Controlling traffic key to grass yields

Published 13 September 13

Controlling field traffic key to grass yields

Controlling traffic and reducing tyre pressure on tractors crossing fields can increase forage crop yields by over 15%, according to Professor Dick Godwin and Dr Keith Chaney, speaking at the DairyCo Research Day Knowledge Transfer Event at Harper Adams yesterday (September 11).

“Think about every journey you make over a field, particularly if made in a road-based vehicle such as a pick-up truck, which has high tyre pressure,” said Professor Godwin. “Recent research at HAU which mapped harvesting equipment in a silage field at first cut shows that almost 65% of the area is driven over in one harvesting operation under random trafficking systems,” continues Professor Godwin.

Keeping tractors to the same tracks repeatedly was discussed by farmers and scientist at the event, with research showing that after three or four passes, soil structure did not appear to deteriorate any further. Tankers, which carry heavy loads of slurry, can also be particularly detrimental to soil structure, with low pressure tyres and umbilical systems suggested as a way to reduced soil compaction. 

Dr Chaney, who is working on a DairyCo-funded project looking at the applicability of precision farming techniques to British dairy farms, also outlined how differences in soil structure can be associated with yield variability across a field.

The project mapped two uniform fields growing grass silage and analysed them for magnesium, pH, conductivity and micronutrients, as well as soil structure. Grass yield at first, second and third cut was then measured in quadrants. Results showed large variations in grass yield across the field with areas close to each other producing dramatically different results, sometimes as much as half the yield of neighbouring areas.

The researchers found that it was the soil’s physical condition that had the strongest correlation with yield, particularly at first cut. More information on the impact of soil compaction on grass yields can be found here.

Dr Chaney also outlined how, this year, they are examining novel techniques for measuring herbage yields on GB dairy farms. “We are testing how both ultrasound and reflectance techniques which have been developed in the arable sector can be adapted to measure grass covers on dairy farms,” he said.