Effects of soil type and municipal solid waste compost as soil amendment on Cichorium spinosum (spiny chicory) growth

The application of municipal solid waste compost (MSW compost) improves soil fertility and increases crop yield due to the high content in organic matter, macronutrients and essential trace elements, but can entails potential risks to human health and to the environment due to the presence of heavy metals. The purpose of this study was to evaluate the effects of soil type and MSW compost on the growth of spiny chicory, an edible wild leafy plant with great nutritional and commercial value. Mature MSW compost was applied in sandy and clayey soils, at rates equivalent to 0, 60 and 150 t ha−1. The experiment was conducted in pots under semi-controlled conditions, and two harvests were carried out during the experimental period. The marketable yield of spiny chicory was higher in the sandy than in clayey soil, even in the absence of MSW compost. The application of MSW compost improved the soil fertility and increased the yield of spiny chicory in both soils. No significant differences were observed in growth and yield of spiny chicory between the application rates of 60 and 150 t ha−1. The contents of the macronutrients in the above ground part of spiny chicory were not affected by soil type or MSW compost addition. Although the bioavailability of trace elements (Cu, Zn, Fe, Mn, Cr, Ni, Pb, Cd) in both soils was increased due to MSW compost application, their contents in the edible part of the plants remained within the normal thresholds. Overall, the MSW compost as organic amendment can be used to improve spiny chicory yield in both sandy and clayey soils. Sandy soils with 60 t ha−1 MSW compost amendment is recommended.