32 



CALIFORNIA CITRUS CULTURE. 



Marker or Furrower. The marker, for making the irrigation fur- 

 rows, is not unlike the cultivator in strength and design, except that 

 it carries on its beam only two, or three, sometimes four or five, stout 

 broad shovels, depending on the number of furrows desired. It is a 

 common practice among smaller growers to alter the cultivator each time 

 marking out is necessary by the mere substitution of shovels for the 

 teeth, reversing the operation again before cultivation is necessary. 

 Thus one tool serves a double purpose. 



The marker may be extended in the same way as the cultivator. 



Subsoiler. (Fig. 15). This is a most important tool in the citrus 

 orchard, and yet it is probably the tool that has been used least of all. 

 Cross subsoiling to a depth of from sixteen to eighteen inches at right 

 angles to the irrigation furrows and midway between the trees greatly 

 facilitates deep irrigation and improves the aeration of all of the soil. 



FIG. 15. Subsoiler at work in an orchard. (After Lelong. ) 



An occasional subsoiling, say every third year, of the entire cultivated 

 area at intervals of two feet and in two directions to a depth four 

 inches below the deepest plowed and cultivated depth will break up 

 plow sole or irrigation hardpan and supply the much needed air that 

 is too often shut out from the roots. 



Drills. The seeding of cover-crops is usually done with the drill. 

 The "disk" drill instead of the "hoe" drill has many advantages 

 where trashy ground may be encountered. 



Commercial fertilizer is usually drilled into the soil and to as great 

 a depth as possible. A tendency to believe in applying a part of the 



