DEEP PLOUGHING. 



143 



seven to ten or twelve inches, according to the crops it is 

 designed to cultivate. 



450. If much of a poor subsoil should be brought up 

 to the surface at once, the farmer would have to wait two, 

 three, or even four years before he would obtain the 

 largest results, though after that time the good effects of 

 deep tillage would be seen. 



451. Deep ploughing has much the same effect as 

 thorough draining, though in a less degree. It enables 

 the roots of plants to penetrate deeply in search of nour 

 ishment, carries off more or less of the surface water, 

 warms the soil, and without doubt makes it more fertile 

 by allowing the air to circulate through it, and by a 

 mixture of the soils of different depths. Besides, deep 

 ploughing makes it much easier to do the other work 

 which is necessary in preparing the soil for planting, and 

 increases the effect of all manures which are applied. 



452. Deep ploughing is especially needed in the culti 

 vation of deep or tap-rooted plants like carrots, parsnips, 

 and ruta-bagas, but it is beneficial to all crops if it is 

 properly done. 



453. The subsoil 

 plough, (Figs. 17 and 

 18,) is designed to fol 

 low in the furrow of 

 the common plough, to 

 loosen and break up the 

 lower layers of the soil 

 without bringing them 

 to the surface. With this 

 implement it is easy to 

 loosen the subsoil six or 

 eight inches below the 

 furrow left by the ordi- 



13* 



Fig. 18. 



