Effects of olive pomace spreading on soil cultivated with maize and grapevine

Olive pomace (OP) is the solid by-product obtained from olive processing to extract virgin olive oil by the mechanical means of pressure and centrifugation systems. In the past, OP was generally utilized to extract pomaceoil by solvent, but at present the industry prefers using OP obtained by pressure system, because it has a higher oil content and a lower moisture content. OP obtained by centrifugation system, particularly that obtained by the 2-phases centrifugal decanter, has, instead, a high moisture content and a low oil content and for these reasons it is not valued from the industry and must be differently utilized. Being OP a vegetable product having a high content of organic matter, it appeared interesting to use OP as amendment and fertilizer of agricultural soil. To evaluate the agronomic benefits, OP was spread in different quantities on soil cultivated with maize and grapevine. The results obtained indicated that the use of 5-10 kg of OP/m 2 did not significantly increase the productivity of maize and grapevine, but it helped avoid, or reduce, the use of chemical fertilizers.