MECHANICAL DIVISION OP SOILS. 89 



draught, facilitates turning the plow at the end of the fur- 

 row, and regulates its depth. The cutter or coulter, which 

 is made of wrought iron, with steel edge, divides the sod or 

 earth before the plow, thus lessening the draught, and giving 

 a smoother edge to the furrow. 



Plowing Clay lands, Whenever practicable, these 

 should be plowed in the fall, for planting and sowing the 

 ensuing spring. (For exceptions, see page 18 ; and for fur- 

 ther directions and observations on the subject of plowing, 

 see management of soils preceding, and various subsequent 

 tillage crops.) The tenacity of the soil may thus be tem- 

 porarily broken up by the winter frosts, its particles more 

 thoroughly separated, and the whole mass reduced to a finer 

 tilth than can possibly be effected in any other manner. 

 A still further and important advantage from this practice 

 ensues, from the attraction existing between the clay and 

 those gases that are furnished from the atmosphere, snow, 

 rains and dews. In consequence of being thus thrown up 

 and coming in contact with them, it seizes upon the ammo- 

 nia and carbonic and nitric acids, which are in the air, and 

 holds them for the future use of the crops ; while their great 

 affinity for manures, effectually prevents the waste of such 

 as are in it. _ There is an additional benefit sometimes deri- 

 vable from this practice, in turning over the soil late in the 

 season, and after such worms and insects as are injurious 

 to the crops, have taken up their winter quarters. They 

 are thus thrown out and exposed to the elements, when 

 they are too chilled to seek seclusion again, and are thus 

 destroyed. 



The furrows of clay soils, should be turned over so as to 

 lap on the preceding, and lie at an angle of 45, as illustra- 

 ted by the following cut : 



Tm 

 FIG. 2. 



and for this purpose, the depth of the furrow slice should be 

 about two thirds its width. Thus a furrow six inches deep, 

 should be about nine inches wide ; or if eight inches deep, 

 it should be twelve inches wide. This will allow of the 

 furrows lying regularly and evenly, and in the proper posi- 

 tion for the drainage of the soil, the free circulation of air, 

 and the most efficient action of frosts, which in this way, 

 have access to every side of them. Land thus thrown up, 



