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Losses of soil organic carbon often occur because of intensive agricultural practices that lead to removal of organic carbon following harvest production and to insufficient inputs. Organic amendments can be very appropriate for enhancing organic carbon content in very stressed agricultural soils. By enhancing soil organic matter, they generally play an important role in environmental matrices due to their capacity in retaining water and in enhancing nutrient availability to plants. Therefore, understanding the mechanisms by which organic amendments interact with other chemicals in the environment is of paramount importance. The attention was focused on farms near Sele river (Campania region, Italy), an area characterized by intensive agriculture. Two farms, with contrasting geopedologic properties (clay vs. sandy), were selected in order to study the effect of different doses of organic amendments containing compost from municipal solid wastes and wood-wastes (scraps of poplars pruning) at different ratios. The organic fractions were extracted from soil, after one and twelve months from amendment, and were analysed in order to establish their elemental composition and properties by FTIR, CPMAS 13C NMR spectroscopy and FFC-NMR relaxometry. Results showed an important role of soil geopedologic characteristics and experimental time in the evolution of humic acids. In less aerobic conditions as occurs in clay soils, organic matter was more stable, rich in carbonyl groups belonging to aldehydes and ketones, whereas under more aerobic conditions, occurring in sandy soils, organic matter had undergone a faster degradation, due to oxidative conditions and more intensive microbial activity.

Two commercial TiO2samples, a 100% anatase and a 100% rutile, were used for the fast field cycling NMR experiments. The results showed a different behavior between the different samples. In particular, water molecules were unbonded to the solid surface for the rutile sample, whereas they appeared to chemically interact with the surface through H-bond formation with the anatase sample. The above findings accord with the generally lower activity of rutile with respect to anatase reported in literature for photocatalytic oxidation reactions in water. The difficulty of water to interact with rutile surface, indeed, could hinder the formation of OH radicals, which are the most important oxidant species.

In semiarid environments, time of sowing is one of the most important factors influencing seed yields. For coriander (Coriandrum sativumL.), the most commonly recommended cropping technique is spring sowing (March–April), since the optimum soil temperature for seed germination ranges between 20 and 23°C, and the crop shows a remarkable sensitivity to frost and cold. In many semiarid areas of southern Italy, however, the occurrence of prolonged dry periods in summer and spring does not allow for the scheduling of summer crops without irrigation. However, the generally mild winter temperatures and the typical rainfall distribution, which is mostly concentrated over the winter months, could allow sowing time to be moved to the winter season to take advantage of the winter rainfalls. To evaluate the effect of moving the sowing time of coriander on seed yield and plant performance in semiarid Mediterranean environments, a field trial was performed in 1998–1999, 1999–2000, and 2000–2001 at Sparacia (Cammarata, AG, Sicily). Coriander seeds were sown in rows 50 cm apart every month for 5 mo from December to April. The fruits were harvested from mid‐June to mid‐July. The time from sowing to harvest was greatly dependent on the sowing date; the duration was 193 to 195 d for the December sowings, and 91 to 100 d for the April sowings. In all 3 yr, the most productive sowing time was December, and sowing after this date resulted in lower yields.

AbstractFennel is an industrial source of anethole but, recently, further interest has came from the suggested possibility of many industrial uses of this plant.The volatile substances from the seeds of Fennel grown in Sparacia (Cammarata – AG – Sicily; 37° 38’ N; 13° 46’ E) have been investigated and compared on a statistical base with previously reported data. The variety grown in Sparacia fall into the “high fenchone” chemovariety. The substances α-toluene, α-terpinene, β-phellandrene+limonene and camphene appear the components most sensitive to environment and grow condition modifications.

AbstractThirty-one samples of Coriandrum sativumL. fruits, of different origin, year of cultivation (harvest) and crop management systems were subjected to volatile component analysis by combining Head Space Solid Phase Microextraction (HS-SPME) with GC/MS. In order to determine the importance of the major sources of volatile variability, some statistical analyses, including Cluster Analysis (CA) and Principal Component Analysis (PCA), were performed on the obtained data. The compounds, which gave the main contribution to the partition and classification of the original data, were α-pinene, p-cymene, γ-terpinene and linalool. The age of the fruits, which ranged from 1–16 years, seemed to generate rather identifiable effects such as a decreasing trend on α- and γ-terpinene, terpinolene and linalool, and an increase in p-cymene. The same components also seemed to vary depending upon the geographic location of the cultivation. No statistically relevant differences were detected between the biological and conventional cropping management techniques.

