41 



Experiments were made at Cleghorn and ten other farms in 1893 

 and 1894 on clay loams, and the average per acre of air-dried hay 

 was with 2 cwt. of muriate of potash 27 cwt. 2 qrs. ; with 2 cwt. 

 of muriate and 2 cwt. of superphosphate it was only one quarter 

 more; but if 1 cwt. of nitrate of soda was added, 38 cwt. The 

 use of so much nitrate of soda is, however, not advisable, as the other 

 herbage and grasses may be too much stimulated at the expense of 

 clover (see Plate VI.) At Cleghorn itself the crops were respectively 

 36 cwt., 42 cwt., and 46 cwt., or 6, 12, and 16 cwt. of hay over the 

 unmanured plots, so that the total profit per acre was l/13/, 2/4/, 

 and <3/19/, calculated at 3 per ton. At Rothamsted as soon as 

 potash was withheld from any plot of permanent pasture the 

 produce declined, and in the period of fourteen years, from 1862 

 to 1875, it gave only three-fourths of the amount of total produce 

 recorded from the potash-manured plot. From 1876 to 1892 

 the potash plot still further increased its lead by 50 per cent, more 

 produce. No other mineral substance supplied as manure neither 

 lime, nor phosphoric acid, nor any other exercised such an in- 

 fluence on the yield of hay as potash. Leguminous plants flou 

 rished, and the grasses became denser. 



PLATE VT. 



Experiment on the Feldberge (810 metres above the sea), 

 without a nitrogenous manure. 



Un- manured. Manured with 



Average of 5 years, Thomas Phosphate, 4 cwt. 



1,056 Ibs. per acre. Kainit, 4 cwt. l.ime, 10 cwt. 



Average of 5 years. 

 3,320 Ibs. per acre. 



Dr. G. Smets says in his "Phosphoorzuur in den Landboiiw" 

 that in experimenting with superphosphate and Thomas phosphate 

 he had on moist pastures from Thomas phosphate in three years 

 5,852 Ib. more per acre, and from superphosphate 3,692 Ib. more 

 than from unmanured land. On very dry pastures he had from 

 Thomas phosphate 5,836 Ib. more per acre, and from .superphos- 

 phate 5,128 Ib, more than from unmanured land. He recommends 



