EXPERIMENT STATION WORK WITH APPLES. 551 



Yellow Fninsparcnt, iiiKl Ilibcnml. It is thought hy the station 

 that, had the cralj been generally nsed lor root i^rafting the apple in 

 the Northwest, the loss from root killing would have been reduced at 

 least one-half. 



Based on the assumption that the roots of trees are as hardy as the 

 tops, it is a frequent practice to plant trees (juite deep in order not 

 only to protect the roots, but also to encourage the scion to send out 

 roots. This is especially desirable when tender stocks are used. 

 Professor Hansen, however, states" that these roots are not hardy 

 against test winters, and in South Dakota no roots from the scions 

 should be permitted. Only Pyru.s haccata stock is perfectly hardy. 

 As an aid to the protection of nursery stock he strongl}' advises water- 

 ing trees in the fall before the ground freezes and then applying a 

 heavy mulch. 



CULTIVATION AND COVER CROPS. 



Of late years the practice has been growing among farmers of giving 

 orchards clean cultivation from early spring until midsunmier, and 

 then seeding down to some croj) that will make a fair growth in the 

 fall and keep the ground protected over winter. The purj)ose of 

 stopping cultivation in midsununer and of putting on the soil a grow- 

 ing crop is to dry out the soil In' evaporation of moisture through the 

 growing plants and thus to ripen up the wood growth of the tree 

 before winter comes on. In addition to this, the cover crop when 

 turned under enriches the soil in hunms and also in nitrogen, should 

 it be a leguminous cro}). It also prevents the .soil from freezing as 

 deeply in winter and keeps it from winter washing. 



That cultivation during part of the season at least rather than crop- 

 ping of orchards is a correct pi-actice is demonstrated by actual trials 

 at a number of experiment staticjns. Measurements of the normal 

 growth of about 600 trees through .several seasons by Prof. J. C. 

 Whitten at the Missouri Station'' showed the average growth of mis- 

 cellaneous varieties of apple trees given clean cultivation until mid- 

 summer, then seeded to a cover crop, to be 13.6 inches, w hile trees in 

 blue-grass pasture made an average growth during the .same period of 

 but 6.2 inches, or less than half the growth of the cultivated trees. 

 In the same ex])eriment trees of the (ienet variety in clover without 

 cultivation made an average growth of 10.2 inches [)er year for 4 

 years. Trees of Ben Davis given clean cultivation throughout Ciich 

 growing .season made an average growth of 21.75 inches per .sea.son, 

 while other trees of the same variety in clover grew but 13.4 inches. 

 It was ob.served in these exi)eriments that the cultivated trees made a 

 more uniform growth than the uncultivated trees and were less atfectcd 



aSouth Dakota Sta. P.ul. ^^^^. f> Mi.s.s«mri .'<ta. Bill. 49. 



