EXPERIMENTAL WORK WITH RAW ROCK PHOSPHATE. 83 
TABLE XLVIII.—Yields of certain crops obtained in pots containing 110 
pounds of poor sandy soil treated with available nitrogen and potash, etc., 
and various phosphates. j 
Fertilizer. Honor San as EP eee 
a per pot. | Oats. Rye. Beans, | Vetch. |Cabbage.| Rape. 
ec Sr a RS ae ae at ee Bae gL EN ae Bea 
Grams. Grams. Grams. Grams. | Grams. Grams. | Grams. 
Acidsunhosphate: <a... --2-55----- 4 93.5 226.8 22.4 PES? bY/sa) 61.4 
Florida rock (floats)...........- 4 85.7 205.5 13.8 85.7 53.0 55.2 
Mnhomasslagee re Ne 4 Meal 212.0 14.8 98.8 54.8 60.7 
Redonda phosphate...-.....-- : 4 93.0 215.0 16.9 87.6 S357 59.5 
iNolphosmhateseee 2s see aes 90.7 194.0 13.3 75.3 53.0 45.8 
No fertilizer (of any kind)....../.......... 7.3 39.5 Le 75.6 13.0 11.4 
TABLE XLIX.—Yields of certain crops obtained in boxes containing 46 pounds 
of pure sand (99.6 per cent SiOz), treated with available nitrogen and potash, 
etc., and with various phosphates. 
Yield of crops (1898-99). 
Appli- 
Form of phosphate. ra f ae 
£ 2 oma- ab- 
box. | Barley 5 Millet. | Oats. | Clover.| Vetch. toes. | bage. Rave r 
Grams.| Grams.| Grams.| Grams.| Grams.) Grams.| Grams.) Grams.| Grams. 
Acid phosphate-.-..........--- 3 | 189.6 29: 2)| 21052 93. 8 88.5 58. 7 82. 2 91.4 
Florida rock (floats)....--..- 3 9.3 1.1 9.1 2.6 31.8 1.8 64.5 TAS 
pithomasislapemere scene ace sass 3 | 181.4 8.8 | 198.9 74.0 67.5 48.4 80. 0 98. 4 
Redonda phosphate....-...-. 3} 150.1 14.4 | 170.2 37.1 61.9 57. 2 65. 4 74.9 
No Boe phate BREE SER ee eral oyoye a5) qe9 1.2 6.8 2.4 orden neniower os .8 
No fertilizer (of any kind)...|....-.-.-- 10.9 Tal 10.0 4.5 PE BAS ae 3.6 3.4 
TABLE L.—Yield of certain crops obtained in boxes containing 46 pounds pure 
sand (99.6 per cent SiO.), treated with available potash and nitrogen, etc., 
and with various phosphates. 
Yield of crops (1899-1900). 
Form of phosphate. 
PSE - Toma- | _Cab- 
box. | Barley.| Peas. | Vetch. | jo... bage.l Rape.l 
Grams. | Grams. | Grams. | Grams. | Grams. | Grams. | Grams. 
INCIGEMhOSPHAbearee sess sca Scie ee 1.5 34. 2 19.8 9.6 11.5 38.3 29.3 
Florida rock (floats)......-..-------.-- 15 8. 8 12.5 “Se Ose Gc ose 46.0 28.1 
GMM ASISIA Des ee se ee bee oho cic a SSS 1.5 21.1 15.9 8.1 8. 4 45.8 10.9 
Redonda phosphate...-..-..----...--- 1.5 18. 6 13.8 8.3 7.6 20. 0 Zep 
ING hosphatesettsse= Soe S och tet. ose eck 6.8 7.7 2:56: ecsis Son) sacs ses eee eee 
No-fertilizer (of any kind).............|.....--.- 4.g 3.7 O.0o lei clieo 
1 Cabbage and rape were grown on the sand used the previous year to which 4 grams of P2:O5 were added 
in the various forms given above. 
A study of Tables XLVITT, XLIX, and L will show that the cru- 
ciferous plants (cabbage and rape) seemed to utilize the phosphoric 
acid of raw rock phosphate almost as well as they did the more solu- 
ble forms, but that nearly all the other plants gave greater yields 
where they were treated with acid phosphate. In Table LXVIII, 
where a sandy soil was used, the difference between the soluble and 
insoluble phosphate pots was not so marked, owing in part no doubt, 
to the fact that the soil originally contained phosphates. In the 
