840 research outputs found

    Incorporation of diverse catch crop mixtures in crop rotation cycles increase biodiversity and nutrient availability in soils

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    Catch cropping have positive impacts on plant nutrition, on biological, chemical, and physical soil properties and reduce the amount of fertilizers. Mixtures of diverse catch crops with varying rooting depth and microbial associations can have additional impact on the nutrient and water acquisition from the subsoil. The decay rate of the catch crop litter during the crop rotation controls the release of nutrients for the succeeding crop. This study investigates the release of nutrients and the microbial community in the cause of litter decomposition from catch crops of varying biodiversity. Therefore, litter-bags filled with litter of the previous catch crop rotation was buried in 15 cm soil depth beneath the main crop maize. The experiment used a fallow treatment as control, mustard as single catch crop, a mixture of crimson clover, oat, phacelia and mustard, and the commercial mixture TerraLife® (12 plant species). All treatments were applied in triplicates and straw from the previous main crop (winter wheat) was used as control. The litter decay was investigated at five time points, each every four weeks. At each time point 14 macro and micro-elements where measured. The temporal fluctuation within the decomposer community was investigated by phospholipid-fatty-acid and neutral-fatty-acid analysis (PLFA/NLFA) and quantitative-PCR techniques. Mustard litter showed the longest residence time in soil and decrease over the four mix and wheat straw towards the TerraLife mix. Significantly higher amounts of P, K, Fe and Al were found in the litter of the two catch crop mixtures compared to mustard and the control. Phosphorous and K from the mixed catch crops were released in the early stage of decomposition and meet the nutrient demand of those elements in young maize plants. The diversity index and total microbial biomass increasing in the order: fallow, mustard, four mix and TerraLife. Particularly the markers for saprophytic and arbuscular mycorrhiza fungi indicated doubling of their biomass in the mix treatments compared to mustard and the fallow. Application of high diverse catch crop mixtures support the nutrient demand of main crops and support higher microbial biomass and diversity. Crop rotation with high diverse catch crops leads to continuous soil health and is recommended as a sustainable form of farm land management

    Greening boosts soil formation and soil organic matter accumulation in Maritime Antarctica

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    Global warming in the Antarctic Peninsula, Maritime Antarctica, within the past 45 years has accelerated rapid glacier retreatment, forming temporal gradients of soil development that concurs with the colonization of the ice-free soils by phototrophs. In the past decade the paradigm emerged that above- and belowground processes are interconnected, e.g. recently gained carbon fuels microbial activity and thus drives soil organic matter built-up and decomposition as well as mineral weathering. Studies of carbon allocation for Antarctic ecosystems, occurring in harsh conditions are lacking. Little is also known about the contribution of bacteria and fungi to decomposition of different soil carbon pools with different turnover rates in these soils, which is of utmost importance for the prediction of the future feedback of the Antarctic carbon balance to climate change. We followed soil horizon formation, soil organic carbon accumulation and carbon exchange with the atmosphere along a gradient of phototrophs of different trophic complexity level at King George Island by combining soil chemical analyses, field CO2 flux measurements, C-13 in situ labeling and molecular methods (PLFA and metabolomics). Our study revealed that colonization of the ice-free soils by vascular plant (Deschampsia antarctica) was leading to the formation of well-developed soil, with high contents of organic carbon and with a relatively high rates of photosynthesis and CO2 soil efflux. The soils sampled under D. antarctica showed the impact of this higher plant on the soil organic matter, containing significantly higher amounts of carbohydrates and amines, presumably as a result of root exudation. As determined by the C-13 labeling experiment more than 15% of the carbon recently assimilated by D. antarctica was transferred belowground, with a major flow into soil fungi. This suggests that not bacteria, but rather fungi preferentially and faster utilize the recently assimilated low molecular compounds allocated to the soil. Probably, successful performance of vascular plants in Maritime Antarctica may significantly foster biological weathering via enhanced microbial activity

    Hot moments in the Antarctic due to climate warming?

