ot; 



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ENGLISH AGRICULTURE. 109 



materials. Secondly, it sometimes brings up hidden matter 

 of sour and injurious character which did no harm as long as 

 it was below the plough-sole, but which does harm mixed 

 with the surface soil sour unoxidized products, which have 

 been known not only to stop all crops growing, but even all 

 weeds, and to render the ground for a time absolutely barren. 

 It will also sometimes bring up a most extraordinary crop 

 of weeds, and that has given rise in the minds of many 

 farmers to a firm belief in spontaneous generation. Farmers 

 will tell you that if they plough deep they will fill their fields 

 with charlock, and so they will. If they plough even a little 

 deeper than they ought they will stock their ground with such 

 a crop of charlock as it may take years to get rid of. Such 

 an extraordinary fact requires a few words of explanation. 

 If we walk over the fields in the height of summer we will 

 see how they are cracked, a walking-stick can sometimes be 

 ushed down the cracks a yard deep, and how much deeper 

 hey extend it would be difficult to say. Charlock has a 

 small, round, compact and oleaginous seed, and it no doubt 

 ickles down these cracks probably two and even three feet 

 neath the surface, and when the ground is ploughed to a 

 eater depth than usual we bring up the charlock and reap 

 he evil consequences of so doing. 



These are some of the disadvantages of too deep ploughing, 

 t in some cases trench-ploughing is useful. It must be 

 nsidered good when we have a continuation of good soil 

 a considerable depth, as in alluvial soils or riverside lands, 

 here a soil may be two or three feet deep. In such cases 

 e shall probably produce a good effect. On loamy soils 

 hrough which the air has free access we need not fear the 

 sence of poisonous materials; they have long ago been 

 idized and neutralized. 



The best method, perhaps, is to deepen the soil a little 

 every time it comes into course fur roots, or about once in 



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