwct.org.uk/allerton) estimates that soil is lost to water at a rate of about 0.5 tonnes per hectare per year. This quite considerable loss has an obvious impact upon the crops on the land and on the ecosystems in the water courses into which the soil runs.

In addition to the amount of physical soil that runs off the fields, there is growing concern about the chemicals that also enter the rivers, particularly phosphorous which comes from run-off from farmland and also from sewage effluent. Managing the run-off and the water levels is extremely important and much work is being carried out looking into methods of control and changes of practice, so that the dual threats of soil erosion and ecosystem contamination can be removed.

dam01

John Wright, in his recent book The Natural History of the Hedgerow, notes how marshy the land was before land drainage was introduced. For those fields around streams and rivers, particular management schemes were introduced to allow flooding during the winter months and to drain them in the spring. AG Street in 1940’s Wiltshire talked of the very important ‘drowner’ who managed the irrigation of the water meadows. He would be more or less the sole occupant of this part of the farm from October to January, maintaining the ditches and controlling the flow of water in order to produce the best possible grazing.

Here in the Uplands of Northamptonshire – a term that deserves some explanation I shall leave that for another day – we have no ‘drowners’. As I look round, I can see that the arable land, which makes up the majority in the area, has lost its winter cover crop and whilst some fields have their main crop coming through, others are waiting for a seed drill or perhaps a bit of warmth to spring into action. Meanwhile, the levels in the ditches are slowly going down, as is the stream that winds through the fields though it is still flowing at speed. The permeable dam in Thunder Field is doing its job and has collected lots of the silt washed off the land. And I will still be pleased to see the rooks and the yellowhammers, the larks and the kestrel, even if there aren’t any visiting swans.

Advertisements

Leave a Reply

%d bloggers like this: