422 BOARD OF AGRICULTURE. [Pub. Doc. 



other families cannot do this, which renders them so much more valu- 

 able than most other crops for cover and green manuring. It is the 

 purpose of this article to consider especially clovers as forage crops. 

 A brief statement of the principal reasons for their great value as 

 such may be useful. 



1. The cost of manures and fertilizers needed to produce them is 

 low. As has just been stated, the clovers under the right conditions 

 take their nitrogen from the air. They draw upon the soil simply for 

 the mineral constituents of plant food, such as lime, phosphoric acid, 

 potash and magnesia. These mineral elements of plant food are rela- 

 tively abundant, and can be purchased at comparatively low prices. 

 Nitrogen, on the other hand, if purchased in the form of either manure 

 or fertilizers, will usually cost from 16 to 18 cents per pound. Phos- 

 phoric acid and potash cost only 3 to 5 cents per pound, the price 

 varying according to the material selected. Lime and magnesia cost 

 still less. The latter, indeed, need seldom be purchased, for it, as well 

 as the other mineral constituents found in plants, is almost invariably 

 sufficiently abundant in all soils. Striking evidence that the manurial 

 cost of producing clovers is low is afforded by the results in one of the 

 fields of the Hatch Experiment Station. A plot in this field was 

 manured annually for fifteen years at the following rates per acre: 

 dissolved bone black, 320 pounds; and muriate of potash, 160 pounds. 

 The crops raised on this field, in the order of their production, were as 

 follows: corn, corn, oats, hay, hay, corn, rye, soy beans, white mus- 

 tard, corn, corn, hay, hay, and corn. The hay crops have consisted 

 in all cases of mixed grass and clovers. During the fifteen years re- 

 ferred to, the entire field has received two applications of lime, at the 

 rate in each case of 1 ton to the acre. The annual cost of the dissolved 

 bone black and muriate of potash applied to this plot has been at the 

 rate of about |5 . 50 per acre, while the cost of the two applications of 

 lime has been sufficient, spread over the fifteen years, to amount to 

 about $1 per acre amiually. The total cost of manuring this land, 

 then, has been at the rate of about $6.50 per acre annually. This 

 plot has invariably produced good crops. Its fertility does not appear 

 to have decreased. In 1902 it produced shelled corn at the rate of 

 56 bushels to the acre. Clover has always predominated in the hay 

 crops. The yield of hay (two crops) in 1901 was at the rate of 3,400 

 pounds to the acre. That portion of this field which has not been 

 manured during the fifteen years will at present yield corn at the rate 

 of about 7 bushels of shelled corn per acre, and hay at the rate of 

 about 600 pounds. 



Some of the fields of the Massachusetts Agricultural College farm 

 are kept permanently in mowing. A number of acres have not been 

 broken up for about twenty-four years. In 1889, when the writer took 

 charge of these fields, they were producing rather light crops of Ken- 

 tucky blue grass, much mixed with the white daisy. For the last few 



