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We present an atlas and follow-up spectroscopic observations of 87 thin stream-like structures detected with the STREAMFINDER algorithm in Gaia DR3, of which 28 are new discoveries. Here, we focus on using these streams to refine mass models of the Galaxy. Fits with a double-power-law halo with the outer power-law slope set to − β _h = −3 yield an inner power-law slope of $-{\gamma }_{h}=-({0.97}_{-0.21}^{+0.17}\,)$ , a scale radius of ${r}_{0,h}={14.7}_{-1.0}^{+4.7}\,\mathrm{kpc}$ , a halo density flattening q _m _, _h = 0.75 ± 0.03, and a local dark matter density of ρ _h _,⊙ = 0.0114 ± 0.0007 M _⊙ pc ^−3 . Freeing β yields $\beta ={2.53}_{-0.16}^{+0.42}$ , but this value is heavily influenced by our chosen virial mass limit. The stellar disks are found to have a combined mass of ${4.20}_{-0.53}^{+0.44}\times {10}^{10}\,{M}_{\odot }$ , with the thick disk contributing 12.4% ± 0.7% to the local stellar surface density. The scale lengths of the thin and thick disks are ${2.17}_{-0.08}^{+0.18}$ and ${1.62}_{-0.13}^{+0.72}\,\mathrm{kpc}$ , respectively, while their scale heights are ${0.347}_{-0.010}^{+0.007}$ and ${0.86}_{-0.02}^{+0.03}\,\mathrm{kpc}$ , respectively. The virial mass of the favored model is ${M}_{200}={1.09}_{-0.14}^{+0.19}\times {10}^{12}\,{M}_{\odot }$ , while the mass inside of 50 kpc is M _R _

One challenge in predicting soil parameters using in situ visible and near infrared spectroscopy is the distortion of the spectra due to soil moisture. External parameter orthogonalization (EPO) is a mathematical method to remove unwanted variability from spectra. We created two different EPO correction matrices based on the difference between spectra collected in situ and, respectively, spectra collected from the same soil samples after drying and sieving and after drying, sieving and finely grinding. Spectra from 134 soil samples recorded with two different spectrometers were split into calibration and validation sets and the two EPO corrections were applied. Clay, organic carbon and total nitrogen content were predicted by partial least squares regression for uncorrected and EPO-corrected spectra using models based on the same type of spectra ("within domain") as well as using laboratory-based models to predict in situ collected spectra ("cross-domain"). Our results show that the within-domain prediction of clay is improved with EPO corrections only for the research grade spectrometer, with no improvement for the other parameters. For the cross-domain predictions, there was a positive effect from both EPO corrections on all parameters. Overall, we also found that in situ collected spectra provided an equally successful prediction as laboratory-based spectra. [ABSTRACT FROM AUTHOR]

Resenha do livro Línguas Indígenas e Gramática Universal.

The application of visible and near-infrared (vis–NIR) spectroscopy to characterize soil samples has gained growing interest as a fast and cost-effective methodology forsoil fertility assessment.In orderto profit from the full potential of vis–NIR spectroscopy, the acquisition of soil spectra directly in-situ would increase the possibility to obtain data rapidly and at a high spatial and temporal resolution. In the present study, we test and propose the best practice to characterize a set of fertility-related parameters (i.e. texture, organic carbon, pH, cation exchange capacity and major nutrients) of agricultural soils by measuring vis–NIR spectra in the field. To reach this goal, we compare the spectra obtained from different scanning positions with two portable spectrometers, that is, a micro-electromechanical systems (MEMS)-based spectrometer and a research-grade vis–NIR spectrometer. On the basis of 134 soil sampling points, vis–NIR spectra were recorded from: (1) the cutaway side of a soil sample collected with an Edelman auger to a depth of 20 cm, (2) the raw soil surface, as well as (3) the cleaned and smoothed soil surface. Partial least squares regression (PLSR) calibration models were built for the selected soil parameters, scanning positions and different spectral pretreatments for both spectrometers. The model performance was evaluated based on the ratio of performance to interquartile range (RPIQ), the R2 , the root mean squared error (RMSE) and Lin's concordance correlation coefficient (CCC). Overall, the following soil parameters were successfully predicted: clay, sand, pH, organic carbon, cation exchange capacity, total nitrogen and exchangeable magnesium. In contrast, total and exchangeable Ca, K and P, as well as total Mg could not be predicted at a satisfactory level for both the spectrometers. The best scanning position for the successfully calibrated models was along the cutaway sides of the Edelman auger. Although the research-grade spectrometer gave better performance indicators for most of the parameters, the calibrations with the MEMS-based spectrometer still resulted in satisfactory predictions. Based on these findings, the proposed best practice for obtaining in-situ soil vis–NIR scans is to scan along the cutaway sides of a soil core using at least five replicate scans. [ABSTRACT FROM AUTHOR]

