AMERICAN WHEAT AND CORN. 93 



4. With equal supply of nitrogen very variable amounts of it are 

 found in the total produce per acre of the different plots according to 

 the associated mineral supply. 



5. Of individual ash constituents there was more in the total produce 

 j>er acre with some of the artificial manures than with farm-yard manure. 

 Comparing the plots with equal ammonium-salts, but different potash 

 supply, the amounts of potash in the total produce are in the order of 

 the supply. 



6. Comparing plots 126, 136, 146, and 76, all with the same nitrogen 

 supply, but the first and third with a decreasing residue of potash from 

 previous applications, and the second and fourth with an annual supply 

 of it, the amounts of potash in the total produce per acre per annum over 

 the first ten years are, 45.4, 53.2, 49.8, and 56.0, but the amounts in the 

 grain are 11.4, 11.3, 11.3, and 11.9 ; over the second period, with the 

 further exhaustion on tbe first and third plots (126 and 146), the amounts 

 of potash in the total produce are 37.8, 55.2, 39.1, and 53.0, but the 

 amounts accumulated in the grain are 11.4, 12.2, 11.6, and 12.3. Thus 

 the amounts in the total produce are directly influenced by the supply 

 or exhaustion, especially over the second period ; but over each period 

 the amounts in the grain are neary identical on the four plols, showing 

 only slight relative deficiency over the second period on plots 126 and 

 146, with their reducing residue of potash supply. 



7. The amount of phosphoric acid in the total produce per acre varies 

 much with equal supply of it and of nitrogen, and is obviously much 

 dependent on the available supply of potash. The amounts of mineral 

 constituents accumulated in the total plant (as indicated by the amounts 

 in the total crop) are very directly influenced by the supply or exhaus- 

 tion ; but, other things being equal, the final distribution in the grain is 

 influenced much more by the seed-forming characters of the season than 

 by the amounts of the constituents in the total plant, provided there be 

 xiot a deficiency. 



8. Percentage composition of the ashes. As in the case of the mean re- 

 sults from the ten plots, so in that of each plot (excepting plot 3, with- 

 out manure), there is a higher percentage of potash in the grain ashes 

 of the second period with its better seed-forming and maturing tenden- 

 cies. The percentage of potash in the grain ashes only varies from 31.7 

 to 34.0 over the first, and from 32.1 to 34.1 over the second period; but 

 in the straw ashes it varies from 14.8 to 24.1 over the first, and from 

 14.1 to 25.0 over the second period. The variations in the straw ashes 

 -are consistent with the variations in the supply. 



9. Comparing plots 126, 136, 146, and 76, the percentages of potash 

 in the grain ashes are over the first period 32.8, 32.9, 32.6, and 32.9, and 

 over the second period 33.3, 33.5, 33,1, and 33.4; but in the straw ashes 

 they are over the first period 20.1, 24.1, 22.0, and 23.7, and over the 

 second period, with the increasing exhaustion on the first and third 

 plots, 126 and 146, 17.2, 25.0, 18.5, 24.6. 



