74 



get the poorest results that we can get anywhere. But where we 

 keep the grass growth down with mulch without any cultivation, 

 we get the excellent results you see here. 



This and other similar results raise the question as to whether 

 we have not over-emphasized the necessity of stirring the soil about 

 the roots of trees. The natural condition for tree growth is with 

 an undisturbed root system, and it is a question whether the tillage 

 of trees has not been over emphasized, especially so far as it applies 

 to apple trees. 



Question. Does that hold good in peaches? 



Dr. Stewart. I would not want to say, because our opinion is 

 that the peach needs tillage much more than the apple, and until we 

 get some definite basis for changing that opinion we will let it stay 

 as it is. I should not be surprised, however, in view of these results, 

 that a person could also develop a very satisfactory system of 

 mulching and fertilization for peaches as well as for apples. 



While we are on this question of young orchards and cover 

 crops, I want to call your attention to some of the figures we have 

 here. We have tried thirteen different cover crops with the results 

 indicated on the chart. Notice the best of these has been alfalfa, 

 when used as a permanent cover and a mulch. We do not let the 

 alfalfa grow over the tree roots, however. You see the percent, of 

 gain is 206. The next best is vetch which has 160%. The third 

 in value to the trees is crimson clover ; fourth is rape, which we have 

 recently changed to a combination of rape and cow-horn turnips. 

 Then comes millet. Millet, I am inclined to think, has a lot of virtue 

 as a cover crop that it has not been fully credited with. Some of 

 these others, soy beans, etc., are far down in the list. 



Of course we can't guarantee that this will happen everywhere, 

 but that is what is happening in our experiment at the Station. 

 We are getting very good crops of the beans and also of cowpeas 

 and other annals, but the trees are not showing any particular 

 benefit from these crops, and the fact that the crops themselves are 

 so good may help to explain what has checked the growth of the 

 trees. 



Vetch comes out just as expected. It is much superior to the 

 other annual covers, probably largely because its moisture draft is 

 so low. It also fixes nitrogen from the air. 



W. E. Grove. Have these crops been fertilized? 



Dr. Stewart. They had one uniform fertilization and received 

 an application of lime once. 



C.J.Tyson. Has the culture of the soil been uniform? 



Dr. Stewart. The culture of the soil has been uniform in all 

 cases except alfalfa. The alfalfa is a mulch proposition and was 

 cultivated but once, at the beginning of the experiment, to get the 

 alfalfa started. 



R. A. Wickersham. Are these crops ever allowed to grow 

 over the roots ? 



