145 research outputs found
Biosolids affect the growth, nitrogen accumulation and nitrogen leaching of barley
Biosolids are organic fertilisers derived from treated and stabilised sewage sludge that increase soil fertility and supply nitrogen to crops over a long period, but can also increase the risk of nitrogen (N) leaching. In this work, spring barley was grown in lysimeters filled with soil amended with biosolids, and with and without mineral N fertilisation. Biomass and the N concentration and content of shoots and roots were determined at flowering and maturity, and the N remobilization was calculated during grain filling. Drainage water was collected and analysed for N leaching. Biosolids increased soil porosity and soil nitrate, and positively affected the growth and N uptake of barley. Compared to mineral fertilisers, biosolids produced 18% higher vegetative biomass and 40% higher grain yield. During grain filling, both N uptake and N remobilization were higher with biosolids, which increased the grain N content by 32%. Nitrogen loss in leachates was 1.2% of plant uptake with mineral fertilisers and 1.7% with biosolids. Thus, soil fertilisation with biosolids greatly benefits spring barley, only slightly increasing N leaching
Characterization and origin of organic and inorganic pollution in urban soils in Pisa (Tuscany, Italy).
We assessed the quality of 31 urban soils in Pisa by analyzing total petroleum hydrocarbons (TPH), Cd, Cr, Cu, Hg, Mn, Ni, Pb, Zn and the platinum group (PGEs). The risk was evaluated by the geological accumulation index (Igeo) and the enrichment factor (EF). Results were compared with those obtained from a non-urban site and with the quantitative limits fixed by Italian legislation. In nearly all the monitored sites, the legal limit for TPH of 60 mg/kg in residential areas was exceeded, indicating widespread and intense pollution throughout the entire city area. The Igeo indicated no Cd, Cu, Mn, Ni and Zn pollution and minimal Pb and Cr pollution, due to anthropogenic enrichment. Legal Hg and Zn limits of 1 and 150 mg/kg respectively were exceeded in about 20% of sites, Cd (2 mg/kg), Cr (150 mg/kg) and Cu (120 mg/kg) in only one site, the Ni legal limit of 120 mg/kg was never exceeded. Some urban soils showed a higher Hg level than the more restrictive legal limit of 5 mg/kg concerning areas for industrial use. Based on the soluble, exchangeable and carbonate-bound fractions, Mn and Zn showed the highest mobility, suggesting a more potential risk of soil contamination than the other metals. The TPH and both Cr and Hg amounts were not correlated with any of the other monitored metals. The total contents of Cd, Pb, Zn and Cu in soils were positively correlated with each other, suggesting a common origin from vehicular traffic. The PGE values (Pt and Pd) were below the detection limits in 75% - 90% of the monitored areas, suggesting that their accumulation is at an early stage
Root dynamics and soil-enzyme activities in field bean/barley intercrops
The study and design of cropping systems that better exploit ecological processes is a priority of the scientific community and intercrops, involving two or more crop species growing simultaneously on the same field, are considered valuable to increase the productivity of traditional family farming and for the sustainable intensification of industrial agriculture.
Advantages of intercrops are based on ecological principles such as diversity, complementarity, facilitation and replacement, which are enhanced in cereal/legume associations because of the differences in the morphology and distribution of the root systems and in the use of different N sources. Understanding the complexity of plant-plant and plant-soil interactions is crucial because beneficial complementarity and facilitation relationships can rapidly turn into negative competition.
The field experiment consisted of a barley (Hordeum vulgare L. subsp. polystichum, var. Jallon) field bean (Vicia faba minor Beck, var. Vesuvio) intercrop (IC) and the respective sole crops (SC) grown at low (0 kg ha-1) and high (120 kg N ha-1 and 100 kg P ha-1) fertilizer inputs. Seed density was100 seeds m-2 for Fb, 250 seeds m-2 for B, and 100:125 seeds m-2 in the Fb:B IC, where plants were arranged in a 1:1 row ratio spaced 15 cm. At barley heading, soil and root samples were collected from the 0-20 cm soil profile and roots were cleaned from the soil with a water flow and then separated by species. Root morphological traits such as length, diameter, surface area and volume were analysed with WinRhizo, then samples were oven dried. On soil samples dehydrogenase, ß-glucosidase, alkaline phosphatase and arylsulphatase activities were determined, and the geometric mean (GMea) of the assayed soil enzyme activities was calculated.
Root density of IC was intermediate between Fb and B SC, the former displaying the highest density on dw basis, the latter on length basis. In both SCs root density was higher without fertilizer input, demonstrating a higher investment in roots in response to NP limitation. In contrast, fertiliser input increased root density in the IC, which we interpreted as a competitive root growth stimulated by the higher nutrient availability in soil.
The specific root length (SRL, m/g) increased in Fb SC in response to NP supply, demonstrating an energy investment in root elongation instead in feeding N2-fixing bacteria when mineral N was available, which is confirmed by the lower nodule density. The opposite occurred in the B SC, where SRL was reduced by mineral supply. In the IC, NP input increased the SRL of both species, demonstrating strong interspecific competition for nutrient acquisition and not complementarity, as it is generally supposed for cereal/legume intercrops. As a result of the higher investment of resources in root elongation, in Fb, nodule density decreased dramatically. In the fertilized IC soil also the GMea was higher, suggesting a major production of exudates from roots
Changes in biological properties and antioxidant capacity of an agricultural soil amended with sewage sludge
The effects of applying sewage sludge (SS) to agricultural soil (at low rate
of 22.5, LRS, and at high rate of 45 t ha−1 dry basis, HRS) were monitored
over a 120-d experimental period. Total organic carbon (TOC), water-
soluble organic carbon (WSOC), alkali-soluble phenols, basal respiration, 10
specific enzyme activity, dehydrogenase activity (DH-ase), metabolic
potential (MP) and FDA-hydrolytic activity (FDA) were strongly increased
by both rates of SS applications. In the SS amended soil, about 70% of
the organic C added with the material remained at the end of the
experiment. Basal respiration increased with increasing SS doses. The 15
specific enzyme activity and the MP indicate an increase in the enzyme
activity in soil.
