CHAPTER IX. 



FERTILITY AND BARRENNESS. 



T7ERTILITY and sterility are relative terms. One soil 



Jr 1 j 



is more fertile than another and one more sterile than 

 another. In nature there is no soil so absolutely barren that 

 no method of draining, irrigation, manuring, or other treat- 

 ment, has resulted in vegetation. Even usar lands of the 

 N. W. P. and Oudh have been made to grow trees and grass- 

 es and superior crops, by a method of enclosing the land, 

 of drainage and irrigation, and of manuring it with cowdung. 

 Drainage and irrigation help the soil to get rid of its 

 excess of efflorescent salts. Hard rock with RO soil on it will, 

 of course, grow no superior plants on it. But even soils which 

 look like pure sand contain enough of plant food to yield 

 crops of indigo, mustard, til and barley, if there is sufficient 

 moisture in them. 



114. Fertility. (i) We have already seen that a fertile 

 soil should contain all the essential ash constituents of plants 

 in a sufficient and available form. But these cannot be readily 

 ascertained. (2) A ten plot or five plot experiment is a practi- 

 cal guide for ascertaining their presence. (3) A still readier 

 method of judging the fertility of soils is the ascertaining of 

 the following facts: ist, Do earthworms and grubs of insects 

 abound to a sufficient depth in the soil? 2ndly, Do plants of 

 various natural orders, including the leguminosae, grow abund- 

 antly and luxuriantly on the soil ? 3rdly, Are the bones of 

 animals habitually living on the soil large-sized? 4thly, Do 

 shells of snails &c., abound in the soil ? A soil which is helpful 

 to the growth of wild vegetation and which is able to support 

 wild animal life in abundance and build the solid parts of 

 their body which are rich in phosphoric acid and lime, must 

 be rich soil. (4) The greater the absorbent co-eficient of a 

 soil the greater is its fertility ; and the larger the proportion 

 of the decomposable silicates present in them, the more fer- 



