Mycorrhizal colonisation of three hybrid papayas (Carica papaya) under mulched and bare ground conditions

The use of straw mulching has been demonstrated to decrease soil loss and to improve soil moisture and soil organic matter content in conjunction with papaya (Carica papaya) cultivation. Mulching may also benefit soil biota. In this study, mulching was demonstrated to significantly (P < 0.05) improve arbuscular mycorrhizal fungal colonisation of papaya roots (by a factor of 2.4), but decreased spore density and species diversity (by a factor of 1.5), compared with cultivation in bare ground. The genera Glomus, Acaulospora, Gigaspora and Sclerocystis dominated in both mulched and bare ground systems. The increased mycorrhizal activity in the mulched treatments was matched by an increase in leaf phosphorus in 1995 but not in 1997.