Slurry has a massive role to play on farms as it can be used to replace nutrients within the soil, and after silage has been harvested is a key time for this to happen.
The last week or so has seen some farmers move to harvest their first cut of silage, while others await a break in the weather.
Once the crops have been harvested however, the focus then quickly shifts to preparing for second cut.
Most, if not all the area that was cut for first cut, will likely be harvested again for second-cut silage.
Slurry
After silage has been harvested it is important that the nutrients taken off by the crop are replaced.
Slurry is the easiest way to replace the phosphorus (P) and potassium (K) that has been removed.
On a farm where seven bales or 5,600kg/ac of fresh-weight silage were harvested, there is an offtake of about 70 units of nitrogen (N), 11.2 units of P, and 70 units of K.
On a typical dairy farm, about 3,500 gallon/ac are needed to replace the P and K that has been removed.
Having slurry tested will determine the exact amount of slurry that is required.
On most dairy farms, slurry should have a nutrient value of 21 units of N, 10.5 units of P, and 73.5 units of K.
The yield farms are aiming to achieve from their second cut should determine the amount of chemical N required to be spread.
To achieve 8t to the acre, fresh weight, about 80 units/ac is needed. This can be reduced 60 units/ac for a target of 6t/ac (fresh weight).
The N within the slurry should be included in the total N requirement for the silage crop.
Testing
The way to get the most out of your slurry is to get it tested, which will determine its nutrient value.
Once this has been done you can then alter your nutrient management plan and fertiliser application based on what is contained with your slurry.
Depending on the results there could be potentially massive savings to be made from a reduction in the use of chemical fertilisers.