BROADBALK FIELD DlJAlNAdi: W ATFKS -j?,:) 



tliroiigh into the drain is vciv low, ^o iIk.iou'jIiIv liavc ihc 

 nitrates been removed l)y tlic m'owinu croj). From Srjitcnil.fr 

 onwards, however, to FrFmarv, the (•(.iiccntratioii ..I" tlir \\;itcr 

 is comparatively high, and as tlie (h-ains Ix-gin to lun tncly 

 (hu'ing this period wlicn tlie crop is ofV tlic i^rouiid. mrat I<»»(v 

 of nitrate are Hkely to occnr. Nilrifuatioii goes on thronghont 

 the winter; even in years when the rainfall of the early antinini 

 is so excessive as to wash the soil clean ol'all nitivitcs pi-oduccd 

 (luring the first nitrification following t lie icnioval of the cinp. 

 yet fresh nitrates are still produced in considerahle (inantily, 

 and find their way into the drains in Deceml>er and January. 

 Nothing, in fact, short of the absolute freezing of the ground 

 stops the production of nitrate and its consequent loss when 

 ever the rainfall is heavy enough to wash through into tin- 

 subsoil. 



If the results obtained on the drainage water fioni the 

 manured plots be examined, it will be seen that nitrification 

 of manures like ammonium-salts is extremely rapid ; if there is 

 Any percolation, nitrates begin to appear in the drainage water 

 immediately after the application of the mamu'e. Even in 

 autunm an application of anunonium-salts is converted into 

 nitrate in a very short time, a.s may be seen from the followinu' 

 series of analyses of the water running from tln^ drain below Plot 

 1.'), in October 1880. 



On October 25th of that year, mixed anunonium-salts citn- 

 taining 86 lb. of nitrogen and 110 lb. of chlorine per acre 

 were applied to Plot 1 ') and plougluMl in. Heavy rain followed, 

 so that on October 27th the drain l)eneath the pl(»t was 

 running; other rain fell at short intervals, and yielded ilie 

 series of samples set out in the table. It uill be noticed 

 tliat in the first runnings, taken within forty iiours of tin- 

 application of the manure, some anunonia was to be found. 

 Tliis is a very exceptional oecuri-ence, but the large excess in 

 which the chlorine was present in the w, iter show e.l th.it ilie 

 decomposition of the annnonium chloride and retention ot 

 the anunonia by the soil had progressed considerably. 



