Can bulrushes and sphagnum moss be best friends?

Our team has been braving the elements to plant sphagnum moss at our bulrush wetter farming trial in Lancashire. But why?

Gore House Farm in South West Lancashire is the home to what at first might seem like a flooded field, but is in fact the first stages of an exciting bulrush wetter farming trial. The farm is typical of many in our region in that it is sited on an area of drained lowland peatland. Historically much of our lowland peat has been drained and converted to agricultural use, but this is not always completely successful, leaving many areas wet, boggy and increasingly difficult to farm.

And not only that, as soon as you drain the water from a peatland this causes the release of large amounts of carbon that was previously locked safely away in the peat. In fact 3 per cent of UK greenhouse gas emissions come from drained lowland agricultural peatlands. But what can we do to help address the dual issues of carbon emissions and unprofitable farmland? One answer could be wetter farming.

Blog: What is wetter farming?

Bulrushes covered in fluffy white seeds at the edge of a pond — Bulrushes - credit Katrina Martin/2020VISION

Also known as paludiculture, wetter farming is the practice of farming land with a naturally higher water table. By reversing historical drainage (often through ditch blocking and installing waterproof peat barriers called bunds) the peat can be re-wet which helps to significantly reduce carbon emissions. The challenge then is to find a profitable crop which will happily grow in these wetter conditions, and this is where bulrushes come in as they naturally grow in wet and boggy areas.

Find out more about our bulrush wetter farming trials

So we have worked with the farmers Lisa and Cameron Edwards along with the Environment Agency to turn a particularly difficult to farm field on Gore House Farm into a bulrush wetter farming trial. Looking to see how to quickly and efficiently re-wet the land, investigating different methods of sowing and harvesting, and how well the bulrushes will grow as a commercial crop.

Drone bulrush seed sowing - Gore House Farm (https://www.youtube.com/watch?v=Juhfm0UEHto)

Drone sowing bulrush seeds into the wetter farming trial

Green sphagnum moss plug plant — Sphagnum moss plug at the bulrush wetter farming trial - Rachael Foster

Why are we planting sphagnum moss?

One exciting part of the Gore House Farm bulrush wetter farming trial is that we are looking at more than just the bulrushes themselves, including if there are any benefits of companion planting sphagnum moss along with the bulrushes.

Sphagnum is the main building block of peatlands and forms a spongy, mossy carpet on a healthy bog. This not only works to create more peat as the lower layers of vegetation partially decompose in the oxygen poor and acidic conditions of peatlands, but the mat of vegetation helps to protect the peat and reduce methane emissions from any areas of standing water.

And we are hoping that sphagnum could do just the same thing on our wetter farming trial. The bulrushes will grow through the sphagnum, whilst the moss is doing its job of covering any areas of bare peat, protecting it from erosion and potentially drying out in any drought periods.

Area of wet field with standing water — The Gore House Farm wetter farming trial has been re-wet to grow a crop of bulrushes - Rachael Foster

We will also be monitoring both the carbon and methane release from the site closely. As the peat re-wets we expect to see the carbon emissions reduce, but the converse can sometimes be true of methane whose emissions can increase from any areas of standing water on a re-wet peatland. Whilst methane is much shorter lived than carbon dioxide in our atmosphere, it is 28 times more potent. Although methane emissions as monitored at our Winmarleigh carbon farm wetter farming trial were shown to be negligible, no more than 0.001 grams of methane (converted into CO²e for the calculations) were released per m² per hour*, we can’t automatically assume the same will be true at Gore House Farm and so we need to do all we can to limit the release of both of these harmful greenhouse gases.

What could go wrong?

As this is a trial we don’t expect to get everything right first time. As the trial site is downstream from a water treatment works there are some concerns that there could be too many nutrients in the water for the sphagnum to thrive (as peatlands are naturally nutrient poor). On the other hand though we are hoping that the bulrushes themselves will act as a reedbed and help to filter nutrients out of the water, naturally purifying it, which could give the sphagnum a greater chance of establishing.

There is also the worry that the newly planted sphagnum plugs will prove irresistible to the local geese, especially as the site is very close to our Lunt Meadows nature reserve. However, we have planted the sphagnum quite densely and as we are a Wildlife Trust we don’t mind sacrificing a few plugs for their dinner!

What next?

We will keep a close eye on the sphagnum plugs over the winter and continue to monitor both carbon and methane emissions from the site. We are also looking forward to seeing how our first sowing of bulrush seeds has fared when the plants germinate in spring. Watch this space!

*Data from Dr Anna Keightly, Manchester Metropolitan University

Sphagnum cuspidatum being collected to be translocated on Little Woolden Moss - Credit: Lancashire Wildlife Trust

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