PEAT BOG PREPARATION: HOW TO CHOOSE THE RIGHT HARROW
A good bog preparation can significantly increase the productivity of the bog. Harrowing being an essential part of bog preparation, it is important to choose the proper type of harrow according to peat and weather conditions.
Here are six types of harrows and a brief description of their purpose and advantages, which should help you choose the perfect one for your needs.
The tooth harrow is the more versatile and also the one which will loosen the greater quantity of peat. It is the first harrow a peat producer should have and is the most common one in North America. When adjusted to a small depth, it can be used to loosen as well as slightly dry the peat. It produces flat chunks of peat, the size of which will vary according to the depth at which the teeth are adjusted: the deeper the teeth will go, the coarser the peat chunks will be. The traveling speed must be adjusted according to the adjusted depth: low speed when harrowing deeper, higher speed when harrowing on the surface.
The rotary point harrow is designed to break peat into small, round chunks. This harrow is often used to minimize fine dusty particles. It must be used at a good travelling speed in order for it to be efficient.
The rotary disk harrow is designed to break peat moss into small, flat chunks. It usually loosen a greater quantity of peat than the rotary point harrow. The travelling speed should go from medium to high speed.
The spoon harrow is mostly used for speeding up the drying step. It is designed to turn over the top layer of peat moss and make small furrows after harvesting. The spoon harrow is most efficient in favorable weather as it exposes the moist part of the lose peat. It is not recommended in less favorable weather (rain with few sunny days in between).
The conditioning harrow is a combination of rods (tines) and spoons. It is designed to remove small roots and stumps and to loosen the top surface, speeding the harvesting after a light rain. This harrow is best used during less favorable weather conditions as it shuffles peat instead of turning it over, which helps drying without getting the moist peat on the surface. The drying process on the surface is then faster, though less deep, and allows harvesting small quantities of peat at closer intervals.
The spring harrow is very similar to the conditioning harrow and used for the same purpose, except is has a second row of fingers (springs) and these fingers are bigger.