Corn Silage Population
PRIDE Seeds has some great corn silage options for your operation. We offer silage specific hybrids that are highly digestible and palatable, have a large plant structure and a wider harvest window due to slower dry down. These silage specifics have flint genetics and showcase a white cob. Dual-purpose hybrid are another option for silage growers. Dual-purpose hybrids are bred for grain but when harvested for silage they have high energy and allow for more flexibility at harvest.
The purpose of this special project was to evaluate corn silage yield and quality when different hybrid types (silage specific (SS) and dual purpose (DP)) are planted at different populations.
Project Design
This trial was planted west of Coaldale, Alberta on May 9, 2020 in a field with pivot irrigation and silt loam soil type. The trial was harvested on September 25, 2020. Harvest data from the hybrid trial was used in conjunction with harvest data from the population trial for all three hybrids. Silage samples were collected while silage was unloaded at the pit and sent to Activation Labs in Ancaster, ON for moisture and feed test values. 
Since corn silage yield is a balancing act of yield and quality, 7 different assessment factors were considered for this project.
Results
Observed populations were determined by counting 1/1000th of an acre 3 times per strip then calculated average population per strip. Observed populations were close enough to target populations to confirm that what was targeted by the farmer at planting is what was in the field and harvested.
Yield averaged from 22.77 ton/ac. The SS hybrids out yielded the DP hybrid at 32,000 and 42,000 PPA. Yield of the SS suffered at 17,000 PPA. Yield for the A4939G2 RIB was comparatively consistent at all populations compared to the SS hybrids. Highest yield for all hybrids was at 32,000 PPA.
Higher starch levels were observed for all hybrids at 17,000 PPA. AS1047RR EDF has the lowest starch results out of the data set. This is likely due to the high corn stover to grain ratio. AS1047RR EDF produces a good size ear, but the large plant biomass likely dilutes out the starch content of this hybrid. Starch levels at 42,000 and 32,000 PPA are consistent between A4705HMRR and A44939G2 RIB.
Neutral detergent fibre digestibility (NDFd) values were equally and most digestible at 17,000 PPA for all hybrids – SS and DP. Digestibility decreases as population increased. A4705HMRR NDFd value was the lowest of the data set when planted at 32,000 and 42,000 PPA. NDFd values for AS1047RR EDF gradually decreases as population increased. NDFd values for A4939G2 RIB (DP) were lower but consistent at 42,000 and 32,000 PPA compared to 17,000 PPA.
The average TDN value across the data set was 61%. A4705HMRR and A4939G2 RIB had the highest TDN values at 17,000 PPA, while AS1047RR EDF had the highest TDN value at 42,000 PPA. AS1047RR EDF highest TDN value was equal to the data set TDN average. A4939G2 RIB and AS1047RR EDF resulted in average and below average in all populations expect for A4939G2 RIB at 17,000 PPA.
Milk production potential (pounds of milk generated per ton) values ranged from 3208 to 2756 lbs/ ton and averaged 2914 lbs/ton. A4705HMRR and A4939G2 RIB has the highest pounds of milk/ton value at 17,000 PPA. AS1047RR EDF pounds of milk/ac values are relatively consistent between the three planting populations and A4705HMRR and A4939G2 RIB at 32,000 and 42,000 PPA.
Potential milk production per acre values averaged 22,698 lbs of milk/ac. The same pattern is noticed in the SS hybrids – higher values/ac at 42,000 and 32,000 PPA compared to 17,000 PPA. This is due to the higher yield observed by the SS hybrids at 42,000 and 32,000 PPA. A4939G2 RIB (DP) has the highest values/ac at 17,000 PPA and the higher populations are not far off. 
Revenue was determined by considering the value/ton ($/ton) of silage corn when contracted to a feedlot in Southern Alberta. Price per ton ranges from $45-50/ton delivered. For these revenue calculations, a value of $48/ton was used.
It was also important to consider the price of seed. For these revenue calculations the price of a SS hybrid bag of seed was $240/bag and $260/bag was used as the price for the DP hybrid seed bag. The DP seed is more expensive because it is a G2 hybrid (contains trait for above ground insect control) compared to SS hybrids that are Round-up Ready hybrids.
Highest revenue return for all hybrids occurred at 32,000 PPA with and without the inclusion of seed costs. A4705HMRR planted at the lower population resulted in $255 revenue loss when seed cost was consider compared to A4705HMRR at 32,000 PPA. A1047RR EDF planted at the lower population resulted in $204 revenue loss when seed cost was considered compared to AS1047RR EDF at 32,000 PPA. A4939G2 RIB planted at the lower population and high population resulted in $47 revenue loss and $84 revenue loss respectively compared to A4939G2 RIB at the 32,000 PPA.
Conclusion
From a silage yield perspective – SS are probably the best option if yield is the number one thing you’re looking for. SS tend to perform well at average to high populations, but not as well when population is pushed very low. When considering silage quality – an important parameter for feed – I think lower to average populations are going to result in better quality silage.
Revenue – Arguably one of the most important values to consider depending on the end user and customers needs. For the sake of this project and write up it was easy to put a value on yield, however it would be interesting to know how much value farmers put on starch, fibre digestibility and TDN value. 32,000 PPA was the most profitable and highest yielding population tested.
Going forward and testing populations closer to 32,000 PPA could be valuable for producers.
Click here for the PDF of this project and the rest of the PRIDE Seeds 2020 Agronomy Projects
