| Popis: |
Grain losses from the processor with properly-adjusted modern combines can be extremely low, forexample well below 1 % for separator and shoe in corn and soybeans. However there are otherharvest losses that can be much larger. They are not well accounted for because these other losses aredifficult to measure in the field. Traditional grain loss measuring methods do not pick them out, butthey are capable of assessment. By carefully monitoring field and harvested yield, the differencebetween what is in the field and what ends up in the combine grain bin is determined. Thediscrepancy is made up of - pre-harvest losses - gathering head, processor and body losses, and - grain damage, leading to fines and powdered material being blown out the back. Estimates of field yield were made by hand harvesting multiple quadrats at a number of test sites.Bin yield of seven different combines was recorded contemporaneously using electronic-recordingweigh carts for yield from measured areas. The grain damage in corn and soybeans associated withthose tests was measured to see if there was any correlation between damage and yield loss.Each combine was found to have a certain sweet spot where the harvested or bin yield is optimalunder the given crop conditions. Grain damage was shown to play a role in the location of theoptimum harvested yield, since grain damage increases at low throughputs.An hyperbolic relationship was established between grain damage and harvested yield.Using harvested yield measurement as the dependent variable provides an integrator. Harvestedyield indirectly accounts for all machine-related losses. The significance of the sweetspotmeasurement is that it delineates harvest efficiency and it relates directly to farmerprofitability. |
