ABSTRACT
Summary The practice of accumulating growth of cool-season grasses in the late summer and early autumn for subsequent grazing in late autumn and winter, known as stockpiling, has been widely accepted by beef cow-calf producers. The objectives of our study were to determine the growth characteristics of cool-season grasses in the autumn under nitrogen (N) fertilization and to investigate utilization of stockpiled forages. Tall fescue (Festuca arundinacea Schreb.) has many attributes that make it highly suited to stockpiling. On Maury silt loams, Kentucky 31 tall fescue accumulated 6,500 kg/ha of dry matter from 16 August 1979 to 12 December 1979 with N at 100 kg/ha. Boone orchardgrass (Dactylis glomerata L.) accumulated 4,300 kg/ha, and Kenblue Kentucky bluegrass (Poa pratensis L.) accumulated 2,200 kg/ha. During the first month of stockpiling (mid-August to mid-September) orchardgrass outgrew tall fescue and Kentucky bluegrass with mean crop growth rates of 77, 65, and 43 kg/ha/day, respectively, but in the second month, with the onset of cooler weather, tall fescue accumulated dry matter at the rate of 84 kg/ha/day, and orchardgrass and bluegrass grew at 47 and 41 kg/ha/day, respectively. In the third month (mid-October to mid-November) tall fescue grew at twice the rate (33 kg/ha/day) of the other two grasses. Water-soluble carbohydrates in stockpiled tall fescue increased with rate of N fertilizer and accounted for 19% of dry matter in mid-November. Silage made from tall fescue at this time (N = 100 kg/ha) had a pH of 4.4, and lactic acid accounted for 2.5% of silage dry matter. Conversion of tall fescue stockpiles into silage in late autumn seems to be a feasible method of using them in regions where severe weather impairs their utilization or accelerates their deterioration.
