The effects of application of composted olive mill wastewater sludge (A) and depotassified sugarbeet vinasse (V) on total diethylenetriaminepentaacetic acid (DTPA) and sequential extracted micronutrients were investigated. The mineralogy of the fine fraction of soils was also studied. The soils used were a Typic Rhodoxeralf (soil R), a Typic Xeropsamment (soil S), and a Typic Xerorthent (soil C). Fertilization with A and V during 3 years, in general did not significantly affect the total concentration of Fe, Cu, Mn, and Zn versus the control. However, the elements extracted with DTPA generally increased with the organic amendments, more with A than with V. The BCR (European Community Bureau of Reference) sequential extraction indicated that the addition of organic matter generally increased Zn and Mn in the two more available fractions. A great amount of Fe was found in the second and third fractions from the unamended and amended soils. Nevertheless, the sum of the three fractions was enhanced for the organic amendment, except for calcareous soil. The distribution of these elements in the different fractions was significantly affected by the type of soil. The addition of both fertilizers caused modifications in particle size and consequence redistribution of the calcite content between the different fractions.

The authors wish to thank the Junta de Andalucía (Spain) through projects PAI RNM 166 and AGR108.

15 páginas.-- 3 figuras.-- 6 tablas.-- 36 referencias

Peer reviewed