Our Organisation Search
Quick Links
Toggle: Topics

Climate Actions for January

Climate Actions for January 2023 all information in text below

Climate Actions for January

Get your slurry analysed for nutrient content

In response to a changing environment where fertiliser price has risen and there is a target to reduce chemical nitrogen use by 20% by 2030, there is an increased focus on maximising the use of the nutrients available on the farm. Dairy / drystock advisers in the Teagasc Kilkenny Waterford region embarked on a project with discussion groups to establish the nutrient content of slurry in the region. 

A number of dairy discussion groups in the Kilkenny Waterford Advisory Region carried out a slurry analysis project in the spring of 2021. Farmers were asked to:

  1. agitate slurry as normal
  2. fill the vacuum tanker
  3. release some slurry back to a half a plastic barrel
  4. fill a two litre plastic bottle with a subsample of slurry for analysis.

Samples were kept pre dispatch to FBA laboratories in a cool dark store to eliminate the risk of plastic bottle bursting from the enclosed gasses in the sample bottles. All samples were clearly labelled with the farmers name, herd no. & discussion group details. Samples were analysed for dry matter percentage (DM) and total N, P & K in kg of nutrient per 1,000 kg of slurry. Results were returned to farmers in advance of the main slurry application period for 1st cut silage. These results formed the basis of very good discussion group meetings in the late March / early April period focussing on fertiliser programmes for silage and grazing fields. Results were converted to units per 1,000 gallons with 40% of N being deemed available and 100% of P & K contents.

The results outlined below showing the significant effect DM% has on nutrient composition. The other major finding was that K content at approximately 40 units per 1,000 gallons was significantly higher than the 30 units per 1,000 gallons of slurry benchmark figure, as reported in other studies.

Grouping analyses by type of slurry storage tank sampled:

  • the standard covered slatted tank slurry came back on average at 7.2% DM, 6 units N, 5 units P & 41 units K per 1,000 gallons
  • slurry lagoons analysed averaged 3% DM, 3 units N, 2 units P & 14 units K per 1,000 gallons
  • dairy washings tank slurries at 2% DM, 2 units N, 2 units P & 14 units K per 1,000 gallons.

Fertiliser programmes on these farms need to be adjusted appropriately.

With the current cost and availability of chemical fertiliser can you afford not to get your slurry analysed this Spring?

  Standard slurry tanks Slurry lagoonsDairy washings 
Number of farmers 46 5 4
Average DM% 7.2 3 2
DM% range  3.45 to 10.3 1.8 to 3.5 1.35 to 2.86
Range of Slurry value - units N-P-K  N 4 - 10 
P 4 - 9 
K 17 - 67 
N 2 
P 1 - 2
K 6 - 21 

N 1 - 3
P 1 - 2
K 15 - 25

  Average value N-P-K units/1000 gallons 6-6-41 Average value N-P-K units/1000 gallons 3-3-14  Average value N-P-K units/1000 gallons 2-2-14
  • 2000 Gallons of slurry can save you 12 N, 10 P & 60-80 units K per acre
  • Slurry samples were higher in K than originally thought
  • Dairy washings are often not under the 1% DM figure that is required for them to be classified as soiled water / dairy washings.

Contributed by: Pat Moylan, Owen Power, John Bergin & Richard McEvoy

Create a slurry spreading plan with your adviser

Right Place - Use your soil tests to guide manure to low  P and / or low K fields, target fields with the highest demand for P and K i.e silage ground, set-aside 2,500-3,000 slurry/ac for the silage ground on grassland farms, use a dribble bar/trailing shoe to get the best N value from the slurry.

Right Rate - Match your slurry application to the demand for P and K, adjust application rate based on your slurry test results or the type of tank you are taking the slurry from.

Right Timing - Retain enough slurry to cover the 1st cut silage ground as it has the highest nutrient demand. 

Right Source - Identify the tanks in your farmyard that are better suited to silage ground or Index 1 or 2 ground vs grazing ground

Get more information here Fertiliser Focus - Get more slurry nutrients to save costs in 2022 (PDF)

Order your protected urea now  

Protected urea (protected with a urease inhibitor) is cheaper than CAN and straight urea on a cost per kg of nitrogen basis. It may appear slightly dearer than ordinary urea but it will give the same “effective N” for the plant as urea, at a 12.0% lower spreading rate.  While the cost per kg of nitrogen is cheapest for straight urea (Table 2), when the extra losses associated with straight urea are accounted for, protected urea is cheaper. See example 1 below. 

Table 1 

Relative Cost per kg N for Different Fertiliser Types
 CANNBPT Protected UreaUrea
kg N / tonne 270  460  460
€ / tonne 750 1,000 950
€ / kg N  2.78 2.17 2.06

Example 1Assuming a rate of 50 kg of N spread as protected urea or 50 kg of N spread as CAN in March 2022.  The equivalent quantity of N as straight urea that would need to be spread is 57kg to achieve the same plant available N, allowing for the extra losses with straight urea.  If we assume costs of urea = €950/t, protected urea = €1,000/t, CAN = €750/t, Table 2 highlights the difference in cost with protected urea being the cheapest option.

