1 90S.] 



Farmyard Manure. 



i73 



The proportion the number of roots on each plot bears 

 to the possible number, as calculated from the width 

 of the rows and the distance apart at which they are singled, 

 for three plots, one of which receives farmyard manure only, 

 one minerals and nitrate of soda, and one minerals, together 

 with an organic source of nitrogen in the shape of rape cake, 

 is as follows (Average of Seven Years, 1901-07) : — - 



Farmyard Manure ... ... ... ... ... ... 70 per cent. 



Minerals and Nitrate of Soda ... ... ... ... 62 



Minerals and Rape cake ... ... ... ... ... 83 



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 (2,000 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 the texture without getting the soil too open, 

 a defect which is now beginning to overtake the plot so con- 

 tinuously treated with large amounts of farmyard manure. 



A soil which has been enriched in humus through repeated 

 applications of farmyard manure will resist drought better 

 than one in which the humus is low ; the difference is seen 

 not so much in the greater amount of moisture present in the 

 soil containing humus as in the way it will absorb a large 

 amount of water temporarily during heavy rainfall and then 

 let it work more slowly down into the soil, thus keeping it 

 longer within reach of the crop. Good examples are afforded 

 by the Rothamsted plots ; samples of soil from the wheat 

 land were taken on 13th September, 1904, on the previous day 

 0*262 in. of rain had fallen, but for nine days before there 

 had been little or no rain. The portions of the plots from 

 which the samples were drawn had been fallowed through 

 the summer so that the drying effect of the crop is eliminated. 

 Samples were also taken from the barley plots on 3rd October 

 of the same year; 0*456 in. of rain had fallen on the 30th 

 September, before which there had been 15 days of fine weather. 

 Table XV shows the water in the soil of the unmanured and 

 the continuously dunged plots respectively, as percentages 

 of the fine earth from which the stones had been sifted. 



