MANURES 



111 



Taking the results of the two years together, it is evident that 

 growth-activity, and, consequently, sensitiveness to the evil 

 effects of a surface crop, may practically cease at an early period 

 in the season from mid- June to mid- July and that, whilst the 



FIG. 16. 



periodic rainfall undoubtedly may influence considerably the 

 rate of growth, conditions will often occur, as in 1906, when 

 such influence is inappreciable, the growth in that case having 

 probably been more dependent on the condition of moisture of 

 the soil, than on the fluctuations of the rain falling at the time. 



