THE FLORIDA CATTLEMAN AND LIVESTOCK JOURNAL
White Clover Management in South Florida
It is common to hear about the great stands of white clover that once covered the pasturelands in South Florida and it is not well understood the causes of the decline in white clover stands in the region. In many occasions, the explanation for the decline of white clover is a mixture of science, romance, and personal opinion. The objective of this article is to try to encompass the most likely scientific cause for the decline in white clover stands in South Florida.
White clover(Trifolium repens) is a stoloniferous plant with a shallow root system. The primary stems of white clover usually die before the second year, and the life of the plant depends upon the stolons and their haphazard root development. In subtropical regions, white clover is usually an annual clover that may reestablish from seeds.
White clovers are classified into three distinct types. Small types, normally less than 3 inches tall, are often found in lawns and other areas frequently mowed or grazed short. Large types, sometimes 2 feet tall, are the most productive and sometimes called "ladino" clover. Intermediate type white clovers, sometimes called "common" or "white dutch," have plant heights, leaf size, petiole size, flowering date, and growth habit midway between the others. The most frequently planted cultivars in Florida have been Louisiana S-1 (intermediate type) and Osceola (intermediate toward ladino type). Some of the more recent releases include Patriot (intermediate - large type), and Durana (intermediate type). The intermediate types are excellent seed producers for natural reseeding, but plants lack summer persistence.
White clover grows in soils with pH range from 6.0 to 7.5. White clover needs adequate phosphorus and potassium for establishment, persistence and growth and it is especially responsive to cool, moist conditions. It grows best between 50 and 85 degrees Fahrenheit. It also responds to irrigation or poorly drained soils because of its shallow root system.
Clovers are an attractive option to decrease the production cost associated with N fertilization because legumes have the ability to fix atmospheric N. Annual clovers can contribute about 75-100 lb N/acre for the subsequent grass crop. They are, however, only able to fix N from the air if specific strains of Rhizobia bacteria are present in nodules on their roots. To ensure that the best strain of Rhizobia is present for each clover species, the seed must be inoculated with the proper Rhizobia strain before planting. Pre-inoculated seed of most legume species is available. The majority of N in legumes is transferred to the soil by unused plant material that is returned to the soil and by grazing livestock that return over 90% of the consumed nutrients to the soil through the feces and urine. If the clover crop is unsatisfactory or removed from the pasture as hay, haylage, or silage, the legume N contribution is reduced.
Research was conducted at the Range Cattle Research and Education Center, Ona, FL in 2007 to verify the production of five white clover cultivars (Osceola, Royal Regal, Regal, Durana, and Patriot). The plots were seeded in November 2006 on a prepared seedbed and fertilized with 400 lb/ac of 00-20-20 in December 2006. The plots were not irrigated. There was no difference in forage production among cultivars and the total average forage production was 240 lb DM/ac. The forage N concentration was 3.4%, therefore, the total N contribution of those plots was approximately 8 lb/ac. The main reason for the failure to establish and produce white clover in this trial was the lack of moisture in the fall.
The limiting factor in the establishment and reseeding of white clover in South Florida has certainly been the limited moisture levels during the growing season. In the past, the low prices of fuel allowed producers to irrigate the white clover fields and maintain the soil moisture at appropriate levels to optimize white clover production. The increased price of fuels has limited the economic feasibility of irrigating winter annual forage crops for grazing beef cattle in Florida. In addition, the usually low pH and fertilization levels used on bahiagrass pastures have contributed to the decline in the white clover production and persistence.
Is it possible to grow white clover in South Florida? Yes, as long as the producer has the capacity to maintain the soils with high moisture concentrations and adequate pH and fertility. However, it may not be economically viable due to the high cost of the inputs required.