PORTO RICO EXPERIMENT STATION. 387 



cent of angular gravel or broken stone which the sample contained. 

 This soil contains a considerable percentage of sand, which, together 

 with the contained stone, makes it loose and friable. It admits of the 

 ready permeation of rains, and retains moisture well. 



Nos. 5925 and 5926 are soil and subsoil, respectively, from level 

 land at Rio Piedras which has been leased for cultural experiments by 

 the station. Owing to its sandy nature it was considered especially well 

 adapted to the growing of annual crops, particularly vegetables. The 

 soil to 10 inches in depth is sufficiently sandy to make it easy of cul- 

 tivation, while the subsoil at 12 to 30 inches contains sufficient clay 

 to make it retentive of fertilizers and yet sand enough to make good 

 drainage comparatively easy. 



Nos. 5917 and 5916 are from the land of the Agronomic Experiment 

 Station, which was maintained at Mayaguez by the Spanish Govern- 

 ment from 1889 to 1897. This land, consisting of 7 acres, is of two 

 types — a low, level portion classed as a heavy loam and adapted to the 

 growing of sugar cane and grass, and a hilly part classed as a red clay. 

 The latter is a heavy refractory clay, identical with that of the best 

 coffee lands of the interior. It contains an aggregate of 3^ per cent 

 of sand and larger amounts of silt and clay. The content of organic 

 matter is not real, for in soils of this character the loss in heating to 

 100° C, is partly due to the loss of water of crystallization. If of 

 higher elevation and farther removed from the coast this would be 

 typical coffee land. 



Nos. 5920, from near Yanco, and 5921 from near Ponce, are from 

 the heavier type of loam soils now used for the growing of sugar 

 cane on the south side of the island. Their content of clay and silt is 

 sufficiently high to demand careful management in irrigation and 

 cultivation. 



No. 5921 is the surface soil, to 6 inches, from a virgin forest in 

 Mamayes. This soil is almost wholly silt clay and organic matter. 

 The high content of the latter is due to a considerable coating of vege- 

 table mold, the result of the decaying leaves from the forest. This 

 land, when cleared, will be typical for coffee. 



Nos. 5922 and 5923 are the soil and subsoil from a young coffee 

 plantation at Isolina, Mamayes. The soil is red in color and very 

 heavy in texture. It clings tenaciously to the sidehills, which are so 

 steep that good drainage is always afforded, and even with the torren- 

 tial rains is subject to but little washing. As will be seen from the 

 analyses, this is a very heavy soil, and in case of the subsoil contains 

 less than 3 per cent of all grades of sand. It is considered represen- 

 tative of the best coffee lands of the interior. These analyses empha- 

 size the extremely heav}^ texture of the mountainous coffee lands, and 

 enable one to better understand why so little of the soil is carried away 

 from the steep slopes by the torrential rains. 



