No. 4.] MAXrRIAL PROBLKMS. 1«)3 



The potato manure was mixed according to the same for- 

 mula as in the three-year rotation (.see page 157). In the 

 earlier years of the experiment a very large portion of 

 the })otato manure was spread broadcast and harrowed into 

 the soil, but in 1900 for the first time the entire amount 

 was applied in the drill, doubtless with material advantage. 



After the removal of the potato crop the land was limed, 

 but at such a rate that it shall receive in a long series of 

 years the same total amount of actual lime (calcium oxide) 

 per acre as the plots in the three-year rotation. At the out- 

 set lime was not applied in all cases, and a little later some 

 irregularities in its application occurred, which have since 

 been equalized. According to the present plan, each plot is 

 to receive 53(3 pounds of actual Imie (calcium oxide) at each 

 round of the rotation. 



At the time of liming, 3fiO pounds per acre of finely 

 ground steamed bone are sow^n jbroadcast, and winter rye is 

 sown at the rate of 1.34 bushels per acre. The following 

 ]\Iarch or early in April common red clover seed is sown 

 broadcast, preferably on a light snow, at the rate of 15 

 pounds per acre. Later, after the rye has somewhat pro- 

 gressed Avith tillering, a top-dressing of nitrate of soda, at 

 the rate of 120 pounds per acre, was at first applied. This 

 has subsequently been omitted. The clover which follows in 

 the same 3'ear as the rye, and in the following year, received 

 at the outset no manures, but is now top-dressed the last year 

 with 200 pounds per acre of muriate of potash. It is, how- 

 ever, possible, as suggested in connection with the three- 

 year rotation, that an a})i)lication of the double sulfate of 

 potash and magnesia might be employed more advanta- 

 geously than the muriate as a top-dressing for the clover. 



The plots are laid out, introduced into the rotations, 

 manured over the entire two-fifteenth-acre plot, and har- 

 vested in the same manner as described in connection with 

 the previous rotation. The land was of the same general 

 character, but was somewhat poorer in 1892 ; for Indian 

 corn, grown in that year without manure, was not able to 

 form grain, and the total yield per acre of corn stalks, weighed 

 without drying, ranged from 270 pounds per acre on Plot 18 



