176 HOW CROPS GROW. 



d. The soil, or the supplies of food, manures included, 

 have the greatest influence in varying the proportions of 

 the ash -ingredients of the plant. It is to a considerable 

 degree the character of the soil which determines the 

 vigor of the plant and the relative development of its 

 parts. This condition, then, to a certain extent, in- 

 cludes those already noticed. 



It is well known that oats have a great range of weight 

 per bushel, being nearly twice as heavy, when grown on 

 rich land, as when gathered from a sandy, inferior soil. 

 According to the agricultural statistics of Scotland, for 

 the year 1857 (Trans. Highland and Ag. Soc., 1857-9, 

 p. 213), the bushel of oats produced in some districts 

 weighed 44 pounds per bushel, while in other districts it 

 was as low as 35 pounds, and in one instance but 24 

 pounds per bushel. Light oats have a thick and bulky 

 husk, and an ash-analysis gives a result quite unlike that 

 of good oats. Herapath (Jour. Roy. Ag. Society, XI, 

 p. 107) has published analyses of light oats from sandy 

 soil, the yield being six bushels per acre, and of heavy 

 oats from the same soil, after "warping,"* where the 

 produce was 64 bushels per acre. Some of his results, 

 per cent, are as follows : 



Light oats. Heavy oats. 



Potash 9.8 13.1 



Soda 4.6 7.2 



Lime 6.8 4.2 



Phosphoric acid 9.7 17.6 



Silica 56.5 45.6 



Wolff (Jour, fiir Prakt. Chem., 52, p, 103) has anal- 

 ysed the ashes of several plants, cultivated in a poor soil, 

 with the addition of various mineral fertilizers. The in- 

 fluence of the added substances on the composition of the 

 plant is very striking. The following figures comprise 

 his results on the ash of buckwheat straw, which grew 



Thickly covering with sediment from muddy tide-water. 



