LIME AND LIMING LAND 83 

 AGRICULTURAL SALT 



The packing houses have large quantities of refuse salt which they are 

 glad to get rid of at a low price, and there is a persistent effort to persuade 

 the farmers that it is valuable as a manure. The editors of agricultural 

 papers are continually applied to by their* readers for information in regard 

 to the value of salt as a manure, and there are some writers who are continu- 

 ally claiming that soda, of which salt is largely composed, can be profitably 

 used as a substitute for potash. Though experiments have continually shown 

 that this is not the case, and that soda cannot take the place of potash, the 

 subject seems to be a perennial one for some. Salt, or chloride of sodium, 

 furnishes in itself no element of plant food essential to vegetation, and what- 

 ever good effect may result from its use is due to its action in aiding the de- 

 composition of organic matter in the soil, "increasing the absorbing power of 

 soils, and, by its reaction with lime, acting as a solvent for phosphate." Prof. 

 Voorhees, in his work on fertilizers, well says, "There would seem to be no 

 good reason for paying from $4 to $6 per ton for this substance, when practi- 

 cally the same effect can be obtained from the salt contained in the crude 

 potash salt, kainit, one-third of the weight of which is common salt. This, 

 too, may be had free of charge, or for the handling, as the market price of 

 the kainit is based upon its content of potash." 



SHELL MARLS. 



The shell marls of the Atlantic coast are almost entirely carbonate of 

 lime, and can be used for about the same purpose as the air slaked lime. 

 Properly used in connection with the culture of legumes, these marls have 

 a value, but it must not be assumed that, like the green sand marl, they will 

 furnish other forms of plant food, and, when applied heavily to soils deficient 

 in humus, their effect may be disastrous to the fertility of the land for a long 

 time. 



TAN BARK ASHES. 



These are another waste product about which inquiries are continually 

 being made. Farmers, knowing the value of hard-wood ashes, are apt to con- 

 clude that the ashes from the spent oak bark will have considerable value. 

 While good hard-wood ashes may contain from 5 to 7 per cent, of potash, the 

 tan bark ashes seldom have over 2 per cent, of potash, associated with a small 

 percentage of phosphoric acid and about 30 per cent, of lime. They are not 



