Impact of nitrification inhibitor (DMPP) on soil nitrous oxide emissions from an intensive broccoli production system in sub-tropical Australia

Vegetable cropping systems are often characterised by high inputs of nitrogen fertiliser. Elevated emissions of nitrous oxide (N2O) can be expected as a consequence. In order to mitigate N2O emissions from fertilised agricultural fields, the use of nitrification inhibitors, in combination with ammonium based fertilisers, has been promoted. However, no data is currently available on the use of nitrification inhibitors in sub-tropical vegetable systems. A field experiment was conducted to investigate the effect of the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on N2O emissions and yield from broccoli production in sub-tropical Australia. Soil N2O fluxes were monitored continuously (3 h sampling frequency) with fully automated, pneumatically operated measuring chambers linked to a sampling control system and a gas chromatograph. Cumulative N2O emissions over the 5 month observation period amounted to 298 g-N/ha, 324 g-N/ha, 411 g-N/ha and 463 g-N/ha in the conventional fertiliser (CONV), the DMPP treatment (DMPP), the DMMP treatment with a 10% reduced fertiliser rate (DMPP-red) and the zero fertiliser (0N), respectively. The temporal variation of N2O fluxes showed only low emissions over the broccoli cropping phase, but significantly elevated emissions were observed in all treatments following broccoli residues being incorporated into the soil. Overall 70–90% of the total emissions occurred in this 5 weeks fallow phase. There was a significant inhibition effect of DMPP on N2O emissions and soil mineral N content over the broccoli cropping phase where the application of DMPP reduced N2O emissions by 75% compared to the standard practice. However, there was no statistical difference between the treatments during the fallow phase or when the whole season was considered. This study shows that DMPP has the potential to reduce N2O emissions from intensive vegetable systems, but also highlights the importance of post-harvest emissions from incorporated vegetable residues. N2O mitigation strategies in vegetable systems need to target these post-harvest emissions and a better evaluation of the effect of nitrification inhibitors over the fallow phase is needed.

An XPS study of the surface oxidation states of metals in some oxide catalysts

Calcined samples of chromia supported on Al2O3, ZnO, or SnO2 show both Cr(VI) and Cr(III) on the surface, Cr(VI) being preponderant in the case of Al2O3-supported catalysts. The proportion of Cr(VI) decreases with increase in Cr content of the calcined catalysts. Reduction of the supported chromia catalysts in H2 at 720 K for 1 hr gives rise to Cr(III) and Cr(V). On carrying out the dehydrogenation of cyclohexane on the chromia catalysts a higher proportion of Cr(V) is found than after treatment with hydrogen. Vanadia supported on Al2O3 or MoO3 shows significant proportion of V(IV) on carrying out the oxidation of toluene on the catalysts. Calcined MoO3 (10%)/Al2O3 shows only Mo(VI) on the surface at 300 K, but on heating to 670 K in vacuum shows the presence of a considerable proportion of Mo(V) which on cooling disproportionates to Mo(IV) and Mo(VI). Mo(V) is noticed on surfaces of this catalyst on reduction with hydrogen as also on carrying out dehydrogenation of cyclohexane. While Bi2MoO6 shows only Mo(VI) on the surface at 300 K, heating it to 670 K in vacuum changes it entirely to Mo(V) which then gives rise to Mo(IV) and Mo(VI) on cooling.

Lanthanide perchiorate complexes of 4-cyano puridine N-oxide, 4-chloro 2-picoline-B-Oxide and 4_dimethyl amino-2-Picoline N Oxide

Complexes of lanthanide perchlorates with 4-cyano pyridine-1-oxide, 4-chloro 2-picoline-1-oxide and 4-dimethyl amino 2-picoline-1-oxide have been isolated for the first time and characterized by analysis, conductance, infrared, NMR and electronic spectra.

Australian feature films and distribution: Industry or cottage industry?

Feature films remain critical flagships to any national film industry. Australian feature films can be highly commercial endeavours that also perform symbolic functions by embodying the national imaginary in big screen based sound and imagery. They conduct a dialogue with domestic audiences as well as showcase key aspects of Australia in the global film festival circuit. As the pre-eminent filmmaking form, feature films also serve as important launchpads for the careers of many Australian writers, directors, actors and technical crew. In the wake of over a decade of diminished share of local box office obtained by Australian feature films, Australian Feature Films and Distribution: Industry or cottage industry, examines issues in the production sector affecting the performance of Australian feature films and some responses by the central funding and support screen agency, Screen Australia.

