Slurry

Slurry Considerations

Getting the most nutrient value from slurry is vital, given rising fertiliser costs and NVZ regulations.

Slurry can be worth £273 a hectare to the average dairy farmer if it is used correctly. With the cost of bagged fertiliser now at its highest recorded price, farmers are being encouraged to stop treating home-produced slurry and farmyard manure as a waste product, but to instead use it correctly as a means of producing cheap grass.

With this in mind, the makers of SlurryBugs have developed a unique product which allows common slurry to be used as an effective fertilizer on farms up and down the country.  Saving money and becoming a truly green product, encouraging many farmers to recycle and reuse something that would otherwise be thought of as waste.

Storage

Considerations When Storing Slurry

Crusting

During slurry storage the formation of a crust caused by fibrous particles floating to the top of the slurry prevents oxygen and light entering the lagoon. This lack of basic life source for aerobic bacteria leads to lower microbial activity in the lagoon to break down manure solids and volatile anaerobic life forms dominate.

The enzymes produced by SlurryBugs in combination with the enzyme mix in the SlurryBooster application degrade much of the undigested fibre that causes crusting. This achieves more liquefied slurry with less odour.

Odour

The production of ammonia from slurry releases unpleasant odours and can lead to ammonium deposition which can cause acidification of soils and over-fertilisation of sensitive crops. The SlurryBugs process of metabolising ammonium into organic nitrogen reduces odour and provides a slow release mechanism that helps prevent acidification of the soil.

Greenhouse Gas Emissions

Slurry is responsible for the emissions of the greenhouse gases carbon dioxide, methane and nitrous oxide. If carbon dioxide is considered as the baseline strength of greenhouse gas then methane is 25 times more potent and nitrous oxide 250 times more so. Furthermore, despite ammonia not being classed as a greenhouse gas, it can be effectively converted to nitrous oxide, which as described above is an extremely potent greenhouse gas.

Gas tests at Lancaster University during the summer of 2010 revealed that after 5 weeks treatment with SlurryBugs there was a threefold decrease in CO2 levels and a twofold decrease in methane emissions following treatment with SlurryBugs in comparison to untreated slurry taken from the same cows.

Recently published data from ADAS and DEFRA assume 70% of all nitrogen in 6% dry matter cow slurry is lost to the atmosphere. Through use of SlurryBugs & Booster at the correct rate over 2/3rds of this lost nutrient can now be captured for plant uptake.

Toxic Fumes

Care must be taken with slurry storage under slats when using plasterboard-based bedding which gives off hygogen sulphide. This results in reduced oxygen levels in the sheds as well as toxic gas production which can be a hazard to animals kept indoors.

Management

The Value of Slurry Management

For dairy, beef and pig farmers, considering efficient management of slurry can improve the fertiliser value of their waste, along with easier handling and reduced odour.

DEFRA, the EA and ADAS are actively encouraging farmers to value their slurry and improve the management of this naturally available nutrient source which is often neglected. With European legislation forcing farmers to store their slurry for longer, the retention of these beneficial nutrients is becoming a more arduous task.

Investment in sufficient storage offers excellent return on capital, the slurry should be stored during the coldest part of winter and applied when the soils warm in the spring. This improves nutrient application, increases microbial populations and humus formation in the soil leading to improved crop growth.

Fresh cattle slurry can lose up to 80% of its nitrogen value through gaseous emissions, loss of ammonia and leaching from the soil by the time it is spread. Therefore finding a way to introduce aerobic bacteria into fresh slurry as near to the cow as possible is a cost effective way of ensuring nitrogen is retained in its organic form in the slurry. Trapping this nitrogen in bacteria ensures the volatile nitrogen is fixed, and when spread this nitrogen encourages soil micro-organisms and worms for improved crop growth.

Crusting is a sign of lost nutrients as the watery slurry under the crust is generally anaerobic, this is due to less light and oxygen entering the slurry. Stirring slurry is a costly process which causes loss of nitrogen compounds to the atmosphere in the form of ammonia and nitrous oxide. However SlurryBugs is designed to digest through fibrous crusting without disturbing the surface of the slurry and condition the slurry into a homogenous solution.

The decision to manage the nutrients in your slurry will return long term benefits.  At least one bag of ammonium nitrate per acre can be saved on 1st cut silage if slurry is treated with an additive such as SlurryBugs & Booster. Spreading becomes easier, smells are significantly reduced and the soil benefits from increased organic nitrogen.