Investing in slurry storage and using inoculants is saving a Welsh dairy farmer time and money while increasing grass yields. Farmers Guardian reports
A Welsh dairy farmer estimates he is growing an extra 1,000 tonnes of grass a year since using slurry more efficiently.
Rhys Watkins, who milks 480 cows at Pantglas Home Farm near Carmarthen, invested in a new clay-lined 3-million-gallon slurry lagoon three years ago to help him manage the slurry better.
“Our old lagoon only gave us 3–4 weeks of storage, so we couldn’t use the slurry as efficiently as possible. Spreading slurry over winter is a headache, and there are no nutrient benefits to spreading at that time of year. With the winters getting wetter, we decided to invest in the infrastructure” he says.
Cows are housed inside all year round, as are the 300 followers throughout the winter. All the slurry from the housing is scraped into slats, which then feed into the lagoon. Slurry is applied via an umbilical system with a dribble bar, with 3,000 gallons per acre applied before the first cut of silage and after each subsequent cut, with 4–5 cuts taken a year.
“We are short of land and feed our cows heavily, so we need to get as much out of the ground as possible” he says.
His cows are housed year-round and fed a diet of grass silage and a pre-mix containing maize gluten, and water. The cows are yielding 9,700 litres, with a fat content of 4.29% and protein at 3.4%.
When he first installed the lagoon, he found the slurry was too thick to pump, so they had to add water to thin it down.
“It was too thick to do anything” he says.
“It didn’t make sense to be adding water, and then the time it was taking to mix. We had 2.5 feet of crust, and that was separating. We needed to improve efficiency, and that’s when we decided to use SlurryBugs from EnviroSystems” he adds.
Mr Watkins says before using SlurryBugs, it would take contractors 10–12 hours to mix the slurry due to the thick crust, compared to only 2–3 hours now. “It’s taking just a quarter of the time, and we don’t have to keep the mixer going while spreading slurry, so diesel use is a lot less,” he adds.
SlurryBugs are added once a year to the lagoon in the spring. The bugs rapidly colonise the store and start breaking down new fibrous material. The five strains of bacteria and fungi contained within SlurryBugs are unique and have been found to work most effectively on maximising the complex lignocellulosic biochemical pathways within slurry stores.
The bacteria secrete enzymes that break up undigested fibre (cellulose and other plant matter), releasing soluble nutrients and making them available for spreading onto land, producing a more homogenous liquid slurry.
Research by EnviroSystems has found increases in the following nutrients in treated slurry: ammonium nitrogen +21%, phosphorus +48%, potassium +17%, and sulphur +31%. This is because organic materials are released into the slurry when the crust is broken down.
Mr Watkins can vouch for the improved nutrient content of the slurry based on the improvements to his grass quality.
“This year our soil fertility has improved, and the quality of the silage is improving too. Sugar levels have gone right up, and the fermentation in the clamp is a lot better, and we put that down to the slurry. It’s definitely a more valuable product we’re putting on the grass. Over a season, we’re producing an extra 1,000 tonnes of grass by having proper slurry storage, applying the slurry when needed, and having the bugs working. We want to maximise the yield potential of grass and reduce fertiliser costs. We are seeing the benefits, with the returns on the infrastructure certainly filtering through” he says.
Mr Watkins says leys are a visually a lot thicker, and grass isn’t going to head, which he believes is because the slurry is being applied at the correct time, resulting in improved soil P and K levels. “This means we are getting a lot more grass per cut—at least a tonne extra per acre,” he says.
Grass is harvested 4-5 weeks after slurry is applied, compared to just 2-3 weeks before investing in the new slurry infrastructure, which is also making the grass more palatable to the cows.
Research on Slurry Inoculants
A two-year study, funded by Innovate UK and conducted in collaboration with Myerscough College, Preston, shortlisted almost 30 strains of bacteria and fungi and narrowed it down to a final five, which were tested under laboratory-controlled conditions.
These microorganisms were found to work most effectively on maximising the complex lignocellulosic biochemical pathways within slurry stores. The results showed:
● 29% reduction in crust formation using SlurryBugs and 23% reduction when using SlurryBugs Maintenance
● 10–15% increase in each of the following nutrients in the treated slurry: nitrogen, phosphorus, potassium, and sulphur. This is because organic materials are released into the slurry when the crust is broken down.
