EXPERIMElirTAL WORK WITH EAW EOCE PHOSPHATE. 



83 



Table XLYIII. — Yields of certain crops oMained in pots containing 110 

 pounds of poor sandy soil treated with available nitrogen and potash, etc., 

 and various phosphates. 



Fertilizer. 



Applica- 

 tion of 



per pot. 



Yield (1896-97). 



Oats. Rye. Beans. Vetch. Cabbage. ' Rape. 



Acid phosphate 



Florida rock (floats) 



Thomas slag 



Redonda phosphate 



No phosphate , 



No fertilizer (of any kind) . 



Grams. 

 4 

 4 

 4 

 4 



Grams. 

 93.5 

 85.7 

 115.1 

 93.0 

 90.7 

 7.3 



Grams. 

 226.8 

 205.5 

 212.0 

 215.0 

 194.0 

 39.5 



Grams. 

 22.4 

 13.8 

 14.8 

 16.9 

 13.3 

 11.1 



Grams. 

 111.2 



85.7 



75.3 

 75.6 



Grams. 



57.5 

 53.0 

 54.8 

 53.2 

 53.0 

 13.0 



Grams. 

 61.4 

 55.2 

 60.7 

 59.5 

 45.8 

 11.4 



Table XLIX. — Yields of crrlain crops obtained in boxes containing 46 pounds 

 of pure sand {99.6 per cent SiOz), treated icith available nitrogen and potash, 

 etc., and with various phosphates. 



Form of phosphate. 



Acid phosphate 



Florida rock (floats) 



Thomas slag 



Redonda ph -sphate 



No phosphate 



No fertilizer (of any kind). 



Appli- 

 cation 

 per 

 box. 



Grams. 

 3 

 3 

 3 

 3 



Yield of crops (1898-99). 



Barley. 



Grams. 



189.6 



9.3 



181.4 



150.1 



7.9 



10.9 



MiUet. 



Grams. 

 29.2 

 1.1 

 8.8 

 14.4 

 1.2 

 LI 



Oats. 



Clover. 



Grams.': Grams. 



210.2 



9.1 



198.9 



170.2 



6.8 



10.0 



93.8 



2.6 



74.0 



37.1 



2.4 



4.5 



Vetch. 



Toma- 

 toes. 



Cab- 

 bage. 



Grams. 



Grams. 



Grams. 



88.5 



58.7 



82.2 



31.8 



L8 



64.5 



67.5 



48.4 



80.0 



61.9 



57.2 



65.4 



2.7 





.5 



2.7 





3.6 



Grams. 

 9L4 

 72.3 

 98.4 

 74.9 

 .8 

 3.4 



Table L. — Yield of certain crops obtained in boxes containing Jf6 pounds pure 

 sand {99.6 per cent Si02). treated tcith available potash and nitrogen, etc., 

 and with various phosphates. 



Form of phosphate. 



Acid phosphate 



Florida rock (floats) , 



Thomas slag 



Redonda phosphate 



No phosphate 



No fertilizer (of any kind) . 



Appli- 

 cation 

 per 

 box. 



Grams. 

 1.5 

 L5 

 1.5 

 1.5 



Yield of crops (1899-1900). 



Barley. 



Grams. 

 34.2 

 8.8 

 2L1 

 18.6 

 6.8 

 4.9 



Peas. 



Grams. 

 19.8 

 12.0 

 15.9 

 13.8 

 7.7 

 3.7 



Vetch. 



Grams. 

 9.6 

 4.8 

 8.1 

 8.3 

 i6 

 2.0 



Toma- 

 toes. 



Grams. 

 11.5 



8.4 

 7.6 



Cab- 



Gram*. 

 38.3 

 46.0 

 45.8 

 20.0 



Rape.' 



Grams. 

 29.3 

 28.1 

 10.9 

 17.1 



1 Cabbage and rape were grown on the sand used the previous year to which 4 grams of P2O5 were added 

 in the various forms given above. 



A study of Tables XLVIII, 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 



