36 WALL'S MANUAL 



in large excess they become injurious, as, for example, 

 in a marshy, swampy piece of ground. 



Vegetable matter in a state of decomposition is abso- 

 lutely essential to a high degree of fertility. In a soil 

 having the proper mineral elements alone, a plant may 

 come to maturity and bear seed, obtaining the neces- 

 sary organic food from the air, through its leaves and 

 roots; but & full crop cannot be expected in such a 

 case. A soil to be fertile, must contain both vegetable 

 matter and ammonia. 



Let us place side by side the analysis of three soils 

 differing in quality. The first is fertile for all ordinary 

 crops without manure. The reason for this is manfest 

 in the presence of an abandance of those substances 

 found in the ashes of plants. The second is a soil 

 which produces well, with the application of plaster 

 er gypsum, furnishing lime and sulphuric acid, and 

 ashes furnishing potash and lime. The third is a poor 

 soil, requiring much manuring. 



Fertile with 



Fertile. Ashes and Plaster. Infertile. 



Vegetable Matter 10.0() 5.RO 6.00 



Potash 0.40 0.01 (deft) Deficient 



Soda 0.20 0.20 Deficient 



Lime 5.90 0.80 0.50 



Magnesia 0.80 0.70 0.80 



Oxide of Iron 2.10 4.00 8.00 



Alumina or Clay 10.70 . 25.00 25.30 



Phosphate of Lime 0.40 0.20 Deficient 



Sulphuric Acid 0.30 Deficient Deficient 



Carbonic Acid 0.00 0.00 Deficient 



Silica or Sand C3.90 GO.OO 58.00 



Chlorine 0.02 0.07 Deficient 



It will be seen from the above analysis of a fertile 

 soil, that even such a soil may have but a small per 

 centage of several ingredients which are absolutely 

 necessary in the production of every crop. ~No crop, 

 for example, can be produced without potash and 

 phosphate of lime j and yet those form a very small 



