The Effect of Different Soil and Plant Cultivation Methods on Yield and Chemical Composition of Scorzonera Roots

In 1997-2000, field experiments were carried out on a grey-brown podzolic soil. The experimental plant was scorzonera (Scorzonera hispanica L.) cv. Einjährige Riesen. The aim of the experiments was to assess the yields of scorzonera roots in different soil and plant cultivation systems: ridge and flat cultivation, reduced soil tillage prior to sowing (shallow tillage), and the application of cover crops (Sinapis alba L., Vicia sativa L., Phacelia tanacetifolia B., Avena sativa L.) in conservation tillage and no-tillage systems. Reduced spring tillage did not have a negative effect on the yields of scorzonera roots. Cultivation of plants on ridges had a positive effect on the total and marketable yields of roots in comparison with flat soil cultivation. Mulching with cover crops had a significant influence on the increase in the marketable yield of roots. No-tillage cultivation did not have a negative effect on the total and marketable yields of roots. Reduction in spring tillage prior to sowing, soil mulching, and no-tillage cultivation had no negative effects on the inulin content of scorzonera roots. Among the investigated cover crops, Sinapis alba L. was the most beneficial plant for increasing the inulin content of roots. Cultivation of plants on ridges and flat soil, and reduction in spring pre-sowing tillage did not have a significant effect on the protein content of roots. Irrespective of the soil cultivation methods, a significantly higher protein content was found in the roots harvested from the plots mulched with Vicia sativa L. The various plant cultivation conditions exerted a considerable influence on nutrient uptake. Roots of the plants cultivated on ridges contained higher amounts of P, K, and Ca. Soil mulching created better conditions for nutrient absorption. A significant effect of Sinapis alba L. in increasing the P and K content of roots was also observed.