Heim (1990) and Kripke (2009) argue that the adverb too is a trigger of presuppositions that cannot be accommodated, i.e. a hard trigger (Abusch 2002). Contrary to this view Zeevat (2003,b) proposed that too should rather be analyzed as a marker of additive discourse relations, which he argues explains its resistance to accommodation. In this squib, I show that presuppositional analyses of too are actually as explanatory as the discourse marker analysis in this respect, and that the latter faces serious issues with sentences with contrastive topics. I conclude that nothing is gained by reanalyzing hard presupposition triggers as discourse markers.Keywords: presuppositions, discourse markers, too

Marginal land conversion to perennial energy crops can provide biomass feedstocks and climate change mitigation. However, the effect of perennial energy crop cultivation on soil organic carbon (SOC) sequestration and its underlying mechanism in marginal land still remains incomplete. Here, SOC turnover, stability, and its potential sequestration were evaluated based on 10 years of land use change from C3 grass‐dominated marginal land to C4 energy crops Miscanthus and switchgrass cultivation. The naturally occurring 13C signature down to 60 cm depth was used to determine the energy crops‐derived C. Compared to reference marginal land, Miscanthus plantation increased the SOC stock at 0–60 cm depth by 17.8% and 64.3% in bulk and root zone, respectively. Similarly, the SOC stock under switchgrass was also 16.5% and 93.0% higher in bulk and root zone than in reference marginal land, respectively. The higher SOC stock in the root zone of switchgrass relative to Miscanthus was supported by the higher contribution of C4‐derived C to SOC (44.5% vs. 32.4%). The mean residence time of old C was higher under switchgrass than Miscanthus in the bulk zone across 0–60 cm (p < 0.05) but remained the same at 0–20 cm in the root zone. Specific SOC mineralization and temperature sensitivity were lower in soils under Miscanthus and switchgrass compared to reference marginal land. The partial least squares path model revealed that perennial energy crop cultivation enhances soil C stock via increased C4‐derived C input and reduced mineralization. In conclusion, marginal land conversion to perennial energy crops is a win–win strategy for C sequestration to mitigate climate change and support the growing bioenergy sector with biomass supply. [ABSTRACT FROM AUTHOR]

In recent decades, mounting evidence has indicated that the expansion of oil palm (OP) plantations at the expense of tropical forest has had a far pernicious effect on ecosystem aspects. While various deforestation‐free strategies have been proposed to enhance OP sustainability, field‐based evidence still need to be consolidated, in particular with respect to savanna regions where OP expansion has recently occurred and that present large area with potential for OP cultivation. Here we show that the common management practice creating within the plantation the so‐called management zones explained nearly five times more variability of soil biogeochemical properties than the savanna land‐use change per se. We also found that clayey‐soil savanna conversion into OP increased total ecosystem C stocks by 40 ± 13 Mg C ha−1 during a full OP cultivation cycle, which was due to the higher OP‐derived C accumulated in the biomass and in the soil as compared to the loss of savanna‐derived C. In addition, application of organic residues in specific management zones enhanced the accumulation of soil organic carbon by up to 1.9 Mg ha−1 year−1 over the full cycle. Within plantation, zones subjected to organic amendments sustained similar soil microbial activity as in neighboring savannas. Our findings represent an empirical proof‐of‐concept that the conversion of non‐forested land in parallel with organic matter‐oriented management strategies can enhance OP agroecosystems C sink capacity while promoting microbe‐mediated soil functioning. Nonetheless, savannas are unique and threatened ecosystems that support a vast biodiversity. Therefore, we suggest to give priority attention to conservation of natural savannas and direct more research toward the impacts of the conversion and subsequent management of degraded savannas. [ABSTRACT FROM AUTHOR]

Increasing soil organic carbon (SOC) in agroecosystems is necessary to mitigate climate change and soil degradation. Management practices designed to reach this goal call for a deeper understanding of the processes and drivers of soil carbon input stabilization. We identified main drivers of SOC stabilization in oil palm plantations using the well‐defined spatial patterns of nutrients and litter application resulting from the usual management scheme. The stabilization of oil palm‐derived SOC (OP‐SOC) was quantified by δ13C from a shift of C4 (savanna) to C3 (oil palm) vegetations. Soil organic carbon stocks under frond piles were 20% and 22% higher compared with harvest paths and interzones, respectively. Fertilization and frond stacking did not influence the decomposition of savanna‐derived SOC. Depending on management zones, net OP‐SOC stabilization equalled 16–27% of the fine root biomass accumulated for 9 years. This fraction was similar between frond piles and litter‐free interzones, where mineral NPK fertilization is identical, indicating that carbon inputs from dead fronds did not stabilize in SOC. A path analysis confirmed that the OP‐SOC distribution was largely explained by the distribution of oil palm fine roots, which itself depended on management practices. SOC mineralization was proportional to SOC content and was independent on phosphorus availability. We conclude that SOC stabilization was driven by C inputs from fine roots and was independent of alteration of SOC mineralization due to management. Practices favouring root growth of oil palms would increase carbon sequestration in soils without necessarily relying on the limited supply of organic residues. [ABSTRACT FROM AUTHOR]

