Plant biomass from heathland management: a possible peat substitute?

Abstract

For good regeneration, in northern Germany heathland is mowed by special machines. This material has to be disposed somehow. Since it is low in pH and nutrients, it might be used as peat substitute. To test this possibility, a germination test with Chinese cabbage was carried out. At the end of the germination test fresh and dry matters as well as N, P, K in the plants were analyzed. Root growth was evaluated visually. Variants were: 100% (Vol) heather biomass, 100% (Vol) peat (H2-H5), a mixture with each 50% (Vol) of these materials. All variants were limed and fertilized according to the procedure of the germination test. Furthermore, the stability of the N-household and CO2-evolution of the variants were investigated in incubation tests for 20 resp. 27 days. Shoot growth of Chinese cabbage and % N and K in the dry mass did not differ significantly between the variants. Root growth in all variants was good; however slightly, but significant less in 100% (Vol) heather biomass. This was not the case for the mixture. All tested materials showed a stable N-household. Cumulated CO2-evolution with time was significantly higher for 100% (Vol) heather biomass compared to the mixture, and both were higher compared to 100% (Vol) peat. The results encourage the use of 50% (Vol) biomass from heathland management as peat substitute. Further investigations concerning the degradability of the material, here expressed as CO2-evolution, and possible consequences for the structure stability and the water- and air-household are needed. Additionally, since a random sample of biomass was taken, its homogeneity on a bigger area of heathland should be checked.