VALUTAZIONE DELLE POTENZIALITÀ DEL BIOCHAR COME COMPONENTE DEI SUBSTRATI DI COLTIVAZIONE
Tesi di Dottorato
Data di Pubblicazione:
2016
Citazione:
VALUTAZIONE DELLE POTENZIALITÀ DEL BIOCHAR COME COMPONENTE DEI SUBSTRATI DI COLTIVAZIONE / F. Bedussi ; tutor: P. Zaccheo ; coordinatore: G. Zocchi. DIPARTIMENTO DI SCIENZE AGRARIE E AMBIENTALI - PRODUZIONE, TERRITORIO, AGROENERGIA, 2016 Jan 15. 28. ciclo, Anno Accademico 2015. [10.13130/bedussi-floriana_phd2016-01-15].
Abstract:
The possibility of using biochar as a soil amendment for agricultural land has been
intensively investigated, but it is only recently that biochar is proposed for greenhouse
applications. Biochar can be used as a partial substitute of commercial peat for the
cultivation of potting plants, so reducing the use of a non-renewable material like peat.
In fact peat has a slow regrowth rate of 0.5-2 mm per year, and costs of extraction and
transportation of peat are increasing.
In this dissertation, the effects of four biochars added to a peat-based growing media are
explored. Biochars are produced via pyro-gasification of plant derived feedstocks,
(chipped and pelletized poplar and spruce wood), and analized for their properties useful
to predict their behaviour in a potting mix. All the studied biochars are alkaline, show
good physical stability (lack of shrinking), are richness in basic cations, particularly
potassium, and show different particle size distributions.
The first experiments carried on on mixtures of biochar and peat focuse on: 1) the liming
power of biochars; 2) the influence of biochars on the pore water composition; 3) the
effects of biochar application on the plant growth and nutrient uptake.
When added to an acidic peat in a dose of 30% v/v , biochars neutralize both peat acidity
and the acidification induced by root activity, that is inversely related to the size of
particles and not influenced by biochars pH. Incubations of mixtures with and without
plants highlight a dramatic influence of biochars on pore water composition.The poplar
wood biochar induces an almost complete depletion of the fertilizer-derived NH4
+-N and
high levels of NO3
--N in pore water, even though a decline over time is detected. On the
contrary, in the sprucewood biochar added mixture NH4
+-N is immobilized in a lesser
extent and only trace amounts of NO3
--N are detected.
Further, the abilities of biochars to adsorb ammonia and nitrate are explored and a
greater capacity for ammonia adsorption is detected. Then biochars are loaded with
ammonium and an incubation test and a plant growth trial are performed on the
ammonium-enriched materials added to a peat based growing media, compared with
(NH4)2SO4 and with a loaded zeolite. Ammonia from the loaded biochars are more
bioavailable than that carried by zeolite and both the studied biochars promote plant
nitrogen uptake. Lastly, a trial is conducted in a commercial greenhouse using two
biochars for total replacements of lime and partial substitution of the inorganic component (perlite). The growth of Ciclamen persicum plants results only slightly
influenced by the biochars while pore water solution composition is deeply modified by
the biochars.
It can be concluded that biochar efficiently substitutes lime in buffering peat acidity and
may be used as a partial replacement for peat and a source of potassium. Its highly
reactive surfaces account its potential to significantly alter soil solution chemistry.
Tipologia IRIS:
Tesi di dottorato
Keywords:
Biochar; Peat; Potassium; Nitrogen
Elenco autori:
F. Bedussi
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