Rates and timing are keys to nitrogen use

By Dairy News

MURRAY DAIRY hosted ‘Making It Stack Up’ — a workshop about getting the most from spring silage in Echuca recently.

Incitec Pivot’s Lee Menhenett spoke on maximising production through strategic fertiliser and water use, understanding how pasture systems utilise nitrogen, rules around nitrogen and the links between water and nitrogen.

Mr Menhenett said the key driver behind profitability of nitrogen use was rates and timing.

“If you don’t use it you lose it and if you get those things right, you will be able to kick some serious goals,” Mr Menhenett said.

David Lewis from Lallemand Animal Nutrition provided information on getting quality cereal silage into your stack through harvest timing decisions and quality over quantity, managing cereal silage if the season cuts out and increased ensiling challenges of cereals in the region.

Whole crop cereal silage can be ensiled at two stages:

Flag leaf: Boot stage — lower yield, generally higher metabolisable energy (ME) and crude protein (CP). Cut crops at 10 cm height and use tedder immediately after mowing or a mower conditioner, harvest ideally with a precision chopper.

This is a difficult stage of growth to wilt because it is early in the season and Mr Lewis recommends the use of silage additives if the silage isn’t wilted enough.

The stack should be sealed straight after harvest or bales must be wrapped in four to six layers at the site within hours of baling.

Avoid cutting at clear liquid stage because it often has low palatability.

Late milk: Soft dough stage — higher yield, variable ME and lower CP. For the best results use a precision chop forage harvester with direct cutting front, a precision chopper with pick-up front can be used but mow only, leave swath wide and avoid raking to minimise leaf and grain loss. The addition of aerobic spoilage inhibitor additives is beneficial.

Using a loader wagon is risky because the chop length is often too long and impossible to compact well, while the use of a baler can cause dry matter and quality losses through grain and leaf loss.

Mr Lewis recommends if storing in round bales to use normal additives to assist fermentation, while large square bales under sheets require aerobic spoilage inhibitor and vermin must be controlled because they will chew through the plastic to get to the grain.

He also touched on the characteristics of different fodder types:

Barley is okay to cut early, although it is low-yield and best suited for a whole crop high-starch yield. It has a short harvest window and the lowest NDF and is prone to lodging.

Wheat is a good option for both early cut and whole crop.

Triticale grazing helps quality on forage types; select grain variety for a whole crop. It has high lignin.

Oats are a great option for higher protein and digestibility but not ideal as a whole crop due to low grain-to-plant ratio and dry at grain fill stage.

Grain types are generally suited for whole crops while forage varieties are more suited for early cut and grazing options.

Among the crowd of 40 farmers at the workshop were David and Denise Gebbie from Timmering.

The dairy farmers are currently milking 300 cows.

They planted extra crop for hay this year to rebuild reduced fodder stocks, but they fear an early end to the irrigation season due to high water costs will force them into hand feeding earlier then they would like.

“We have around 130 ha of crop for hay and another 40 ha of sub for silage,” Mr Gebbie said.

“We planted extra oats to take through to hay this year and they are all looking fairly handy, as long as the rain keeps coming.”

Business discussions at this stage have centred around using irrigation to finish off the crops to get hay on the ground if required.

“At this stage we are anticipating keeping stock numbers the same but if things turn really bad we will be destocking like everyone else,” Mrs Gebbie said.