32 



The nutritive value of one and the same species or variety of 

 grasses is liable to differ in a more serious degree, ivhen raised under 

 more or less advantageous circumstances, than many of our reputed 

 meadow grasses are represented to differ among themselves, when 

 raised under conditions tvhich favor their successful growth. 



Forage crops, above all other crops, suffer more seriously in re- 

 gard to quality from a scant supply of plant food than any other 

 class of farm crops. Large areas of grass lands are still too 

 frequently treated with all kinds of manurial substances, without 

 any definite idea of what they can or shall accomplish. A short 

 discussion of some of the more prominently mentioned substances 

 frequently used for manurial purposes upon permanent grass lands 

 may illustrate that statement- 

 Common salt is known quite frequently to act beneficially on 

 grass lands ; it acts, however, more decidedly on the physical 

 qualities of the soil than as a direct plant feeder ; it assists in 

 the absorption of moisture from the air and economizes inherent 

 resources of moisture, and is thus apt to act better on dry lands 

 than on moist ones ; it assists in the diffusion of potash and phos- 

 phoric acid, but does not materially benefit the supply of the most 

 essential article of plant food. The beneficial effect usually ceases 

 after a few applications of from four hundred to five hundred 

 pounds per acre ; the lands are more exhausted after its exclusive 

 use as a manure than before. 



Gypsum, or plaster, aids in the absorption of the ammonia com- 

 pounds of the air ; it counteracts the tendency of a clayish soil to 

 become hard and impervious in dry weather ; it assists, like salt, in 

 the general diffusion of potash and phosphoric acid present, by 

 causing favorable transformations of existing compounds, A few 

 repeated applications of from six hundred to seven hundred pounds 

 per acre usually terminate its good services, which are frequently 

 marked rather by a more liberal growth of clover and of leguminous 

 plants in general than by that of grasses. Aside from lime and 

 sulphuric acid, nothing is added to the future fitness of the soil, as 

 far as essential articles of plant food are concerned. Gypsum, 

 as a sole manurial matter used on grass lands, assists in bringing 

 nearer the time of their failure as a remunerative fodder source. 



Air-slacked lime, lime-kiln ashes and various other kinds of lime 

 refuse are noted for their good influence on grass lands ; they 

 assist in producing a favorable decomposition of organic matter 

 by neutralizing accumulated organic acids and securing thereby 

 conditions favorable to the action of a beneficial microbic life in 

 the soil. They aid in the disintegration of potash-containing 

 silicious soil constituents, and render thereby inherent sources of 



