Florida and Flatwoods

J. R. Henderson and F. B. Smith.

The Florida Peninsula and adjacent Flatwoods include all or part of 10 counties in eastern South Carolina, 20 counties in eastern Georgia, and 64 of the 67 counties in Florida.

It is a low coastal plain, which has more than 5 thousand miles of indented coastline. No point is more than 100 miles inland from the Gulf of Mexico or the Atlantic Ocean. Inward from the coast a series of seven old shorelines mark the boundaries of marine terraces whose maximum elevations are 25, 42, 70, 100) 170, 215, and 270 feet above sea level. The highest points are in Pasco and Polk Counties in Florida.

The drainage systems are variable. Several large streams enter from the north and west and receive drainage from tributaries that rise within the region. Streams are rare in the central ridge of the Florida Peninsula. Most of the surplus water seeps rapidly into numerous lakes that dot the terrain or into underground cavities caused by the dissolving of the underlying limestone. The lower lying flat terraces do not have well-defined drainage systems. Runoff moves slowly through broad sloughs into the shallow lakes or sluggish streams and finally into the gulf or ocean.

Relief and parent materials, with their accompanying effects on drainage and related conditions, have been dominant factors in forming the characteristics of the soils. Except for alluvial deposits along the larger streams and organic deposits in wet areas, the formations upon which the soils have developed consist of limestones, marls, and noncalcareous marine deposits of mixtures of sands, silt, and clay.

Limestones underlie the entire region but are exposed in only a few places, mainly in central Florida, where they have weathered to form the parent materials of an important group of phosphatic soils.

The thickness of the unconsolidated mantle varies. It is quite thick in some places. It is so thin in other places that the calcium status and other characteristics of the soil are influenced by the underlying limestones.

Soil characteristics are major factors that affect the practices used in the production of crops, but climate, especially seasonal temperature, is more important in determining the kinds of crops and the seasons they are grown.

The average January temperatures range from 48.7 F. at Horry, S. C., to 69.9 at Key West, Fla. Summer temperatures have a narrower range; the averages for July range from about 80 to slightly above 83 .

Temperatures in summer are lower and winter temperatures are higher near the coasts than they are inland. The heat of summer is tempered by sea breezes, and winter temperatures are moderated by the warm waters of the gulf and ocean. Lakes, which are numerous in the central part of the Florida Peninsula, also have a moderating effect on temperatures locally.

The average number of days without killing frost is approximately 250 in inland points of the northern part to 365 at Key West, off the southern tip of Florida.

No part of the mainland is frost free, but sometimes several winters in succession may have no frost in sections of central and southern Florida. Cold waves occasionally do considerable damage to crops, especially citrus fruit and winter vegetables.

The average annual rainfall at stations on the mainland is 46 to 64 inches. The annual rainfall generally is highest at the southern and western extremities of Florida and lowest along the northern part of the Atlantic coast and in areas inland from the middle part of the gulf coast. Rainfall varies considerably from year to year. Longtime records indicate that the totals for the wettest years may double those of driest years at any given place.

Seasonal distribution of rainfall is characterized by a rainy season June, July, August, and September when more than half of the annual precipitation occurs. Otherwise the monthly distribution of rainfall usually is good, but in some months crops suffer from lack of water. April and November are the driest months, but dry periods may occur in any month. Occasional heavy downpours, sometimes accompanied by winds of high velocity, damage growing crops considerably.

The favorable climate permits successful production of a variety of crops,even though many of the soils are inherently of low productivity. This fact tends to lessen the significance of soil differences and increase the importance of good soil management.

The major problems of soil management include selecting soils within climatically favorable areas that are (or can be made) suitable for the crops to be grown, establishing favorable conditions of soil moisture, controlling erosion and leaching, and liming and fertilizing to overcome nutrient deficiencies and meet crop requirements.

Citrus, avocados, gladiolus, mangoes, and winter vegetables are grown in the warmer areas in central and southern Florida. Most field crops, tung, and pecans are grown in the northern parts. Citrus fruit, other fruit, nuts, watermelons, and most field crops are grown on well-drained soils. Sugarcane for syrup is grown mainly on well-drained soils in the northern section. Sugarcane for sugar is grown mainly on organic soils in southern Florida. Most vegetables are grown on soils whose water table is not far below the surface.