Environmental determinants of plant species diversity in organic and conventional vineyards

The factors affecting the plant biodiversity in organic (manure application) and conventional vineyards (variety Agiorgitiko for both) in southern Greece were examined separately for each vineyard type. The index for plant biodiversity was chosen to be the Shannon one (SH). The Pearson correlation coefficients disclosed that the common factors in both vineyards types affecting the SH were the concentrations of the soil organic C and organic N, the nitrates -N, the available (Olsen) P, available Cu, exchangeable K and the CaCO3 percentage. The C/N ratio in soils affected positively and significantly the SH index in both vineyards types. That means that the supply of N is not a problem with regard to decomposition but the organic C as a source of energy can be a limiting factor to plant diversity. The earthworm population density in the two vineyards types was also a significant positive factor to the SH. The concentrations of the available Mg, Zn and ammonium-N in soils affected the SH index significantly only in the conventional vineyards although their concentrations in soils did not differ. We can conclude that chemical fertilization can also affect plant variability.

Automated summary

The study found that factors such as concentrations of soil organic carbon and organic nitrogen, nitrate-N, available phosphorus, available copper, exchangeable potassium and CaCO3 percentage were significant in affecting plant biodiversity in both types of vineyards. The C/N ratio in soils and earthworm population density were also positively correlated with plant diversity. Additionally, chemical fertilization can also impact plant variability in vineyards.