RESIDUES OF NITKOGENOUS MAM IM.S I'-r 



acre; the four ])lot.s wliicli liad nM-civcl niii-om'u as riilici 

 nitrate of soda or aininoiiiiiiH-salts pi\(> soiin-wliat less. Imi 

 still over 60 bushels ; wliilo tlie tnui" plots witliont niii()u'<'ii in 



Table LXXX. — Total proiucd witliout Mnnnrc, folloxpiiuj l'otitto>s 

 mamLred for 26 years. 



Lb. per acn». 



Manure applieil to the Potatoes, ijTu-ljnl. 



1902. 



Unmanured | 3602 



Unmanured, 1882 and since, pre\nously Dung . i 3804 



Dung alone, 188.". and since 9024 



Dung alone, 1883 and since I 9072 



S<o lb. N. as Ammonium-salts . . . . i 6981 



86 lb. N. as .Sodium Nitrate j 7692 



86 lb. N. as Ammonium-salts -Minerals . . ' 7792 



86 lb. N. as Sodium Nitrate -r Minerals . . .1 82.->3 



Superphosphate only 3720 



Complete Minerals 2953 



lUrky. 



previous years gave between 25 and 35 Itiisliels. In thi- 

 following season these differences were still to be seen, and the 

 leading position of the previously dunged plots was naturally 

 more manifest than ever; while in the third season (oats) aftci- 

 the manuring had been discontinued, the order of the plots 

 remained the same, although only the dunged plots now grew 

 a large crop. 



That the increase on the plots which had previously 

 received nitrate of soda or ammonium-salts was due to 

 crop residues rather than to the return of nitr.ites diri\<'d 

 from the manure and stored in the .subsoil, is probable from 

 the superiority of the crops on Plots 7 and 8, wliere iniiici-als 

 liad accompanied the nitrogenous manure-s over Plots 5 aii«l 

 6, where the same nitrogenous manures had been used alone. 

 When residues are being cropped out, the size of the cereal 

 crop grown is almost wholly determine<l l»y thr availablr 

 nitrogenous supply, and Plots 7 and 8, which foiinerly grew the 

 larger crops of potatoes, give better yieMs than Plots 5 and «). 

 <ilthough they had initially the same .supjily nf niticjcn 



On 



