Estimate crop yield using yield components: plant population, grains/ear, and test weight (1000-grain weight).
Estimate crop yield before harvest using yield components: plants per hectare, grains per ear/head, and 1000-grain weight. Get yield in kg/ha, tons/ha, bushels/acre, and total production. Works for corn, wheat, rice, and soybean. Essential for marketing, storage planning, and harvest logistics.
You looked at your corn field in August and thought "this looks like a 200-bushel crop." At harvest, you got 145 bushels. The plants looked great, but ears had only 350 kernels instead of the 500 you assumed — hot weather during pollination reduced kernel set. A 5-minute yield estimate in late August would have told you 150 bushels, and you could have arranged less storage and sold forward at the August price premium instead of taking the harvest-time price dip.
Pre-harvest yield estimation helps with marketing, storage, and logistics planning.
Yield (kg/ha) = plants/ha × grains/plant × 1000-grain weight (g) ÷ 1,000,000
A: Typical accuracy: ±10-15% if done 2-3 weeks before harvest. Accuracy improves as the crop approaches maturity. Sources of error: uneven plant stands, variability in grain fill, harvest losses (5-15% for combines), and moisture shrink. Take 5-10 representative samples across the field, not just the good-looking spots. Do not estimate from the road — get out and walk the field.
A: Test weight is the weight of grain per volume unit (pounds per bushel in US, kg/hectoliter in metric). It measures grain density and quality. Corn standard: 56 lb/bu (72 kg/hl). Wheat: 60 lb/bu (77 kg/hl). Low test weight = shriveled kernels = lower yield and possibly price discounts. Test weight is affected by growing conditions, especially moisture and heat during grain fill.
A: Combine harvest losses: 1-3% for well-adjusted combines in standing crops, 3-8% for lodged crops, 5-15% for crops down by weather. Pre-harvest losses: shattering (1-5% for canola, wheat), bird damage (1-10%), lodging. Total field losses typically 5-15%. When estimating marketable yield, subtract 10% from your field estimate. Good combine maintenance and operator skill can reduce losses significantly.