EXrERIMENT STATION WORK WITH APPLES. 



559 



of j^rain per acre extracts from the soil 6.5 pounds potash, 12.4 pounds 

 phosphates, and 25 pounds nitrogen. If the straw be added the total 

 amount of these elements removed is 82 pounds potash. 20 pounds 

 j)ho.>^phates. and 85 pounds nitrogen per acre. 



A consideration of all these data indicates that the annual diaft of a 

 bearing orchard on soil fertility is fully as great as the annual draft of 

 a good crop of wheat and hence, if it be nece.ssar}^ to fertilize for wheat, 

 itisjustas essential to fertilize for apples. Robertsal.so analyzed thrifty 

 young apple trees from the nursery, and from the data obtained esti- 

 mated that an acre of nur.se ry apple stock 83'ears old would remove from 

 the .soil about 2i) i)ounds nitrogen, 10 pounds phosphoric acid, and 20 

 pounds potash. Tliese are nmch smaller amounts of fiM-tilizing ele- 

 ments than would be removed l)y a good crop of wheat in a single 

 year. Similai* analyses at the New York State Station" showed nurs- 

 ery stock to be nnich less exhaustive on the soil than a crop of grain. 

 The usual failure to raise nursery stock with success continuously on 

 the same land is believed to be due to the fact that the readily available 

 fertilizing materials have been exhausted in the rapid growth of the 

 stock and to the fact that the ground is not alwa3^s cultivated when it 

 is in the best condition. 



At the Iowa Station '' apple twigs of hard}" and tender varieties were 

 analyzed to determine* whether there exists in midwinter a character- 

 istic difference in the composition of the new growths. The same 

 twigs were also studied micro.scopically. While some difl'erences were 

 found no definite conclusions could be drawn from the work. 



In a study of the moisture content of the twigs of different varieties 

 of apples Shutf found that there was a ''distinct relationship between 

 the moisture content of the twig and its power to resist the action of 

 frost, and that those trees who.se new growth contains the largest 

 percentage of water as winter approaches are in all probability most 

 tcndcM'." 



The Missouri Station'' al.so made an examination of aj)i)l(' twigs, 

 analvs<'s bcinjr made of the ash of water si)routs and the bearino' twiu's. 

 Striking differences were found, as is shown in the following table: 



Compusitifm of the (ixh of vater sj>rontK a nd fruit firiffs. 



Wator sproiit.s 

 Fniit twigs . . . 



aNew York .SUiti- Sta. Tlpt. 1892, ]>. 173. 

 ''Iowa Sta. Bui. 4. 



cTrauH. Roy. Soc-. Canada, S. ser., 5» (1903), Set-. IV, \k 149. 

 t'Mis.MoMri Sta. Rpt. 1898, j.. 77. 



Phosphoric 

 acid. 



J'tr rrnl. 

 0.2916 

 .4651 



