31 January 2013

2 minute read

Europe

Before taking any action producers need to carry out a soil assessment by digging holes. This may reveal that the situation isn’t as bad as initially thought and will help prioritise fields needing attention.

If soil compaction is identified, producers may decide that using aerators to deal with compaction in the top 5-10 cm of soil, or sward lifters, which deal with compaction 10-25 cm down, is appropriate.

Guidelines from ADAS work in the 1980s provide some clear messages for producers when using topsoil looseners. The most timely one is to aim to remedy compaction in the autumn, as dealing with compaction in the spring may cause more problems.

The ADAS guidelines are as follows:

1. Do not use topsoil looseners unless there are clear signs of soil compaction and the moisture content is suitable:
   • Examine the soil by digging holes to find out the nature and depth of any compacted layers, as well as the moisture content and friability of the soil
   • Topsoil loosening in conditions which are too wet will potentially lead to increased soil damage through smearing and wheel slip
   • Topsoil loosening in dry conditions is likely to lead to the formation of large clods, sward tearing and excessive surface heave giving an uneven surface finish



2. Topsoil loosening is not recommended in poorly drained soils if there is no drainage system present, as this is likely to cause excessive wetness in low lying areas which will potentially be at further risk of poaching and re-compaction. In these situations, and on heavy textured soils, a mole plough may be more effective in improving the soil drainage status than topsoil loosening



3. Topsoil loosening should be carried out in the autumn when grass growth is declining. If carried out in the spring or summer when grass is growing rapidly, disturbance to the root system can lead to severe sward death



4. Use the appropriate equipment and set it up correctly. The depth of compaction will dictate the depth of working required - make sure the compacted layer is about 2.5 cm above the critical working depth of the implement used and examine the extent of shatter on a trial run, adjusting the equipment if necessary



5. Recently loosened soil is very sensitive to re-compaction and it is important to allow the newly loosened structure to be stabilised by root activity and natural soil processes:
   • Cut or graze the site immediately before treatment to ensure sward height is low (<4 cm)
   • Avoid grazing after loosening and conserve rather than graze in the first spring after treatment
   • If late growth needs utilising, use sheep rather than cattle to minimise re-compaction damage
   • Do not spread slurry on recently loosened fields

Adapted from ADAS Technical Briefing notes (ADAS, 1984; 1987).