AQ10
The addition of SS led to higher values than the control of all the
tested parameters up to the end of the experimental period. The anti-
oxidant capacity (trolox equivalent antioxidant capacity, TEAC) was influ- 20
enced by SS addition only when applied at HRS. After 120 days only HRS
value of TEAC (5.13 mM g−1) was higher than control (4.09 mM g−1). The
pattern of TEAC did not enable any link to be established between
antioxidant capacity and both alkali-soluble phenols and basal respira-
tion in soil
Esca symptoms appearance in Vitis vinifera L.: influence of climate, pedo-climatic conditions and rootstock/cultivar combination
This study investigated the appearance of esca
symptoms in relation to environmental factors and
the rootstock/cultivar combination in an experimental
setting between 2004 and 2009. Among the common
genotypes showing susceptibility to the esca disease,
four cultivars were considered: ‘Cabernet Sauvignon’,
‘Sangiovese’, ‘Trebbiano Toscano’ and ‘Chardonnay’.
These cultivars were studied own-rooted and in combination
with two rootstocks: Kober 5BB and 1103
Paulsen. The difference in susceptibility of cultivars to
esca appeared negatively related to the graft. No clear
relation was found between esca appearance and environmental
factors. Moreover, an unexpected discordance
between esca incidence percentage and mortality
rate was observed
Microbially-enhanced composting of olive mill solid waste (wet husk): Bacterial and fungal community dynamics at industrial pilot and farm level.
Bacterial and fungal community dynamics during microbially-enhanced composting of olive mill solid
waste (wet husk), used as a sole raw material, were analysed in a process carried out at industrial pilot
and at farm level by the PCR-DGGE profiling of the 16 and 26S rRNA genes. The use of microbial starters
enhanced the biotransformation process leading to an earlier and increased level of bacterial diversity.
The bacterial community showed a change within 15 days during the first phases of composting. Without
microbial starters bacterial biodiversity increased within 60 days. Moreover, the thermophilic phase was
characterized by the highest bacterial biodiversity. By contrast, the biodiversity of fungal communities in
the piles composted with the starters decreased during the thermophilic phase. The biodiversity of the
microbial populations, along with physico-chemical traits, evolved similarly at industrial pilot and farm
level, showing different maturation times
Paraoxonase-1 55 LL Genotype Is Associated with No ST-Elevation Myocardial Infarction and with High Levels of Myoglobin
It is well known that serum paraoxonase (PON1) plays an important role in the protection of LDL from oxidation. PON1 55 polymorphism is currently investigated for its possible involvement in cardiovascular diseases. The objective of our study is to verify if PON1 55 polymorphism is associated with risk of acute coronary syndrome (ACS) and with biochemical myocardial ischemia markers, such as troponin I, creatine kinase (CK)-MB, myoglobin, and C-reactive protein. We analysed PON1 55 polymorphism in a total of 440 elderly patients who underwent an ACS episode: 98 patients affected by unstable angina (UA), 207 AMI (acute myocardial infarction) patients affected by STEMI (ST elevation), and 135 AMI patients affected by NSTEMI (no ST elevation). We found that individuals carrying PON1 55 LL genotype are significantly more represented among AMI patients affected by NSTEMI; moreover, the patients carrying LL genotype showed significantly higher levels of myoglobin in comparison to LM + MM carriers patients. Our study suggests that PON1 55 polymorphism could play a role in the pathogenesis of cardiac ischemic damage. In particular, the significant association between PON1 55 LL genotype and the occurrence of a NSTEMI may contribute to improve the stratification of the cardiovascular risk within a population
A Process Calculus for Molecular Interaction Maps
We present the MIM calculus, a modeling formalism with a strong biological
basis, which provides biologically-meaningful operators for representing the
interaction capabilities of molecular species. The operators of the calculus
are inspired by the reaction symbols used in Molecular Interaction Maps (MIMs),
a diagrammatic notation used by biologists. Models of the calculus can be
easily derived from MIM diagrams, for which an unambiguous and executable
interpretation is thus obtained. We give a formal definition of the syntax and
semantics of the MIM calculus, and we study properties of the formalism. A case
study is also presented to show the use of the calculus for modeling
biomolecular networks.Comment: 15 pages; 8 figures; To be published on EPTCS, proceedings of MeCBIC
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RF Design of the X-band Linac for the EuPRAXIA@SPARC_LAB Project
We illustrate the RF design of the X-band linac for the upgrade of the SPARC_LAB facility at INFN-LNF (EuPRAXIA@SPARC_LAB). The structures are travelling wave (TW) cavities, working on the 2π/3 mode, fed by klystrons with pulse compressor systems. The tapering of the cells along the structure and the cell profiles have been optimized to maximize the effective shunt impedance keeping under control the maximum value of the modified Poynting vector, while the couplers have been designed to have a symmetric feeding and a reduced pulsed heating. In the paper we also present the RF power distribution layout of the accelerating module and a preliminary mechanical design
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