Rosaria D'Ascoli

Intensive agricultural systems negatively affect soil quality principally because of a reduction in soil organic
matter (OM). Sustainable practices providing organic amendments could be useful to maintain or increase OM
content in agricultural soils, preserving and improving soil fertility. In this study, biomass with a large C:N ratio
was applied to intensively farmed agricultural soils to maximize the increase of soil OM and hence chemical and
biochemical fertility. In particular, 30 and 60 t ha−1 of two mixtures of compost and scraps from poplar pruning,
A1 and A2, with different C:N ratios (15 and 25, respectively), were applied to soils of two farms (F1 and F2)
in a Mediterranean area (southern Italy) on an annual basis for two consecutive years. An effective, long-lasting
increase of soil OM, on average of 60 and 55% in F1 and F2 soils, respectively, was reached at the end of the
experiment. As well as a progressive increase in the C:N ratio, total N and available P also increased with organic
amendments, with positive effects on soil microbial activity as demonstrated by the enhancement of the seven
studied enzymatic activities. Principal component analysis demonstrated different responses to various organic
amendments between F1 and F2 soils because of their geopedological diversity. The results indicate that the C:N
ratio of the mixture is an important factor, but what is the best rate of addition to use is still not obvious. The use
of a smaller amount (30 t ha−1) of the A1 mixture (10:1 compost:wood) appears, in these types of soils, to be the
most suitable strategy to produce significant benefits.

"In a Mediterranean area of Southern Italy, affected by low- and high-severity experimental fires, burned
and unburned soils were analysed, at 245, 364 and 728 days after fire, for total and active fungal
mycelium mass, abundance, species density and species composition of total, xerotolerant and heatstimulated
culturable fungi, oribatid mites and springtails. Principal Component Analysis was used to
compare species composition of fungal community and faunal groups in burned and unburned plots.
Independently of severity, fire generally caused a decrease in fungal mass, an increase in culturable total,
xerotolerant and heat-stimulated fungi abundance (CFU), and minor changes in fungal species density. In
parallel, fire induced a reduction in abundance and species density of studied faunal groups, generally
correlated with fungal changes, and was consistently associated with the appearance of fungal and faunal
species not present in control. Moreover, qualitative and quantitative changes in fungal community and
faunal groups were recorded in association with sampling time. The results also suggested that the
mosaic of burned and unburned areas, typical of a Mediterranean maquis affected by fire, could promote
biodiversity in soil by favouring the contemporary presence of species typical of disturbed and undisturbed
areas."

Concerns about groundwater contamination as well as pesticide residues in food and soil have fuelled vigorous
debates about the sustainability of chemical-intensive agriculture. Search has been prompted for
agronomic strategies with lower environmental hazards. In this multidisciplinary study we compared
the characteristics of soils from 20 agricultural farms selected in five geographical areas of Southern
Italy with different soil types. In each farm, fields with management regime classified as high-input
(HIMR, intensive cultivation under plastic tunnels) or low-input (LIMR, tree orchards) were selected.
Soil samples were analyzed for 31 parameters including physical and chemical properties (bulk density,
water holding capacity, texture, pH, limestone, electrical conductivity, organic C to a depth of 0–20 and
20–40 cm, total N, P2O5, Ca2+, Mg2+, K+, Na+, cation exchange capacity), enzymatic activities (dehydrogenase,
arylsulphatase, -glucosidase, phosphatase and urease) and microbiological features (potential
respiration, functional diversity of microbial populations by BIOLOG EcoPlatesTM, microbial biomass, fungal
mycelium, culturable actinomycetes, bacteria and fungi, pseudomonads and bacterial species richness
by 16S rDNA-DGGE). Finally, a soil bioassay was performed in order to evaluate the plant growth of a
biotest plant (Lactuca sativa) and soil suppressiveness of the Rhizoctonia solani–L. sativa pathosystem.
Results showed that many soil properties were influenced by management regime more than by the
sampling area. Compared to LIMR, HIMR soils consistently had reduced soil organic C (−24%), enzymatic
activities, microbial biomass and fungal mycelium (−40% and −18%, respectively), functional diversity
(−18%) and bacterial species richness (−14%). On the contrary, the same soils showed a remarkable
increase in the values of the parameters related to the mineral soil fraction (electrical conductivity +370%;
P2O5 +72%; Na+ +86%). Management regime did not affect cation exchange capacity, pH, limestone and
soil texture. The lettuce bioassay showed a higher plant growth (+17%) in the LIMR compared to HIMR
soils, despite the lower content of mineral nutrients. Suppression of R. solani was not influenced by
management regime, but significant differences were recorded among farms. Differences among the
assessed soil parameters indicate a trend of soil quality deterioration under the high-input management
regime.