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    Climate warming is severely affecting maritime Antarctica, causing accelerated glacier retreat and thus leading to an ongoing exposure of once ice- covered land. This initiates a succession of plant and soil development. Nevertheless, the temporal dynamics and controlling factors of these processes, like C and N status of soils and the effect of root exudation are widely unknown under these harsh climatic conditions. Topsoil samples from three different sites of a chronological soil sequence in the forefront of a retreating glacier of the Fildes Peninsula, King George Island, were collected and incubated at 2 °C for three weeks. To mimic the influence of C and N containing root exudates (primers) on the mineralization of soil C, we added 13C labeled glucose or alanine and compared CO2 evolution in comparison to samples without C and N addition. Soil microbes covered up to 90% of their C demand for anabolic functions with the added C-sources in the case of late soil successions while it was only 50% for the young soils. These findings were independent of the form of primer. Both primers increased the mineralization of soil carbon in the young soils as compared to the control. For the later stages of soil development, we found negative priming which was strongest for the latest stage. These results give evidence for a clear shift in the microbial community of the three investigated sites. While sites with initial soil formation seem to be dominated by k-strategists with low turnover rates that rather use complex C-sources, a significant number of r-strategists in the soils of the older sites uses simple C-substrates very efficiently. As this leads to a relative decrease in SOM mineralization for the late stages of soil development, it is questionable if higher plants can improve their nutrition by stimulating free living soil microbes with root exudates or if they rather have to rely on mycorrhiza

    Hyperfine interactions and internal rotation in methanol

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    We present a rigorous derivation of the nuclear spin-rotation and spin-torsion coupling terms in the hyperfine Hamiltonian for molecules with internal rotation. Our formulas differ from the expressions derived by Heuvel and Dymanus [J. Mol. Spectrosc. 47, 363 (1973)], which these authors used and which were also applied recently by others to interpret experimental hyperfine spectra of such molecules. In the present work, our theoretical results are applied to methanol. We calculate the nuclear spin-spin magnetic dipole-dipole interactions and the nuclear contribution to the spin-torsion coupling vectors from the nuclear coordinates as functions of the internal rotation angle γ, compute the spin-rotation coupling tensors by ab initio electronic structure methods also as functions of γ, and obtain the missing parameters for the electronic contribution to the spin-torsion coupling from a fit to measured spectra. The resulting hyperfine Hamiltonian is then used to compute hyperfine transition frequencies and intensities for twelve torsion-rotation transitions in methanol. With the use of the ab initio calculated spin-rotation coupling parameters without any modification, and physically reasonable values for the spin-torsion coupling parameters from the fit, we find good agreement with all of the measured spectra

    Mobilization of phosphorus from secondary minerals by the arbuscular mycorrhiza Rhizophagus irregularis and consequences for carbon sequestration in soils

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    Phosphorus can be a major limiting factor for plant growth due to its slow diffusion and high degree of immobilization in soils. Understanding the strategies evolved by plant-symbiont couples increasing P uptake is crucial, under the aim of adopting the involved mechanisms by modern sustainable agriculture. This study aims to explore whether tomato plants mycorrhized with the arbuscular mycorrhizal (AM) fungi Rhizophagus irregularis have the ability to mobilize P from secondary minerals and organic sources. Our hypothesis was that AM-bearing plants will invest more carbon to their fungal symbiont in case P must be exploited from less accessible P sources. For this, we carried out a time course experiment (91 days) with split-chamber mesocosms ensuring the mobilization of P by the mycorrhizal partner only. Orthophosphate (OP) and phytic acid (PA) in their free state and adsorbed to goethite (GOE-OP; GOE-PA) have been offered to the host plant. According to our knowledge, this is the first report where an organic P source bonded to a secondary mineral has been tested as a plant P source via the mycorrhizal P uptake pathway. The PLFA 16:1ω5c is known to be part of the membrane constituents and it is considered a good AM biomass estimator (Olsson and Wilhelmsson 2000). In our study it correlated positively with incorporated P and the AM plant root activity (arbuscules %) for all provided P sources. Additionally, those AM plants which accessed OP and GOE-OP also showed a positive significant correlation of the arbuscules percentages, with the incorporated P, the PLFA 18:1ω7c, and in case of GOE-PA also with the PLFA 18:2ω6,9. These two PLFA biomarkers have been previously found in R. irregularis hyphae (Olsson et al. 2002) and might indicate that AM fungi modified their fatty acid composition in the hyphae during the mobilization of P from the different P sources. As fungal energy storage we also measured the NLFA 16:1ω5c. It was significantly higher for both P sources bonded to goethite compared to free OP and PA. These results point towards different C investment to uptake of P though the mycorrhizal pathway having a direct consequence for the carbon sequestration in soils

    Neurochemistry of response inhibition and interference in gambling disorder: a preliminary study of γ-aminobutyric acid (GABA+) and glutamate–glutamine (Glx)