Electrical and optical properties of amorphous semiconducting GeSe and GeSbSe films

The electrical activation energy and optical band-gap of GeSe and GeSbSe thin films prepared by flash evaporation on to glass substrates have been determined. The conductivities of the films were found to be given by Image , the activation energy Ea being 0.53 eV and 0.40 eV for GeSe and GeSbSe respectively. The optical absorption constant α near the absorption edge could be described by Image from which the optical band-gaps E0 were found to be 1.01 eV for GeSe and 0.67 eV for GeSbSe at 300°K. At 110°K the corresponding values of E0 were 1.07 eV and 0.735 eV respectively. The significance of these values is discussed in relation to those of other amorphous semiconductors.

Experimental investigation of catalytic and non-catalytic surface reactions on SiO2 thin films with shock heated oxygen gas

The present study is to investigate the interaction of strong shock heated oxygen on the surface of SiO2 thin film. The thermally excited oxygen undergoes a three-body recombination reaction on the surface of silicon dioxide film. The different oxidation states of silicon species on the surface of the shock-exposed SiO2 film are discussed based on X-ray Photoelectron Spectroscopy (XPS) results. The surface morphology of the shock wave induced damage at the cross section of SiO2 film and structure modification of these materials are analyzed using scanning electron microscopy and ion microscopy. Whether the surface reaction of oxygen on SiO2 film is catalytic or non-catalytic is discussed in this paper.

Viscoelastic Properties of Nanocrystalline Films of Semiconducting Chalcogenides at Liquid/Liquid Interface

The interfacial shear rheological properties of a continuous single-crystalline film of CuS and a 3D particulate gel of CdS nanoparticles (3−5 nm in diameter) formed at toluene−water interfaces have been studied. The ultrathin films (50 nm in thickness) are formed in situ in the shear cell through a reaction at the toluene−water interface between a metal−organic compound in the organic layer and an appropriate reagent for sulfidation in the aqueous layer. Linear viscoelastic spectra of the nanofilms reveal solid-like rheological behavior with the storage modulus higher than the loss modulus over the range of angular frequencies probed. Large strain amplitude sweep measurements on the CdS nanofilms formed at different reactant concentrations suggest that they form a weakly flocculated gel. Under steady shear, the films exhibit a yield stress, followed by a steady shear thinning at high shear rates. The viscoelastic and flow behavior of these films that are in common with those of many 3D “soft” materials like gels, foams, and concentrated colloidal suspensions can be described by the “soft” glassy rheology model.

Soybean rotation and crop residue management to reduce nitrous oxide emissions from sugarcane soils

NITROUS OXIDE (N2O) IS a potent greenhouse gas and the predominant ozone-depleting substance in the atmosphere. Agricultural nitrogenous fertiliser use is the major source of human-induced N2O emissions. A field experiment was conducted at Bundaberg from October 2012 to September 2014 to examine the impacts of legume crop (soybean) rotation as an alternative nitrogen (N) source on N2O emissions during the fallow period and to investigate low-emission soybean residue management practices. An automatic monitoring system and manual gas sampling chambers were used to measure greenhouse gas emissions from soil. Soybean cropping during the fallow period reduced N2O emissions compared to the bare fallow. Based on the N content in the soybean crop residues, the fertiliser N application rate was reduced by about 120 kg N/ha for the subsequent sugarcane crop. Consequently, emissions of N2O during the sugarcane cropping season were significantly lower from the soybean cropped soil than those from the conventionally fertilised (145 kg N/ha) soil following bare fallow. However, tillage that incorporated the soybean crop residues into soil promoted N2O emissions in the first two months. Spraying a nitrification inhibitor (DMPP) onto the soybean crop residues before tillage effectively prevented the N2O emission spikes. Compared to conventional tillage, practising no-till with or without growing a nitrogen catch crop during the time after soybean harvest and before cane planting also reduced N2O emissions substantially. These results demonstrated that soybean rotation during the fallow period followed with N conservation management practices could offer a promising N2O mitigation strategy in sugarcane farming. Further investigation is required to provide guidance on N and water management following soybean fallow to maintain sugar productivity.

