129 



ill whicli the ])cr cent oh' nit ro^'cn. |)li()S|)li()ric acid, and potash in the 

 fertilizers and the rehitive i)er cent ol' herd's-orass, clover, and ivd- 

 top in the hay ai'e stated for each phit. The followino- illustrations 

 are taken from this tal)le: 



Composition of fertilizer. 



Relative amounts of hay. 



Nitrogen. Phosphoric acid. 



Potash. 



Clover. 



Herd's-grass. 



Redtop. 



Those results are 'similar to those obtained in the well-known ex- 

 periments of Lawes and (xilbert in England. The development of 

 clover where mineral fertilizers, especially those containing potash, 

 were used, coupled with the fact, which may l)e regarded as pretty 

 well established, that leguminous plants obtain nitrogen from the air, 

 makes the use of such fertilizers a very inii)ortant matter in regions 

 like this. 



The I)ulletin also contains a number of formulas for mixtures of 

 dissolved bone-black, muriate of potash, and sulphate of ammonia, 

 which have been tested and found well adapted to soils in Xew Hamp- 

 shire. It should, however, be remembered that the results of hun- 

 dreds of exi>eriments show that such formulas should be used with 

 great caution, since the needs of particidar soils vary greatly. 



Praefical eonelvsions. — The following are among the practical 

 inferences drawn from the exjjeriments reported in this bulletin : 



(1) So far as results have been obtained we are justified in saying 

 that chemicals riglitly proportioned can be used as a complete sub- 

 stitute for farm-yard manure; that they will produce as great a 

 value of crop, dollar for <lollar. as manure; and that they improve 

 the (|uality of the hay by iuci'easing the clover, and, indirectly, the 

 supply of available nitrogen. 



(2) Farmers are advised to buy dissolved Ijone-black, containing 

 1C5 per cent of solul)le phosphoric acid; muriate of potash, containing 

 50 per cent of actual potash ; and sulphate of ammonia, containing 20 

 per cent of nitrogen: and from these crude materials to mix such 

 combinations as are best suited to the soil and crops under cultivation. 



(3) Every farmer can experiment for himself if he buys his defi- 

 cient plant food in these separate substances for he is at liberty to 

 mix them in any proportion that he pleases, and in time it would be 

 possible for each farmer to sui)ply those elt^ments which the soil most 

 needs, and to withhold those not specially required. 



