Soaring Fertiliser Costs proving Importance of Soil Fertility

Fuel shortages, spiraling costs, lack of labour and talks of power outages are among the topics that are covered when talking to farmers in the last few weeks. Keith Fahy, Teagasc Athenry advisor recommends soil sampling to identify lime deficiency and correcting this to reduce fertiliser bills

Meal prices have gone up another €20 to €30 in the last few weeks and some merchants aren’t even quoting fertiliser prices. I spoke to three merchants last week about fertiliser and the conclusion is it cannot be got. Even considering some fertiliser prices have increased by up to €200/tonne in 12 months, farmers still cannot physically get fertiliser in their yards due to supply issues. One merchant told me that before the chemical fertiliser deadline, some farmers paid up to €500 per tonne for smaller amounts of 18-6-12, the same fertiliser started off around €330 last January. It certainly is a year like no other. All this brings farmers back to the basics and they were never as important. We need to make the most of the soil we have and ensure that we are as efficient with inputs as possible as they are too valuable to be wasting.

Pilot Soil Sampling Programme:

Minister McConalogue recently opened up the pilot Soil Sampling Programme for applications.  The aim of the pilot programme is to analyse the soil nutrient status including both macro and micro nutrients, analysing soil carbon and it will also look at the level of harmful bacteria in soil at farm level. With only approx. 10% of Irish soils in the optimum range for pH, Phosphorous and Potassium, this should identify fields that are low in certain nutrients and will help farmers in matching the correct fertiliser with the demands of individual fields. When the intake closed last Friday there were over 15,000 applications.

Liming:

With chemical fertiliser prices soaring and availability limited farmers seriously need to look at the soil profile of their farm. A tonne of fertiliser at current prices can cost up to €500 while lime is only €25/tonne. With a large proportion of beef and sheep farmers taking part in environmental schemes such as GLAS etc. and many dairy farmers following derogation guidelines, there is a large amount of soil information available. As part of GLAS, thousands of farmers took soil samples. A lot of farmers analysed these results carefully but there were a lot of samples thrown in the back of the press also. Lime is the cheapest form of fertiliser and without the correct pH, fertiliser’s will not work as well as they should. Mark Plunkett from Teagasc Johnstown Castle, Co. Wexford recently brought out an informative “10 Facts on applying Lime” I will summarise these below;

10 Facts on Applying Lime:

1. Paddock Availability

• Once grass covers are low this is an ideal time to apply lime
• Identify fields that require lime by soil sampling (Approx. €25/sample)
• 20 tonnes of Lime will cover 10 acres @ 2t/acre

2. Lime residue on grass

• Applying lime on low covers reduces lime residue risk
• Rainfall will wash most of lime off grass plant into the soil
• A small amount of lime on plant will not harm grazing animals

3. Softening of the ground/sod

• Soil types with thick 5-10cm Organic layer are more prone to poaching
• This organic layer stores most of acidity
• Liming this layer will raise pH and create more biological activity thus softening the sod
• To reduce risk of softening do not apply more than 2t/acre or 5t/Ha

4. Silage fields

• Leave three months min between lime application & closing for Silage
• Give time for lime to wash down if cut before this as it can raise the pH of silage thus cause spoilage during conservation

5. Lime & Slurry

• Spreading slurry on fields that recently got lime and where not washed in can create Nitrogen loss of up to 50%
• Spread Slurry first then lime 7-10 days after

6. Lime & UREA

• Similar to Lime and Slurry
• Nitrogen loss may occur where UREA is applied on recently limed land
• Apply UREA first then lime 7-10 days after. (Protected UREA less of an issue)

7. Lime & High Molybdenum Soils

• Soils with High Molybdenum may increase risk of copper deficiency
• In this case do not over lime and ensure pH does not exceed 6.2
• Copper may need to be supplemented

8. Speed of Reactivity

• Once applied & washed in lime starts to adjust pH
• >35% of ground limestone Is < 0.15mm and fast reacting 0-6 months
• The remaining 65% has a larger particle size & takes 6-24 months to break down

9. Return on Investment

• Research shows that liming acidic soils can increase grass growth by 1tDM/HA
• For Drystock farms this is worth €105/tDM & €180/tDM on a dairy farm
• ROI is €4-€7 per €1 spent

10. Lime Type

• There are two types of Lime – Calcium & Magnesium
• Calcium lime is most commonly used whereas Magnesium Lime is more common in the South East.

So by taking and analysing soil samples you can identify what fields need lime and correct this immediately this winter and you will make better use of fertiliser, improve soil biological activity and grow more grass thus improving farm profitability.

For more information on soils and fertility see  www.teagasc.ie/crops/soil--soil-fertility/

Teagasc Advisors are regular contibutors of articles here on Teagasc Daily. If you require any help or advice in the area of soil sampling, applying lime or growing grass, contact your local Teagasc Advisory Office here: Advisory Regions.