36 



they take plant food away from the trees in the autumn and 

 thus help to ripen them up; that they catch and hold nitrates 

 in the soil after the growth of the trees has stopped, and 

 when these substances might otherwise be washed out of the 

 soil; that they help to pulverize and rot down the sod, which 

 is especially important at the beginning; that when they are 

 plowed under the following season they furnish humus, which 

 in turn furnishes plant food to the trees; and that, in the 

 case of soy beans and the vetches, they help to keep up the 

 store of nitrogen in the soil by what they take up from the air 

 and store in their roots. This is by no means all that these 

 cover crops do, but it covers the main points, and serves to 

 show how important they are. The general plan of their use 

 would be this: that the orchard would be plowed as early in 

 the spring as the soil would permit and thoroughly fitted as 

 outlined earlier. Then thorough cultivation would continue 

 up to the first week in July, when the cover crop would be 

 sown. The only important deviation from this course would 

 be in the case of some of the leguminous cover crops mentioned, 

 particularly soy beans, which often give better results if 

 sown in drills earlier in the season (the middle of June), and 

 cultivated several times before the orchard is laid by. Of 

 course the objection to this is that the cultivation by this 

 method is much more costly, since it must be done with a 

 one-horse cultivator, a row at a time, instead of with a disc 

 or spring-tooth harrow, covering three or four times the 

 space. But even this objection is often, if not usually, over- 

 balanced by the much better growth of the cover crop. 



After cultivation ceases and the cover crop is sown, nothing 

 further is done to the soil until the following spring, when 

 the cover crop is plowed under, and the program begins 

 again. Where a good growth of one of the nitrogenous cover 

 crops can be secured it is often possible to obtain all the 

 nitrogen needed for the orchard in this way. 



I should feel inclined to begin with buckwheat as a cover 

 crop in starting an old orchard because it is peculiarly effective 

 in rotting down sod and putting the soil in fine physical 

 condition. This might be followed in a year or two by 

 either soy beans or a mixture of one half bushel of buck- 

 wheat, and one peck of summer or winter vetch. 



