We have considered the agricultural effects that could derive from successive applications of a municipal compost from the city of Seville, with a high contamination capacity. The study was carried out in a green-house using a markedly calcic soil (CaC03 > 20%) as the substrate. Compost was applied up to a maximum (total loading) that would be equivalent to 200 t ha-1/4 years (experiment with Lolium multiflorum), 300 t ha-1/3 years (Trifolium fragiferum) and 400 t ha-1/6 years (tomato). Improved germination and yield were also found in Lolium with a total compost loading of 450 t ha-1 in relation to adose of 50 t ha-l. Compost accumulation caused a significant increase of Zn, Cu and Na in the plants, despite the markedly calcic substrate used. The copper in Trifolium increased to nearly 25 ppm, at which level it could begin to be toxic for sheep, and the Na in the Lolium leaves surpassed by more than 400% the level in the controls. On the contrary, Mn levels in the tomato plants decreased as a consequence of compost accumulation.

10 pages, 4 figures, 8 tables, 14 references.

Peer reviewed