Monitoring feedstock losses over five months storage of olive tree pruning hog fuel in piles. Comparison of covered vs. uncovered storage

Abstract

Aim of the current paper is the monitoring of feedstock losses during a five-month storage period of olive tree pruning (OTP) hog fuel, by comparing two storage solutions: i) uncovered, open-air storage and ii) fleece-covered open-air storage. For this task, two identical conical piles of harvested prunings were built and monitored for calculating the changes in dry matter and energy value of the stored material over time. One pile was left uncovered, while the other was covered with a breathable fleece. For each pile, net bags were used in order to obtain samples for analysis. Overall, the covered pile showed improved storage performance than the uncovered pile, which was much more influenced on weather conditions. The covered pile presented i) lower dry matter losses after five months of storage with an average value of 1.1% compared to 4.6% of the uncovered pile; ii) stable moisture content throughout the storage period at around 10% (as received), compared to the fluctuating moisture content of the uncovered pile from 11% to 24%; and finally, iii) recoverable energy gain with an average pile value of 12.1% compared to recoverable energy loss of 5.1% in the uncovered pile after the storage period.