Farm Ireland
Independent.ie

Wednesday 19 September 2018

Spreading fertiliser in February can help slash winter feed costs

Soils can soak fast at this time of year
Soils can soak fast at this time of year
Joe Kelleher

Joe Kelleher

Ground conditions are poor at present but a few dry days would sort out most free draining soils, a fortnight or so will be required to sort out the heavier soils.

However, soils can soak fast at this time of year and it is vital that we assess the conditions of fields in the field and not in the farmyard.

Fodder is running low in many yards and it is important that we ensure that there is plenty of grass outside when­ever cows do get out to graze it. 1kg of Nitrogen in spring will grow 10kgs of dry matter.

So to put this in real terms; if we spread 2 tonne of Urea across 80acres (23units/acre) in February, we will grow 9t of grass dry matter, which has the equivalent volume of feed of approximately 45 bales of silage (except of much higher quality).

One price I saw this week was for Urea at €345/t so this equates to €690 for the 2t, which equates to €15/bale. You won’t find too many bales around the country at this price.

Urea is generally the product of choice for springtime nitro­gen for two reasons; 1. It is the cheapest source of Nitrogen available and 2. Its ability to bind with soil is better than CAN based products in times of high rainfall.

Of course having the grass outside in the field isn’t of much benefit if we don’t get out to eat it. The target is to graze 30pc of the farm in February and 60pc in March.

This equates to 1pc of the farm grazed per day in February and 2pc in March.

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This is key to having suf­ficient grass on the farm at the beginning of April, as this allows the grass two months to grow a sufficient cover. For those on heavier soils, we need to constantly assess the drier paddocks on the farm to see when they are suitable to al­low cows out for three hours grazing. Trials have shown that cows can eat 90pc of their daily intake in two bouts of grazing lasting three hours each.

National statistics show that approximately 90pc of our soils nationally are deficient in terms of soil fertility.

Many argue that this has oc­curred as a result of restrictions applied under REPS and other schemes, and this is probably

true on some individual farms, but the reality is that it is no coincidence that as the price of compound fertilisers were in­creasing over the past 10 years, their usage was falling. This, I suspect is the main reason why our national soil fertility has remained low.

fertiliser table.PNG

Amendments

One tonne of 18.6.12 can be bought today for €350/t approximately. While this is €50 dearer than last year, we should remember that this figure was nearer to €400 two years ago, so it still represents value for money at €350. Under the new amend­ments to the Nitrate regula­tions (in place since January of this year), farmers in with a stocking rate of greater than 130kgs/ha can avail of higher phosphorus (P) and potassium (K) allowances.

For a farmer who has all his/ her soils at index 1 for P and K, they are now permitted to spread approximately 40 units of phosphorus/acre which is a substantial increase on the previous allowance.

It should be noted that that a new fertiliser plan has to submitted to the Department of Agriculture before March 31 to avail of this increase, which in many cases may involve taking new soil samples.

With this in mind, table 1 shows how spreading 40 units of P/acre can be achieved in practice.

Sulphur is another element that has to be remembered, particularly on sandy or free draining soils. Sulphur is essen­tial for the formation of amino acids, the building blocks for proteins which are needed for growth and development in plants and animals. It is also required to convert Nitrogen to plant dry matter.

As grass grows, both S and Nitrogen are used together so an S deficiency will decrease nitrogen use efficiency and so reduce yield.

It is recommended to apply 16 units of sulphur annually to grazing swards.

Joe Kelleher is a Teagasc advisor based in Newcastle West, Co Limerick


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