EXPERIMENTS OX POTATOES WITH DIFFEPtEXT MAXUPES, 289 



then shows a great superiority, giving nearly 1^ tons more. This 

 looks as if some form of nitrogen ready for immediate use by the 

 plant were necessary to its early growth, and a more slowly de- 

 composing form of nitrogen were necessary to carry on the later 

 growth. SuljDhate of ammonia is seen throughout to have had a 

 remarkable effect, especially when in conjunction with a soluble 

 phosphate, having increased the crop with bone superphosphates 

 by 3 tons 15 cwts. above bone superphosphates alone, and by 

 2 tons 2 cwts. with coprolite superphosphates above coprolite 

 superphosphates (almost) alone ; whereas with ground coprolites 

 it has only ia creased the crop by 1 ton 2 cwts. above the ground 

 coprolites (almost) alone. 



Table III. speaks for itself, and shows the monetary results. 

 The price of £3 per ton is taken as under the price obtained on 

 the average for Champions in this neighbourhood when taking 

 the large and small together. The diseased potatoes have not 

 been valued, but have been given in for luck to pay for extra 

 expense in sorting the heavier crops. 



At the bottom of the tables, and independent of the experi- 

 ments, the result of 10 tons of farmyard dung is given. It is 

 not an actual part of the experiments, because it was not 

 analysed, and it must only be taken for rough comparison. 



Paet it. 



After the description of the agTicultural portion of the experi- 

 ments, it becomes necessary to describe somewhat fully the 

 chemical results, and to give an account of the materials which 

 brought about those results. 



The following figures represent the composition in parts per 

 100 of a carefully selected sample of the dried soil : — 



Analysis of Soil {calculated on the dry). 



62-00 



