1921.] 



Mole Draining. 



977 



MOLE DRAINING. 



There is no doubt whatever as to the value of drainage, 

 especially on heavy land. On land that is badly drained the 

 best type of herbage can never be obtained, while at the same 

 time the grazing season is practically limited to the drier summer 

 months. At other seasons stock cannot be carried on such land 

 without grave risk both of illness and disease to themselves and 

 of lasting damage to the texture of the soil. 



In the case of arable land, work is retarded and rendered 

 difficult and expensive. Crops cannot be depended upon. They 

 have frequently to be sown out of season and are apt to fall an 

 easy prey to various pests and diseases. 



The present cost of la\T[ng down extensive systems of pipe 

 drainage is very high, but on heavy clay soils quite as efficient, 

 if not quite as permanent, drainage can be obtained at relatively 

 little cost by the use of the mole plough. On such land mole 

 drains will last from eight to ten years and under favourable 

 conditions even twice as long. The inclusive cost (about 

 50s. -65s. per acre) is often fully recovered in the increased crops 

 obtained the first year. 



Mole draining is not adapted to every kind of soil, but wher- 

 .ever heavy clay land, to which it is specially adapted, is to be 

 found, it deserves, as one of the cheapest and surest methods of 

 improvement, full and careful trial. On more friable soils mole 

 draining may be successful, but in such cases there must always 

 be a good fall and intermediate main drains should be provided. 

 There should be few, if any, stones so large that they cannot 

 be turned aside by the coulter ; and the ground must not be too 

 uneven, as the drain will naturally follow the inequalities of the 

 surface. If the field is laid up in ridges and furrows the drains 

 must follow the line of the furrows and not run across them. 



As regards fall, if a field has a sufficient fall on the surface 

 for a water furrow to run. there will be sufficient fall for the 

 proper working of a mole drain. Less fall is required on a heavy 

 plastic clay than on a more friable soil, where water standing 

 in the mole would tend to make the walls fall in. 



The mole plough consists of a round steel plug about three 

 inches in diameter attached to the lower end of a strong coulter 

 which is fitted to a suitable frame mounted on wheels. It is 

 worked, like an ordinary steam plough, by cable and winding 

 drum. 



