BY OPEN OH COVERED DRAINS. 251 



make land more dry, but it allows the soil to have the full benefit 

 of the sun's heat, rendering it warm and congenial to plant growth, 

 and ready to benefit bj r the least shower of rain, at the same time 

 raising the temperature of the surrounding atmosphere. Draining 

 also makes soil of a stiff or tenacious nature more friable, and 

 better prepared to receive the fibrous rootlets of plants, and by the 

 action of the atmosphere hard pans or crusts are broken and 

 pulverised, so that the roots may enter them, a result which could 

 not otherwise be obtained without subsoiling or trenching. 



Before commencing the operation of draining many things are to 

 be considered, such as the kind of drains to produce the best and 

 most lasting effect upon the ground, whether they should be open 

 or covered ] Again, if covered drains be best, whether they should 

 be laid with drain pipes, or tiles ; or should the bottom consist of 

 stones set on edge in a triangular form, with a few inches of broken 

 stones over them, or be filled with broken stones to the depth of a 

 foot or 15 inches'? and the best line to run the drains, the depth, 

 and the distance one from another, so as most effectually to dry the 

 ground at the least expense, are points calling for careful considera- 

 tion. These may be usefully dealt with in detail. 



First, As to the kind of drains. Open drains are most used for 

 plantations, and have many advantages over covered ones, whether 

 laid with tiles or stones ; the greatest objections are, the liability to 

 become choked with soil, leaves, branches, &c, which necessitates 

 their being often cleared out ; the width necessary to keep them 

 from falling in when of good depth ; their inconvenience in the 

 removal of timber, and their unsightly appearance in home planta- 

 tions. But where the surface water is the great evil to be removed, 

 they render the ground dry although of no great depth, and are there- 

 fore not so objectionable in such circumstances. In few cases, 

 however, is surface water the oidy moisture to be removed, and 

 open drains are seldom effective if less than two feet deep, however 

 close they may be to each other. Covered drains, on the other hand, 

 especially in hardwood plantations, are liable to be choked by the 

 roots of trees, and this, after heavy rain, causes the water to burst up 

 and saturate the ground, making it more wet than if it had not been 

 drained ; another result of this is that the roots of the trees are 

 starved and rotted, and the ground made so spongy and soft, that 

 the least storm of wind may overthrow the trees. Such effects are 

 often seen in home parks and demesnes, where trees are growing 

 near to covered drains, and the work of lifting, clearing, and relaying 



