586 Report of the Department of Horticulture of the 



Table VI. — ■ Comparative Weights of Grape Leaves in Fertilizer Experiments. 



Note. — 300 leaves are considered in each determination, 5 being taken from each 

 of 60 vines. The first leaf beyond the last cluster is taken. 



It seems reasonable to suppose that differences in foliage existed 

 before they were discernible to the eye and an examination of 

 Table VI indicates that such was the case. This table gives leaf 

 weights, green and dry, of 300 leaves from each plat. These were 

 taken from 60 vines. The first leaf beyond the last cluster was 

 selected from each of five canes, which were located at about the 

 same level for all vines. Owing to other demands at the time only 

 one-half of the plats were calculated in 1911 but the records are 

 complete for 1912 and 1913. Shortly after the leaves were gathered 

 they were weighed. They were then air-dried and reweighed. From 

 this data, it would appear that nitrogen is increasing the size of the 

 leaf. 



ANNUAL WOOD GROWTH. 



There were no indications either, in 1909, 1910 or 1911, that 

 fertilizers were producing any increases, apparent to the eye at 

 least, in wood growth. In the fall of 1911, as fast as the plats 

 were pruned, the wood was stripped from the wires, taken to the 

 end of the rows and weighed. The weights included the weights 

 of the canes put up for the year previous in each instance. Owing 

 to unfavorable weather but six plats were weighed at this time. 



