24 



BULLETIN 42, U. S. DEPARTMENT OF AGRICULTURE. 



There was a decrease in the yield in the manganese plot in every 

 year except 1909. In 1909 there was an increase of 40 bushels. In 

 1907 there was a decrease of 69 bushels, in 1908 a decrease of 40 

 bushels, in 1910 a decrease of 51 bushels, in 1911 a decrease of 91 

 bushels, and in 1912 a decrease of 24 bushels per acre. 



ACIDITY OF THE SOIL IN THE VARIOUS PLOTS. 



Acidity tests of the various plots used in this experiment were 

 made in May, 1912, after the experiment had been in progress for 

 five years. All of the plots, both treated and untreated for each 

 crop, were acid. Samples were taken of each plot and lime require- 

 ment determinations made. 



The sampling was done with a soil auger to a depth of 6 inches. 

 Five borings were made in each plot and a composite sample made 

 from the individual borings. The determinations were made on air- 

 dry soil. 



The lime requirement determinations were made by means of the 

 Veitch method. 1 Table XVI shows the amount of lime required 

 according to this method for each plot to produce a neutral condition 

 in the soil. The soil in each plot required approximately a ton of 

 lime per acre. Where wheat was grown the manganese and the 

 untreated plots were equally acid. In the rye, corn, and cowpea 

 plots the manganese plots had a higher lime requirement than the 

 untreated plots. With rye the manganese plot required 2,492 

 pounds of lime and the untreated 2,136 pounds per acre. With corn 

 the manganese plot required 2,492 pounds and the untreated 1,780 

 pounds. With cowpeas the manganese plot required 2,492 pounds 

 and the untreated 2,136 pounds per acre. Where potatoes were grown 

 the untreated plot had a greater lime requirement than the manganese 

 plot. The manganese plot required 2,451 pounds of lime per acre 

 and the untreated plot 2,743 pounds. 



Table XVI. — Showing the pounds of lime (CaC0 3 ) required per acre in the various plots. 



Wheat. 



Rye. 



Corn, 



Cowpeas. 



Potatoes. 



Manganese plot. 

 Untreated plot. 



Pounds. 

 1,780 

 1,780 



Pounds. 

 2,492 

 2,136 



Pounds. 

 2,492 

 1,780 



Pounds. 

 2,492 

 2,136 



Pounds. 

 2,451 

 2,743 



The results of these determinations show that the soil is an acid 

 one and that the manganese tests were made under acid conditions. 

 The results obtained on this soil are supported by the statements of 

 other investigators, that the best effects of manganese can not be 

 secured under acid conditions. 



i Jour. Amer. Chem. Soc, 24, 1120 (1902); 26, 637 (1904). 



