490 



Journal of Agricultural Research 



Vol. XV, No. 9 



In Table III appear the results obtained with wheat and red clover 

 recorded as in Table I (see PI. 34). 



Table III. — Results of the growth of wheat and red clover in quartz-sand cultures, with 

 potassium supplied by greensand and greensand marls 



Quartz sand plus iwtassium sources. 



Culture solution (no potassium) . 

 Shive solution complete 



Courtland, Va., greensand: 



I ton per acre-foot 



5 tons per acre-foot .... 



10 tons per acre-foot. . . . 



20 tons per acre-foot .... 



30 tons per acre-foot .... 



Total . 



Pamvmkey Valley, Va., shell marl: 



I ton per acre-foot 



5 tons per acre-foot 



10 tons per acre-foot 



20 tons per acre-foot 



30 tons per acre-foot 



Total . 



Control (no potassium) . . 

 Shive solution complete . 



Red Bank, N. J., greensand, lower layer: 



I ton per acre-foot 



5 tons per acre-foot 



10 tons per acre-foot 



20 tons per acre-foot 



30 tons per acre-foot 



Total . 



Red Bank, N. J., marl, upper layer: 



I ton per acre-foot 



5 tons per acre-foot 



10 tons per acre-foot 



20 tons per acre-foot 



30 tons per acre-foot 



Total. 



Potassium in ' .^^^^ ^ 

 pounds per . . - .'- 



acre. 



O. O 

 103- 7 



433 



866 



1,772 



2, 659 



(air dry). 



Gm. 



o- 75 

 2. 09 



23 

 14 

 40 



3. 20 



30- 5 

 152.5 

 305-0 

 610. o 

 915.0 



^■33 

 1.79 

 1.78 



1-95 

 2. 12 



8.97 



. o 

 103- 7 



126. 6 

 633- o 



1, 266. o 



2, 532- o 



3, 798. o 



112. 3 



561. o 



1,123.0 



2, 246. o 



3. 369- o 



96 



1-59 

 1-95 

 2. 00 

 2. 27 

 2. 02 



10.83 



I. 00 

 I. 62 



1. 96 

 1.89 



2. 07 



8.54 



Red clover 



tops (air 

 dry). 



Gm. 



0.43 

 2. 84 



Dead. 

 Dead. 



•8S 

 .68 

 24 



1.77 



1. 10 



1-37 



2. 05 

 I. 82 

 1.87 



8. 21 



•47 

 1.49 



1. 10 



2. 60 

 I. 90 

 I. 60 

 I- 52 



8. 72 



.82 

 1.36 

 1.87 



1. 67 



2. 10 



82 



The work reported in Table III was carried out in two series, the 

 Courtland greensand and Pamunkey shell marl with their controls, pre- 

 ceding the experiment with the two Red Bank deposits and their con- 

 trols. It is believed, however, that all may be compared, since the 

 surrounding conditions were subject to no significant variation. 



It will be noted that, owing to the widely varying potassium content 

 of these deposits, the same tonnage applied gave widely different quanti- 



