This can be done by counting, weighing, and sampling the number of corn stalks in 1/1000th of an acre. corn plants are chopped at a stubble height of 8 – 12 inches and weighed to “estimate” the tones of wet corn silage per acre. This should be done at 3 – 5 locations in the field. If the plants are chopped and dry matter determined, the tons of silage dry matter yield can be calculated. If the number of ears per stalk is counted, then the ears per acre can also be determined. The number of plants to count and weigh depends on the spacing of the rows. The weight of the plants divided by 2 will provide the estimated silage yield.
Example: The plants from 17 feet, 5 inches with a 30″ row spacing weigh 40lbs. This gives an estimated yield of 20 tons per acre (40/2). If the plant dry matter was 35%, then the calculated dry matter yield per acre would be 7 (20 • 0.35).
There are also some rule of thumb calculations that can be used: One estimate of silage yield for corn plants without ears or poorly pollinated ears is 1 ton of dry matter (30%) for each foot of plant height. This does not include the tassel. Corn that is 4 feet high would yield about 4 tons of 30% dry matter corn silage.