Growth, mineral nutrition and mycorrhizal colonization of red clover and cucumber plants grown in a soil amended with composted urban wastes

摘要

The utility of an urban solid waste, either freshly composted or vermicomposted, for improving plant growth in a soil B horizon (Cambisol) was investigated in pot experiments. Growth, mineral nutrition and arbuscular mycorrhizal (AM) colonization ofcucumber and Trifolium pratense plants were studied in an experiment carried out under controlled growing conditions, using different mixtures of soil and composts as plant substrates. Soil inoculation with the AM fungus Acaulospora sp. did not benefitplant growth when soil was used as the only substrate, possibly due to its poor fertility. Results showed that neither mycorrhizal plant species grew when soil was mixed with composted urban waste or when compost was used as the only substrate. However,amendment of soil with 10 or 50% vermicompost significantly increased dry matter yields of T. pratense and cucumber plants, compared to treatments where soil was the only substrate. Addition of vermicompost also increased Olsen-P and other mineral elements in soil and shoot P, Ca, Mg, Cu, Mn and Zn concentrations, but caused a significant reduction in root length colonized by AM fungi in T. pratense. It is concluded that application of high amounts of vermicomposted urban wastes to soils might cause a significant reduction in the activity of AM fungi, which must be taken into account when using these organic amendments in agricultural systems.