. The Alexandria Research Center. Forests and forestry Research. S ? 1947 (NORMAL RAINFALL) ? 1948 I VERY DRY) 1949 (VERT WET) ? 3-TEAR AVERAGE (Po'obolic regression). 14 26 12 26 15 29 13 2' AUGUST [SEPTEMBER OCTOBER Figure 22. --Cumulative grass pro- duction on very open forest range dominated by bluestem grasses. Central Louisiana, 1947-49. of close and repeated grazing on the production and nutritive value of range forage. Grass production on an un- grazed range with very few trees was about 2, 121 pounds per acre (air-dry) during 1947, a year of near-normal rainfall. In 1948, when t
. The Alexandria Research Center. Forests and forestry Research. S ? 1947 (NORMAL RAINFALL) ? 1948 I VERY DRY) 1949 (VERT WET) ? 3-TEAR AVERAGE (Po'obolic regression). 14 26 12 26 15 29 13 2' AUGUST [SEPTEMBER OCTOBER Figure 22. --Cumulative grass pro- duction on very open forest range dominated by bluestem grasses. Central Louisiana, 1947-49. of close and repeated grazing on the production and nutritive value of range forage. Grass production on an un- grazed range with very few trees was about 2, 121 pounds per acre (air-dry) during 1947, a year of near-normal rainfall. In 1948, when there was a record drouth, production was 1,308 pounds of grass, or 40percent less than the normal year. The 1949 growing season was comparatively wet, and grass production jumped to 3, 083 pounds or 42 percent above the average year. A "normal" grass produc- tion curve, drawn from these data, showed that about half of the grass was produced by June 1, 75 percent by July 22, and 90 percent by September 5. Further, there was enough winter-spring moisture each year to insure 1,200 to 1,500 pounds of grass by July 1. Growth thereafter varied greatly with the 2C rainfall (fig. 22). Close and repeated har- vesting seriously reduced grass production. Areas harvested 15 times during the season produced only 1,300 pounds of grass per acre in 1947, while areas har- vested only at the end of the season yielded 2, 121 pounds (fig. 23). Furthermore, 35 to 50 per- cent of the grass stand was killed by this close harvesting in just one season. It was clear that heavy grazing will materially re- duce grass production the first year and, if continued, will de- stroy the valuable bluestem gras Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Southern Forest Experiment Station (New Orleans, La. ); Cassady, John
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