



United States Department of Agriculture, 



BUREAU OF CHEMISTRY. Circular No. 11. 

 H. W. WILEY, Chief of Bureau. 



PRELIMINARY CROP AND SOIL DATA FOR THE COOPERATIVE STUDY 

 OF AVAILABLE PLANT FOOD. 



The data obtained from the crops which have been grown in the 

 cooperative soil work, as outlined by this Bureau, are compiled in the 

 tables on pages 6 to 9, inclusive. 



The plan was for each station which cooperated in the work to grow 

 the four cereals, oats, barley, rye, and wheat, on adjacent plots 30 feet 

 square. At the juncture of these four plots the sample of soil was 

 taken. This was done by laying off a definite area, 4 square feet, and 

 taking the soil out to successive depths of 9 inches, three depths being 

 taken. These samples of soil were forwarded to the Department of 

 Agriculture. 1 Here control pot experiments were conducted, the oat 

 plant being used, about 25 kilos of the first 9 inches and of the second 

 9 inches being put in separate pots in each case. The soil from the 

 third 9 inches was not seeded. 



Table A shows the data from the plots calculated to pounds per acre. 

 The crops were harvested even with the ground and the grain was not 

 separated. The numbering is the same throughout the tables and cor- 

 responds to the number on the soil samples that were sent out. The 

 blanks indicate that the crops were failures, but pot experiments were 

 conducted on all the soils represented. 



Table B gives the data from the pots on the growth of oats. The 

 pairs of columns in parallel indicate the first 9 inches and correspond- 

 ing second 9 inches of the same soil. The weight of the soil in the 

 pots is given in the first pair of columns, the weight of the total crop 

 in the next pair. In the third pair the crop weight is calculated to 

 parts per 100,000 of the soil, in order that they may be comparable. 

 This is necessary, as the weights of the soil used were not constant. 

 In the fourth pair of columns the figures represent what the yield would 

 have been on an acre in area and to the same depth and under the same 

 conditions as existed in the pot. The other columns represent the 

 amount of plant food that was removed, expressed in parts per million 

 of the soil. 



J The samples were put through a 2 mm. sieve and were very accurately sub- 

 sampled by a sampling machine. A 4-pound sample of each of the first and 

 second 9 inches from every station was sent to each station. Reserve samples 

 are 011 hand and can be supplied when wanted. 