The relationship between pollution by heavy metals
and soil microbial community was investigated in an area
of Southern Italy mainly used for agriculture but also
affected by industrial and extractive activities as well as
vehicular traffic. Soil samples were seasonally collected in
permanent crop fields (i.e. citrus and peach orchards, olive
groves and vineyard) and uncultivated areas (coniferous
and mixed forests, shrublands, grazing lands). Soil samples
were analysed for chemical (water content, pH, cation
exchange capacity, organic C, Cr, Cu, Zn, Pb and Cd contents)
and biological properties (microbial biomass, fungal
mycelium, soil respiration, potentially mineralizable nitrogen,
metabolic quotient and carbon mineralization rate).
The results showed that heavy metal contents in the studied
soils generally fell within the limit values after Italian law,
with the exception of soil from vineyard that generally exceeded
the limit value for Cu, probably because of the large
use of copper-containing fungicides. The soil Pb content
was always above the values reported for typical unpolluted
soils and sometimes the same was also observed for Cd
and Cu. The data suggest that Cr, Cu and Zn mainly derive
from agricultural activity, whereas Pb and Cd were
mainly introduced by cement industry associated with extractive
activity. The soil microbial community was negatively
affected by increased Cr, Cu and Zn contents, but not
by Pb and Cd. Among the heavy metals considered, Cr and
Zn had the highest negative effect on soil microbial community.

The impact of different land use types on soil quality was evaluated by measuring several soil properties
that are sensitive to stress or disturbance and by using two synthetic approaches, i.e. a numerical quality
index and multivariate analysis. A Minimum Data Set of soil indicators was selected including physical
(texture, bulk density and water holding capacity), chemical (pH, cation exchange capacity, electrical
conductivity, organic carbon, total and mineral nitrogen, available K, Ca, Mg, P contents and total Cd, Cr,
Cu, Pb and Zn contents) and biological (microbial biomass, fungal mycelium, soil potential respiration
and potentially mineralizable nitrogen) parameters. These parameters were assayed on soil samples
collected with seasonal frequency (except for physical parameters, determined only in autumn) in an
area of Southern Italy under different land use types (i.e. permanent crops, grazing lands, shrublands,
coniferous and mixed forests). Moreover, formost of the land use types, a further distinction on the basis
of topographic position (hill, middle-hill and plain) was carried out. Annualmeans of the data (except for
texture) were used to calculate a soil quality index (SQI) and elaborated by multivariate analyses (Cluster
Analysis and Principal Component Analysis, PCA) in order to distinguish among different soil quality
classes. Data indicated a clear difference in soil quality among the studied areas: low soil quality
(SQI < 0.55) in almost all permanent crops; intermediate soil quality (0.55 < SQI < 0.70) in shrublands,
grazing lands, coniferous forest and middle-hill olive grove (the only crop with an herb layer on the soil
surface); high soil quality (SQI > 0.70) in mixed forests. Results suggested that the permanent crop
management had generally a strong negative impact on soil quality, while the moderate grazing activity
and the crop management that leaves an herb cover on the soil had a lower negative impact.
Nevertheless, the abandonment of cultivated lands, with consequent development of shrublands,
produced an improvement of soil quality suggesting a good recovery capacity in the studied soil.

