Our Organisation Search
Quick Links
Toggle: Topics
Placeholder image

Making Good Quality Silage

07 May 2019
Type Media Article

By Keith Fahy Drystock Advisor, Teagasc Galway/Clare Region

Making Good Quality Silage
By Keith Fahy Drystock Advisor, Teagasc Galway/Clare Region

“Insanity is doing the same thing over and over again and expecting different results” this was of course a quote by the late Albert Einstein, now I don’t think the theoretical physicist was referring to making good quality silage however the theory could be used to improve silage quality. We will not improve the quality of silage being made if we continue to cut silage later in summer and avoid cleaning off the dead material prior to fertilising for silage. Every year we analyse a large volume of silage sample results and it is safe to say that silage quality is an area which really needs improvement.

With the cost of making silage increasing we must strive to make the best quality silage we can. A question that we often get asked at group meetings and events is “What does it cost to make a round bale”. If we look at the Association of Farm and Forestry Contractors “guide rates” excluding VAT for 2019 it states that it can cost €13 to cut, mow, bale and wrap a round bale of silage, excluding silage plastic. If we take a roll of plastic to come in around €75 a roll with a roll wrapping approximately 25 bales, this is adding another €3 euro onto the cost, we are now up at €16 per bale. If we are spreading 5 bags of chemical fertiliser per acre at €380 per tonne this equates to approximately €19 per bag or €95 euro per acre. With the aim of having a target minimum yield for first cut silage of around 5 tonne of dry matter per hectare (This equates to 2 tonne dry matter per acre, taking a 650kg round bale with a dry matter of 30% this is giving each bale a dry matter of 195kg per bale equating to approximately 10 round bales to the acre), taking 10 round bales per acre our fertiliser cost is coming in at €9.50 per bale adding this onto our existing cost of €16, we are now at €25.50. So it is of paramount importance that we are making the best quality silage we can that will preserve well, have a high leaf content, high sugar content and that bales are moved carefully as any error in this will increase spoilage thus costing more money to the farmer.

Time of cutting plays a huge factor in terms of both silage quality/DMD% and yield; understandably there is a happy medium in that we want the optimum quality and quantity of silage. Below please see the importance of an early cutting date with DMD% dropping 10 units from the 1st of May to the 5th of June.

Time of day when cutting also plays a huge factor in terms of sugar content. We can test for both Nitrogen and sugar content and there can be a massive difference in sugar content depending on when we receive the grass sample. Sugar contents in grass are highest around 4pm in the evening as the grass has received light/heat all day thus reducing water quantity in grass which will increase the concentration of sugar content. Ideally grass samples should have sugars at around 3% when cutting. Where this is not always possible wilting plays a huge role in reducing the water content in the sward, tedding out swards and wilting for 24 hours will help increase the dry matter of the silage to approximately 27-30%.

Cutting height also plays a huge roll when making silage. Cutting too low or in fields that may have been poached could introduce undesirable soil microorganisms such as Clostridia into bales/pit. This could cause Listeria in silage and reduce the preservation/fermentation of the silage.

Ensure that the Nitrogen has been used up by the plant; there is a huge variance depending on age of sward, growing conditions, weather etc. when looking at the rate of Nitrogen uptake by the plant. As a rough rule of thumb approximately 2-3 units of Nitrogen get used up every day, so where a farmer has spread 100 units it could take 50 days/7 weeks for this Nitrogen to be fully taken up by the plant. Nitrogen in the grass can be tested giving the most accurate result when wondering if all Nitrogen has been used up.

Weed control is another area which plays a massive role both in terms of quality and yield. Docks are probably the main culprit in reducing silage yields and quality. Ideally spray 3 to 4 weeks prior to cutting. (Always read the label and record rates etc.).

With silage season approaching it is always a very busy and dangerous time on both farms and roads, keep children in a safe place when silage is being made and take care on the roads.