The compounds 4,4′-bipyridinium(2+) pentachloro-bismuthate(III) (1), [4,4′-(C10H8N2)BiCl5] and 2,2′-bipyridinium(2+) pentachloro-bismuthate(III) (2), [2,2′-(C10H8N2)Bi2Cl10] have been obtained by reacting bismuthate oxide and 4,4′-bipyridine or 2,2′-bipyridine in HCl acid medium. They have been characterized by single crystal X-ray analysis. (1) crystallizes in the triclinic space group $$P\bar 1$$ with a= 9.776(2), b= 11.009(3),c= 8.346(1) Å, α = 101.58(2), β = 98.63(2), and γ = 112.86(2)°. (2) crystallizes in the monoclinic space group P21/cwith a= 14.239(2), b= 14.226(2), c= 16.275(3) Å, and β = 110.15(2)°. The crystal structure of (1) consists of 4,4′-bipyridinium(2+) cations interacting through hydrogen bonding with [Bi2Cl10]2−dimers giving rise to endless double chains, while that of (2) is formed by 2,2′-bipyridinium(2+) cations and [Bi4Cl20]8−tetramers extensively interacting through hydrogen bonding. The different polynuclearity of the anions seems related to the different directions along which each cation can form hydrogen bond interactions.

The reaction between bismuthate oxide and phen (1,10-phenanthroline) in acid medium led to the isolation of the unusual [(PhenH)(PhenH2)][BiCl6]·2H2O derivative, which has been characterized by X-ray analysis and IR spectroscopy. The compound crystallizes in the triclinic space group $$[\text[P\bar 1]]$$ with a= 8.313(2), b= 9.349(2), c= 9.807(3) Å, α = 86.39(3), β = 110.27(3) and γ = 106.48(3)°. The crystal structure is made of [BiCl6]3−anions and [(PhenH)(PhenH2)]3+cations. A network of hydrogen bond interactions involving the two clathrated water molecules, the phenanthroline moiety and the chlorines characterizes the entire structure.

Iron(ii) can be exchanged into layered γ-Zr(H2PO4 )(PO4 )–diamine and γ-Ti(H2PO4 )(PO4 )–diamine composites (diamine=2,2′-bipyridyl, 1,10-phenanthroline, 2,9-dimethyl-1,10-phenanthroline). Mössbauer spectroscopy indicates that an in situ iron–amine coordination occurs in the case of iron–bipyridyl– and iron–phenanthroline–γ-zirconium phosphate: Fe2+ low-spin trischelates [Fe(bipy)3 ]2+ and [Fe(phen)3 ]2+ are formed between the layers of the host; high-spin Fe2+ also forms complexes in the interlayer region and the chromophores could be any of the possibilities provided by the formulation [FeNxO6-x] (x=1–4). Iron(ii) partially transforms into iron(iii) when the former is not stabilized by the formation of strong complex species. The thermal behaviour of the exchanged compounds has been investigated and correlated with the composition of the materials. X-Ray patterns of some of the new materials are also reported.

Mössbauer, far-infrared, and X-ray photoemission spectroscopy (XPS) studies have been made on doped (SnCl2or SnCl4) (PEFl) and polyphenylacetylene (PPA). The nature of the tin as it is incorporated into the polymer is examined. The resistance values of the doped polymers are followed with relative humidity. Results point to tetrahedral (SnCl4and octahedral (SnCl4· 2H2O) species in the SnCl4doping. With SnCl2doping, the nature of the species is less certain, although both Sn(II) and hexacoordinated Sn(IV) appear to be present. Index Headings: Mössbauer

The synthesis and the crystal and molecular structure of the difluoro(hydroxodi-2-pyridylmethoxo-NN'O) antimony(III) compound determined by single crystal X-ray diffraction analysis are reported. Crystals are orthorhombic, space group Pbcn,a=12.732(2),b=12.165(2),c=15.936(2) Å. Refinement based on 1516 observed reflections led to a finalR value of 0.025 (Rw=0.028). In the crystal the di-2-pyridyl ketone behaves asfacial-(NN'O)-terdentate in the Sb coordination, the square pyramid geometry around the metal is completed by the coordination of two fluorine atoms.