Recovery from soil acidity

In much of the world, the impetus is thus towards soils becoming more acid. One of the ways of counteracting this and slowing it down is to add lime. The growth of plants can often be greatly improved by the additions of lime, a fact known to farmers for centuries. Liming is carried out by farmers to create a favourable pH for growing their crops. The most commonly used liming materials are carbonates, hydroxides and silicates of calcium and magnesium. While these are rarely used in natural and semi-natural areas because of the lack of money to meet their cost, they are regularly used by farmers to achieve the required pH of their soils. Additions of lime not only reduce the level of soil acidity and provide a nutrient source for the crops but also encourage increased activity by soil organisms and an improved soil structure.

There are thus major benefits to liming of most soils.The problem of acidity caused by acid rain is a much more difficult problem with which to deal. While it may be possible to identify many of the sources of pollutants, the fact that once in the atmosphere they can be distributed world wide means that their movement is virtually impossible to regulate. Only once the damage caused becomes apparent can the potential effects be addressed. The mechanisms of acid rain, set in motion by the Industrial Revolution, will take time to bring under control. Above all, it needs the driving force of governments combined with the acceptance of the main industrial polluters to reduce the outflow of the would-be pollutants. Acid rain affects not only the soil but also the health of water bodies such as lakes, rivers and oceans, the health of human beings and the lifespan of many buildings, statues and monuments.

Knowledge is an important thing. This is illustrated by two examples. It is important when making changes to the way soils are used soils that their nature is well understood. This clearly has not been the case with the acid sulphate soils described above and it is likely that these often substantial areas of soils have been damaged for all time. The important message is know what type of soil one is dealing with and its characteristics. Acidification as a result of fertilising the land is a different matter. Most farmers understand their soils well and it is in their interests to prevent soil acidity by regularly checking the fertility status of their soils and using fertilisers carefully, and where necessary reducing acidity by liming.