1004.] PUBLIC DOCUMENT — Xo. 83. 135 



on those plots where the clover so hirgely predominated. 

 The plots receiving high-grade sulfate of })otash lodged very 

 badly, — more seriously than any other plots in the tield ; 

 and, as bad weather necessitated cutting the crop somewhat 

 late, the vigor of the plants was undoubtedly lowered, as 

 shown by the relatively low yield of rowen on these plots. 

 They without doubt exhibited the highest average develop- 

 ment of clover during the early part of the season, and with 

 a more normal season should have given the heaviest rowen. 



What is true of the high-grade sulfate of potash plots is 

 doubtless also true in somewhat lesser degree of the plots 

 manured with the silicate, carbonate and nitrate. 



The experiment of this year lends additional support to 

 the advice which has previously been given, viz., that " on 

 soils with good retentive qualities sulfate of potash should 

 generally be preferred to muriate or kainite for clovers," in 

 spite of the fact that the total yields, including timothy, are 

 heavier on these plots. 



V. — Comparison of Phosphates ox the Basis of Equal 

 Application of Phosphoric Acid. 



In this experiment, which has now been in progress seven 

 ye,ars, Ave are endeavoring to determine by means of the 

 gi'owing crops the relative availability of a number of differ- 

 ent phosphates. Those under comparison are as follows : 

 apatite. South Carolina rock })hospliate, Florida soft phos- 

 phate, phosphatic slag, Tennessee phosphate, dissolved bone- 

 black, raw bone, dissolved bone, steamed bone, and acid 

 phosphate. 



All phosphates under comparison are used in amounts 

 sufficient to furnish actual phosphoric acid at the rate of 96 

 pounds per acre, and each is applied annually in finely ground 

 form to the same plot. The field contains thirteen plots, 

 of about one-eighth of an acre each. Three of these plots 

 have received no application of phosphoric acid since the 

 beginning of the experiment. One of these is at either end, 

 and the other in the middle, of the field. All plots are sup- 

 plied alike with materials furnishing nitrogen and potash in 

 available forms in liberal amount and in equal quantities to 



