Effect of biodynamic preparations on the soil biological and agrochemical properties and coloured potato tubers quality

The aim of this research, which was undertaken in three years (2013-2015), was to evaluate the effect of biodynamic (BD) preparations 500 and 501 on soil biological and agrochemical properties and potato tuber quality. The soil samples were analyzed for: available phosphorus, available potassium, ammonia nitrogen, nitrogen (sum of nitrate and nitrite nitrogen) and mineral nitrogen. The potato samples were analyzed for: total polyphenols content, total anthocyanin's content and antiradical activity. The research revealed that significantly the highest concentrations of available phosphorus, available potassium, nitrogen and mineral nitrogen in the soil throughout the growing season were identified on the 14th day after soil application of BD preparation 500 (before potato planting). As well as, soil spray application of BD preparation 500 resulted in higher enzyme activity (urease and saccharase). When the BD preparation 501 was applied, the content of total phenolic compounds in the tubers of cultivars Blue Congo and Red Emmalie was significantly higher, 20.1% and 5.4%, respectively; the content of anthocyanins were significantly higher in the tubers of three tested cultivars. However, the application of this preparation did not have any effect on the content of total phenolic compounds and on the antioxidant activity of Vitelotte tubers. The use of both preparations (500+501) had significant effects only on anthocyanins accumulation in the tubers of Blue Congo and Vitelotte. The application of preparation 500 significantly decreased the content of anthocyanins in the tubers of cvs. Red Emmalie and Vitelotte.