58 



CONTROL SERIES No. 54 



Dwarf Essex Rape was the crop grown. Each pot was seeded with three seeds 

 per hill, five hills per pot, the plants later being thinned to one good vigorous plant 

 jier hill or five per pot. The crop was harvested when most of the plants had ap- 

 jjarently reached their maximum growth. The yield from each pot was artificially 

 drietl at a low temperature and analyzed for dry matter and phosphoric acid. 



It was observed at the time of harvesting that some pots had one small and 

 four large plants, others two small and three large, while others had only three or 

 four plants in all. In attempting to interpret the effect of these omissions or 

 differences on the dry matter yields or phosphoric acid recovery, it was noted that 

 as often as not the pots with the smaller number of plants, or with some small and 

 others normal in size, gave the higher yield of both dry matter and phosphoric, 

 acid. The differences due to stand of crop were therefore not considered sig- 

 nificant. 



In the preparation of the soil, fertilizer application, and general care of the ex- 

 periment, including the harvesting of the crop, credit is given to George J. Lar- 

 sinos. Albert F. Spelman and John B. Zielinski, Jr. assisted in the chemical 

 analysis of the phosphates, and H. Robert DeRose assisted in the analysis of the 

 crop. 



Series I. Minimum Phosphoric Acid. 



