42 MASSACHUSETTS HORTICULTURAL SOCIETY. 



he can only suggest possibilities. The particular sample of soil 

 Avhich he analyzes may be deficient in certain elements, but a sam- 

 ple two rods distant may tell an entirely different story. Again, 

 the chemist is unable to tell how much of the plant food present 

 is available to the plant; differences of mechanical conditions 

 having an important influence in this respect. Even the poorest 

 soils, as pointed out by Roberts,* have an abundance of food for 

 several crops, while the richer ones may have enough for several 

 hundred. By the action of the acids present in the roots of growing 

 plants, and by exposure to the open air, due to tillage, this natural 

 supply of food is gradually made available. Frequently, however, 

 the amount available at any one time is not sufficient to produce 

 satisfactory returns; hence the necessity of an artificial supply, 

 in other words, fertilizer. 



The Need of Lime. 



For more than two thousand years, lime, in some form, has 

 been employed for agricultural purposes. Its effect upon plant 

 life is not as a direct fertilizer, but as an agent for neutralizing 

 an acid condition of the soil, which is unfavorable to plant growth, 

 and liberating plant food which may be in an available form. 

 In New York, Pennsylvania, and especially in Rhode Island, 

 liming is practiced extensively and with very favorable results. 



The need of lime on upland soils is often indicated by a growth 

 of sorrel and by the failure of grass, clover, root crops, etc. to make 

 a satisfactory growth, even when well tilled, properly drained, 

 and thoroughly enriched. A simple chemical test may also be 

 TQade by placing a piece of blue litmus paper, which may be ob- 

 tained at any drug store, in contact with a little moistened soil 

 from the field. If the soil is in an acid condition, the blue paper 

 will become red. 



Lime, when added to the soil, unites with the acid substances 

 tending to neutralize or "sweeten" the soil. It also acts upon 

 potash compounds in such a way that lime takes the place of the 

 potash, setting the latter free for the use of the plants. It favors 



* Roberts, Fertility of the land. 