Soil microbial activities and chemical properties related to the N cycle were investigated in function of
variations in plant cover type in a Mediterranean area of Southern Italy. Several biological (microbial
biomass, soil respiration, protease activity, degradation of 7 amino acids, net N mineralization, net
nitrification, potential net nitrification and denitrification) and chemical properties (water content, pH,
organic C, total and mineral N, C/N ratio) were determined in soil samples collected in spring and early
autumn under three plant cover types (high maquis, low shrub community and meadow) epitomizing
distinct successional stages following disturbance. Water content, organic C and C/N ratio were higher in
soil from high maquis than in soils from the other plant cover types; in contrast, no difference was
generally observed between the three soil types as for total and mineral N content. Likewise, no clear-cut
difference was recorded for most of the tested biological parameters if these were expressed per unit of
soil dry weight, with the exception of protease activity and soil respiration, which were significantly
higher in the high maquis. However, when biological data were expressed per unit of organic C, meadow
soil showed higher values of microbial biomass, asparagine degradation (only in spring), net
mineralization and net nitrification (only in autumn) compared to the other soils. Statistical analysis
pointed to seasonal fluctuation of water availability as an important limiting factor formicrobial biomass
and activity, with the exceptions of net N mineralization, net nitrification, glutamine and glutamic acid
degradation activities which appeared to be mainly driven by organic matter content in soils. Overall, the
results suggest that, in the investigated Mediterranean environment, variations in plant community
ranging from meadow to high maquis produce little changes in soil biological activities linked to the N
cycle, these being primarily affected by the availability of water and soil organic matter during the
annual cycle.

The present study investigates the impact of fire
(low and high severity) on soil fungal abundance and
microbial efficiency in C assimilation and mineralisation in
a Mediterranean maquis area of Southern Italy over 2 years
after fire. In burned and control soils total and active fungal
mycelium, microbial biomass C, percentage of microbial
biomass C present as fungal C, metabolic quotient (qCO2)
and coefficient of endogenous mineralisation (CEM) were
assayed together with several chemical properties of soil
(i.e. pH and contents of organic C, total and mineral N,
available K, Mg, Mn and water). Fire significantly decreased
the fungal mycelium, whereas it stimulated
microbial growth probably through the enhancement of
bacterial growth because of the increase in organic C and
nutrient contents in burned plots. This shift in microbial
community composition might explain the observed
reduction in soil microbial efficiency of C assimilation
(high qCO2) and the increase in C mineralisation rate
(CEM) in the first 84 days after fire. Therefore, fire might
increase CO2 input to the atmosphere not only during
combustion phase but also in the post-fire period.

The Mediterranean area of Southern Italy is characterized by different natural plant covers that mainly reflect different successional stages (i.e. low maquis, high maquis, Quercus ilex wood) and managed areas with introduced plant species (such as Pinus species). Soil properties could be affected by plant cover types as well as by plant species. Our objective was to determine the relationships of plant cover types and plant species with the chemical and biological characteristics of the soil. In four neighbouring areas with different plant cover types (low maquis, pure high maquis, high maquis with pines and pinewood, with pines planted by foresters in both cases), soil samples were collected under different plant species in order to evaluate the effect of plant cover types and plant species on soil properties. Soil samples were analyzed for nutrient content, microbial biomass, soil potential respiration and enzymatic activity (phosphatase, arylsulphatase, β-glucosidase and hydrolase activities) as well as for pH, water holding capacity (WHC) and cation exchange capacity (CEC). Application of cluster analysis and principal component analysis to the data revealed that the plant cover type was the key factor influencing soil properties more than plant species. In fact, the largest differences were observed between pure high maquis soils and all other soils, with pure high maquis soils generally showing the highest values of WHC, CEC, nutrient content, organic and microbial C, soil respiration, phosphatase, arylsulphatase and β-glucosidase activities. The significantly lower values of these variables in the low maquis relative to the pure high maquis probably reflect the effect of ecological succession on soil. The high maquis with pine, differing from the pure high maquis only for the presence or absence of pine, showed values of soil physical, chemical and biological characteristics similar to those found in the low maquis, thus suggesting that the presence of pine retards soil development.

