As the cheapest feed source available to Irish farmers, grass, when conditions are favourable, can be grown in abundance. However, research conducted by Teagasc has shown that up to 85% of Irish soils are lacking the correct nutrients required to maximise grass growth. We recommend developing helpful habits such as recording poor-performing silage fields and identifying problem areas within your grazing platform which may require reseeding this year in order to increase the productivity of your paddocks.
Here are our top tips to assist in improving grass yield and overall farm profitability.
The basics for soil health and fertility
It is important to have the basics right, ensure that Phosphorus (P), Potassium (K) and Lime are at the correct levels for optimum soil nutrition. Once these levels are correct, it is only then that the full benefit from Nitrogen (N), the driving force of grass yield, can be achieved. The target nutrient levels are as per the table below:
|Phosphorus (P)||Index 3 (5.0 – 8.0mg/l)|
|Potassium (K)||Index 3 (101 – 150mg/l)|
|Lime||pH 6.3 (mineral soils)|
Reaching the levels in the above table is an investment that will give you an immediate return and only maintenance levels will be required thereafter. It is recommended to use soil analysis to identify nutrient soil levels and to plan crop nutrition based on the results. A soil analysis needs to be completed every 3 – 5 years. It is recommended to build a file of soil analysis as this will serve as a library of information to maintain soils health and nutrient status into the future.
When selecting your fertiliser products as per your fertiliser application plan, avoid basing your fertiliser choice on price. Base it on what product best suits your soil fertiliser status, there could be a cost saving by identifying specific P and K deficits in fields and using your resources more efficiently. This also means nutrients are being applied where they are readily available and absorbed by the plant. To do this, work off the most recent soil analysis. Your ideal soil should be Index 3 for both P and K to maximise grass production.
According to Teagasc, up to 65% of Irish soils are deficient in lime. Lime can give a 1:4 return on investment, therefore give primary attention to the pH status and correct these where necessary by applying ground limestone, or for a quick fix, use granulated lime. The target pH level for clay type soils is 6.3, while for more peaty soils, a level of 5.8 is the target. A general recommendation is to apply 2 tonnes of ground limestone per acre or 2 – 3 bags of granulated lime. Correcting your pH will increase your nutrient use efficiency by increasing the availability of NPK and other soil reserves.
It is important to note not to use urea as a source of N if lime was applied in the previous eight weeks as it will cause the urea to volatilise.
Fertiliser application following soil analysis
Following correction of soil fertility levels, consider fertiliser application to maintain the N, P and K levels in the soil. For grazing and maintenance, it is recommended to apply a high N fertiliser that has the best balance of P and K to suit your fertility status. It can take time to build up P and K levels in the soil, especially P on mineral soils at Index 1. Generally, if you have large deficits of P, it is recommended to apply it early in the season within the first three rotations and then apply maintenance levels thereafter.
When rectifying large K deficits, it is best to do this towards the end of the year, when animals are housed and there is reduced risk of luxury uptake of K. This reduces the Magnesium (Mg) available in the plant, causing grass tetany.
Soil indexes and the response to fertiliser
|Index Description||Response to Fertiliser|
What are my fertiliser options?
Target Fertilisers have a wide range of grass fertilisers to meet your requirements for early N, P and K in one application. Following your soil analysis results, develop a farm nutrient plan prior to selecting your fertiliser from the Target Fertilisers’ product range that suits these requirements.
Below is a list of suitable products from the Target Fertilisers’ range:
- 0 – 10 – 20
- 18 – 6 – 12
- 10 – 10 – 20
- 27 – 2.5 – 5
To view the full range of Target Fertilisers’ grassland fertiliser products, click here
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