320 SALT, NITRATE OF SODA, SALTS OF AMMONIA, ETC. 



plied was evidently too high, and the excess brought 

 down the crop below that obtained with nitrate of soda 

 alone. 



Upon the more exhausted field in 1858 the crop 

 obtained by guano in corn and especially in straw ex- 

 ceeded all the rest. In the arable soil of this field the 

 amount of nutritive substances was on the whole smaller, 

 and the addition of fresh elements of food made itself 

 felt in a much higher degree than the distribution or 

 dissemination of the substances already present in the 

 soil. Still by the addition of common salt the crop of 

 wheat was also increased. 



The effect of potash upon wheat is as striking as 

 that of soda upon barley. 



As regards the effect of common salt and salts of 

 soda generally, the analysis of the ash of turnips and 

 potatoes, kitchen -garden and meadow plants, shows 

 that, as a rule, the ashes of the former contain a con- 

 siderable quantity of soda, and the ashes of the latter 

 are proportionately rich in chlorides. The grass of a 

 meadow, which has been manured with common salt, 

 is eaten by cattle with greater relish, and preferred to 

 any other, so that even from this point of view com- 

 mon salt deserves attention as a manure. 



As that part of the action of nitrate of soda, sea-salt, 

 and salts of ammonia, which consists in effecting the 

 distribution in the soil of other elements of food, may 

 consequently be replaced by careful tillage, the effect 

 produced upon the crops by these salts affords a pretty 

 safe indication of the condition of a field. If all other 

 circumstances are the same, their effect will be much 

 less marked upon a w^ell tilled field than upon one not 

 in the same condition. 



Gypsum. Among the recent investigations respect- 

 ing the action of gypsum on clover,* those made by Dr. 



* That excellent and most ably conducted agricultural journal, 

 4 Zeitschrift des landwirthschaftlichen Vereins fiir Rhein. Preussen,' con- 

 tains, in Nos. 9 and 10, September and October 1861, p. 352, the follow- 

 ing statement about the remarkable fertility of a field for clover : 



* Twenty-three years ago Farmer Kirfield, of Rhon, in the hundred of 



