13 



The plats were prepared as follows : Holes of tl:e requii-ed size and 

 depth were excavated in a clay soil, leaving a bank 3 feet wide be- 

 tween each plat. These holes were filled with clay, sand, and dis- 

 integrated hmestone in such proportions as to furnish soils of approx- 

 imately equal texture and with the above percentages of calcium 

 carbonate. Plat I was made up of approximately 33 per cent clay 

 and 67 per cent sand; Plat II of 34 per cent clay, 60 per cent sand, 

 and 6 per cent hmestone; Plat III of 33 per cent cla}-, 47 per cent 

 sand, and 20 per cent hmestone; Plat IV of 32 per cent clay, 30 per 

 cent sand, and 38 per cent hmestone. The soil in each plat was made 

 uniform bj- long-contmued mixing. The texture of the soil m Plats 

 I, II, and III was practically equal, that in Plat IV was somewhat 

 heavier although good. As the iouT plats were surrounded bj- a 

 ditcli, there was no drainage or wash from one plat to the other. 



The hmestone used was the finely dismtegrated material formed 

 b}' the breakmg down of coraUme rock.' The acid analyses of the 

 soils m the four plats are given in Table I\. 



Table I^'. — Anah/sis of (he soils of lliejhur plats. 



Insoluble matter 



Loss on ifrnition 



Ferric oxitUFe-O;,) 



Aluminiooxid (AI.O3) 



Liino(CaO) 



Ma^icsia (MgO) 



Potash (K.O) 



Phosphorus pentoxid (P.O5.) 



Total 



Nitrogen (N) 



Carbon dio-xid (CO2) 



Calcium carbonate (CaCOg). . 

 Reaction to litmus 



11.97 

 11.30 

 1.03 



Flat II. Plat III. Plat IV. 



Per cent. 

 69. 09 

 10.97 

 10.82 



Per cent. 

 50. 7-1 

 18.17 

 9.26 

 12.11 

 10.90 

 .79 

 .15 



Wliile these soils were of good loamy texture, they were very low in 

 organic matter, and were purposely kept so by remo\'ijig the roots of 

 the various crops, since in the work previouslj- reported ^ there was 

 evidence to show that in the presence of a large amount of organic 

 matter the carbonate of lime would not exert its characteristic effect 

 on the plants. Nitrogen, potash, and phosphoric acid were applied 

 frec^uently and in such Ciuantities that the growth of plants was not 

 checked by a lack of these elements in any of the plats. Water was 

 also supphed when the rainfall was insufficient. In these plats the 

 plants were grown under natural conditions of soil temperature, root 

 space, and water supplj^, and the growths made were fuUy equal to 

 those obtained under ordinary field conditions. 



1 Analysis and dcscriptiur 

 ! Porto Rico Sta. Bui. 11. 



of this material i 



I imder sample 216 in Porto Rico Sta. Bui. 11, p. 22. 



