National Soil Fertility Trends
In 2021 Teagasc analysed a total 33,876 soil samples comprising dairy, drystock and tillage enterprises. 2021 shows that soil fertility declined on dairy farms for the second consecutive year. Lime use increased by ~ 50% compared to the average lime applied in Ireland over the last 10 years.
Overall in 2021 the number of soil samples increased by 13%. This was primarily driven by the significant increase in the cost of N, P and K fertilisers projected in mid-2021. The following is a summary of the main changes for soil pH, phosphorus (P) and potassium (K) in 2021.
National Highlights - All Soil Samples
- All farm enterprises took more soil samples in 2021 = +13%
- Overall decline in soils with optimum soil fertility to 16% = -3%
- Soil pH declined to 54% of soils with a >pH 6.2 = -8%
- Soil P levels at Index 1 & 2 increased by 4% while soils at Index 3 & 4 decreased by 4%
- Soil K levels remain similar with a slight decrease in soils at K index 4 by 4%
Enterprise Highlights
Dairy
- 16% of soils have optimum pH, P & K - a 3 % decrease
- 53% of soils with a soil pH >6.2 - a 10% decrease
- 55% of soils at P index 1 & 2 - a 4% increase
- 48% of soils at K Index 1 & 2 - no change
Drystock
- 13% of soils have optimum pH, P & K - a 2 % decrease
- 47% of soils with a soil pH >6.2 - a 10% decrease
- 61%of soils at P index 1 & 2 - an 11% increase
- 50% of soils at K Index 1 & 2 - a 3% increase
Tillage
- 18% of soils have optimum pH, P & K - a 6 % decrease
- 61% of soils with a soil pH >6.5 - a 13% decrease
- 57%of soils at P index 1 & 2 - a 7% increase
- 32% of soils at K Index 1 & 2 - a 2% decrease
In 2021 optimum soil fertility levels have decreased in the range of 3 to 6 % for dairy, beef and tillage farms compared to 2020. On these farms, soil at P Index 1 and 2 have increased by 4 to 11%, while soil K levels have decreased slightly on drystock farms, no change on dairy farms to slight improvements (+2%) on tillage farms.
Soils with optimum soil pH levels have decreased by 10 to 13% across all three-farm enterprises. National lime applications increased by 50% in 2021 to 1.33 million tonnes, compared to the average application of ground limestone in the previous 10 years. This will help halt the decline in soil pH levels as reported in 2021.
Challenge
The challenge now and in the next number of years will be to halt this new emerging soil fertility trend. Controlling fertiliser costs is critical to farm profitability but it should not be at the expense of mining valuable soil fertility levels, which have been built up over the last number of years. Maintaining good soil fertility will especially be central to improving the utilisation of N and reducing N losses.
Read the National report Teagasc Soil Fertility Report 2021 (PDF)
A County by County breakdown will be available wihin the next few weeks