H.j SCARIFY WHEAT. j 53 



or three teeth may be worked in the space of nine 

 inches, without damage to the rows of wheat. If 

 t\vo, they may be drawn in a breadth of three 

 inches ; if three, in that of four inches, and these 

 spaces widened at pleasure, but still so as to keep 

 quite clear of the rows of wheat. By loading the 

 harrow, the teeth are forced to the proper depth. 

 The scarifier has teeth of various breadths, but for 

 working at this season between nine or twelve 

 inch rows, the narrowest are to be preferred. The 

 intention of the operation now performed is, to 

 loosen the surface earth and let in the air. The 

 hoe of the scarifier may cut two inches deep safely, 

 ft will do this without raising any such surge of 

 moulds as to bury the plants, and in its motion 

 through the earth, it loosens without removing it. 

 There the air immediately penetrates, and comes 

 in contael with the roots, which, from the soil being 

 moved, can spread with the greater ease. Another 

 motive for hoeing is, to loosen and pulverize the 

 mere surface when bound by rain or other weather. 

 This has relation to the coronal roots of the wheat, 

 which shoot out at this time of the year, when the 

 seminal ones decay ; and there is a curious circum- 

 stance noted by Bonnet, which is, these coronal 

 roots striking not under the surface, but above it, 

 into the air, and entering the earth at a small dis- 

 tance. It is then of consequence that the surface 

 be in a pulverized state, to permit their free pene- 

 tration. All hoeing before that moment must ne- 

 cessarily be beneficial, because preparing the sur- 

 face 



