Grass quality

Rain has been welcomed by most farmers around the country this week. Growth rates had halved on some farms towards the end of last week, but are back up again this week after rain in most parts.

Where fertiliser has been spread, we can expect a big boost in growth rates,with predictions of between 50-70kg/DM/day across the country. This will bring challenges in terms of maintaining quality.

Where grass has shot out, you are better to try and cut this and take it out as bales.

Don’t be tempted to leave it and cut it in a few weeks. Take it out now and go back with fertiliser and slurry. Remember that taking silage off paddocks will also take off P and K, so you need to replace that with fertiliser or slurry.

In an ideal world and with good growth you should be able to manage with 10-12 days of grass ahead of stock at the moment.

Any more and grass quality will suffer. If you have grazed some strong paddocks during the dry spell, clean them out with a disc mower if you can. This will make sure the grass that comes back is better quality and prevent the grass plant from going to seed.

Second-cut silage fertiliser

First-cut yields of silage have been variable. On some farms that got out with fertiliser and slurry early, there have been some good crops ensiled. On other farms where cuts were completed earlier than normal some have bulked up small, so the second-cut will be an important addition to winter feed supplies.

If you are targeting a 6 tonne/acre crop of grass for your second-cut (most crops will yield between 4-8 tonnes/acre) you will need about 60 units of N, 10 units of P and 60 units of K/acre.

Spreading 2,000 gallons of slurry/acre if you have it will supply the P and K requirements, which means you will need 1.5 bags of protected urea/acre or two bags of CAN/acre to meet the crop’s demand.

Maximise cattle slurry application at this time of the year so that slurry tanks are emptied before next winter. Cattle slurry applied by splashplate in June will have a lower nitrogen (N) value compared to low emission application techniques.

Don’t forget about sulphur. Research has shown that sulphur plays a key role in increasing grass dry matter yield, fertiliser N efficiency and reduced N leaching. For second- cut silage crops aim to apply 6-12 units/acre per cut.

See Table 1 below for N values.