To break lumps and clods left by the plow and spade and to further pulverize the soil.
Harrowing and raking aid in controlling soil ventilation, and put the soil in better condition to absorb moisture.
They check the loss of moisture by making a mulch of fine loose earth on the surface.
The harrow and rake destroy the weeds.
The harrow brings about conditions favorable to the even distribution of seeds.
It is also the tool generally used to cover seeds sown broadcast.
Harrowing is generally done just before planting, and with some crops just after, to cover seeds or to smooth the ground. Harrowing is also done in the first stages of growth of some crops to kill weeds and make a soil mulch. The harrow should always follow the plow within a few hours unless it is desired to leave the land in a bare fall or winter fallow. At other times of the year the lumps of earth are apt to dry out and become hard and difficult to break. If there is but one work team on the farm it is a good plan during the plowing season to stop the plow in time to harrow the day's plowing before the day's work ends.
HARROWS
There are several types of harrows in use. They may be classified according to the style of their teeth or cutting parts; they are as follows:
Rolling cutter harrows.
Spring-toothed harrows.
Spike-toothed harrows.
Coulter-toothed harrows.
Chain harrows.
Brush harrows.
Plank or drag harrows.