Hello, I have a small disc harrow for the vineyard and I would like to know whether I should change the disc and if so, which ones I should replace them with. How do I know when they must be changed? And how can I find out what the original diameter is that I need? The disc references have been rubbed off. I want to use the disc harrow to till the soil that is difficult to penetrate and break up a few vine shoots and grass. Should I put notched discs on or discs that are more concave? Thanks very muchJonatan culleré
From what you say it must be a light harrow, with a gap of about 23 cm between the discs, designed to break up waste and till the superficial layer of the soil in the vine rows. The harrow must weigh less than 60 kg/disc, or, the equivalent of such, at least 350 kg/metre of working width. With this type of harrow 22 inch diameter (560 mm) discs are normally used, although 24 inch discs are also suitable.
With regard to the diameter of the discs, those that have a smaller diameter are easier to drive into the soil, while those of a larger diameter are better to break up the waste. If discs with more concavity are used you can turn over the soil you are working on much better, although I think that it wouldn’t be of any use in this case.
You could break up the waste better if you used notched discs. If there is a lot of waste it would be a good idea to put them in the front socket of the harrow.
The working depth achieved with the harrow discs is usually less than a fourth of the diameter of the disc, which means that with 560 mm discs, a working depth of about 14 cm can be attained, as long as there is enough load on the disc.
Recommendations for the case in question:• Use a disc with a diameter of 22 inches (560 mm) and a concavity of between 60.5 and 71.5 mm. Bellota references 1904, 1905 or 1906.• Change the discs if any uneven wear and tear is observed (loss of the circular shape) or if there are cracks on the edge. The disc can still be used if less than 10% of its diameter has worn away evenly, as long as the blade is still sharp, although the smaller the diameter of the discs the worse the quality of your work will be.• If there is a lot of superficial waste and you want to increase the amount that you can break up, put notched discs in the front socket of the harrow, although in light harrows this is not usually necessary.