Yield and Quality of Switchgrass Grown Without Soil Amendments1
- J. A. Balasko,
- D. M. Burner and
- W. V. Thayne2
Although cool-season forages usually produce ample forage in spring and fall, there is a lack of summer pasture in many middle latitude and northern states in the USA. Low productivity in summer is accentuated in areas with soil and topographical limitations. The purpose of this study was to evaluate the productivity and nutritive value of ‘Blackwell’ switchgrass (Panicum virgutum L.) grown without addition of fertilizer or lime on a site of marginal fertility and harvested according to 10 cutting schedules. Plots were established on a fine-loamy, mixed, mesic Ultic Hapludalf mapped as Culleoka-Westmoreland and harvested according to one-cut, two-cut, and three-cut schedules for 3 years. A residual harvest was made in early summer of 1981 to measure effects of previous cutting schedules on yield. Annual yields from the one cut per year schedules and the two cuts per year schedules with second harvests after frost were similar (7.3 to 8.1 Mg ha−1) and larger than those from other two and three cuts per year schedules. In vitro dry matter disappearance of switchgrass harvested at boot ranged from 504 to 576 g kg−1 and decreased from 612 g kg−1 on 10 July to 365 g kg−1 on 16 September. Crude protein ranged from 30 to 70 g kg−1 for all first cut forage. Quality of regrowth forage harvested before frost was higher than that of first cut forage, but regrowth usually represented less than 20% of seasonal yield. Results suggest that switchgrass managed in an extensive manner can contribute significantly to the amount of forage available to grazing beef cows in summer. Supplementation with protein, P, and Mg may be required as the opportunity for selective grazing is reduced.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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