Analysis of header loss from pod stripper combines in green peas

The development of the pod stripper combine has provided a viable method of efficient once-over harvesting for several vegetables. Although the pod stripper header has increased throughput by reducing material other than peas (MOP) intake, the resulting increase in productivity does have disadvantages. Previous studies on the performance characteristics of pod stripper combines in green peas and lima beans indicate that field losses are high, averaging over 10% and 20% of yield, respectively for all the combines manufactured in the USA. Results for both crops revealed that over 75% of the field loss occurs at the header of the pod stripper combine. Using dimensional analysis, an expression for header loss from pod stripper combines in any crop is developed. Experiments with green peas were used to verify the analysis procedure, using a conventional pod stripper combine, field experiments were conducted in which header loss was measured over a wide range of field and operating conditions. Results indicate that header loss can be minimized at a combination of forward speed and picking reel speed of 2.2 km/h and 205 rev/min, respectively. Furthermore, a control system which matched picking reel speed to ground speed would not significantly reduce header loss over the range of forward speeds evaluated in green peas. (C) 1997 Silsoe Research Institute.