This week, we go into a bit of detail on the costs involved in sourcing additional silage.

The reality is that many farms ate into their silage reserves last winter. Rebuilding those reserves wasn’t helped by the fact that silage ground was late being closed and fertilised, and some farmers had to go back in and graze some silage fields again.

The very first step is to work out how much silage you need for the winter and how much is growing and will be grown for second cut. In general, you would expect around 6t DM/ha from good first cut and 4t DM/ha from good second cut.

Between the dry period, buffering at shoulders and a reserve, each cow will need about 1.5t DM of silage. Feeding straights is also an option worth considering, but I would be wary of supply as severe flooding in South America could hamper deliveries, so keep that in mind.


In recent years, the advice for the mid-season nitrogen rates has been 0.8 units/acre per day, and less on high clover swards or swards getting soiled water. This is a good strategy for those that will have enough grass in front of cows and enough silage in the yard.

Where that is not the case, the argument could be made for higher rates over the coming weeks. So rather than spreading the 0.8 units/day, it could be increased to one unit or 1.1 units/day for a few weeks.

This will drive extra grass growth that will enable a smaller area for grazing and a larger area for silage. Make sure the farm has an allowance for the extra N.

I’m not overly concerned about the impact on water quality of spreading more N now. Response is high and soil N reserves are low.

Many farmers are wondering what to do with paddocks that are gone too strong – cut for silage now, or fertilise and cut later. Grass will start to head from next week, so this is a factor to consider.

If the field is hungry looking and already stemmy, I’d be inclined to cut now and start again. But if the field has been well fertilised to date and is leafy, then closing it up for a couple of weeks will add bulk.

Silage ground will use up two units of nitrogen per day in good growing conditions.


Switching between units/acre and kg N/ha is confusing and complicated. Many farmers think in terms of units/acre, so it’s often easier to communicate in this way. Essentially, to convert kg N/ha to units N/acre multiply the kilos by 0.8.

To convert units/acre to kg N/ha multiple the units by 1.25. Now, fertiliser spreaders are set up to apply fertiliser in kg/ha, but you must remember this is kilos of product per hectare, not the rate of nutrient per hectare.

The rate of nutrient is determined by the percentage of nutrient in the product and the rate per hectare. For example, you have a bag of 46% protected urea in the yard and you want to spread 18 units of N/acre.

This is the same as spreading 22.5kg N/ha. To apply this, the rate on the fertiliser spreader should be set at 49kg/ha because 22.5 divided by 0.46 (46% N in the fertiliser product) is 49kg/ha.