Intensive agriculture determines a decrease of soil quality mainly due to a strong organic matter reduction. Use of organic amendments is generally seen as a key tool for soil health and sustainability in intensive agriculture systems, in terms of organic matter recovery.
Aim of this work was to study the recovery of fertility in agricultural soils cultivated under permanent plastic cover, by supplying organic amendments characterized by a slow mineralization, such as wood scraps. After yearly addition of organic amendments, crop yields and soil fertility, by monitoring the main chemical, biochemical and biological properties, were evaluated for two years.
Results showed generally positive effects of organic amendments on soil chemical properties, in particular as improvement in organic carbon and nutrient contents, as well as in biological properties. Our results demonstrated that the use of compost enriched with low mineralization materials, such as wood scraps, can enhance soil biochemical and chemical properties compared with synthetic fertilizers, and consequently improve crop yields, but above all to guarantee an organic matter recovery that kept stable over time.

Intensive agricultural practices can determine a decline in soil fertility which represents the main constraint to agricultural productivity. In particular, the progressive reduction in soil organic matter, without an adequate restoration, may threaten soil fertility and agriculture sustainability. Some soil management practices can improve soil quality by adding organic amendments as alternative to the sole use of mineral fertilizers for increasing plant quality and growth. A large number of soil properties can be used to define changes in soil quality. In particular, although more emphasis has been given in literature to physical and chemical properties, biological properties, strictly linked to soil fertility, can be valid even more sensitive indicators. Among these, soil enzyme activities and microbial biomass may provide an "early warning" of soil quality and health changes. The aim of this work was to study the effect of preventive sterilization treatment and organic fertilization on enzymatic activities (dehydrogenase, arylsulphatase, beta-glucosidase, phosphatase, urease) and microbial biomass C in an agricultural soil under crop rotation. The study was carried out on an agricultural soil sited in Campania region (South Italy). At the beginning of experiment sterilizing treatments to control soilborne pathogens and weeds were performed by solarization and calcium cyanamide addition to soil. Organic fertilization was carried out by adding compost from vegetable residues, ricin seed exhaust (Rigen) and straw, singly or in association. Three samplings were performed at three different stages of crop rotation: I) September 2005, immediately after the treatments; II) December 2005, after a lettuce cycle; III) January 2007, after peppers and lettuce cycles. The soil sampling followed a W scheme, with five sub-samples for each plot. Soils were sieved at 2 mm mesh and air dried to determine physical and chemical properties; in addition a suitable amount of soils was stored at 4 °C for biological analyses. On soil samples, organic C, dehydrogenase phosphatase, beta-glucosidase and urease activities as well as microbial biomass C and fungal mycelium were assayed. Results showed that sterilization treatments (solarization+calcium cyanamide) depressed almost all the enzymatic activities studied. By contrast their values were enhanced by the addition of compost combined with Rigen and/or straw. During the time the dehydrogenase activity strongly fell whereas slightly decreases occurred for the activity of phosphatase, beta-glucosidase and urease. Accordingly, a decrease in organic C content was measured. Conversely, arylsulphatase showed an activity increase at the second and third sampling. Microbial biomass C was improved by compost or compost + Rigen addition, in accordance with organic C trend. Normalizing the microbial biomass to the organic C content (microbial quotient) only in one plot a higher and significant value was obtained. Conversely the fungal growth was not influenced by amendment practices, rather in the time it was significantly depressed. Data showed an ameliorant effect of organic amendments, especially when compost was combined with other ones, on chemical, biological and biochemical properties of studied soils. Further investigations related also to crop production should however be carried out to achieve a clearer and comprehensive picture of the relationships between soil quality and soil management practices.

