Effects of species diversity and fungicides on organic matter and available soil phosphorus (P)

The objective of this study was to determine whether the availability of soil P and soil organic matter were affected by the plant species richness and the restriction of arbuscular mycorrhizal fungi (AMF). The research took place in Northern Greece. Availability of soil nitrogen and P was deficient for plant growth. Six C3 grasses, three legumes and four forbs native and relatively abundant in the study area, were used. These plants were sown as monocultures and in randomly selected mixtures of 2-3-4-7-10 and 13 species. These species were planted in containers containing 30kg of soil deficient in N and P for plant growth. To restrict the AMF colonization, the fungicide benomyl at first and the combination of fungicides thiophanate methyl and carbeplus after, were applied at half of the replications. At the end of the growth season soil samples were taken to determine organic matter content and soil P concentration. The results showed that both soil characteristics were not affected by the species richness in the mixtures.. The monocultures of grasses, legumes and forbs produced the same results. However the fungicide application reduced the organic matter content and the soil P availability. These effects of fungicides are probably due to the N that they contain.