Thursday, October 14, 2010

Soil pH levels in Ireland: A growing problem

The British Society of Soil Science published an article recently, submitted by H. Tunney, F.J. Sikora, D. Kessel, A. Wolf, L.. Sonon, and K. Goulding realating to some interesting thoughts on the pH levels of the soil in Ireland and the liming, or lack there of, which this soil receives in regards to agriculture. Soil pH is a significant factor in the agriculture industry and controlling it is an important factor in ensuring good yields from crops each year.

Now, while liming may not seem like a very important topic or be heard about often it actually controls soil pH so as to prevent soil from becoming so acidic that fields can no longer yield crops. It also provides nutrients to the soil and prevents other harmful chemicals from building up such as manganese. Between these effects liming has a very significant effect on agriculture and ensuring adequate liming is an important part of any country’s agricultural industry. This fact has important implications currently in Ireland. That is what this study focused on, what liming levels are currently like in Ireland, the problems it is causing and possible ways to fix it. Ireland currently has its lowest liming levels in over 50 years and this is shown in its low soil pH level.

A lot of research is currently being done in the US about determining the lime requirements of their soil. However, not many countries in the EU have been following suit. This has led to some of the lowest liming levels in decades in several EU countries, in particular Ireland. In fact under their current liming conditions Ireland’s soil is in fact becoming significantly more acidic each year.

Lime requirements are estimated in many ways, using different methods. This specifically was what the study focused on. Researchers were trying to find out what problems Ireland was having due to their current soil pH levels and also what method they should use to try and calculate a new liming requirement. (As a background, the method Ireland uses currently, the Shoemaker et al. buffer method is quite old and many of the new methods being tested are more recent and generally more widely used.)
Several factors are under scrutiny such as how much liming Ireland should do, what their pH goal for their agricultural soil should be and also what method they should use for determining these things. As a result much of the study focused on using some of the other available methods for measuring how much liming soil in certain areas require.

57 samples were collected from several areas around Ireland, 3 from each pH values ranging from 4.4 to 6.5 at intervals of 0.1. These samples were then split up between 3 various American labs all of whom tested them with other liming methods to determine a better lime requirement for Ireland to use for its agricultural soil.
The results of this study concluded that any of the other four available methods studied yielded approximately the same results for lime requirements and any of them would be a preferable system to use in Ireland over the Shoemaker et al. buffer method.

These other methods lead to a lower estimated requirement of lime. In fact Ireland’s current recommended lime requirement values “is high compared with that in several other countries.” This seems to be unrealistic as one of the main recommendations of the study was that Ireland needs to lower its advised liming requirements so that they can set up a simpler liming schedule over a period of every 4 or 5 years. This would allow for a more coherent long term plan to be created. The journal concludes that if Ireland were to lower its advised soil pH level from 6.5 to 6.2 this would allow for a simple 4 or 5 year liming cycle to keep the soil at these levels.

Ireland and I believe much of the EU would in fact benefit from taking heed of this study to try and research newer methods of liming and to set out a concrete plan before their soil pH levels become any more difficult to fix. Their current liming levels are inadequate and are creating undue problems for the country which, by the results of this study, have relatively simple solutions.

Connor Gibney

H. Tunney, F. J. Sikora, D. Kissel, A. Wolf, L. Sonon, K. Goulding 2010. “A comparison of lime requirements by five methods on grassland mineral soils in Ireland” Soil Use and Management. 25 Feb 201., British Society of Soil Science.

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