Improving grass silage production with controlled traffic farming (CTF): agronomics,system design and economics

Grassland silage management is generally semi-organised with no conscious attempt to re-use wheel ways as with arable fields. The total number of machine passes can be 15 or more with normal traffic (NT) systems resulting in potentially large areas of a field suffering from direct damage to the crop and soil. Literature suggests there can be grass dry matter yield reductions of 5 to 74% under NT through compaction and sward damage, with a mean of 13% in the UK. Commercially available grass forage equipment with widths of 3 to 12 m set up for controlled traffic farming (CTF) could reduce trafficked areas (which is typically 90% to 80% for NT) to 40% to 13% for CTF. This study compared grass dry matter yield between CTF and NT for a three-cut silage system based on a 9 m working width in a permanent silage field in the southwest of Scotland, UK in 2015. Results showed a 13.5% (0.80 t ha^?1) increase in yield for CTF for the 2nd and 3rd cuts combined. The CTF trafficked area covered was 57% less than the NT system (30.4% compared to 87.4%) over the three silage cuts. An economic analysis based on a 13% increase in dry matter yield (for 2- and 3-cut systems) and a reduction in trafficked area from 80% (for NT) to between 45% and 15% (for CTF), increased the yield by between 0.53 t ha^?1 and 1.36 t ha^?1 for 2- and 3-cut systems, respectively with an equivalent grass value of between £38 ha^?1 and £98 ha^?1. Introducing CTF for a multi-cut grass silage system is cost-effective by increasing yields due to a reduction in compaction and sward damage.