MICROBIAL FERMENTATION OF GRASS RESIDUES TO ORGANIC ACIDS AS A FACTOR IN THE ESTABLISHMENT OF NEW GRASS SWARDS

Summary Extracts from anaerobically decomposed shoots of a range of grass species were toxic to other grasses and clover. This phytotoxicity was less after 20 days than after 10 and seemed to be caused by organic acids. The residues produced byFestuca rubra, Alopecurus pratensisandAgrostis stoloniferawere the most toxic. After aerobic decomposition for 10 days extracts from these three species were phytotoxic, but after a further 10 days decomposition they caused a stimulation in grass and clover root growth. These results are discussed in relation to the poor establishment that sometimes follows reseeding old pasture land.