Giuseppe Celano

Sustainability evaluation of Sicily's lemon and orange production: An energy, economic and environmental analysis

The island of Sicily has a long standing tradition in citrus growing. We evaluated the sustainability of orange and lemon orchards, under organic and conventional farming, using an energy, environmental and economic analysis of the whole production cycle by using a life cycle assessment approach. These orchard systems differ only in terms of a few of the inputs used and the duration of the various agricultural operations. The quantity of energy consumption in the production cycle was calculated by multiplying the quantity of inputs used by the energy conversion factors drawn from the literature. The production costs were calculated considering all internal costs, including equipment, materials, wages, and costs of working capital. The performance of the two systems (organic and conventional), was compared over a period of fifty years. The results, based on unit surface area (ha) production, prove the stronger sustainability of the organic over the conventional system, both in terms of energy consumption and environmental impact, especially for lemons. The sustainability of organic systems is mainly due to the use of environmentally friendly crop inputs (fertilizers, not use of synthetic products, etc.). In terms of production costs, the conventional management systems were more expensive, and both systems were heavily influenced by wages. In terms of kg of final product, the organic production system showed better environmental and energy performances.

Genetic, Functional, and Metabolic Responses of Soil Microbiota in a Sustainable Olive Orchard

The aim of the present work was to evaluate the effects of two soil management systems so called sustainable treatment (ST) and conventional treatment (CT) on the composition and on genetic, functional, and metabolic diversity of soil microbial communities in a Mediterranean olive orchard. The ST system included no-tillage, integrated chemical fertilization, and organic matter inputs from drip irrigation, spontaneous cover crops, and pruning material. Microbial analyses were carried out by an integrated approach of culture-dependent (microbial cultures and Biolog) and culture-independent methods (denaturing gradient gel electrophoresis [DGGE]). After 7 years of treatment, average olive yield was 8.4 and 3.1 t ha−1 year−1 in ST and CT, respectively. Conventional treatment had a significantly higher number of total culturable bacteria and actinomycetes compared with ST, whereas fungi were significantly lower. In ST, the number of ammonifying bacteria, proteolytic bacteria, and Azotobacter in the wetted areas under the drippers (ST-WET) was significantly higher than along interrows (ST-INTER). The DGGE analysis of microbial 16S/18S rDNA showed differences between ST and CT, whereas 16S/18S rRNA DGGE bands of ST-WET clustered differently from those of CT and ST-INTER. Some Biolog metabolic indexes were significantly different between ST and CT. The results revealed qualitative and quantitative changes of soil microbial communities in response to sustainable agricultural practices that stimulate soil microorganism activity and improve olive yield and fruit quality.

The Stable Isotopes Approach to Study C and N Sequestration Processes in a Plant–Soil System

This chapter reviews the main methods for tracing N and C stable isotopes in natural and agricultural systems following organic and mineral amendments to soil. Moreover, we present the results obtained from two field experiments conducted, within the MESCOSAGR project, to evaluate either the fate and flow rate of N added as 15N-compost in a maize–soil system or the contribution of sorghum roots to soil organic carbon. Compost contribution to plant nutrition was about 20% of applied N in the first experimentation year, while this value decreased in the following 2 years. The mineralization rate in the first year was anyhow variable depending on compost maturity and composition, while compost amendments mostly affected the inclusion of 15N in soil macro-aggregates. The compost-derived nitrogen sequestered in soil, due to repeated amendments, was estimated to account for 34.2, 38.2 and 42.5% of total N-compost for the first, second and third years, respectively. On the other hand, it was found that soil carbon derived from sorghum residues reached about 28% after 3 years, though this percentage decreased with depth, and more rapidly below 30 cm.

Changes in composition and activity of soil microbial communities in peach and kiwifruit Mediterranean orchards under an innovative management system

The aim of this work was to evaluate the effects of 2 soil management systems, so called ‘innovative’ (INN) and ‘conventional’ (CON), on genetic and metabolic diversity of soil microbial communities of peach and kiwifruit orchards. INN system included minimum tillage, organic matter inputs from compost and cover crops, winter pruning, and adequate irrigation and fertilisation. CON system was characterised by conventional tillage, zero organic input, empirical pruning, strong chemical fertilisation, and excessive irrigation. After 4 years of treatments, soil samples were collected in different orchard sites. In peach and kiwifruit INN orchards, average fruit yields were significantly higher than in CON. INN orchards had a significantly higher total number of bacteria. The patterns of denaturing gradient gel electrophoresis of bacterial 16S rDNA/RNA from peach orchard showed differences between soils under drip emitters and along the inter-rows, whereas those from kiwifruit orchard clearly distinguished between INN and CON for both bacteria (16S rRNA) and fungi (18S rDNA/RNA). Shannon’s substrate diversity index, evaluated by Biolog® metabolic assay, was affected by soil treatment in peach orchard and by soil depth in kiwifruit orchard. Principal component analysis of Biolog® values clearly discriminated INN and CON soils of both orchards. The results revealed qualitative and quantitative changes of soil microbial communities in response to an innovative and sustainable soil management.