2i8 ^ FARMYARD MANURE [chap. 



been supplied, the tilth is bad, and in trying seasons, 

 when drought succeeds heavy rain soon after sowing, 

 the plant obtained is so imperfect as to reduce the yield 

 considerably. If the conditions are favourable to 

 germination and the plant once becomes established, 

 then, as we have previously seen in Table LXVII., the 

 plot manured with minerals and nitrate of soda will 

 grow a bigger crop than that receiving dung ; but this 

 superiority is masked in many seasons by the defective 

 plant resulting from the bad texture of the soil. Table 

 LXVII I. shows the proportion the number of roots on 

 each plot bears to the possible number, as calculated 



Table LXVII I.— Number of Mangold Plants as Percentages of 

 THE Possible. Average of 7 years, 1901-1907. 



from the width of the rows and the distance apart at 

 which they are singled, for three plots, one of which 

 receives farmyard manure, minerals and nitrate of soda, 

 another only the minerals and nitrate of soda, and the 

 third, minerals and rape cake, as an organic source of 

 nitrogen. 



These are average figures for a period which includes 

 several years when a very good plant was obtained all 

 over the field, and only one of the occasional years 

 when the plant failed entirely on the plots receiving no 

 organic manure. It is noticeable that the plot receiving 

 rape cake (2000 lb. every year) is actually better as 

 regards the number of plants it carries than the dunged 

 plot, because the repeated dressings of an organic 

 manure like rape cake supply enough humus to maintain 



