ORG.VMC MATTER IN SOILS. 53 



as}', imi on burning wood or straw, excepting 



th;i > far more of it. 



The ash trora plants, it will be remembered, is but 

 a small proportion of their weight, from one to four- 

 teen lbs. in a hundretl: in soils the incombustible part 

 is usually more than ninety lbs. in a hundred, freauent- 

 ly ninety-five. In some peaty or rich forest lands, 

 indeeii, t" lic part is lan^^est; but, as all know, 



these cui, -ut a small proportion of our ordinary 



•oils. This organic matter was not originally present 

 in the soil: it has all accumulated there by the death 

 and decay of plants and animals. The first soil, 

 formeil by the crumbling and decom(K)sition of the 

 bare rock, must have been entirely destitute of this 

 part Some species of living things, however, existed 

 even there, some forms of vftjetation and of animal 

 life; as these died, th< ; I with the broken down 



rocks, and became fo w plants of higher or- 



ders; thus their remains gradually gathered, until the 

 result was our present surface soils. 



Fertile soils always contain a cxinsiderable propor- 

 tion of this organic matter. There is no rule as to 

 the Quantity that shotdd bo present: we find them very 

 fertile, containing all the way from two to r 



rent, Hnd even upward; though it may be t 



titly rich strong soils seldom contain !• - iiini 

 I to ten per cent 



\\ t ' u there is more than fifty per cent, and the soil 

 16 luoist, an injurious elFecl is prtnluced, the soil be- 

 coming what is called sour : nothing but poor wiry 

 grass will grow. Tli. ^ of and the r. '. r 



this result, will Ik* couv . a subsequent - 



• I h»vi» Mid that th*T« in no rulr aa to thfl pri>cia« quantity of 

 organic matter tha! i>ai?ht to )>.■ loi-.Mit iK.it ■> u.ii.m. ■. <.. 40 or 

 M p*r cent O „f 49 

 per cant teem* y baa 

 4 to 3 per ernl. 1: .,Uly m u> MV 

 laary proportion 



ft* 



