84 



BULLETIN 699 U. S. DEPARTMENT OP AGRICULTURE. 



other two experimentvS, however, the sand used contained no phos- 

 phate, except that added and it is rather surprising that such addi- 

 tions of raw phosphate as were made, applications supplying from 

 0.008 to 0.014 per cent of phosphoric acid, which is less than that 

 contained in a soil abnormally low in this element, should have 

 proved so effective, particularly in the absence of organic matter. In 

 order to test the influence of fine grinding on the availability of raw 

 rock phosphate and bones two pot experiments were conducted under 

 the direction of W. H. Jordon^ of th-e Geneva station. In one of 

 these experiments (1899-1900) 58 pounds of pure quartz sand per pot 

 were used to which no organic matter had been added, and in the other 

 (1903-4) 43 pounds of sand per pot were employed to which about 3 

 per cent of dried ground sphagnum moss was added. In both ex- 

 periments all the pots except the blanks were supplied with the nec- 

 essary fertilizer elements, the phosphoric acid, however, being 

 applied in the forms of acid phosphate, bone, and ground raw rock 

 of various degrees of fineness. 



In the first experiment three successive crops of rape were grown 

 without renewing the phosphate treatments for the second and 

 third crops, but the barley was grown in a separate set of pots. In 

 the second experiment the crops grown were peas, barley, and rape, 

 but each in separate sets of pots. The plants in every instance were 

 allowed to attain the fullest development possible under the condi- 

 tions. They were then harvested and weighed. The results ob- 

 tained are given in part in Table LI which is compiled from two 

 tables taken from Bulletin No. 358, of the Geneva station. 



Table LI. — Box experiment to test the effect of raw rock phospliate of variout 

 degrees of fineness on different crops; boxes contained Jf6 pounds each of pure 

 quartz sand supplied with all fertilizer elements. 





AppU- 

 cation 

 ofPsOs 

 per 

 box .2 



1899-1900 



1903-4 



Treatment. 



Rape, 

 first 

 crop. 



Rape, 

 second 

 crop. 



Rape, 

 third 

 crop. 



Barley. 



Peas. 



Barley. 



Rape. 



Blanks 



Grams. 



Grams. 



Grams. 



Grams. 



Grams. 



Grams. 

 8.4 

 69.9 



64.1 

 63.1 

 62.8 

 60.3 

 67.5 

 68.0 



59.8 

 60.4 

 62.7 

 61.6 

 59.6 



Grams. 

 12.2 

 166.7 



140.0 

 165. 7 

 176.3 

 164.4 

 172.9 

 162.7 



160.0 

 168.7 

 175.3 

 164.6 

 177.0 



Grams. 





3 



3 

 3 

 3 

 3 

 3 

 3 



3 

 3 

 3 

 3 

 3 



72.3 



47.5 

 36.5 

 37.6 

 46.3 

 45.2 

 52.8 



54.8 

 53.0 

 54.5 

 60.9 

 49.2 



49.3 



30.9 

 30.1 

 28.5 

 28.4 

 34.0 

 35.6 



36.9 

 35.9 

 40.1 

 35.1 

 39.4 



26.2 



25.0 

 27.6 

 29.3 

 29.4 

 31.3 

 32.4 



32.7 

 33.0 

 32.7 

 36.0 

 26.7 



66.4 



7.6 

 9.0 

 6.8 

 7.8 

 7.3 

 11.1 



9.8 

 7.3 

 6.9 

 6.9 

 9.5 



48.6 



Florida rock: 



60-mesh 



54.5 



80-mesii 



58.2 



100-mesh 



56.3 



Bolting cloth 



58.7 



Fine 



58.8 



Floats 



57.7 



Bone meal: 



60-mesh 



46.5 



80-mesh 



46.8 



100-mesh 



40.7 



Bolting cloth 



44.8 



Finest 



48.6 







> N. Y. Agr. Expt. Sta. (Geneva), Bui. No. 358 (1913). 



' la the experiments conducted in 1903-4 only iJs grams of PjOj per pot were used, but organic matter 

 was added in the form of sphagnum moss. 



