296 EXPERIMEXTS OX POTATOES WITH DIFFERENT MANURES. 



action of ammonia has been to raise the quantity of albuminoids, 

 but this influence is counteracted by the addition of potassium 

 manures, and more especially when potashes were employed ; as 

 was the case with starch, so with albuminoids, the action of the 

 three kinds of phosphates has been very dissimilar, and when in 

 one set we find " Cop. Super " (3) with low albuminoids, we 

 find it elsewhere with high albuminoids (2) ; still,' looking at it 

 as a whole, the effects of ammonia and potash are as above 

 stated, the unmanured plot shows the smallest quantity of non- 

 albuminoid nitrogen.* 



As might perhaps be expected, " amides," &c., were present in 

 greatest quantity in these potatoes manured with ammonia 

 (average =0'1 399 per cent. X.), but this quantity was greatly 

 reduced by the addition of potash as kainit (average =0'1212 

 N., plots 3, 8, 13), and it was further reduced when potashes were 

 employed (average= 0-1127 K, plots 33, 38, 43), and the amides 

 were in greater quantity than when " supers " were used alone 

 (average = 0'097 per cent. N.). Probably this figure would have 

 been still lower if there had been no ammonia at all present 

 with the phosphates. If any conclusion may be drawn from B, 

 it is that the non-albuminoid nitrogen has been reduced to a 

 minimum by the iucreased ratio of potash to superphosphate. 



Effect on the Ash. — The influence of the manures on the ash 

 was very indefinite, as the quantity produced by the variation 

 of the phosphate employed was so different. It appears, how- 

 ever, that the highest ash was produced by phosphates and 

 ammonia (average of plots 2, 7, 12 = 1-31), while the addition of 

 potash in any form reduced the quantitv of mineral matter 

 (plots 3, 8, 12 = 0-914, and 33,38,43 = 1-047 per cent.) and when 

 the superphosphate was applied in smaller amounts (plot B), 

 we find 0-561 as the percentage of ash, closely approximating 

 that found in Plots A and 24. Pleischer {Biecl. Centr., 1880), 

 considers that phosphoric acid and kainit increase the ash by 

 100 per cent. ; I have not found so great an increase, but cer- 

 tainly the results obtained by us point in the same direction. 

 "What has been said concerning;- the ash, also holds good concern- 

 ingr the fibre. 



Total Solids. — As regards " total solids," under which heading 

 are included the small percentage of fat, &c., it appears, firstly, 

 that insoluble phosphates have had a depressing influence on the 

 yield of dry matter, but that soluble phosphates have been ad- 

 vantageous, and that as regards their source but little influ- 

 ence is decernible. Taking the average yield of each separate 

 class, we obtain (plots 18,^23, 28) 29*26 per cent. ; (plots 2, 7, 



* The supplementary Plot A shows but a low percentage of albumin, while 

 in B it is found to be high, whereas the "amides" are present in but small 

 amounts. 



