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Annual Forage Alternatives to Corn Silage

Annual Forage Alternatives to Corn Silage
This past year has been one of the wettest on record in many parts of Pennsylvania. As a result, field progress through the fall of 2018 and spring of 2019 have been behind average. With corn planting delayed this spring, you may be wondering if there are options other than corn silage to bale or fill the silo. In our climate, we have several options for annual forages to take the place of corn silage.
Forage Sorghum
Forage sorghum is an annual warm-season grass and can be grown and harvested for silage. The feeding value, or Total Digestible Nutrient (TDN) content, of forage sorghum is approximately 85-percent of that of corn silage, with a similar protein content. Forage sorghum makes a relatively similar replacement for corn silage in rations. The optimal planting date is approximately two weeks later than that of corn, and early maturing varieties can be ready to chop for silage in most areas of the state by mid-August.
When compared to corn silage, production costs per ton of forage sorghum are significantly lower. Tables 1.12-3 and 1.12-6 (below) in the Penn State Agronomy Guide illustrate enterprise budgets for each of these forages. Forage sorghum can also be advantageous in areas with heavy deer pressure. Studies have shown reduced deer feeding in forage sorghum compared to corn.
Prussic acid and nitrate accumulation can be problematic in forage sorghum production. However, these compounds are of the most concern when fed to grazing livestock. They are not often an issue when it is harvested for silage, as the harvesting and ensiling processes can reduce the concentration of both compounds in harvested sorghum by as much as 50% after the fermentation processes is complete.
Table 1.12-6. from the Agronomy Guide 2019-2020. Alternative field crop production budgets (no-till practices), Pennsylvania, 2019 estimates.
ItemGrain sorghumForage sorghumCanolaYour estimate
Receipts$420.00 (grain)$630.00 (silage)$500.00 (grain) 
Variable Costs    
Cover crop seed$0.00$15.00$0.00 
Soil test$2.00$2.00$2.00 
Repairs and maintenance$8.28$10.41$9.44 
Custom combining$32.30----$32.30 
Custom chop and fill----$178.00---- 
Interest on operating capital$5.13$3.89$6.60 
Total variable costs$238.27$301.38$229.19 
Fixed costs    
Total fixed costs$118.25$121.67$120.83 
Total costs$356.52$423.05$350.02 
Net returns to management$60.89$216.40$92.77 
Break-even price$2.97/bu (at 120 bu/A)$21.15/T (at 20 T/A)$7.00/bu (at 50 bu/A) 
Break-even yield101.9 bu/A (at $3.50/bu)13.4 T/A (at $31.50/T)35.0 bu/A (at $9.50/bu) 
*Fertilizer rate for forage sorghum adjusted assuming application of 8,000 gallons of dairy manure.
Table 1.12-3. from the Agronomy Guide 2019-2020. Corn silage production budgets, Pennsylvania, 2019 estimates.
ItemConventional tillageReduced tillageNo-tillYour estimate
Corn Silage$925.00$925.00$925.00 
Variable costs    
Corn seed$100.80$100.80$100.80 
Cover crop seed$15.00$15.00$15.00 
Soil test$2.00$2.00$2.00 
Repairs and maintenance$17.74$13.40$11.40 
Custom chop, haul, and fill$222.50$222.50$222.50 
Crop insurance**$20.10$20.10$20.10 
Interest on operating capital$8.55$8.07$7.89 
Total variable costs$555.40$541.06$530.90 
Fixed costs    
Total fixed costs$138.76$130.10$123.59 
Total costs$694.16$671.16$654.49 
Net returns to management$230.84$253.84$270.51 
Break-even price    
@21 T/A$33.06/T$31.96/T$31.17/T 
@25 T/A$27.77/T$26.85/T$26.18/T 
@29 T/A$23.94/T$23.14/T$22.57/T 
@ __ T/A    
Break-even yield    
@$33/T21.0 T/A20.3 T/A19.8 T/A 
@$37/T18.8 T/A18.1 T/A17.7 T/A 
@$45/T15.4 T/A14.9 T/A14.5 T/A 
@$ __ /T    
*Fertilizer rate adjusted assuming application of 8,000 gallons of dairy manure. 
**Crop insurance cost based on yield protection at the 75 percent coverage level for a medium-risk county.
Sudangrass is another warm-season annual grass that can provide forage in a late planting situation and can be chopped for silage or baled for baleage. According to the Penn State Agronomy Guide, it can be planted as late as July 15th. Sudangrass should be harvested for optimal nutrition at the early head to early bloom stage. Multiple cuttings of Sudangrass may be taken throughout the growing season. Be sure to leave at least 6 inches of stubble at cutting time to improve the speed of regrowth. Prussic acid can also be a concern with Sudangrass but is less problematic in ensiled forages. New varieties produce lower levels of prussic acid than their older counterparts. BMR varieties with a higher feeding value than conventional varieties are also available.
Millets are another annual grass that can provide forage when planted late. Millet is often considered an inferior forage to Sudangrass in terms of nutrient value and yield. However, it may be better suited to cool, poorly drained soils and they also tolerate lower pH soils than other common warm-season annuals. Along with being adapted to poorly drained soils, millets are also known to be hardy in droughty situations as well. Like Sudangrass, some varieties of millet regrow after harvest.
Pearl millet is unique in its characteristic of not having prussic acid accumulation after the first frost of the year. This forage is ideal for not only harvesting and ensiling, but also grazing because of it’s ability to regrow and it’s absence of the risk of livestock poisoning due to prussic acid toxicity.
Oats are a cool-season annual and can be summer seeded (July-August) for a late fall (October) harvest. Oats have the best quality to yield ratio when harvested at the boot stage and provide a much higher quality diet than warm-season annuals.
When growing oats for forage, the seeding rate should be higher than when sowing for grain. We recommend at least 2 bu/acre with nitrogen applied at a rate of 60-100 lb/acre for optimal forage accumulation. Another advantage to forage oats is often they only require a 60-day growing window until they can be harvested.