14 



Cultivate with the disc harrow or other cultivator soon after roIHng 

 to form a dry earth mulch, which prevents the loss of moisture by eva- 

 poration. Subsequently cultivation should be g'iven as soon as possible 

 after every rain, and about every two weeks in dry weather to maintain 

 an effective dust mulch. These latter cultivations may usually be per- 

 formed by means of light harrows. If weeds and grass get a start, 

 the spring-toothed cultivator with the broad points should be used to cut 

 them off. Cultivation should be continued until about the middle of 

 July or the first of August, by which time the trees should have practi- 

 cally ceased growth. Cultivation after the first of August has a ten- 

 dency to cause late growth of wood, which will not have time to properly 

 mature and is liable to be killed back during the winter. If trees are 

 making very rapid growth, it may be desirable to cease cultivation even 

 earlier than the middle of July in order to check the growth. At the 

 time of the last cultivation a cover crop should be sown. 



Cover Crops. 



What is an orchard cover crop ? It is a crop sown on the ground 

 at that season of the year when trees have ceased their growth. If 

 man makes no effort to cover the ground, nature forms a cover of weeds 

 and grass in her endeavor to protect the soil. 



Cover crops may benefit in many ways, of which the following are 

 some of the most important : (i) A cover crop, by adding a large 

 amount of fibre to the land, prevents hard soils from cementing or pud- 

 dling. (2) On bare and rolling land, where the rains quickly run off 

 and snows blow off the high portions, a growing crop tends to hold 

 these until they have time to soak into the soil. (3) Land covered by a 

 growing crop dries out more quickly in the spring, owing to the trans- 

 piration of moisture through the leaves, and consequently may be plow- 

 ed under earlier in the season than land which is bare. This is a very 

 important point as it enables the orchardist to gain several days in the 

 busy season of spring. (4) Ground covered with vegetation will hold 

 the snows in winter and thus prevent deep freezing, therby avoiding the 

 liability of root killing. (5) A cover crop affords the most economical 

 means of furnishing a supply of humus in the soil. (6) The roots of a 

 cover crop assist the tree roots in rendering available certain 

 mineral plant food in the soil. (7) A large amount of plant food is lib- 

 erated in the soil after the tree growth has ceased. This is taken up 

 by the growing crop and held in a readily available form for the follow- 

 ing season. (8) Leguminous crops, such as clover, vetch, alfalfa, peas, 

 and beans, by virtue of certain bacteria which form nodules on the roots, 

 are able to assimilate nitrogen from the air. As nitrogen is one of the 

 most expensive fertilizing elements, the value of this class of plants can- 

 not be too highly appreciated. 



Cover crops should be sown about the middle of July so that they 

 may make a good growth the same season. It is also wise to check the 



