158 MASS. EXPERIMENT STATION BULLETIN 154. 



had an annual application of fine-ground bone meal at the rate 

 of 600 pounds per acre. Throughout this entire period no 

 manure has been applied to the land, and no other fertilizer 

 of any kind with the exception of lime. Hydrated lime at 

 the rate of 2 tons to the acre was applied broadcast upon the 

 rough furrow in April, 1910, and deeply worked in by the use 

 of the disk harrow. 



Two plots in this field were sown to common alfalfa on 

 Aug. 2, 1910. The seed did not germinate well, and the 

 grow^th being too thin the plots were plowed July 12 and 

 reseeded Aug. 5, 1911. One-half of each plot was sown to 

 Grimm alfalfa and one-half to the common northern-grown 

 seed. The yields on the two plots are shown in the table, 

 page 157. It will be noticed that in every case the yield 

 obtained on the sulphate of potash has been materially greater 

 than that obtained on the muriate. The average rates of 

 yield per acre for the two years on the two potash salts have 

 been as follows : — 



Muriate of 

 Potash 



(Tons per 

 Acre). 



Sulphate of 



Potash 



(Tons per 



Acre). 



Grimm alfalfa, 

 Common alfalfa, 



3.734 



2. 886 



4.231 

 3.636 



Whenever the crop is in active growth (and this has been 

 true almost ever since the little seedlings appeared above the 

 surface) there is a striking difference in the shade of green of 

 the foliage on the two potash salts. The leaves on the sulphate 

 of potash plots are of a much darker shade, which would be 

 characterized as dark green. Those on the muriate of potash 

 plots are much lighter. The shade would be characterized 

 as yellowish or pea green. A similar difference in shade of 

 foliage has been noticed in the case of other plants when 

 grown on these potash salts. It is believed that this indicates 

 a difference in character or number of the chlorophyl bodies 

 of the two types of plants, ■ — a difference which we have not, 

 however, been able to demonstrate by scientific tests, but 

 which apparently gives the chlorophyl bodies of the darker 

 green plants a higher degree of functional activity. 



