ENVIRONMENTAL LIMITATIONS TO POTENTIAL FORAGE PRODUCTION DURING THE WINTER MONTHS IN FLORIDA.

Authors: Sinclair, Thomas; BENNETT, J. - UNIV. OF FLORIDA; Ray, Jeffery - Jeff

Submitted to: Soil and Crop Science Society of Florida Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 11/12/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Beef calf production is a major agricultural industry in Florida. One of the important constraints for the beef industry is low amounts of feedstock for the cattle during the winter months. Even though the temperature is relatively warm in the winter months, pasture production tends to decline dramatically. The purpose of this analysis, by scientists of the Agricultural Research Service in Gainesville, FL, was to determine the role of decreased sunlight, rainfall, and temperature in the winter months in decreasing the inherent capacity of forage growth during this period. This analysis indicated that forage yields would necessarily be decreased to less than half of the summer yields because of these environmental constraints. Nevertheless, actual yields are decreased much more severely than suggested by this analysis. These results indicated that substantial benefit could be gained in developing plants that sustain growth, probably by negating plant dormancy, during the winter months.

Technical Abstract: Low productivity of Florida pastures in the winter is well documented. The objective of this study was to use simulations of forage production in response to solar radiation, rainfall, and temperature, to assess the environmental limits to forage production. Simulations were performed using a number of years of weather data from Gainesville, Tallahassee, and Belle Glade. The annual cycle of solar radiation was important in establishing the seasonal variation in forage yield. These simulations indicated that maximum forage yields in the winter could only be about half the maximum summer yield. Rainfall was also an important constraint on forage yield. This was especially true for the dry spring bimonthly periods of March-April and May-June when the lack of water substantially decreased the potential forage yield. Water limitations at Belle Glade were also important during the winter months even though temperatures were adequate for growth. In the North Florida locations persistent cold night temperatures substantially decreased photosynthetic capability. The results of these simulations indicated the importance of environmental constraints on limiting forage production, particularly during the winter months.