120 The Roihainsted Barley Experiments. 



greater retention of nitrates than would be anticipated con- 

 sidering their solubility, and hence a more lasting effect 

 from previous applications than would otherwise be expected. 

 On the other hand, where, as in the case of the experiments 

 at Rothamsted, nitrate of soda has been used in large 

 quantities so many years in succession, the surface soil has 

 retained so much moisture as to be difficult to work after 

 wet weather. It may be added that the greater liability to 

 loss by drainage of the nitrogen, than of the more important 

 mineral constituents of manure, is doubtless one factor in 

 the explanation of the circumstance of the prevailing excess 

 of available mineral constituents, relatively to available 

 nitrogen, in soils generally, under the ordinary course of 

 agriculture in this country. 



It may be laid down as a general rule, applicable to the 

 country at large,, that, on the heavier soils, full crops of 

 barley of good quality may be grown with great certainty 

 after a preceding corn crop, under the following conditions : 

 The land should be got into good tilth. It should bo 

 ploughed up when dry, as soon as practicable after the 

 removal of the preceding crop. In the spring it should be 

 prepared for sowing by ploughing or scuffling as early in 

 March as possible, if sufficiently dry. The artificial manure 

 employed should contain nitrogen, as ammonia or nitrate (or 

 organic matter), and phosphates. From 401b. to 501b. of 

 ammonia (or its equivalent of nitrogen as nitrate) should be 

 applied per acre. These quantities would be supplied in 

 IJcwt. to 2cwt. of sulphate of ammonia, or Ifcwt. to 2Jcwt. 

 of nitrate of soda. With either of these there should be 

 employed 2cwt. to 3cwt. mineral superphosphate of lime. 

 Rape cake is also a good manure for barley ; from 6cwt. to 

 8cwt. would supply about as much nitrogen as would be 

 equal to from 401b. to 501b. of ammonia. With this manure, 

 as with guano, the addition of superphosphate is unneces- 

 sary. Whatever manure be used, it should be broken up, 

 finely sifted, sown broadcast, and harrowed in with the seed. 



