Popcorn, Sweet Corn, and Sorghum as Alternative Silage Crops

Current farm program restrictions limit dent corn (Zea mays L.) acreage planted for grain or silage production. Popcorn, sweet corn, or sorghum [Sorghum bicolor (L.) Moench] have been suggested as alternative silage crops. The objective of this study was to determine the relative forage yields, forage quality, and returns over production costs of the four crops. The silage fermentation characteristics of each crop also were determined. Studies were conducted in southern Minnesota on a Waukegan silt loam (fine-silty, over sandy-skeletal, mixed mesic Typic Hapludoll) and a Webster clay loam (fine-loamy, mixed mesic Typic Haplaquoll). Fodder dry matter yields of popcorn and sweet corn were similar and averaged 42% lower than those of dent corn and sorghum (average yield of 8.9 ton/acre). Dent corn forage crude protein (CP, average of 6.81%) and in vitro digestible dry matter (IVDDM, average 68.2%) were consistently higher and neutral detergent fiber (NDF, average of 43.4%) consistently lower than that of sorghum (CP average of 5.67%; IVDDM average of 60.7%; NDF average of 49.4%) Higher sorghum forage yields, however, resulted in CP and IVDDM yields similar to those of dent corn. Average CP and IVDDM concentrations of popcorn and sweet corn forage were higher than those of sorghum; however, CP and IVDDM yields of popcorn and sweet corn were lower. Desirable fermentation occurred with all four crops. Dent corn produced the highest cash return per acre followed by sorghum. Sweet corn and popcorn lodged and were difficult to harvest. In addition, sweet corn grain dried slowly and was susceptible to spoilage. We concluded that sorghum is a better alternative silage crop than popcorn and sweet corn because of its higher yield of dry matter, CP, and IVDDM and higher economic returns. However, the low intake potential and digestibility of some sorghum cultivars may limit their use for livestock with high nutrient intake requirements.