A comparison of soil quality and yield parameters under organic and conventional vineyard systems in Mediterranean conditions (West Turkey)

Summary

Soil chemical and microbial parameters are commonly used as soil quality indicators to evaluate sustainable land management in agroecosystems. The objective of this research was to evaluate the impact of organic and conventional management strategies on biological,chemicalandyieldparametersinvineyards(Vitisviniferacv.Sultaniseedless). Organic plots received a mixture of barley, vetch and broad bean (25þ35 þ75kg seed ha21) as green manure, and farmyard manure (15t ha21) every year. Inorganic fertilizers (NPK)andpesticideswereusedintheconventionalmanagedvineyards.Conventionaland mulch tillage methods were used in conventional and organic plots, respectively. Microbiological and chemical soil properties were determined in the soil samples which weretakenfourtimesin2004,2005,2006and2007.Inaddition,theyieldandsomequality parameters of vineyards were also determined. Soil microbial biomass, and dehydrogenase, b-glucosidaseandalkalinephosphataseactivityweresignificantlyhigher in organic management than in conventional management. Higher Cmic/Corg and lower qCO2 values were found with the organic management. The response of the chemical indicators (Corg,N t and available nutrient content) of the soils to different management systems appeared after a longer time than with the biological indicators. In the transition zone between continental and Mediterranean climates of West Turkey, soil quality of organically managed vineyards improved after 2 years of the transition period prescribed fororganiccertification.However,soilqualityimprovementsinorganicplotsdidnotresult in higher yield.