Epiphytic microflora on alfalfa and whole-plant corn

Epiphytic microflora were identified and counted on four cuttings of alfalfa, each harvested at three stages of maturity, and on three whole-plant corn hybrids. Enterobacteriaceae were predominant on both crops. Yeasts and molds also were major epiphytic microorganisms on whole-plant corn. The group--including lactobacilli, pediococci, and leuconostocs, which are genera that produce lactic acid and thus are instrumental in silage preservation--constituted only a small proportion of the total population (less than .5%) on both crops. Lactate-fermenting clostridial spores were not detected on standing alfalfa, and occurrences of these spores on standing corn plants were due to soil contamination from rainfall prior to harvest. The numbers of epiphytic microorganisms, except for the lactobacilli, pediococci, and leuconostocs group, were higher on standing corn than on alfalfa. The epiphytic microflora on alfalfa increased with increasing temperature during the growing season. However, neither cutting number nor maturity affected the epiphytic microflora on standing alfalfa, and wilting following mowing had little effect on most populations. Higher temperatures during wilting increased yeast and mold counts but had no effect on other microbial counts. The chopping process tended to increase the epiphytic microflora populations compared with those on the standing crops, and the group containing lactobacilli, pediococci, and leuconostocs was most enhanced. Only yeast and mold counts on the chopped alfalfa increased with greater DM content and buffering capacity.