RESPONSE OF CLOVER TRIFOLIUM-FRAGIFERUM L CV SALINA TO A HEAVY URBAN COMPOST APPLICATION

The clover, T.fragiferum L. cv. 'Salina' was grown for two years in a greenhouse under a heavy rate of urban compost application at sowing ( 100 t ha(-1) year(-1)). An inorganic fertilizer was also applied for c omparison (8N-15K(2)O-15P(2)O(5) 1.2 tha(-1) year(-1)). The legumes Me dicago rugosa Des. cv. 'Paragosa', Trifolium subterraneum L. ssp. subt erraneum, T. subterraneum L. ssp. brachycalycinum were also grown for comparison. The combined N applied with the inorganic fertilizer did n ot impair either seedling emergence or growth of any of the legumes. S eedling emergence of legumes was in general higher under the urban com post treatment than under the inorganic and control treatments, with t hat of T. fragiferum being the highest. This latter species was the on ly one with a higher dry matter production under the urban compost tre atment than under the other treatments. Urban compost application sign ificantly increased N, P, Cu and Zn concentration and export of T. fra giferum, in relation to the inorganic and control treatments. A simila r trend was observed for K, but without significant differences, with clover also showing a reasonable capacity to absorb Na (natrophilic ch aracter). Significant increases in Ni and Cr concentrations, in relati on to the control, were also observed in the last cut carried out in t he second year, although phytotoxic or toxic levels for cattle were ne ver registered for any metal analyzed in T. fragiferum.