BIOCHAR GENERATED FROM KIWIFRUIT VINE PRUNINGS: SCOPE AND CHARACTERIZATION
Allister Holmes and Hasinur Rahman.
PlusGroup Ltd., 37A Newnham Road, RD 2, Te Puna, Tauranga, New Zealand
Biochar is black carbon manufactured through pyrolysis in a low oxygen environment, and is one of the most stable terrestrial carbon stocks, which can have a turnover time of a few hundred to thousands of years in soil. New Zealand has 12,000 hectares of kiwifruit, and each winter approximately 2,000 kg ha-1 of vine material is pruned off mature kiwifruit vines, and this is mulched in situ and ultimately absorbed into the soil or lost to the atmosphere. Biochar derived from kiwifruit prunings could act as a soil carbon sink and a slow release nutrient source which may increase kiwifruit yield and productivity in the long duration. If other perennial crops (apples and grapes) are included, up to 40,000 tonnes of biochar could be produced annually in New Zealand.
The aims of this study were (i) to determine the potential scope for the production of biochar from kiwifruit prunings, and other perennial crops and (ii) to undertake preliminary investigation of the physico-chemical properties of biochar produced from kiwifruit prunings.
Differences in biochar indicate that the addition of biochar to soils from various production systems would change soil fertility and retention of agrochemicals.
Further work is needed to investigate the effect of biochar on the physico-chemical properties of soil used for kiwifruit production; as well as on the carbon footprint of kiwifruit production by using biochar versus the current practice of mulching prunings in situ. Download full article...