An intensive management of agricultural soils is widely carried out to increase vegetation productivity. Nevertheless, the large use of machineries, chemical fertilizers and pesticides can often cause, in time, a substantial decline in soil fertility by affecting soil physical and chemical properties and, in turn, growth and activity of soil microbial community. In fact, alteration in soil structure, nutrient losses and, in particular, changes in quality and quantity of soil organic matter are some of the principal soil degradation processes deriving from an intensive agricultural management that can affect, in different ways, soil biochemical and biological properties. The aim of this research was to assess the impact of intensive management on agricultural soils by measuring soil physical, chemical and biochemical/biological properties. The use of appropriate indicators as quantitative tools could allow to assess soil quality. Moreover, although soil physical and chemical properties have received great attention, soil biochemical/biological properties, such as enzyme activities and microbial biomass, functionally related properties involved in the nutrient cycles, can be considered as sensitive indicators of soil quality and health changes because, they show a faster turn over compared to soil organic matter. Our attention was focused on the Plane of Sele river (Campania region, Italy), an area characterized by an intensive agriculture and greenhouse cultures. Twenty-five farms were chosen, with the aid of regional soil map, in order to get soils with different physical and chemical properties. As common trait, the selected farms, all with greenhouse cultures, used no organic amendments but only mineral compounds to fertilize soils. Moreover, to better understand the impact of intensive agricultural practices on soil of each farm, control soils from orchards or uncultivated plots were chosen. In each farm soil samples were collected in three different plots within a greenhouse or within a field, for control soils. Every sample was formed by 5 sub-samples collected in 5 different points following a W scheme in the plot. All samples, sieved at 2 mm mesh, were stored at 4 °C and characterized by analysing the following soil physical and chemical, properties: soil texture, bulk density, water content, water holding capacity, pH, cation exchange capacity, organic carbon, total nitrogen, phosphorus, potassium, sodium, lime, and electrical conductivity were determined. Moreover the activity of dehydrogenase, beta-glucosidase, urease, phosphatase, and arilsulphatase, the enzymes involved in the biogeochemical cycles of carbon, nitrogen, phosphorous and sulphur, respectively, as well as microbial biomass C were measured. Results of this study seem to indicate that a great variability exists among the farms. A clear evidence is that the control samples, not subjected to intensive farming, always showed better values of chemical properties and higher values of enzymatic activity and microbial biomass to indicate a negative effect of intensive agriculture practices on soil quality and fertility in studied areas. Data confirm that enzymatic activities and microbial biomass can be considered valid and sensitive indicators of soil quality.

The intensive agricultural managements, increased in the last twenty years, have resulted in a decrease in fertility of soils, representing a serious threat to agricultural productivity due to both the increase in production cost, mainly for intensive use of mineral fertilizers, and the loss of the quality of crops themselves. Organic matter content is closely related to the soil fertility and its progressive reduction in cultivates soils, without a satisfactory recovery, could make agriculture untenable, resulting in a high detrimental effect on environment. But an appropriate soil management practices can improve soil quality by utilizing organic amendments as alternative to mineral fertilizers to increase soil quality and plant growth. In this context, demand of suitable indicators, whose are able to assess the impact of different agricultural managements on soil quality, has increased. It has shown that soil biological and biochemical properties are able to respond to small changes in soil conditions, thus providing information on subtle alterations in soil quality. Aim of this study was to evaluate the use of soil biological and biochemical properties as fertility indicators in agricultural soils under different agricultural managements, sited in Campania Region (Southern Italy). After a preliminary monitoring phase of soil fertility on different farms sited in five agricultural areas of Campania Region, we have selected two farms in two different study areas to assess the effect on soil quality of different organic amendments. In particular, a compost from municipal solid waste and wood from scraps of poplars pruning were supplied in different doses and ratios. Soil samplings after one month from the amendment addition and then every 4 months until a year were carried out. All collected soil samples were characterized by main physical, chemical, biochemical and biological properties. In general, the use of different organic amendments showed a positive effect on fertility of both soils under intensive farming. In general, all enzymatic activities and organic carbon content increased after 1 month, and they were still higher after 4 months from amendment application. Microbial biomass and soil potential activity (respiration) showed significantly higher values in soils added with organic amendments, for both farms and samplings, with more marked effects on respiration in the first sampling. In conclusion results showed, in general, a quick response as indicators of the assayed biological and biochemical soil properties and a good recovery in fertility of the studied agricultural soils. The project was founded by CCIIAA of Salerno