116 The Principles of Fruit-growing 



There is much confusion in the popular mind as to 

 the relation of cover-crops to moisture. Some contend 

 that any crop which shades the ground will keep the 

 surface moist and conserve moisture, whereas others, 

 knowing that all plants exhale water, consider that any 

 crop tends to make the land dry. Both these opinions 

 are in part correct. A crop that occupies the land the 

 entire season, and that does not allow of tillage, will make 

 the land dry, whereas one sown late in the season on land 

 that has been thoroughly tilled during May, June and 

 July, does not seriously rob the soil of moisture. At all 

 events, there need be little fear of drying out the soil by 

 sowing a late crop, for the serious injury by drought is 

 usually effected before such crops are established, and 

 rainfall is then becoming abundant; and the trees may need 

 to be checked rather than stimulated, at this season, by the 

 transfer of the nitrates and moisture to other plants. 

 The most marked way in which such crops conserve 

 moisture is by means of the fiber and humus that they 

 add to the land when plowed under; but even this 

 humus cannot compete with cultivation as a retainer of 

 moisture. Both humus and tillage are essential for best 

 results. 



The kinds of cover-crops. 



It should be said at the outset that the choice of the 

 proper crop for the covering of an orchard is a local 

 matter, the same as is the method of tillage or the kind 

 of fertilizer. There is also no one best cover-crop for all 

 purposes and all circumstances. The grower must study 

 the condition of his trees and his land, and then judge as 

 best he may what course he shall pursue. Nature's cover- 

 crops, at least on farms, are weeds, and these may be use- 



