Muck heaps are a valuable tool in the battle against soil depletion, Tim Field explains.

For more on farming, find out why winter is no time for farmers to sit back. Read farmers acting as engineers: masters of engineering.

MUCK HEAPS

In the quiet of a crisp winter’s morning a gentle plume rises from a field edge. The remnants of a bonfire? No, it is steam rising off a mighty muck heap. A community of billions of fungi, bacteria and invertebrates are industriously composting away, letting off steam in the process. The larger beasties wriggle back and forth, aerating and mixing the outer layers, exposing a few weed seeds and husks on the surface. The combination of warmth, bugs and worms, with a side order of seeds and grains, make this a bird feeder of gargantuan proportions. Every rough shoot should cherish a good muck heap – a giant breakfast bowl to sustain birds through a cold snap.

Cow muck is a familiar scent around stock farms on windless winter days, particularly when it’s being shunted around. The beeping of a reversing Loadall is reminiscent of yard scraping, mucking out and turning. In an ideal world, muck is manoeuvred into a covered store before being carted to field when a suitable weather window appears. In well-endowed farmyards a large, concrete pad and silos will allow regular turning without damaging soil structure. Otherwise, it is in-field composting, heaped on a firm piece of ground far from ditches, drains and watercourses. It is turned every six weeks to aerate.

Patiently waiting a year to compost, the spreader kicks into gear when the ground firms up or a hard, frosty day enables muck mobilisation. The valuable crops most in need of nitrogen will be prioritised, such as winter cereals. Giving a dose of nitrogen from well-rotted manure will help the crop get away in spring. Otherwise it could be stubbles ready for the spring drillings or pastures in line for a hay or silage cut at the start of summer. Once the first cut of silage is taken, the muck spreader follows closely behind to give a boost to regrowth before another cut or grazing.

Nutrient cycling with manure is one of the great values of mixed farming. Muck spreading is the means of shifting nitrogen from feed, via livestock to the next crops. It is often forgotten that an animal by itself doesn’t generate fertility, it merely recycles it. A cow grazing a grass pasture is quietly stripping fertility and over time the field will be less productive; unless, that is, feed, muck or fertiliser is brought in to replenish the nitrogen removed by the grazing cow.

However, the miraculous biology of nitrogen-fixation in leguminous plants (such as clover) and other soil microbiology replenish soil fertility. Therefore, an optimal system will fix fertility in leguminous leys, harvest the “fat from the land” (as silage or hay) during peak growing season, conserve to feed in winter and recycle via manure for future plant growth. A few years of building and redistributing nitrogen in the crop rotation allows for increased productivity without the cost of artificial fertiliser or imported feed.

Areas where muck distribution is more of a challenge, such as the steep slopes of downland or saturated flood meadows, become “unimproved” pastures. Without competition from dominant grasses, the sward diversity flourishes with flowering plants and associated assemblages. After a period of considerate fertility building, the farm will present areas less suited to intensive efforts and biodiversity will benefit. While these areas might still be grazed, hay taken or weeds managed, more intensive treatments of subsoiling, muck spreading or reseeding are directed towards the farm’s soils that make up the bread basket.

The Sustainable Soils Alliance was launched at Westminster in October and we heard Michael Gove rolling out facts and figures on our soil’s capacity to yield only 60 more harvests before we lose them beyond repair. He went on to quote Jared Diamond’s book Collapse, which describes how the fall of civilisation on Easter Island coincided with the destruction of the environment – trees, in that case. Drawing comparisons between us now and the Easter Islander community 60 years before the last tree was felled, we got an encouraging message that our Secretary of State wants to arrest the depletion of soils or face civil disaster.

Soil nutrient recycling of mixed farming systems is, without a doubt, part of the solution and there is a reassuring appetite to value the magnificence of manure. As part of the annual Oxford Farming Conferences in January, Agricology will be hosting a fringe event at Daylesford Farm with six farmers representing their different scenarios of integrating livestock to build soil fertility. On that day and all winter, may steaming beacons of muck symbolise enlightened perspectives on soil husbandry.

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