22 
Experiments were made with three different’ types of soil—with a 
loose river sand, with a loamy clay, and with a soil composed chiefly 
of organic matter. This latter soil was prepared artificially by 
mixing a small amount of sandy soil with well-weathered manure. 
The analyses of the soils are as follows: 
Analyses of soils used in pot experiments. 



: : ‘ No. 213 No. 18 No. 222 
Soil constituents and reaction. (sandy soil) (clay loam | (soil rich 
J " soil). in humus). 
Per cent. Per cent. Per cent. 
nsolule miatperse soe ra eee sa = arse Sere aac tele wes he mee te melee 67.38 60. 38 47.4 
PotasieGkaGe 4 ond _& see beee oss 3 eed ee eee eerie OL .30 48 
LUNE ROAO \ecece ste esta cca’ oe sae aetna a een aaa eee 1. 23 85 3. 82 
Myrnasta( ile O))se sr b.8 eek ooese.. Seok Bee hetena. 2Seke- eee eee Ree 2. 21 3. 58 2.92 
Ferric and aluminic oxids (Fe2O3 and AlgO3)....-.-.---.----------- 21.90 23.91 11.49 
‘Phosphorus pentoxigi(hsO,)- -<- 5. =o vee .08 . 20 .85 
Wolstilemattersos cae sete eg cee aoe eee ee ere oa sebaseee 6.59 11.55 33. 25 
MOGs He cee ye stern eS s Oe ee See taae Sat eee 99. 40 100. 77 100. 00 
INdiroren: (Nese desis eee a eee ene ree eee ee eae me ie ene - 05 .19 . 69 
Moisperess. 22 a5) 545 assess. sere as sass sas. a> sae 7.38 11. 46 5. 83 
Carhonidioxid (COs). soce separ. pan cae aerate = Ramana Se eee = None. None. None. 
Caleiumreéarbanate (aC Op). feces ot ote so tas asst. Sea 225. None. None. None. 
IRGRChION £0 GinUS Sens seen aati eee amicmee ne ciara a Sens Neutral. Neutral. Acid. 


Lime was added to these soils in the form of carbonate. The 
limestone used was of coralline origin and occurs naturally in a finely 
disintegrated state. The use of this material made it possible to 
imitate closely natural conditions, as this imestone forms the subsoil 
of many fields and is of the same origin as much of the calcium car- 
bonate occurring in Porto Rico calcareous soils.t_ In all experiments 
except No. IV such a limestone, obtained from Tallaboa, was used. 
The analysis is given below under No. 216. In experiment IV a 
limestone of the same kind but containing more magnesium was used, 
the analysis of which is given under 211. 
Analyses of limestone used in pot experiments. 

No. 216 + 
ee (used in | (Sed in 
Soil constituents. Hone TE experiment 
I, il): 

Per cent. Per cent. 
Sitiew and’ sand (SiOs)- .2 224250 ee ee a Bae re ee ee oe aerate 8. 0. 20 
Tron and alumina (Fe203 and AlyO3)-.....--- Sek LO on Ee ee 9 kee eee 1.90 . 68 
Litrid (Gad) ee es oe eae ae ae eee aot le ee ne Ie re a 50. 76 49. 82 
Magnesium (MgO) 2 ooo kn syria es 2s a eae rae . 84 4.86 
Loss‘on ignitioni<<:5ose55 Shsce soos e Saas eee a ee en eae ne eee 38. 81 44. 32 
"Potal 3se e Sr e ee ee ce teins a Soars Oe Se ae ee a on oe aril = ee etre 100.72 99. 88 


The pots were all fertilized alike from time to time. The fertiliza- 
tion was rather more liberal than necessary in order to show beyond 
doubt that the chlorosis was not induced by lack of nitrogen, phos- 
phorus, or potash. Tankage, sodium nitrate, sulphate of potash, 

1 The effectiveness in the soil of calcium and magnesium carbonate from different sources is compared 
by D. Meyer (Landw. Jahrb., 33 (1904), p. 371). 
[Bull. 11] 
