CULTIVATION OF THE SOIL. 87 



trees each year. In general, it may be said that deep plough- 

 ing is advisable in an orchard only in the first few years of its 

 life, as already said ; and thereafter it is rarely necessary to 

 plough deep. 



If an orchard has not been well ploughed and tilled in the 

 early years, the roots will be so high that deep ploughing is 

 practically impossible when the trees come to maturity. In 

 that case, the effort should be, as a rule, to prepare a surface 

 mulch by bringing the top layer of soil into a fine and mellow 

 condition. This may be done by a shallow ploughing or by 

 cutting up the surface with a spading harrow. Even heavy 

 sod can sometimes be cut and lacerated by a spading har- 

 row, if the work is done in spring when the land is soft and 

 moist. 



In general, it is best to plough orchard lands in spring rather 

 than in fall, since the roots are not exposed ; the spring plough- 

 ing allows the green crop to remain upon the land during the 

 winter, thereby holding some of the rainfall and preventing 

 the surface from cementing and from washing. Fall plough- 

 ing is generally to be discouraged in peaches and other tender 

 fruits, particularly at the North. When land is very heavy 

 or clayey, however, fall ploughing may be a decided advan- 

 tage in order to allow of the weathering of the land. In very 

 hard clays, it is generally important that the land have a cov- 

 ering of stubble, manure, or some other fibrous material, to 

 prevent the snows and rains of winter from cementing or pud- 

 dling it. If one has much land to plough, and is short of 

 team help, he may plough his apple-orchards and other hardy 

 fruits in the fall in order to be forehanded with his work. 

 But, 3 3 before said, the heavy ploughing of an orchard, except 

 for turning out a green crop, should not be necessary after the 

 orchard is a few years old. 



Crops which are used for temporary green manures and 

 protection in the orchard have latterly been called cover- 

 crops. The seed is usually sown at the last tilling in July, 

 August, or very early September. These cover-crops are 

 usually divided into two groups— those which have the power 

 of fixing atmospheric nitrogen (leguminous crops), and those 

 which do not have this power. To the former class belong all 

 the peas and beans, vetch, clovers, and alfalfa. The latter 



