ROOT SYSTEM OF APPLE TREE AND OTHER PLANTS 



1839 



The only disease to which roselle is 

 subject, so far as is known, is a mildew 

 which attacks the plant In the autumn 

 with the approach of cool and damp 

 nights. It is easily controlled by dusting 

 dry sulphur over the plants in the early 

 morning while the dew is still on them. 



Root System of Apple Tree and 

 Other Plants 



The root system of the apple tree is dif- 

 ferent in some respects from other va- 

 rieties of fruit trees, especially peaches, 

 plums and almonds. These latter fruits 

 root near the surface of the ground, ex- 

 tending their roots laterally near the 

 surface, while the apple, especially some 

 varieties, has a central tap root extending 

 deeply into the soil. It is possible there- 

 fore to grow the stone fruits successfully 

 on a soil of less depth than that on 

 which apples could be grown. The root 

 system of the apple is normally as large 

 or nearly as large as the top system and 

 where the soil conditions are favorable 

 extends to very great depth. 



We have seen the peach doing fairly 

 well on a soil where it was only 18 inches 

 to hardpan so solid that no roots could 

 penetrate it. On the same land the apple 

 trees were unhealthy, the tap root mal- 

 formed, sometimes turned upward after 

 having struck the hardpan, and the tree 

 showing every evidence of lack of nour- 

 ishment. 



The fibrous roots are the feeders. The 

 new growth on these fibrous roots is 

 covered with a multiude of minute, uni- 

 cellular projections known as root hairs. 

 These root hairs come into contact with 

 the film of water which envelops the soil 

 particles, and, absorbing this moisture 

 with its contained food, forces it into the 

 root, where under the combined pressure 

 of the multitude of root hairs it is forced 

 upward into the tree. It is therefore 

 important that there be a soil content 

 that furnishes in proper proportions 

 the food best suited to the health 

 of the tree. Sometimes the mistake is 

 made of supposing that because some 

 barnyard manure is good, more is better. 



This is the same as supposing that be- 

 cause the human organism needs some 

 acid as part of the food content that more 

 acid is better and a diet made up prin- 

 cipally of acids is better yet. This would 

 soon bring its results in disease. It is 

 just so with a tree. There are certain sub- 

 stances necessary for its growth, and 

 health, but they must be properly bal- 

 anced. In the arid regions of the North- 

 west most of the soils are rich in min- 

 eral substances, but lack humus. How- 

 ever, it is possible through an attempt to 

 supply humus by the application of barn- 

 yard manure, to injure the tree by the 

 materials which the manure contains if 

 the application is excessive. In some of 

 the volcanic soils of the Pacific Coast 

 states there is a large content of alkali. 

 This substance, in certain proportions, 

 is a fertilizer and is good for the soil, 

 but in larger proportions it destroys the 

 little root hairs that feed the tree. We 

 have discovered that when a tree is dis- 

 eased and the disease is manifest in the 

 top, that much more frequently than we 

 have generally supposed, the trouble or- 

 iginated in the root system on account 

 of some injury, lack of opportunity for 

 root expansion, or soil condition that do 

 not furnish a properly compounded food. 



Distribntion of Feeding Roots of Apples 



This is a question of much interest, both 

 in the application of fertilizers and meth- 

 ods of culture. 



It raises the whole question as to how 

 deeply we should cultivate; or how deeply 

 we can cultivate without injury to the 

 roots. Suppose we put the "breaking 

 plow" into the orchard and turn over the 

 surface soil to a depth of five inches, are 

 we improving or injuring the trees? Sup- 

 pose we put the cultivator into the or- 

 chard and tear up the soil to a depth of 

 three inches, are we improving or injur- 

 ing the roots? 



What is the effect of clover or alfalfa 

 as compared with the breaking up of the 

 surface roots? 



In clean cultivation, do we injure the 

 large roots, so that aphids collect in the 

 wounds, causing galls and other diseases? 



