Lifting soil, lifting yields

Published 11 December 13

At a recent Cheshire Grassland Society visit to Orchards Farm, owned by the Brown family, members heard how Ray and his family are correcting compaction by sward lifting and slit aeration.

DairyCo’s Kate Williams and Dr Debbie McConnell report on developments at the DairyCo-BGS Cheshire demo farm.

A survey of grassland soils in England and Wales shows that 70% of fields are suffering from soil compaction. As a result, the DairyCo Grassland, Forage and Soils Research Partnership in conjunction with British Grassland Society (BGS) has been trialling alleviation treatments both at Scottish Rural University College (SRUC) and on the DairyCo-BGS Demonstration Farm in Cheshire.

Ray and his family manage a 300-cow pedigree Holstein herd, averaging 9,500 litres/cow. The farm focuses on achieving high quality forage and utilises fields close to the parlour for grazing during the summer.

At Orchards Farm the soils are predominantly sandy-clay/clay loams and some of the fields on the grazing platform are susceptible to compaction. This compaction is evident on some of the younger grass leys; therefore ploughing was not an option to remedy this. Instead Ray divided a grazing paddock into four sections last autumn and imposed the following four treatments:

  1. No aeration
  2. Spike aeration in the spring
  3. Sward lift in the autumn and spike the following spring
  4. Sward lift only in the autumn.

Throughout the season Ray, and his son Ryan, have platemetered to assess the impact these treatments have had on grass yields (data shown below includes figures up to the end of September 2013).

 Graph 1: Shows the effect on grass yield (kg DM/ha) of four different soil treatments

Demo farm 2

 

Visually, improvements in grass yield were particularly noticeable early in the grazing season. This improvement remained across the season with the sward lifting treatment resulting in 10% higher grass yields over the course of the season (graph 1).

In contrast, spike aeration resulted in a 4% increase in grass yield, however this was only visible at the first few grazings. There was no significant cumulative benefit of spiking and sward lifting together.

Other benefits to the sward lifting and spike aeration have also been seen. “The grass started growing earlier on the treated areas,” says Ray. “And better drainage allowed us to get the cows out earlier.”

The findings at Orchards Farm echo the DairyCo research trials at SRUC, where initial results indicate that both slit and sward lifting may result in small increases in second and third cut yield on compacted areas.

However, in contrast to Ray’s grazing pasture the initial aeration techniques (slit aeration and sward lifting) undertaken in spring at the research trials resulted in a drop of herbage yields early in the season. This was as a result of the destructive effect of these techniques on the grass plant, damaging grass roots and some of the leaf.

As a result, it may be advisable to undertake aeration techniques in the autumn to reduce the impact on the growing plant.

At costs of £57/ha (£23/ac) to sward lift, it is important to look at field conditions by digging holes, before taking corrective action. Chris Duller, independent grassland expert, says: ‘compaction will reduce grass quality and quantity as well as the amount of days the cows can graze outside. The cost of compaction alleviation must be considered against what a grazing day is worth to you.

“Time spent digging holes to understand your farms compaction is time well spent,’ Chris concludes.

Ray will continue with grassland research trials on his farm over the next year, to find out about the on-going research on the DairyCo-BGS Demo Farms visit www.Dairyco.org.uk