Abstract:
Seasonal accumulation and incorrect disposal of oli
ve mill by-products may be
detrimental to the environment. Conversely, their p
roper recycling as soil amendments
may be a sustainable solution. Therefore, the objec
tives of this three-year field trial were:
(i) Investigating the effects of Olive Mill Wastewa
ter (OMW) and Pomace Compost (PC)
on plant nutritional status and yield in an organic
olive grove; (ii) The impact on main soil
properties, and (iii) Verifying if these experiment
al fertilizers can replace the widespread
fertilization practices. The OMW and PC treatments
were compared to a commercial
Organic-mineral Fertilizer (OF) and green manure of
horse bean (MV). Plant nutritional
status, soil properties and agronomical performance
of treatments were assessed. The
OMW and OF determined yield that was on average sig
nificantly higher than MV and
PC by 191 and 55%, respectively. The best leaves P
contents in PC indicated a more
effective release of this nutrient as compared to t
he other treatments, which can be
matched with more favorable soil conditions. The co
mparable yield and leaves
composition for OMW and OF suggested the possibility
to replace the OF with the OMW.
The effects on olive oil production and soil fertil
ity highlighted that OMW (and PC as a
second choice) could be applied to sustain olive tr
ee production, substituting traditional
fertilizers.
Keywords:
Composting,
Olive grove soils, Olive mill wastewater,
Olive pomace
,
Organic
farming.
