EXPERIMENTAL WORK WITH RAW ROCK PHOSPHATE, 81 
farmers continued their experiments for two years, the published 
reports show that different fields were employed the second year. 
Three other series of field tests were published by the New Jersey 
Station in 1913,1 but none was conducted for more than 2 years, so 
they do not warrant repetition. 
In 1913, however, the New Jersey station carried on two pot experi- 
ments in cooperation with the basic slag committee of the Association 
of Official Agricultural Chemists.? The purpose of this investigation 
was to test the availability of the phosphoric acid in basic slag in 
comparison with other phosphates. Experiment No. 1 was conducted 
in pots holding 20 pounds of clean white sand practically free from 
any fertilizer elements. In experiment No. 2 pots were employed 
holding 18 pounds of gravelly loam, poor in nitrogen and organic 
matter, and containing about 0.07 to 0.08 per cent of P.O, soluble 
in strong hydrochloric acid. Nitrogen, potash, iron, and sulphates 
were supplied to each pot. The phosphates were applied in such 
quantities as to furnish equal amounts of phosphoric acid, except 
the ground raw rock which supplied twice the quantity of phosphoric 
acid furnished by the other phosphates. Each treatment was run in 
duplicate, except the checks of which there were four. The crop 
grown was buckwheat which was harvested when the grain was be- 
ginning to ripen. The results of these experiments are given below 
in Table XLVII. 
- 
TABLE XLVII.—Yields of buckwheat obtained in two pot experiments with pure 
sand and with gravelly loam treated as outlined below. 
Experiment No. 1. Exreriment No. 2. 
Fertilizer. a pulication 
perpov. | Weight | Increase | Weight | Increase 
| _ofcrop. overchecks.) ofcrop. joverchecks. 
Grams Grams. Grams Grams. Grams 
INGIDROS PNAC sease-ses one see = ees cs abeces| occu loon ces De ASOn| meeee =e ias ; 124-10) oso eee : 
NCidiphospRate yas So skce esc shes ce ccc aus 5.82 16.10 13.50 30.35 6.77 
Sodium phosphates se. osc. se secs cs csceece 4.97 3.30 Su 29.65 6.07 
ESIGTCS APPA Ueeeoes aos eee = occas ol Soci 5. 67 14.15 11.55 31.15 7.57 
ASI Gis lave seer meena sea aes cee on 5. 45 16.50 | 13.90 35. 20 11.62 
PRASICISIAG OC ceo nen eee ane Sees eS 7.79 14.95 12.35 27.80 4.22 
BASICS Og Dar ie noe eas wes Sindee aeec = 6.54 15.35 12.75 33.35 9.77 
Bhreneck phosphates oes a5- cc acsccese eon 7.05 9.85 (lees 24.40 . 82 
Double superphosphate......-...........- 2.24 Veo 15.15 31.70 8.12 
INOINOS PM ale ees ee eS tess cess cen oce esos dead D2 30p |e aaeeceee eos 123205 4| pea seceeneee 
1 Average of two pots. 
In experiment No. 1, where the crop was grown in pots containing 
pure sand to which the same amounts of sodium nitrate, potassium 
sulphate, etc., were added, the water soluble phosphates produced the 
1N. J. Agr. Expt. Sta., 34th Ann. Rept. (1914); 35th Ann, Rept. (1915). 
2N. J. Agr. Expt. Sta., 34th Ann. Rept., 481-484 (1914). 
56841°—Bull. 699 —_18—_6 
