Teagasc have posted results of a survey on fertiliser use in the country, which indicates that there has been an overall long-term reduction in fertiliser use.
The study examined the long-term developments in fertilizer use on Irish farms. The study was based on analysis on over a decade’s worth of information collected by Teagasc, as part of the National Farm survey. The ten-year period ran from 2005-2015 when Ireland was still bound by the EU Nitrates Directive regulations which govern fertilizer use.
The study focuses primarily on the use of phosphorus, potassium, lime and nitrogen. It enabled Teagasc to provide a detailed analysis, by farm system, land use class, stocking rates, nitrate zones and agri-environment scheme participation.
The study results indicate that nitrogen, phosphorus and potassium fertilizer application rates on grassland were between 11-16% higher at the start of the study period compared to the end, with more dramatic declines in application rates noticeable in the mid-study period (23-52%).
The years of lowest grassland fertilizer use was 2008-09 and coincided with the period of highest fertilizer prices. Higher than average period application rates in 2013-2014 were associated with the aftermath of a national fodder shortage.
Similarly, the report finds that fertilizer application rates on cereal land were lower in the higher price period of 2008-09. Comparing 2005 with 2015, showed that nitrogen application rates on cereal land actually increased by about 10%. Phosphorus application rates on cereal land in 2015 were broadly in line with usage levels in 2005. Potassium application rates on cereal land showed the largest increase, up 33% in 2015 relative to 2005.
Impact of agri-environmental scheme memberships -
The large impact, which agri-environmental scheme membership has on fertilizer usage, was also evident in the study.
Fertilizer application rates on grassland were on average 36% lower for farms participating in an agri-environment scheme. Nitrogen, phosphorus and potassium application rates for the main cereal crops for agri-environment scheme participants were on average 15%, 10% and 3% lower respectively, over the course of the study period.
A concern raised by the study is that few farms are engaged in ongoing lime application from year to year. Adequate liming is essential to achieve optimum soil pH levels in order to maximise the effectiveness of fertilizers. It is notable that on average just over 20% of farms used lime year-on-year over the study period. The lowest rate of liming was evident in 2006 at just 16% of the farm population and the highest liming rate over the period was recorded in 2013 at 26% of total farms.
“Data showing short-term trends in fertilizer usage can be affected by fertilizer price levels and weather variations and are a less reliable indicator of longer-term developments.” , said Dr. Cathal Buckley of Teagasc of the results.
Teagasc Economist, Dr. Emma Dillon noted the study provided a more in-depth look at fertilizer use.
“The study also provides a more in-depth analysis of fertilizer use patterns at farm level than would be possible to provide through the use of national level fertilizer sales data.”, she said.