Mr. Walker was interested in producing a mixed silage for his dairy cattle. In 1997 he planted corn, sorghum, sunflowers, and peas all mixed together in more or less equal portions in the same 10-acre field. He harvested this mixture, put it away for silage, and had samples analyzed for their protein and TDN (total digestible nutrients) content. He compared the results with data from his usual silage of unmixed corn.
Mr. Walker reports that the mixed forage grew well. He says the corn and sunflowers appeared more vigorous than the sorghum and peas, but no one species was crowded out by the others. He reports no particular trouble with pests, apart from some minor weed problems.
He did not measure fresh forage weight, but believes that tonnage per acre of the mixed forage may have been greater than that of the straight corn. He notes however that the sunflowers were especially moist, and estimates that because of that, the dry matter yield was probably a ton to a ton-and-a-half less than that of the unmixed corn.
TDN analysis was approximately the same for both silages. Protein content was 12% for the mixed silage, compared to 7% for the unmixed corn. Cows fed either silage produced about the same quantities of milk, but that from cows fed the mixed silage had higher percentages of protein and fat. He also reports that planting the mixture was cheaper than planting unmixed corn.
Mr. Walker was so happy with the results that he expanded his mixed forage planting to 85 or 90 acres in 1998 and 1999. His area suffered from drought all three summers from 1997 through 1999, nonetheless his yields were respectable, in large measure because of the drought-tolerance of two components of the mixture, the sorghum and the sunflowers.