Food for Plants. 



103 



sonably cliarged to season and to the effect of the growth 

 of the first crop. On the iiphmd, which was poor in 

 humus and Nitrogen, the 3'ield of the plot without Nitrate 

 differs but little from that of 1905, while on the lowland, 

 the soil rich in humus, the yield without Nitrate is much 

 loAver than in 1905. On the upland the Nitrogen at the 

 disposal of the plant did not exist in easily changeable 

 forms, and hence was not largely exhausted under the 

 energy of the extra mineral food. Tlie lowland, on the 



1 



J 



Hay Weeds 

 Unfertilized 



Hay Weeds 

 Nitrate of Soda 



Hay Weeds , 

 Sulphate of Ammonia 



Hav Weeds 

 Dried Blood 



Hay Weeds 

 :;Limed 



other hand, doubtless contained considerable Nitrogen 

 in easily changeable forms, which under the influence of 

 the available phosphoric acid and lime was made effec- 

 tive on the grass, and resulted in a comparatively large 

 yield, leaving the soil much poorer in Nitrogen for the 

 next crop. 



It would appear from this reasoning, that the need for 

 applied Nitrogen, while greater for the upland in 1905 

 than in 1906, is not so striking as in the lowland. This 



