Useful properties of peat

Press, 20 April 1979, Page 11

Useful properties of peat

Peat is formed by the laying down of successive generations of plants under water which remain in a state of incomplete decomposition mainly due to a lack of oxygen. It is not uniform in texture, being composed of finely divided material plus coarser matter such as bark, twigs, branches and leaves. Most peat contains less than thirty five per cent mineral matter, with up to 3.5 per cent nitrogen, but it is low in phosphorous and potassium. It is relatively weed-free and has a high water holding capacity. The usual form in which

it is sold is in a compressed dry state. Peat is given credit for a variety of virtues and has been thus surrounded by fact and a lot of fantasy. It does have many uses. It can be used in a finely shredded state for covering germinating seed and as an integral part of both seed and potting mixtures. One of its advantages as a propagating medium is that it helps to promote roots from the base of the cutting instead of from the nodes. For this purpose it can be used alone, or with sand. It is most useful as a soil conditioner and can

be used as an adjunct to soil acidification. As it breaks down in the soil it provides humus. But peat has no real plant food value. As a soil conditioner it loosens heavy ground with a high clay content and offers a better root hold to plants, providing that it is thoroughly incorporated in the top soil. In sandy soil it assists in retaining fertilisers which may otherwise be leached out. Because of its absorp-tive-powers, it must be thoroughly saturated before use otherwise it can actually be detrimental by drawing soil moisture away from the plant.

A ground surface mulch of peat can also become more of a threat to the well-being of plants by preventing the penetration of moisture and restricting the free circulation of air. Coarse peat will normally . take considerably longer to reach saturation point and should preferably be shredded before general use. Added as a soil conditioner or as a mulch a depth of scm can be considered as minimal to be of benefit. A compressed bale can be broken up with a front mounted rotary hoe.