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    BackgroundNeurobehavioral research on the role of impulsivity in gambling disorder (GD) has produced heterogeneous findings. Impulsivity is multifaceted with different experimental tasks measuring different subprocesses, such as response inhibition and distractor interference. Little is known about the neurochemistry of inhibition and interference in GD.MethodsWe investigated inhibition with the stop signal task (SST) and interference with the Eriksen Flanker task, and related performance to metabolite levels in individuals with and without GD. We employed magnetic resonance spectroscopy (MRS) to record glutamate–glutamine (Glx/Cr) and inhibitory, γ-aminobutyric acid (GABA+/Cr) levels in the dorsal ACC (dACC), right dorsolateral prefrontal cortex (dlPFC), and an occipital control voxel.ResultsWe found slower processing of complex stimuli in the Flanker task in GD (P < .001, η 2 p = 0.78), and no group differences in SST performance. Levels of dACC Glx/Cr and frequency of incongruent errors were correlated positively in GD only (r = 0.92, P = .001). Larger positive correlations were found for those with GD between dACC GABA+/Cr and SST Go error response times (z = 2.83, P = .004), as well as between dACC Glx/Cr and frequency of Go errors (z = 2.23, P = .03), indicating general Glx-related error processing deficits. Both groups expressed equivalent positive correlations between posterror slowing and Glx/Cr in the right dlPFC (GD: r = 0.74, P = .02; non-GD: r = .71, P = .01).ConclusionInhibition and interference impairments are reflected in dACC baseline metabolite levels and error processing deficits in GD

    Distribution of HLA-DPB1, -DQB1 -DQA1 alleles among Sardinian celiac patients.

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    The Sardinian population in many aspects differs from other Caucasoid populations, particularly for its degree of homogeneity. For this reason we have studied 50 adult Sardinian patients with celiac disease (CD) and 50 control healthy Sardinian individuals by RFLP analysis and by extensive oligotyping for 17 HLA-DPB 1, 8-DQB I and 9-DQA 1 alleles, and established their -DPB I alleles and -DQB I -DQA I genotypes. The heterodimer HLA-DQB 1 *0201/-DQA 1 *0501, present in 96% of our patients, is strongly associated with CD susceptibility, confirming published reports. On the other hand we found in 11 of 50 probands (22%) the presence of the allele -DQB 1 *05021 DQA1*0102. This genotype is extremely rare in other Caucasian populations and appears to confer limited protection in CD Sardinian patients

    Estimation and Validation of Oceanic Mass Circulation from the GRACE Mission

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    Since the launch of the Gravity Recovery And Climate Experiment (GRACE) in March 2002, the Earth's surface mass variations have been monitored with unprecedented accuracy and resolution. Compared to the classical spherical harmonic solutions, global high-resolution mascon solutions allows the retrieval of mass variations with higher spatial and temporal sampling (2 degrees and 10 days). We present here the validation of the GRACE global mascon solutions by comparing mass estimates to a set of about 100 ocean bottom pressure (OSP) records, and show that the forward modelling of continental hydrology prior to the inversion of the K-band range rate data allows better estimates of ocean mass variations. We also validate our GRACE results to OSP variations modelled by different state-of-the-art ocean general circulation models, including ECCO (Estimating the Circulation and Climate of the Ocean) and operational and reanalysis from the MERCATOR project

    Penerapan Quadcopter sebagai Sarana Promosi Area Wisata dengan Visualiasi Interaktif pada Footflag

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    Bacground: Promotion tour area is the activities promoted a tour area to prospective customers / tourists. Means for the promotion of the tourist area with take photo from common camera less attractive from aesthetics aspect.Promotion tour area must make very attractive in other that tourists can interest to visit it. Objectives: Integrating quadcopter with the camera as a device documentation of tourism area with interactive visualizations. Methods: collecting the information, literature and discussions with experts supported aeromodelling especially quadcopter, conducted by making design tool, the main function of the tool implementation and effectiveness of the test tool. Results: Quadcopter creation tool that is integrated with a high resolution camera to get a picture of the tourist area of the air. The workings of this system is the photography with a camera into the air using a quadcopter until it reaches a certain height and is used to take pictures of tourist areas from wider viewing angles. The results of the shooting will be displayed on the website as an attraction partners to increase the number of visitors on the footflag website and attract much the tourists to related tour object. Conclutions: ROCO Pantura (Robot Copter photographer reserve) a fly Devices used to take pictures from the air. This tool is equipped with a high resolution camera to get the maximum imag
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