A VISIT TO ItOTHAMSTKI). 251 



indeed there seldom is in soils which have Iteeii rej^ularly 

 iiuiuured with farmyard manure in ordinary rotations as this 

 lield was l)et'ore it was used for the present experiment. 



The plots of series AA tell tlie same story as those of A, and 

 tlie evenness of the results oljtained in the various sei-ies shews 

 that the land was uniform and well adapted for experimenting-, 

 and it also shews that the manuring has been performed with 

 great care, so as to bring out results which may be fully relied 

 u[)on. 



The 275 lbs. of nitrate of soda are given as equivalent to 200 

 ]1)S. of ammonia salts, and it will be noticed here as in the grass 

 experiments that nitrate of soda compares favourably with 

 ammonia salts as a nitrogenous manure. 



The appearances presented by the various jilots at the time of 

 our visit were very characteristic. The unmanured plot was 

 certainly the poorest, and consisted of dwarf pale coloured corn, 

 with no tendency towards tillering. The heads were small and 

 meaure, the straw thin and short, and the lower leaves so mucli 

 shrivelled that tlie ground was not hidden. All the plots in O 

 where ammonia was absent were starved looking, and the lower 

 lea\'es and lower part of the stem were of a sickly yellow colour, 

 shewing that the nutritive matter there had been reabsorbed by 

 the plant and carried up to assist in the formation of the head. 



In series A, plot 1 w^as of a dark green colour, somewhat short 

 in the straw, l)ut leafy, on plot 3 these characters were not so 

 well marked, wliile plot 2 and 4 seemed equally good. 



Farmyard manure, as shewn by plot 7 (2), has proved a very 

 efficient manure, capable not only of maintaining but of increas- 

 ing the fertility of the soil when applietl at the rate of 14 tons 

 per acre annually. It ought to be noticed, however, that 14 tons 

 per acre of farmyard manure per annum is a very liberal applica- 

 tion, adding to the soil an amount of dry matter far in excess of 

 that taken off the land in the crop. The most important item 

 ( »f that excess as affecting the increase of crop being the nitrogen 

 which is present in good farmyard manure in very large amount, 

 and these 14 tons might easily contain perhaps three or four 

 times as nnich nitrogen as was applied to any of the other plot^. 

 Considering this, it may seem surprising that the result was not 

 more marked, and the explanation which suggests itself is that 

 the nitrogenous matter in farmyard manure is only slowly de- 

 composed, and thus only a part of it is rendered available for 

 the use of the plant during the short period of its growth. 

 During the long periods intervening between the successive 

 crops, the process of decomposition still goes on, and if the soil 

 were able to retam in its upper layer the products of that decom- 

 position we should expect to find in sjning an increase of growth 

 of the young plant proportionate to the amount of nitrogenous 



