520 



EXPERIMENT STATION EECORD. 



Pot experiments icifh 2)hosphoric acid of (liferent origin. — The com- 

 parative value of superpliospliates, boue meal, and bsisic slag for barley 

 was studied in these experiments. The basal fertilizer consisted of 

 Chile salti)oter and "patent kali-magnesia," with a surface fertilization 

 of 2 gm. of saltpeter, the fertilizers being applied at the rate of 188 

 lbs. of nitrogen, and 182.5 lbs. of potash per acre. Four kinds of bone 

 meal were used in the experiments, viz, (1) sifted raw bone meal; (2) 

 unsifted raw bone meal; (3) partially steamed bone meal extracted 

 with benzin, fine sifted through normal sieve; and (4) same, coarser 

 sifted through a J mm. sieve. 



Cylinders 3.28 ft. deep, 1.8 ft. in diameter, were used for the experi- 

 ments. The soil in the cylinders, prepared from Sj^arts of subsoil and 

 1 part humus soil, was watered from below by means of a tube extend- 

 ing to the bottom of the cylinder and terminating in a pipe 1^ in. in 

 diameter, provided with a number of holes. The pipe was covered with 

 a drainage tile, on the top of which was placed a in. layer of line 

 gravel (5 to 10 mm.) ; then came a 4 in. layer of coarse sand (1 to 2 mm.), 

 above which the experimental soil proper was placed. The subsoil and 

 humus soil used contained the following quantities of fertilizing ingredi- 

 ents: Nitrogen 0.033 and 0.047 per cent, phosphoric acid 0.092 and 0.095 

 per cent, potash 0.064 and 0.005 per cent. 



Barley seed previously sprouted was planted 1 in. deep, and 180 cc. of 

 water added to each cylinder. Three parallel experiments were made 

 in each case. The average yields of barley obtained and the quantities 

 of water required for producing 1 gm. of dry matter in each case are 

 given below. The figures in the last columns are corrected for surface 

 evaporation of water, which, according to Hellriegel, was estimated at 

 15 gm. per square centimeter for the fertilized cylinders during the 

 whole experiment (100 days), and 20 gm. for the unfertilized cylinders. 



EestiUs of pot experiments ivith harley. 



