Cover Crops 45 



trees that are easily attacked by fire blight, as pears and 

 quinces, soft wood, such as is produced by continuous cul- 

 tivation, is not desired, because of the immense damage 

 that can be caused by blight. Pear orchards are frequently 

 planted to a permanent sod early in the life of the orchard, 

 simply for the purpose of preventing very soft wood. 



Orchards need to be plowed early in the spring and cul- 

 tivated until mid-summer when they are sowed down to a 

 cover crop that is to remain on the soil during the winter 

 to be turned under the next, spring. In the case of dry 

 seasons when the normal precipitation is scarce, tillage 

 throughout the summer will conserve the moisture in the 

 soil, and by plowing the ground late in the fall and allow- 

 ing to remain rough all winter a still larger amount of 

 water can be stored up in the soil than if left smooth and 

 level. 



Cover Crops 



Cover crop, called also green manures and shade crops, 

 arc such crops as are grown in the orchard for the purpose 

 of clothing the surface of the soil during late summer and 

 winter months. They are used to protect the soil from 

 washing during the winter rains, and for this reason are 

 always to be advised for orchards that are on steep, hilly 

 land. In the arid section of the West they serve to cover 

 the soil and protect it from the sun, thereby guarding 

 somewhat against sun-scalding of the trees. They increase 

 the humus supply when plowed under, and make available 

 or conserve the mineral elements of fertility that might 

 otherwise be leached out of the soil. This is especially 

 true of the soluble nitrates. When some sort of legumi- 

 nous plant is used for a cover crop it adds nitrogen to 

 the soil. 



Cover crops increase the water holding capacity of the 

 'soil through the addition of humus, and thereby improve 

 the tilth and prevent the puddling and baking of the soil. 

 On this account alone cover crops, or rather shade crops, 

 are useful in the orchards of the irrigated sections. There 



