Page 494 - FRUTAS DEL TRÓPICO

494 Frutas del trópico

Calcareous soils:
The definition of calcareous soils by the Soil Science Society of America: soil containing suffi-

cient free CaCO and other carbonates to effervesce visibly or audibly when treated with cold
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0.1M HCl. These soils usually contain from 0.1 to almost 100% CaCO . Therefore, both
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Krome very gravelly loam and Chekika very gravelly loam are also classified as calcareous

soils because they were derived from Miami limestone and usually contains from 30 to 90%

CaCO . The pH values of calcareous soils are greater than 7, usually in the range of 7.4-8.4.
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Textures of calcareous soils can be sandy, loamy or gravelly. Soil depths range from less than 10

cm to over a meter. These soils are important for production of tropical fruit in Florida. Over

85% of Florida’s tropical fruits are grown on calcareous soils in the southern part of the state.
This is done because of favorable temperatures, rather than favorable soil characteristics. Ca-

reful management of nutrients is critically important to the successful production of crops on

calcareous soils.

Nutrient management for calcareous soils

Grow crop tolerant to calcareous soils:

Growing high-pH tolerant crops is a useful management option for coping with calcareous soils.

Plants show chlorosis usually on soils higher than 20% Ca content and has been a problem

since the first commercial tropical fruit groves were established in South Florida. The chlorosis

is mainly nutrient deficiency, especially Fe. Roots of Fe-efficient plants react to Fe-deficiency
stress by strongly enhancing reductase activity, lowering the rhizosphere pH with excretion of

H+, and releasing acids that act as chelates. Those characteristics make it possible to select

Fe-efficient genotypes. So far there is no research report on this topic.

Universidad Autónoma de Chiapas