2o8 MOVEMENTS OF SALTS IN THE SOIL 



mined by the kind of manure applied, but in every instance 

 the water collected at the end of the running contains a much 

 larger proportion of chlorides and nitrates than the water 

 collected shortly after the running commenced. 



In Table XXXV we have a selection from the analyses made 

 of the drainage waters furnished by two plots in Broadbalk field 

 during the wet season, 1879. 400 Ib. of ammonium salts per 

 acre, consisting of equal parts chloride and sulphate, had been 

 applied as a top-dressing on March 12; there was thus at 

 first a great supply of soluble chlorides at the surface, while 

 the nitrification of the ammonia afterwards enriched the 

 surface soil with a liberal supply of nitrates. 



The first running of the drain-pipes occurred on April 7. 

 The first collection was made about one hour after the 

 beginning of the running ; the collection of the water was 

 repeated every hour till the running ceased. No rain fell 

 during the collections. With a surface soil rich in soluble 

 salts, the results are quite different from those shown in the 

 previous table ; the earliest collection of water is now much 

 the strongest, and the proportion of chloride and nitrate in the 

 drainage water steadily diminishes to the end of the running. 



The next running took place on April 1 3. It will be noticed 

 that the first collection of drainage water was considerably 

 stronger than the last of the collections on April 7, the water 

 being now again supplied by the upper layer of the soil. The 

 diminution in the strength of the water as the running comes 

 to an end is less marked in the case of the chlorides than on 

 the previous occasion, these salts being now more evenly dis- 

 tributed throughout the soil ; but it is strongly marked in 

 the case of the nitrates, which are still being formed in the 

 surface soil. 



