The Hindu Business Line : US scientist develops system using two machines to harvest wheat

Farmers world-wide use a wheat-harvesting combine that cuts, threshes and cleans the wheat. But the scientist, Mr Mark Siemens of the US Agricultural Research Service, is investigating the benefits of using two machines to accomplish these tasks - a simple, low-cost harvester, and a stationary thresher.

Instead of cutting wheat in the same way as a combine, Mr Siemens's harvester strips the wheat heads and stores them in a bulk tank. It then chops the standing residue into small bits. The stationary thresher separates the wheat from the chaff.

The scientist is studying the economic potential of segregating wheat with a fluidized bed, which separates solid materials according to density. Preliminary studies suggest this segregation process increases the consistency of grain quality, particularly with the soft white wheat used in pastries, cakes and cookies.

The modern combine found on almost all farms can harvest, thresh, separate and clean, but the mechanism is expensive, especially in the US. The components of Mr Siemens's system are much less expensive, and one thresher could serve multiple farms, significantly lowering overall production costs.

The system also eliminates many problems associated with stubble, the straw stems that remain in the field after harvesting. A typical combine cuts wheat about 16 inches above the ground, but lacks the mechanism to chop the remaining stubble, which can impede subsequent farm operations.

The Agricultural Research Service is an arm of the US Department of Agriculture.