Accurate measurements of yield are important for: reviewing the success of nutrient management strategies, understanding a sites expected yield and also when calculating harvested nutrient offtakes. Utilising weighbridges and/or combine yield mapping is more accurate than relying on the bulk sale of produce from storage sheds. Key principles for using weighbridges to weigh trailer loads of harvested grain include: 1) measure an accurate harvested area. 2) accurately weigh trailers before and after harvest. 3) measuring the moisture content (MC) of harvested grain. Yield (t/ha @ standard MC) = Net weight of harvested grain (tonnes)/area harvested (Hectares)*(100-measured grain MC)/standard grain MC). Key principles for using yield mapping to estimate yield include: 1) Calibrate the yield monitor according to the manufacturers instructions. Ideally test the yield monitor against harvested grain weights over a weighbridge as above. 2) If measuring harvested area with the combine yield monitor, avoid non-full headers and try to keep to a constant speed. 3) Ensure that the yield is corrected to the right moisture content for the crop.
Accurately measuring yield in grain crops
Content Author: ADAS