Evaluation of packaging films to extend storage life of indigenous Australian vegetables and herbs

A study undertaken in Hervey Bay, Queensland, investigated the potential of creating an indigenous agribusiness opportunity based on the cultivation of indigenous Australian vegetables and herbs. Included were warrigal greens (WG) (Tetragonia tetragonioides), a green leafy vegetable and the herb sea celery (SC) (Apium prostratum); both traditional foods of the indigenous population and highly desirable to chefs wishing to add a unique, indigenous flavour to modern dishes. Packaging is important for shelf life extension and minimisation of postharvest losses in horticultural products. The ability of two packaging films to extend WG and SC shelf life was investigated. These were Antimisted Biaxial Oriented Polypropylene packaging film (BOPP) without perforations and Antifog BOPP Film with microperforations. Weight loss, packaging headspace composition, colour changes, sensory differences and microbial loads of packed WG and SC leaves were monitored to determine the impact of film oxygen transmission rate (OTR) and film water vapour transmission (WVT) on stored product quality. WG and SC were harvested, sanitised, packed and stored at 4°C for 16 days. Results indicated that the OTR and WVT rates of the package film significantly (PKLEINERDAN0.05) influenced the package headspace and weight loss, but did not affect product colour, total bacteria, yeast and mould populations during storage. There was no significant difference (PGROTERDAN0.05) in aroma, appearance, texture and flavour for WG and SC during storage. It was therefore concluded that a shelf life of 16 days at 4°C, where acceptable sensory properties were retained, was achievable for WG and SC in both packaging films.

Field measurement of beef pen manure methane and nitrous oxide reveals a surprise for inventory calculations

Few data exist on direct greenhouse gas emissions from pen manure at beef feedlots. However, emission inventories attempt to account for these emissions. This study used a large chamber to isolate N2O and CH4 emissions from pen manure at two Australian commercial beef feedlots (stocking densities, 13-27 m(2) head) and related these emissions to a range of potential emission control factors, including masses and concentrations of volatile solids, NO3-, total N, NH4+, and organic C (OC), and additional factors such as total manure mass, cattle numbers, manure pack depth and density, temperature, and moisture content. Mean measured pen N2O emissions were 0.428 kg ha(-1) d(-1) (95% confidence interval [CI], 0.252-0.691) and 0.00405 kg ha(-1) d(-1) (95% CI, 0.00114-0.0110) for the northern and southern feedlots, respectively. Mean measured CH4 emission was 0.236 kg ha(-1) d(-1) (95% CI, 0.163-0.332) for the northern feedlot and 3.93 kg ha(-1) d(-1) (95% CI, 2.58-5.81) for the southern feedlot. Nitrous oxide emission increased with density, pH, temperature, and manure mass, whereas negative relationships were evident with moisture and OC. Strong relationships were not evident between N2O emission and masses or concentrations of NO3- or total N in the manure. This is significant because many standard inventory calculation protocols predict N2O emissions using the mass of N excreted by the animal.

2,6-Lutidine-N-oxide complexes of rare-earth bromides

2,6-Lutidine-N-oxide (LNO) complexes of rare-earth bromides of the composition $$MBr_3 .(LNO)_{4_{ - n} } .nH_2 O$$ wheren = l for M = La, Pr, Nd, Sm, Gd, Ho, Er; andn = 0 for M = Y have been prepared and characterised by analyses, conductance and infrared data. Infrared spectra of the complexes indicate that the coordination of ligand to the metal ion takes place through the oxygen of the ligand, and the water molecule in the complexes present is coordinated to the metal. A coordination number of seven has been suggested to all the rare-earth metal ions.

Influence of rapid thermal annealing (RTA) on the structural and electrical properties of SnS films

The performance of optoelectronic devices critically depends on the quality of active layer. An effective way to obtain a high quality layers is by creating excess of metal atoms through various heat treatments. Recently, rapid thermal annealing (RTA) has proved a versatile technique for the post-treatment of semiconductor materials as compared to other techniques due to its precise control over the resources. Thus, we carried out a set of experiments on SnS films to explore the influence of RTA treatment on their properties. From these experiments we noticed that the films treated at 400 °C for 1 min in N2 atmosphere have a low electrical resistivity of ~5 Ωcm with relatively high Hall mobility and carrier density of 99 cm2/Vs and 1.3 × 1016 cm−3, respectively. The observed results, therefore, emphasise that it is possible to obtain good quality SnS films through RTA treatment without disturbing their crystal structure.

Molecular orbital studies on some 4-substituted pyridine N-oxides and 4-nitroquinoline N-oxide

The electronic structures of a series of 4-substituted pyridine N-oxides and 4-nitroquinoline N-oxide are investigated using the simple Pariser-Parr-Pople (PPP), a modified PPP, IEH and MINDO/2 methods. The electronic absorption band maxima and dipole moments are calculated and compared with experimental values. The photoelectron spectra of these compounds are assigned. The nature of the N-oxide group is characterized using the orbital population distributions. The antifungal activity exhibited by some of these compounds is discussed in terms of the nucleophilic frontier electron densities, superdelocalizabilities and electron acceptor properties. The effect of the electron releasing as well as the electron withdrawing substituents on the physico-chemical properties is explained.