632 Journal of Agricultural Research voi.xx.No.s 



percentage of total nitrogen, the younger tubers showed a greater content 

 of water-soluble nitrogen than the older tubers. The samples of tubers 

 analyzed in June contained a larger amount of total nitrogen than those 

 analyzed earlier because of the added loss in water and the reduction in 

 sugar and starch of the tubers caused by respiration. 



Ammonia. — The amount of free ammonia in the young sprouts was 

 constant. More ammonia was found in the skins than in the tubers or 

 sprouts. The older tubers apparently contained less ammonia than the 

 younger ones. 



Copper. — All the samples tested showed copper, the sprouts contain- 

 ing somewhat more than the tubers or skin. 



FACTORS WHICH MAY INFLUENCE THE COMPOSITION OF POTATO SPROUTS 



Numerous factors may influence the composition of potato sprouts. 

 Excluding the various physiological and other diseases, a few of these 

 factors may be mentioned briefly. 



Variety. — The analyses indicate that the composition of sprouts of 

 the same age from the three different varieties of tubers examined was 

 uniform. This was true in spite of the fact that the sprouts formed vary- 

 ing percentages of the total moist weight of tubers, skin, and sprouts and 

 contained varying percentages of the total nitrogen, phosphoric acid, 

 and ash. 



Bordeaux spraying. — The results for solids and ash on the Green 

 Mountain sprouts, skins, and tubers from sprayed vines (samples 1,2, 

 and 3) were slightly higher than those on sprouts, skins, and tubers 

 from corresponding unsprayed vines (samples 4, 5, and 6). The distri- 

 bution of the nitrogenous substances showed the same general trend in 

 the two samples. The tubers from both the sprayed and unsprayed 

 plants formed sprouts with equal rapidity, judging by the percentage 

 weights of sprouts and tubers. The sprouts constituted 4.63 and 4.59 

 per cent of the total weight of sprouts, skins, and tubers of the two 

 samples at the time of analysis. The percentages of nitrogen, phos- 

 phoric acid, and a$h removed by the sprouts in the two cases were 

 remarkably uniform. While it is impossible to draw a definite conclu- 

 sion from the analyses of two samples only, the indication from these 

 and other samples is that the percentage of solids and nitrogen is higher 

 in the tubers from sprayed than in those from unsprayed potato vines. 



Soil, climate, and fertilizer. — The potato is no exception to the 

 well-known fact that soil, climate, fertilizer, and other factors often in- 

 fluence the composition of the crop. Calculated to a water-free basis 

 (Table III), the Connecticut tubers and sprouts gave higher results for 

 ash, phosphoric acid, and nitrogen than the other samples, suggesting an 

 influence of soil and climate on the composition of the potato. 



Age and growth. — The age of the sprout apparently influences its 

 composition. A higher percentage of solids and ash was found in the 



