4 1 

 TABLE XIX. 



No NITROGEN. AMMONIA SALTS 



NITRATE OF 

 SODA. 



The increase from the nitrogenous manures, even when 

 applied alone, was considerable, while with minerals in 

 addition heavy crops were obtained. The relative import- 

 ance of superphosphate with the nitrogenous manures, and 

 the small effect from the additional use of potash and other 

 minerals, must be noticed. Thus while superphosphate 

 and either of the nitrogenous manures gave a crop about 

 half as large again as the nitrogenous manure alone, the 

 sulphates of potash, soda, and magnesia yielded with 

 nitrate of soda only f bushel more corn than the nitrate 

 alone, and with ammonia salts 2 bushels more. In the 

 same way, the addition of potash and other minerals to 

 superphosphate and nitrate caused a decrease of -J bushel 

 of corn ; and where the nitrogen was in the form of am- 

 monia salts there was an increase of bushel. This is 

 another instance, though not a very marked one, of the 

 relative importance of potash with ammonia salts, and 

 the slight or even injurious effect of its use with nitrate 

 of soda. 



Passing on to compare the effects of ammonia salts and 

 of nitrate of soda, we see that the latter, whether used by 

 itself or with mineral manures, gave somewhat the higher 

 yield. The higher proportion of straw from nitrate is pro- 

 bably on the whole a disadvantage, as making the crop 

 more likely to be laid an effect more injurious to the 

 value of barley than to that of wheat. 



In the Woburn experiments, the results are similar to 

 those obtained at Rothamsted. It will be remembered, 

 however, that the crops manured with ammonia salts became 

 markedly unhealthy towards the end of the first twenty 

 years of experiment ; owing probably to the continual loss 

 of lime from the soil, occasioned by the use of ammonia 

 salts in considerable quantity year after year. 



One result not shown by the Rothamsted experiments 

 must ,be noticed. On plots at Woburn dressed annually 

 with minerals and in alternate years with nitrogenous 