Table 2 

Relative Cost of an application of N for Different Fertiliser Types
 CANNBPT Protected UreaUrea
kg N spread 50  50 57
€ / tonne 750 1,000 950
Cost of the application € 139 109 118

At these prices, the farmer will get better value for money by using protected urea (as opposed to urea).  The example above, using current fertiliser prices, shows that the extra cost of the urease inhibitor more than covers its cost, if it saves 6 kg of N/ha.  The value of retaining N that had previously been lost as ammonia has increased dramatically in line with the increased fertiliser cost.  Also, in a situation where N application rate is limited, it makes sense to use less of a more effective product.

Continue to spread lime, where you can 

Lime ground in January / early Spring where soil pH is low. Why? Land at pH above 6.3 and at index 3-4 for P and K can release up to 70 kg/N/ha per year every year, an important way to reduce chemical N requirement in 2022.  Read Grassland liming advice (PDF) 

Get your nutrient management plan completed

Work with your advisor to develop a Nutrient Management Plan for your farm.  Your advisor will use NMP Online and together they will give you the best advice. NMP online produces a fertiliser plan for your farm including a liming plan, where to apply your slurry/FYM and what fields to target with specific fertiliser based on soil test results.

The steps to creating a nutrient management plan for your farm:

Step one: is taking our soil sample – the cost of a soil sample can be on a 4ha field will last 4 years and this is €1.23/ha or 50cent/acre and yet we don’t mind spending  €50 on a bag of urea (if Urea is costed at €1,000/tonne).

Step two: is getting these soil samples into NMP Online with the help of our advisor.

Step three: is the key – looking at the NMP Online to get the best return on investment from slurry and bag fertiliser.

Some farmers will have fields that need very little investment. Others will have fields that with the help of soil sample results, we now know exactly what to invest in and where. We know that using slurry again this year in the fields closest to the yard isn’t going to be the best use of this valuable organic fertiliser. But where is the best use of our slurry? Slurry used in the lower index P & K fields is estimated to be worth €53/1,000 gallons based on current fertiliser prices.

Working with NMP Online and your advisor will tell you this and more. Your soil samples combined with your crop demand will deliver advice that allows you to target the fields that need investment. Like any investment, you need a plan. Your nutrient management plan will set out your soil fertility plan.


Starting with lime it will tell you how much and where.  This plan will spread lime across 4 year and allow you to spread the cost of the investment. Lime on a lower stocked farm will have a 4:1 return on investment. This is higher on more intensive farms.

Figure one is an example of a K map which you could also have for your farm. Without even looking at K values, you can see that the fields closest to the farmyard on the left, have received more slurry than the fields that are further from the yard. Convenience can save time, but it will cost in terms of output in the long run. 

Plan spring fertiliser applications for tillage crops 

Considering the cost of nitrogen, it’s a good year for farmers to look at ways to reduce nitrogen use on farm.  There are a number of ways to reduce nitrogen use including; growing your own nitrogen (using legume crops), reduce nitrogen inputs (by using less and increasing the precision of application), use an alternative source of nitrogen (by using organic manures), and changing the source of your nitrogen.  We will look at these one by one.

  1. Grow your own nitrogen from legume crops. Beans are a crop many people may have tried over the past 10 year.  The crop can suffer from yield inconsistency and when the crop is poor it can be very poor (think of 2018) however growers who plant the crop on time (on the correct land) and manage it carefully are achieving quite consistent yields, year on year.  Increasing the area of beans can significantly reduce fertiliser requirements. Take an example of an 80 hectare farm, growing winter barley (20 ha), spring barley (56 ha) and a small amount of beans (4 ha).  If the cropping is adjusted, where winter barley would stay the same (as its already planted) and the farm maximises the area of beans ( e.g. beans at one in five years) and reduce the amount of spring barley sown, this reduces the farm’s nitrogen requirement by 14% or close to 7 tonnes of CAN (or €4,000 @ €600/t for CAN).  These are significant savings and the overall profitability of the farm will not be compromised. 
  2. Reducing nitrogen below the optimum rate for yield is always tricky. Nitrogen recommendations for crops are based on the economic optimum.  This rate generally builds in a little extra nitrogen to ensure high yield, but not necessarily the highest yield.  By increasing nitrogen above this level does not guarantee a higher yield, rather it’s a sum of diminishing returns.  Based on this, and knowing the cost of fertiliser and the sales price for grain, we can calculate the break-even return or BER for crops. 

Teagasc calculations, where CAN is €620/t and grain can be sold for €200/t, then growers should apply 33kg/ha less nitrogen to crops.  Where grain rises to €220/t, then growers should only use €27/ha less nitrogen.  Given the projected cost of nitrogen and the sales value of grain, reducing nitrogen will be profitable for most growers.  

  1. Where growers can get organic manures and maximise the embedded nitrogen then significant savings can be made.  For example, a grower applying good quality cattle slurry 33m3/ha (3,000 gal/ac) to 20 ha (50 acres) can save €6,000 on chemical fertiliser (not including the costs of slurry spreading). 
  2. Changing from CAN to protected urea can help to marginally reduce emissions on a plough based system. Research shows some reductions are possible but other considerations such as achieving the correct spread width (out to 24m or beyond) may be more problematic.