Summary

       In the search of options for the recycling of the residues generated in the olive oil extraction (alperujos), six experiments were realised (three with solid products and other three with liquid products) in greenhouse conditions, with the aim of valuing the effect of different products originated from the alperujos on the parameters of the growth, the production and nutrition in the lettuce and spinach. Of the solid products, in experiment 1, were evaluated on the lettuce three composts (CPI, CPII and CPIII) to five doses of nitrogen (0, 50, 100, 150 and 200 kg N/ha), including a mineral fertilizer to those same doses; in experiment 2, were evaluated, also on lettuce, the three composts indicated previously, to four doses of organic matter (0, 10, 20 and 30 t/ha), applied to the soil; and in experiment 3, the effects of compost and vermicompost were compared, to doses of 5 and 10 t dry matter/ha, on a rotation of two crops: lettuce - spinach. Of liquid products, in experiment 4, the effects of different húmic substances originated from compost and vermicompost were evaluated on lettuce - spinach, as well as three commercial products, applied to the soil, to three doses (0, 12,5 and 25 mg of C/kg of soil); in experiment 5, the effects of the same products and doses were compared that the used ones in the experiment indicated previously, but applying to foliar sprays; and in experiment 6, they were valued, also on the rotation lettuce - spinach, the effects of the water extracts (0, 0,5 and 1 g of product/L), obtained of compost and vermicompost and applied to foliar sprays.
       The productive parameters of the used horticultural crops were little affected by products applied in solid form; however the mineral fertilizer turned out very effective to increase the production of biomass in the lettuce. The values of the indicators of used efficiency of nitrogen also reflected a low value of the three composts and vermicompost like the nitrogen sources. These last fertilizing products affected little to the nutritional parameters of the crops, unlike the happened thing to the mineral fertilizer that originated a considerable improvement in the content and absorption of the nutrients, particularly of nitrogen.
       The three composts compared showed considerable differences of answer in the horticultural crop (lettuce). And the efficiency of vermicompost in comparison with the one of compost, in spite of its better physical - chemical characteristics, was similar in the lettuce, but something better in the spinach. And the effect of the dose of application of organic fertilizers was solely significant in experiment 2.
       The different liquid humic substances applied to the soil did not turn out either effective to increase the biomass of the indicative crops (lettuce and spinach), nor to improve the nutritional state of the same. Also, these humic substances applied by foliar route either did not originate clearly positive effects on the production of the rotation: lettuce - spinach; however, some treatments brought about in the spinach plants an increase in the content and absorption of several nutrients (nitrogen, phosphorus, calcium, iron, zinc and copper) and, generally, the more elevated contents of nutrients were registered with the high dose.
       With respect to the water extracts of compost and vermicompost they turned out effective to increase the vegetable biomass solely in the lettuce crop. And the effect of both types of extracts on the nutritional content of the plants, although more was marked in the lettuce, the differences between both products were little. 
Key words: alperujos, nitrogen, organic matter, compost, vermicompost, production, nutrition, lettuce, spinach.