Putting the focus firmly on soil to give grass a lift from nutrients

Winter grassland management may not be a priority among dairy farmers, but Cumbria milk producer Robert Emerson is putting it at the top of his list.

He’s no longer relying solely on lambs taken for wintering to keep the sward low and add some manure to the soil.

This year he’s applied fertiliser in late autumn and will be back to top-dress fields as soon as he can – possibly in late January when ground conditions permit.

A move away from high concentrate feeding has placed more emphasis on the value of grass for his 220 Holsteins on 104ha (250 acres) at Pembroke House Farm, Brougham, Penrith.

But he believes his fields are capable of yielding more than his annual spend on fertiliser has been producing.

“Fertiliser prices are due for a big hike, so we’re looking at ways of using less.

But trying to reduce these costs can’t come at the expense of grass production.

“We’re going to put more emphasis on improving the soil’s ability to feed grass and getting pH right,” says Mr Emerson.

A soil analysis has indicated a low pH of about five across the farm.

The aim is to get pH up to about six.

Traditionally the farm’s fertiliser programme was based on a 27.5.5 compound.

An initial March application of 490kg/ha (200kg/acre) was followed by 365kg/ha (150kg/acre) after first cut in late May with a further 240kg (100kg/acre) after second cut in early July.

“We haven’t applied any lime for many years and our fertiliser costs are plenty high enough.

We can’t cope with the rise of up to 30% that’s being suggested.

“This year we have used 100t of fertiliser costing 130/t.

But we could be looking at spending up to 16,000 next year with the predicted price rise.”

Mr Emerson believes he could make better use of his slurry.

Currently grazing land around the farmstead receives the bulk of slurry and waste water via an umbilical system, but these fields still receive the same fertiliser as land that doesn’t get slurry.

So Mr Emerson has decided to make a late autumn application of a soil conditioner based on calcified seaweed at the rate of 240kg/ha (100kg/acre) costing 52/ha (21/acre).

The product contains nitrogen to facilitate breakdown of organic matter in soil and an additive to enhance microbial activity.

It also acts to reduce soil pH.

It will be followed in January with a second application of a similar product containing a small amount of nitrogen with additional sulphur to enhance grass palatability.

The aim is to get more nutrients out of the soil and slurry applied to it.

“We have piled on nitrogen for too long and now want grass to be more palatable for both grazing and silage.

We hope that if we turn our attention to soil, our grass will benefit from an improved release of the phosphate, magnesium and sulphate,” says Mr Emerson.

“Hopefully, clover will also return and we can then reduce our nitrogen inputs.

We’re currently using about 240 units/acre a year and reckon we could cut down to about 150 units – but we know we have to get the soil right first.”

The new fertiliser programme should also improve phosphate and potash use, says Joe Langcake, who works with fertiliser manufacturers Timac and has devised the programme for Pembroke House Farm.

“Achieving a correct soil pH and ensuring the bugs in the soil are active is the priority on this farm where grass is the only forage.

“We’ll be using a range of fertiliser treatments.

But where nitrogen is used it will serve to break down organic matter and not as a fertiliser source,” says Mr Langcake.

“We know from national fertiliser surveys that too little potash is used on grass.”

He reckons the amount of bagged fertiliser is only a third of the 140kg/ha (112 units/acre) of that required by grass.

“Slurry may make up some of that, but not all of it.”

He recognises that many dairy farmers believe too much potash will increase risk of grass staggers.

“However, when the correct type of potash is used in autumn, in combination with calcified seaweed to get bugs active and re-align pH, the phosphate is ready to be taken up by the plant for root development early in the season.

“At that time it is impossible to travel on fields to feed grass and plants are hungry even though T-sum 200 hasn’t been reached.”