7 November 1998

HARVESTER HIGHS

Improved beet machine design and more skilful operators – especially among contractors – has resulted in a significant drop in harvest losses. Peter Hill reports.

SUGAR beet growers continue to enjoy reduced lifting losses thanks to improved harvester design, a better understanding of what causes harvest losses, and greater operator skill.

Speaking at Beet UK, Stephen Brown, manager of British Sugars quality harvesting project, calculates growers now earn up to £4.5m more than if losses were at the same level today as six years ago.

"Surveys in 1992 and 1994 showed average losses from harvesting of 4t/ha and 3.5t/ha respectively," he explains. "Last year, that figure was down to 2.25t/ha. We have found out where problems occur and worked with manufacturers, growers and contractors to improve things."

Now, its relatively simple to check damage levels. "From a sample of 100 roots, if 85 have a tap root broken off no more than a fingers width from the end, and the remaining 15 are broken off no more than two finger widths, then losses are acceptably low," he says. "But any greater number in the second category points to a problem that needs examining and correcting."

Sugar losses in stored beet result from increased respiration and repairs to damaged cells. "Bruising from impacts is significant for beet going into short-term as well as long-term storage as the highest sugar losses occur in the first 10 to 12 days in the clamp," Mr Brown emphasises.

Electric demo

The electronic beet, which is likely to be available for in-field harvester checks next year, was used for the demonstrations harvester performance assessment for the first time. No embarrassingly high results were recorded but the figures do show up differences between machines on the day.

At a score of 53, the TIM MkIII SH/1200 two-row trailed tanker returned the lowest impacts but also the second highest tare figure, suggesting the machine had been set up for a gentle touch at the expense of cleaning performance. Tare levels will also have been influenced by the high forward speed – 1kph faster than the next quickest machine.

In contrast, the four- and six-row Garford trailed harvesters recorded the lowest root losses of all but among the highest impact figures.

"Its a matter of finding the right balance on the day, and remembering that it is not necessary to aim for totally clean beet," notes Stephen Brown.

Marginally ahead of the rest among the six-row self-propelled harvesters that lift 70% of the national harvest, the Holmer TerraDos clocked up equal highest forward speed (6kph), average above-ground losses (0.25t/ha), equal second lowest root breakage losses (0.83t/ha), a low dirt tare figure (6.1%) and the second lowest impact score.

Matrots conventional M41H six-row recorded the second lowest root losses overall, while the Franquet Tetra, making its UK debut, lost fewest beet above ground by some margin, a reflection of its topping accuracy and, perhaps, its novel individual wheel depth control for the oscillating shares.

Garfords six-row trailed harvester headed the overall losses table as the only machine to dip below 1t/ha, with the four-row version second best in this respect. Philip Garford reckons the skew bar toppers, which can be set precisely to remove minimal crown, is a key feature, though lifting gear geometry is clearly effective given the low scores recorded for root breakages.

Achieving low losses and lack of impact damage is ultimately down to operator skill and perseverance in setting up the harvester, says Stephen Brown.

"I would say the operator accounts for 60-65% of the end result; the rest is down to machine design and soil conditions," he says.


Harvester Speed Above Root Total Dirt Impacts

kph ground breakage losses tare % joules

losses losses t/ha

t/ha t/ha

Two-row trailed

Juko XJ200 4.5 0.39 1.57 1.96 5.5 95

Kleine KR2 5.0 0.71 1.39 2.10 7.8 65

Three-row trailed

Armer Salmon ST3 6.2 0.87 4.02 4.89 4.5 104

Thyregod T7 5.0 0.54 1.81 2.36 4.9 81

TIM MkIII SH/1200 7.0 0.26 2.10 2.36 8.1 53

Four- and six-row trailed

Garford Victor 4 5.0 0.12 0.94 1.06 6.4 116

Garford Victor 6 4.0 0.20 0.46 0.65 8.7 103

Six-row self-propelled

Agrifac WKM 9000 5.0 0.29 1.44 1.73 6.2 83

Agrifac WKM Big Six 4.8 0.12 1.47 1.59 4.6 106

Agrifac ZA215EH 4.5 0.13 1.04 1.17 5.7 93

Franquet Tetra 5.0 0.06 1.20 1.26 5.2 95

Holmer TerraDos 6.0 0.25 0.83 1.08 6.1 64

Kleine SF10 5.0 0.50 1.72 2.21 6.2 100

Matrot M41H 5.0 0.32 0.80 1.12 4.1 64

Moreau Voltra 6.24 5.0 0.18 1.84 2.02 5.3 81

Riecam RBM300S 4.5 0.21 0.96 1.18 6.2 89

TIM SR2500 6.0 0.31 1.15 1.45 7.1 74

Vervaet Tanker 5.5 0.27 1.20 1.47 6.8 63

Above-ground losses include whole beet left on the surface and in the ground and excess crown from topping process

Impact damage measured using electronic beet; lower score equals less bruising

All machines with holding tanks apart from Garford Victor; on Matrot sufficient for trailer change-over only