Chapter II 

 TIIK TKXTl'KK AND STinCTlK'K OF TIIK SOIL 



1. W'littt Is Meant by 'I'f.iiKre 



4I>. \\'»' ljav«' scrii tliat tlic olliccs of tlif soil 

 art' of two general kiii<ls, — it atYoi'ds a piiysiral 

 iiitHlium in wliieli the jilant can <xro\v (41), and 

 it sh|)|»lies materials that the ]>lant uses in 

 th»' hiiilding of its tissues (4'J). it cannot Ite 

 said that one of these olliccs is more imjtortant 

 than the other, since hoth arc essential; hut 

 attenti«)n lias been so loni^ lixcd upon the mere 

 content of soils that it is im])ortant to eiiijiha- 

 size the physical uttrihutes. Crops cannot j^row 

 on a rock, no matter how nui<-ii j»lant-food it 

 may contain. The passing of nx'k into soil 

 is a matter of change in textui'c and structure 

 more than in plant-food. Textuie refers to the 

 size of th«» j)articles ; structure to the ariaiiL-'c- 

 ment of the particles. 



50. The physical state of the soil may he 

 spoken of as its structure, much as we speak of 

 the stru«*tnre of a house of hrick or stone. The 

 common adjectives that are applied to the condi- 

 tion of agricultural soils are descriptions of its 



(37) 



