Soil compaction is one of the biggest problems facing agriculture today. The main causes of compaction are heavy farm machinery, intensive cultivation, limited crop rotation, intensive grazing and poor soil management. Compaction is aggravated by a low organic matter content and working the land in wet conditions. Here are some tips to avoid soil compaction.
What is soil compaction? The pores that naturally occur in soil are used for the exchange and transport of water and oxygen through the soil. This function is vital for the root zone of plants. Soil compaction reduces the volume of the pores so less water and fewer nutrients can be stored in the soil. This negatively impacts on grass growth. There is strong correlation between soil compaction and reduced grass growth and yield.
Soil compaction is difficult to rectify
Soil compaction is a difficult problem to rectify, so prevention is better than cure. Deep tillage to de-compact the soil is often needed to mitigate the effects, but this affects the natural soil structure. So, it’s best to prevent compaction rather than solve the problems it causes afterwards.
This can be done by always working the land in dry conditions. As this is not always possible, it is important to carefully consider which machinery you will be using. Limiting the number of passes and combining work passes – e.g. baling and wrapping – reduces the risk of soil compaction. Transferring newly wrapped bales as much as possible from the wrapping table to the headland limits field traffic when the bales are collected as less movement of heavy machinery – such as bale wagons, telehandlers or loaders – is necessary over the field.
Preventing soil compaction
To limit the impact of traffic on the soil, it is important to minimise the weight of the combination and, where possible, reduce the tyre pressure. A light machine combined with a trailed implement suitable for the task is the ideal scenario. The basic principle is the lowest possible combined weight.
The tyre pressure of lightweight combinations can be reduced further once in the field. Consult the pressure table of the tyre manufacturer. Opting for an additional wheel axle allows the tyre pressure to be lowered further. With optimum tyre pressure – preferably below 1 bar – the pressure exerted per cm2 on the soil does not increase when the bale chamber fills with grass or when a bale is on the wrapping table. As the weight increases, the tyre will flatten and therefore distribute the weight over a larger surface. This minimise damage to the grassland.