THE EFFECT OF ADDITION OF COMPOSTED GREENWASTE AND BIOWASTE ON ENZYME ACTIVITY OF PEATS OF TWO DEGREES OF DECOMPOSITION

There is little information available on enzyme activity of peats or on the effect of the addition of composted material on the enzyme activity of the peat growing medium. The dilution of peats with recycled materials is becoming important as pressure grows from the environmental lobby to reduce the usage of peat. Consequently, trials were conducted to study the effect of addition of composted greenwaste (CGW) and composted biowaste (CBW) to two types of peat (H₂ and H₅ on the von Post scale) at two rates, on fluorescein diacetate (FDA) and dehydrogenase activity (FDA). Both DH and FDA levels were higher in H₂ peat. Changes in FDA levels were minimal in H₅ peat over 17 weeks, while in H₂ peat it tended to drop for the first 9 weeks and then recover to the same level at 17 weeks as at the start. DH rates in H₅ peat reduced until 9 weeks and then recovered by 17 weeks. In H₂ peat there was large initial increase and then a reduction after 9 weeks and then another large increase at 17 weeks. The application of CGW resulted in an increase in DH activity in both peat types at the higher rate but not at the lower rate in H₂ peat. The application of CGW resulted in a big increase in DH in H₅ peat at both rates but the effect was only at the higher rate for H₂ peat. The application of both CGW and CBW tended to decrease the FDA activity with H₂ peat, but with more decomposed peat it tended to increase, especially at the higher rate of CBW. The relationship between DH and FDA activity was poor except at the last sampling date. Since both FDA and DH have found to have some predicative value for some soil borne diseases, the addition of these recycled materials could have potential benefits.