262 STATE BOARD OF AGKKJULTURE. 



benefit from the use of suit on liis fields. Sandy soils may be greatly benefited 

 by tlie use of salt where heavy clay soils would receive no benefit, but perhaps 

 positive injury. 



At a distance from the sea, on sandy soils, and witli certain kinds of crops, 

 we find that common salt is esteemed as a manure. Where the high price of 

 land demands high farming and abundant manuring, the use of salt is mainly 

 determined by the cost, and a government tax on salt is deplored because it 

 bears oppressively upon agriculture by limiting this use of salt as a manure. 



OVER-PRAISE. 



Like every other really valuable special manure, salt has been over-i)raised 

 and its use recommended without proper discrimination. Like plaster, it has 

 been by some persons recommended as a universal manure, capable of replac- 

 ing all other manures, good for every crop, upon every kind of soil, and in ev- 

 ery season. But the reputation of salt has been injured by such indiscriminate 

 praise, and its use has been restricted rather than extended thereby, because 

 failures are long remembered and more generally made known than successful 

 experiments. 



GENERAL INVESTIGATIONS. 



One reason why salt has received so little notice by writers on theoretical 

 agriculture is in consequence of some extended investigations by German chem- 

 ists into the nature and action of ash-food of plants, in which they have 

 endeavored to ascertain what elements of the ash of plants are "essential'' 

 and what are "accidental." In the ash of all plants grown under agricul- 

 tural conditions we find potash, soda, lime, magnesia, oxide of iron, silica, 

 sulphates, phosphates, and chlorides. Tiie German chemists asked this ques- 

 tion : "Are these materials, each and all, necessary for the growth of the 

 plant, or can plants live and grow in the entire absence of any one of this 

 list?" For the last twenty years very elaborate investigations have been made 

 to answer this question. 



For a long time the fact that any given substance was always found in the 

 ash of a plant was accepted as a proof that it was necessary for the growth of 

 that plant and that it could not live without it. But this did not satisfy the 

 German chemist, who wanted stronger proof than uniform presence, of the 

 absolute necessity of a given material for plant life. 



You will bear in mind the fact that the problems they proposed for solution 

 are very different from those that would attract the attention of the practical 

 farmer. Their investigations had relation solely to the abstract theory of 

 plant life, and the question whether any given substance would increase the 

 production of any crop scarcely attracted their attention. The chemist found 

 a certain list of chemical substances always present in the ash of plants grown 

 under natural conditions, and the question he proposed was this : are all of 

 these substances essential for the life of a plant, or can the plant make com- 

 plete growth {L e., grow from the seed and again ripen seed) in the entire 

 absence of any one of the substances usually found in the ash of plants? When 

 all the physical conditions of plant growth are present, and all tlie ash element 

 except one furnished the young plant, if the exclusion of tliis one element is 

 uniformly attended by an unhealthy condition and ultimate failure of the 

 plant, then such substance is said to be "essential" for the life of the plant. 

 Thus no plant will grow in the entire absence of potash, lime, magnesia, phos- 

 phoric acid and sulphuric acid, and these substances are essential for the plant 



