49 research outputs found

    Microbial Community Structure and Litter Decomposition in Stratified Soils of a Long Term Reduced Tillage Experiment

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    The aim of the present study was to examine decomposition of plant material (maize straw, green and rooibos tea) in stratified soils of the long-term tillage experiment, established in 1999 and shifted from conventional to organic farming system in 2015. The plowing in conventional tillage (CT) has been done by moldboard plow 20 cm deep, while in minimum tillage (MT), soil disturbance has been up to 10 cm deep by a Special disc harrow. More than 15 years of long term Minimum tillage, with reduced soil disturbances and improved residue management, resulted in stratification of soil organic carbon and nutrients with highest concentrations in the very topsoil

    Near-threshold photoelectron angular distributions from two-photon resonant photoionization of He

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    Two-photon resonant photoionization of helium is investigated both experimentally and theoretically. Ground state helium atoms are excited to the 1s4p, 1s5p and 1s6p 1P states by synchrotron radiation and ionized by a synchronized infrared pulsed picosecond laser. The photoelectron angular distributions of the emitted electrons are measured using a velocity map imaging (VMI) spectrometer. The measured asymmetry parameters of the angular distribution allow the phase differences and the ratios of the dipole matrix elements of the 1sϵs and 1sϵd channels to be determined. The experimental results agree with the calculated values obtained in a configuration–interaction calculation with a Coulomb–Sturmian basis set. The effects of the radiative decay of the intermediate state and the static electric field of the VMI spectrometer on the measurements are discussed

    Two-to-one Auger decay of a double L vacancy in argon

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    We have observed L223−M3 Auger decay in argon where a double vacancy is filled by two valence electrons and a single electron is ejected from the atom. A well-resolved spectrum of these two-to-one electron transitions is compared to the result of the second-order perturbation theory and its decay branching ratio is determined

    Potential Energy Surface Reconstruction and Lifetime Determination of Molecular Double-Core-Hole States in the Hard X-Ray Regime

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    A combination of resonant inelastic x-ray scattering and resonant Auger spectroscopy provides complementary information on the dynamic response of resonantly excited molecules. This is exemplified for CH3I, for which we reconstruct the potential energy surface of the dissociative I 3d−2 double- core-hole state and determine its lifetime. The proposed method holds a strong potential for monitoring the hard x-ray induced electron and nuclear dynamic response of core-excited molecules containing heavy elements, where ab initio calculations of potential energy surfaces and lifetimes remain challenging

    Influence of soil amended with zeolite and/or mineral N on agronomic performance and soil mineral N dynamics in a soybean–winter triticale crop rotation field experiment

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    Although there are numerous studies describing the positive infuence of legumes as cereal pre-crops, little information exists on the specifc crop rotation soybean–triticale. Besides that, fertilization of soybean is very complex due to its symbiosis with rhizobia where mineral nitrogen could have negative efect, therefore new soil conditioners, e.g. zeolite, need to be examined. An investigation in growing seasons 2017 and 2017/2018 was established to study these knowledge gaps in a combined feld experiment, where soil mineral nitrogen (SMN) was also monitored. Firstly, the infuence of soybean seed bacterial inoculation (inoculated and non-inoculated seeds) as factor 1, and four fertilization treatments (1—no fertilizer, 2—600 kg zeolite/ha, 3—30 kg mineral N/ha (at sowing)+additional 70–90 kg/ha of mineral N, and 4—combination of treatments 2 and 3) as factor 2 on soybean yield performance and nutritional composition was evaluated. Neither factor infuenced soybean seed yield (average 3128 kg/ha). However, zeolite had favourable efect on root nodulation where the number of nodules and nodule dry mass per plant were signifcantly increased. Secondly, winter triticale was sown after soybean harvest on the same plots. Only 40 kg N was applied at BBCH 30 (beginning of stem elongation) to the whole experiment. Interaction of soybean experimental factors signifcantly infuenced the triticale grain yield. Finally, regression analysis revealed that triticale grain yield (average 5537 kg/ha) was highly dependent (R2=0.927) on initial SMN content, left after soybean harvest

    Resonant inelastic x-ray scattering at the limit of subfemtosecond natural lifetime

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    We present measurements of the resonant inelastic x-ray scattering (RIXS) spectra of the CH3I molecule in the hard-x-ray region near the iodine L2 and L3 absorption edges. We show that dispersive RIXS spectral features that were recognized as a fingerprint of dissociative molecular states can be interpreted in terms of ultrashort natural lifetime of ∼200 attoseconds in the case of the iodine L-shell core-hole. Our results demonstrate the capacity of the RIXS technique to reveal subtle dynamical effects in molecules with sensitivity to nuclear rearrangement on a subfemtosecond time scale

    Auger decay of the 2

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