27 



article to consider especially clovers as forage crops. A brief statement 

 of the jjrinripal 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 tlraw upon the soil simply for the mineral 

 constituents of plant food, such as lime, i)hosphoric acid, potash and 

 magnesia. These mineral elements of plant food are relatively abun- 

 dant and can be purchased at comparatively low prices. Nitrogen, on 

 the other hand, if purchased in the form of either manufe or fertilizers, 

 will usually cost from 16 to 18 cents per pound. Phosphoric 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, in- 

 deed, need seldom be purchased, for it as well as the other mineral con- 

 stituents found in plants is almost invariably sufficiently abundant in all 

 soils. Striking evidence that tlfe manurial cost of producing clovers 

 is low is afforded by the results in one of the fields of the Hatch Ex- 

 periment 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 mustard, corn, corn, hay, hay, and 

 corn. The hay crops have consisted in all cases of mixed grass and 

 clovers. During the fifteen years referred to, the entire field has re- 

 ceived two applications of lime, at the rate in each case of 1 ton to the 

 acre. The annual cost of the dissolved boneblack and muriate of potash 

 applied to this plot has been at the rate of about So. 50 per acre, while 

 the cost of the two applications of lime has been sufficient, spread over 

 the fifteen years, to amount to about SI per acre annually. The total 

 cost of manuring this land, then, has been at the rate of about SO.oO 

 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 pre- 

 dominated 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 kei)t j)ermanently 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 crojjs of Ken- 

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

 years these fields have been subdivided into plots, and various combi- 

 nations of fertilizers employed. To a considerable area, the annual 

 application per acre is at the rate of basic slag meal 500 pounds, and a 

 potash salt sufficient to furnish 75 pounds of actual potash per acre. 

 The areas thus manured have steadily improved unflcr the treatment 

 received. At the start there was but little clover. Under the system 

 of fertilizing followed, the pr()[)ortion of clover has steadily increased. 

 The daisi(!S have almost entirely disaj)po;ired, while the grass as well 

 as the clovers, though in less degree, has improved. The annual cost 

 of the fertilizers used amounts to about S7 per acre. The soil of these 

 fields is natural grass land and is fjuite well adapted for clovers as well. 

 The product under this sy.stem of manuring ranges from about 2 to 

 '2k tons per acre in two crops. Dining the present sea.son these fields 

 have given one of the best as well as one of the heaviest crops produced 

 since 1889. 



