170 



SOILS AND AGRICULTURAL CONDITIONS 



have been grown, and to have done well. But the soil as shown by analysis 

 has generally a salt content too high for snecessful rice cultivation, unless 

 fresh water could be applied in quantities. 



These swamps have but little agricultural value. They are covered with 

 swamp vegetation, mangrove thickets, buttonwood, scrub palmetto, swamp 

 grasses and other water-loving plants. 



The soil consists of yellow clayey marl, filling more or less the numerous 

 pockets in the weathered surface of the underlying rock. Mixed with the 

 marl is a large percentage of small rock fragments and small shells. A me- 

 chanical analysis of a sample of this type follows : 



MECHANICAL ANALYSIS OF BRACKISH SWAMP OR SALINA. 



The chemical analysis of a sample of swamp marl taken near Nassau gave 

 the following results: 



PRINCIPAL PLANT FOOD CONSTITUENTS IN SWAMP MARL. 

 By acid digestion (HCl sp. gr. 1.115). 



Constituents. Per cent. 



Phosphoric acid (P2O5) .036 



Lime (CaO) 43.630 



Potash (KoO) 262 



Nitrogen (N) .025 



The figures show that this material is mainly calcium carbonate. The 

 other important plant-food constituents are present in but very moderate 

 amounts, and the view that has found some credence that this material 

 would prove a valuable fertilizer is shown to lack justification. The amounts 

 of water-soluble constituents in this type were so large that gravimetric de- 

 terminations of them have been made, with the following results : 



