j.hciic acid was made and pctashjr.creased, k the yield was' some- 

 what increased. 



Plot 9 is comparable wan group (e), the object was to. de- 

 crease the niticgen and inciease the potash ; tnis change caused 

 a very decided loss. 



'iaking these plots together we may fairly infer that 7.2 per 

 cent ol phosphoric acid is ample for the soil under considera- 

 tion ; thai 20.4 per cent ol potash is belter than 7, and that 0.7 

 per cent of nitrogen is not enough. 



'Ihere is other evidence that shows that some nitrogen is 

 needed. 



Now, if we remember, that plots 10 and 13 should, without 

 doubt, have averaged more than 210 bushels, we shall see that 

 the substitution of phosphoric acid in plot 3 lor all of the nitro- 

 gen in 10 and 13 lesuhed in loss, and exchanging the greater 

 part of the nitrogen for potash (see Plot 9), also resulted in loss, 

 we must conclude, therefore, that from one to three per cent of 

 niticgen is neeced en soils where potatoes are the hist ciop in 

 a rotation, but had corn or any crop which had leceived manure 

 or a nitrogenous fertilizer pieceded this potato crop it is very 

 likely true that nitrogen would not have been needed. 



(Series 4). prepared fertilizers. 



This series, made up of Plots 7, 8 and 14, were designed to 

 test the relative merit ol $10. co wonh ol plant lood in the best 

 mixea goods, and $10.00 worth in chemicals. 



No. 7, with 26 lbs. of Stockbridge potato fertilizer, yielded 

 194 bushels. 



No. 8, with 26 lbs.^of Bradley's XL fertilizer, yielded 150 

 bushels. 



No. 14, with 28 lbs. of Bowker's Hill and Drill fertilizer, 

 yielded 190 bushels. 



r l he lollowing represents average analyses of these fertili- 

 zers : 



10 



