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Arkansas Animal Science Department Report 2001 ground cover. Forage samples were dried to a constant weight in a forced-air oven (55°C) and yields were expressed on a lb DM/acre basis. Data for each location were analyzed independently as a split-plot design using the GLM procedure of SAS (SAS Inst., Inc., Cary, NC). Whole plots were arranged in a 2 x 4 factorial design that included two initiation dates (August 8 or 10, September 6) and four fertilization rates (0, 33, 66, or 99 lb N/acre). The subplot treatment factor was fall harvest date (October 18 or 19, November 8 or 9, November 29 or 30, and January 8 or 9). Whole-plot sums of squares were partitioned to test for main effects of stockpiling initiation date and N fertilization rate, and to test for their associated interaction; the mean square for the stockpiling initiation date x N fertilization rate x block interaction was used as the error term. Fall harvest dates and all interaction terms with fall harvest date were tested for significance with the residual error mean square. Results and Discussion Mean daily air temperatures and monthly precipitation patterns are shown in Figures 1 and 2, respectively. Ambient air temperatures appeared to follow similar trends at both locations. Temperatures remained relatively high throughout the mid- and late-summer months and were coupled with very little rainfall (Figure 2), which resulted in droughty conditions during this time period. Total precipitation was higher at Fayetteville between August and November, which was the period when stockpiling occurred. At Fayetteville, the stockpiling initiation date x fall harvest date interaction was significant (P = 0.0002); therefore, only interaction means are presented in Table 1. Dry matter yields of stockpiled bermudagrass initiated on August 8 decreased (P < 0.05) between November 8 and November 29, but did not change (P > 0.05) between October 18 and November 18 or between November 29 and January 8. Yields for forage that began the stockpiling period later (September 6) were greatest (P < 0.05) on the November 8 sampling date. At Batesville, the stockpiling initiation date x fall harvest date interaction was significant (P < 0.0001), while the main effect of N fertilization rate approached significance (P = 0.057). Therefore, main effect means of N fertilization are presented in addition to interaction means in Table 2. Previously, Hart et al. (1969) observed similar increasing trends for yields of stockpiled 'Coastal' bermudagrass in response to increased rates of N fertilization. Dry matter yields of stockpiled bermudagrass initiated on August 10 and September 6 followed trends similar to those observed for bermudagrass at Fayetteville. Stockpiled bermudagrass yields on the initial sampling date in our study were lower than those reported for stockpiled bermudagrass harvested from early- to mid-November in Georgia (Hart et al., 1969). In addition, yields throughout the sampling period were lower than those reported by Coblentz et al. (1998) for stockpiled 'Greenfield' bermudagrass harvested during late fall and early winter in Arkansas. Unusually high temperatures and infrequent rainfall events during the early fall clearly influenced trends for yields of stockpiled bermudagrass throughout our study. Unusual weather patterns during the sampling period may have also contributed to unexpected trends for stockpiled bermudagrass yields. The approximate onset of fall dormancy for bermudagrass in Arkansas generally occurs in mid-October, after which little accumulation of bermudagrass forage is expected to occur. However, the first killing freeze at both experimental locations in our study occurred on approximately October 9; low temperatures on this date were 27 and 30°F at Fayetteville and Batesville, respectively. Therefore, high temperatures and low moisture availability during the early fall, coupled with an early killing frost probably limited the yield potential of stockpiled bermudagrass on the first sampling date. Dry matter yields were generally the highest at both locations on the early-November sampling date (Tables 1 and 2). This phenomenon was a result of increased temperatures and rain-fall events during the first sampling interval, which promoted renewed bermudagrass growth between mid- October and early-November. Implications Yields of stockpiled bermudagrass at Fayetteville and Batesville, AR remained relatively low throughout the late fall and early winter, never producing more than 1,565 lb of forage DM/acre. However, unusual weather events that occurred throughout late fall and early winter contributed to unexpected trends for stockpiled bermudagrass yields. Literature Cited Burton, G. W., et al. 1963. Agron. J. 55:500-502. Coblentz, W. K., et al. 1998. Ark. Anim. Sci. Research Series 464. p. 43-47. Doss, B. D., et al. 1966. Agron. J. 58:510-512. D’Souza, G. E., et al. 1990. Am. J. Alternative Agric. 5: 120-125. Hart, R. H., et al. 1969. Agron. J. 61:940-941. Hill, G. M., et al. 1993. J. Anim. Sci. 71:3219-3225. Hitz, A. C., and J. R. Russell. 1998. J. Anim. Sci. 76:404-415. Jolliff, G. D., et al. 1979. Agron. J. 71:91-94. 104
AAES Research Series 488 Table 1. Dry matter yields of stockpiled ‘Common’ bermudagrass at Fayetteville, AR as affected by the interaction of stockpiling initiation date and fall harvest date. Harvest date Initiation date Oct 18 Nov 8 Nov 29 Jan 8 SE 1 ----------------------(lb DM / acre)------------------- Aug 8 1439.1 a 1562.7 a 1038.9 b 963.8 b 66.85 Sep 6 506.5 b 1025.2 a 572.0 b 663.7 b 66.85 a,b Within a row, means without a common superscript letter differ (P < 0.05). 1 SE = standard error of the mean. Table 2. Dry matter yields of stockpiled 'Tifton 44' bermudagrass at Batesville, AR, as affected by the interaction of stockpiling initiation date and fall harvest date, and by the main effect of N fertilization rate. Harvest date Initiation date Oct 19 Nov 9 Nov 30 Jan 9 SE 1 ----------------------(lb DM / acre)------------------- Aug 10 662.4 a 595.3 a 276.8 b 305.2 b 35.44 Sep 6 196.7 b 316.8 a 106.7 b 165.1 b 35.44 N rate (lb N / acre) 0 33 66 99 SE 1 DM Yield 2 , (lb / acre) 226.5 b 297.9 ab 339.8 ab 448.2 a 54.05 a,b Within a row, means without a common superscript letter differ (P < 0.05). 1 SE = standard error of the mean. 2 Significance for the main effect of N fertilization rate on DM yield was P = 0.057. 105
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Arkansas Animal Science Department
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spine copy ARKANSAS ANIMAL SCIENCE
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INTRODUCTION The faculty and staff
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COMMON ABBREVIATIONS Abbreviation T
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The Effects of Nitrogen Fertilizati
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Demographics and Academic Success o
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Efficacy of Mannan Oligosaccharide
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Effects of Dietary Magnesium and Ha
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Effect of Feather Meal on Live Anim
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Maternal Effects for Performance Te
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The Impact of Multiple Antimicrobia
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The Impact of Multiple Antimicrobia
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The Use of Hurdle Technology to Red
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Consumer Acceptability of Forage Fe
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