FORTIETH ANNUAL REPORT. 137 



COVER CROPS. 



BY GEO. W. DEWEY. 



Ladies and Gentlemen : The question regarding cover croi>s in Mich- 

 igan appears to be one of the liveliest and most vital questions under 

 ' discussion as was demonstrated yesterday afternoon when this topic was 

 up for consideration. There were a multitude of different ideas. 



The first and principal reason for cover crops is to establish fertility 

 in the soil. We have three alternatives for making our soils better; 

 one is to apply stable manure ; another to use commercial fertilizers and 

 the last is the cover crop. The stable manure is impossible to get in 

 suflflcient quantities to really make it practical. It would be impossible 

 to get enough stable manure from two states to make a good dressing 

 for all the orchards in Michigan, therefore that must be ruled out. 



Comlmercial fertilizers of course, do make the trees grow better for 

 the time being but they do not improve the physical condition of the 

 soil ; it does not put more humus into it ; it does not increase its water 

 holding capacity. Arguing from induction, this leaves the last and most 

 important one which is the cover crop. The orchard question seems to 

 be analogous to the boarding house table. You must continually feed 

 the table in order that the boarders do not become slim and have that 

 lean and hungry look. So you must also give to the soil of the orchard 

 something from which the tree may take on that healthy appearance as 

 indicated by the vigorous gi'een leaves. This fertility is brought about 

 by using legumes as cover crops. The action of the legumes also when 

 tiirned increases the water holding capacity of the soil and not only that 

 but it increases the humus and prev^ents the evaporation of moisture 

 from the soil. 



Another principal reason for cover crops is to harden up the wood. 

 This will prevent freezing of growing tips and also wards off the at- 

 tacks of many orchard pests. If cover crops had been universal, it 

 would have prevented untold losses to those who were growing peaches 

 four years ago. And it seems to me though all this is theoretical, I 

 believe that the cover crop would, in this case, if planted in the fall, em- 

 ploying such crops as oats, barley and spring vetches, it would tend 

 , to have the same action on the fruit as does the sod culture; that is, 

 it would have a tendency to make the fruit more uniform in size and 

 give it a richer color. 



Another particular reason for the cover crop is to conserve the soil 

 moisture. These cover crops growing late in the fall when the wood 

 of the trees is being hardened off, would take up this extra moisture 

 and then in the spring, when turned under, you have turned it back 

 to the soil and there they lay down in the ground slightly below the 

 surface, thus breaking off the capillary attraction between the surface 

 and the sub-soil and bringing the water up to the roots of the trees 

 but not to the surface so that it will not evaporate into the atmosphere. 

 I have several samples of cover crops here, taken from the college 

 orchard Saturday. This is Spring Vetch, planted in August. This was 



