Eight years of organic amendments in an olive grove
Long-term trials let us examine organic matter, soil properties and tree responses together.
An eight-year Italian trial
University of Perugia researchers compared fresh solid olive mill waste, compost made from it and shredded prunings, and an unamended control in a rainfed Leccino grove near Assisi from 2006 to 2013. Organic treatments supplied equal carbon. The grove retained cover and all treatments also received nitrogen fertiliser.
Compost left a stronger soil effect
Compost was associated with higher organic carbon and nutrients and a greater reduction in bulk density than fresh waste. Despite equal carbon inputs, the composted mixture accumulated more carbon. Researchers linked this with woody components and stabilisation during processing.
Tree responses
Both organic treatments increased fruit production relative to the control. Fruit oil concentration did not differ significantly. Amendment form affected production and soil storage differently.
Organic matter in the web
Residues feed organisms; fungi decompose resistant materials. Food web activity connects with nutrient cycling and structure, as described in the Soil Biology Primer.
Our field work
We plan long-term records connecting compost and liquid applications with microbiology and organic matter in our groves, following our School training.