1907.] 



PUBLIC DOCUMENT — No. 33. 



47 



At the end of last year, calculations based in part upon 

 analyses, and in part upon average ligurcvs for the composi- 

 tion of the crops raised, gave results presented in the follow- 

 ing tables for the totals of plant food applied and removed 

 in the several plots : — 



It will be noticed that on plots 1 and 3 the amounts of 

 nitrogen applied in the manure show a moderate excess 

 above the amount removed in the crops. On the other hand, 

 the application of nitrogen to plots 2 and 4 (lesser manure 

 and potash) is materially less than the amount removed. 

 This result may have been rendered possible in one of two 

 ways : first, the soil on these plots may have been depleted in 

 part of its original store of nitrogen ; second, the excess may 

 have been taken from the air by the clover in the mixed hay 

 crops grown during six of the sixteen years. As these plots 

 show no indication of declining fertility, but, on the con- 

 trary, appear on the whole to be improving from year to 

 year, the latter is with little doubt the correct explanation. 



It will be noticed that under both systems of manuring 

 we have applied phosphoric acid and potash in large excess 

 above the amounts removed. In the case of plots 1 and 3, 

 phosphoric acid has been applied in approximately two and 

 one-half times the quantity removed ; potash, in rather less 

 than twice the quantity removed. In the case of plots 2 and 

 4, phosphoric acid has been applied in considerably less than 

 twice the quantities removed ; potash, in rather more than 

 twice the quantities removed. In view of the fact that nei- 

 ther phosphoric acid nor potash is supposed to be lost to the 

 soil to any considerable extent by leaching, the condition 

 of the soil on all the plots as regards the stock of phosphoric 



