One of the most interesting aspects to last week’s soil health conference was what I can only describe as the ‘missing slurry’ conundrum.
The event was hosted online by Teagasc.
Seemingly, there are a number of intensive livestock farms around the country with soil phosphate (P) and potash (K) indices that are well below three.
However, because their compound feed usage is so high, the nutrient inventory for these enterprises now prevents them from using chemical P and K fertilisers to boost overall soil fertility levels.
So, the question arises – what use was the slurry previously produced on these farms being put to? Or, more to the point, where did it actually end up?
I sense that vast quantities of slurry were put out on the fields closest to the farmyard, with the result that the more distant parts of the farm were never graced by a slurry tanker.
Slurry use
One of the most significant outcomes emanating from last week’s webinar, was the clear need for all farmers to make best use of animal manures.
The reality is that the strategic use of lime and these organic fertilisers would act to significantly boost soil fertility levels across the country.
Moreover, the attainment of this objective would allow chemical fertiliser nitrogen (N) applications rates to be scaled back dramatically, without impacting on the country’s food production potential.
But, there’s another dimension to slurry and farm manures – their energy value. I see no reason why every gallon of slurry and tonne of farmyard manure produced in Ireland is used as feed stock for an anaerobic digestion (AD) plant.
The resultant biogas that is produced from these processes can be used to fuel Ireland in so many different ways, such as in transport, heating and electricity generation.
Energy extraction in no way dilutes the fertiliser value of slurries. In fact, some argue that the digestate emanating from an AD process is a more efficient plant nutrient than the slurry used at the outset.
All of this adds up to a win-win scenario for Irish agriculture, and for the country’s economy as a whole.
Denmark is a very suitable role model for Ireland in this regard. Recent years have seen the Scandinavian country commit to make best use of the slurries and other farm wastes courtesy of a major AD-related investment programme.
The actual tipping point in favour of the entire process, was the fact that Denmark had ready access to a comprehensive natural gas pipeline network that had been developed many years earlier.
So, there is no reason why a similar approach can be used in Ireland when it comes to getting biogas produced from agricultural slurries and other farm manures around the country to where it is needed most.