132 HATCH EXPERIMENT STATION. [Jan. 



which has been previously given, viz., that the sulfate should 

 gxuierally be preferred for the early crops and the muriate for 

 the late on all soils with a fair capacity to retain moisture. 



IV. — Comparison of Diffeeent Potash Salts for 

 Field Crops. (Field G.) 



The experiment for comparison of different potash salts 

 was begun in 1898. The field contains forty plots, of about 

 one-fortieth of an acre each. The plots are fertilized in five 

 series of eight plots each, each series including a no-potash 

 plot and one plot for each of the potash salts under compari- 

 son. Those salts are kainite, high-grade sulfate, low-grade 

 sulfate, muriate, nitrate, carbonate and silicate. Each is 

 ap})lied annually to the same plot, and all are used in such 

 amounts as to furnish equal potash to each plot. In the 

 quantities employed the different salts supph^ annuall}^ 

 actual potash at the rate of K),") pounds per acre. All plots 

 arc equally manured with materials furnishing fiiirly liberal 

 amounts of nitrogen and phosphoric acid. The crop of the 

 past season was mixed clover and timothy. This is the sec- 

 ond year that this crop has occupied the land. The table 

 which follows, showing yields, does not (|uite accurately 

 show the effect of the fertilizers. It was out of the question 

 to separate weeds and grasses from the clover in an experi- 

 ment conducted on the si'ale of this. Most careful exami- 

 nation often repeated during the season made the following 

 points self-evident : — 



1. That on the no-potash plots the clover was \'ery thin, 

 but the weeds of various kinds were relatively abundant. 



2. That on the plots to which kainite was applied the 

 clover was weaker than on any of the other plots receiving 

 ])otash. The timothy, on the other hand, was more abun- 

 dant and apparentl}' more vigorous on the kainite plots than 

 on the others. 



3. On the muriate of potash plots the clover was inferior 

 to all other plots receiving potash except the kainite, and 

 here also timothy was relatively abundant and vigorous. 



4. The clover on the low-grade sulfate of potash plots was 

 distiiicllv inferior to that on the hiah-ijrade sulfate. 