Land-use intensification in the tropics plays an important role in meeting global demand for agricultural commodities but generates high environmental costs. Here, we synthesize the impacts of rainforest conversion to tree plantations of increasing management intensity on carbon stocks and dynamics. Rainforests in Sumatra converted to jungle rubber, rubber, and oil palm monocultures lost 116 Mg C ha−1, 159 Mg C ha−1, and 174 Mg C ha−1, respectively. Up to 21% of these carbon losses originated from belowground pools, where soil organic matter still decreases a decade after conversion. Oil palm cultivation leads to the highest carbon losses but it is the most efficient land use, providing the lowest ratio between ecosystem carbon storage loss or net primary production (NPP) decrease and yield. The imbalanced sharing of NPP between short-term human needs and maintenance of long-term ecosystem functions could compromise the ability of plantations to provide ecosystem services regulating climate, soil fertility, water, and nutrient cycles [ABSTRACT FROM AUTHOR]

The strong affinity of phosphorus (P) to iron (Fe) oxides and hydroxides in highly weathered tropical soils limits P availability and therefore plant productivity in tropics. In flooded soils, however, P fixed by Fe oxides and hydroxides can be released into more available forms because of Fe 3 + reduction to Fe 2 + . These P dynamics in flooded soils are well documented for rice paddies. Such effects are much less studied in other land-use types influenced by seasonal flooding, especially in the tropics during heavy monsoon rains. The aim of this study was to investigate the P mobilization during flooding leading to anaerobic conditions in topsoil and subsoil depending on land-use type. Samples were collected in highly weathered Acrisols from four replicate sites under natural rainforest, jungle rubber, rubber and oil palm plantations in Sumatra, Indonesia. Topsoil and subsoil were taken to ensure a wide range of soil organic matter (SOM) and P contents. Soils were incubated under anaerobic, flooded conditions at 30 ± 1 °C for 60 days. Our results confirmed the hypothesis that soil flooding mobilizes P and increases P availability. Two distinct and opposite periods were observed during the flooding. During the first three weeks of flooding, the dissolved P (DP) concentration peaked, simultaneously with the peak of dissolved Fe 2 + (DFe 2 + ) and dissolved organic carbon (DOC). After three weeks, P availability in soils decreased, although Fe-P (P NaOH ) and available P (P NaHCO3 ) did not reach the initial, pre-flooding levels. The impacts of flooding on P and Fe forms was strong in the topsoil, where P dissolution and availability were generally higher under forest and, to a lesser extent, under jungle rubber. A positive correlation between DOC and DFe 2 + (R 2 = 0.42) in topsoil indicates that the intensity of microbially-mediated Fe 3 + reduction is limited by the amount of available carbon (C) as an energy source for microorganisms and as electron donor. Microbial mineralization of organic P from SOM also increases P availability, and this process requires available C. This interpretation was supported by the strong correlation (R 2 = 0.58) between available P and DOC, as well as between DP and DOC (R 2 = 0.56) in topsoil. The increasing pH in topsoil and subsoil after flooding of all land-use types may also influence the P release over time. In summary, the increase of available P and DP during flooding is due to three main mechanisms: (1) P release via the microbially-mediated reductive dissolution of Fe 3 + oxides; (2) P release during SOM mineralization and (3) solubility of Fe phosphate due to increasing pH. These mechanisms are relevant not only in riparian areas, where flooding occurs, but also in soils waterlogged after regular heavy rainfalls during the wet season. Therefore, we speculate that the P turnover is faster in compacted soils under plantations because of regular changes of oxic and anoxic conditions. Consequently, more P is pumped by the vegetation and then removed from plantations due to yield export. [ABSTRACT FROM AUTHOR]

Deforestation and land-use change in tropics have increased over the past decades, driven by the demand for agricultural products. Although phosphorus (P) is one of the main limiting nutrients for agricultural productivity in the tropics, the effect of land-use change on P availability remains unclear. The objective was to assess the impacts of land-use change on soil inorganic and organic P fractions of different availability (Hedley sequential fractionation) and on P stocks in highly weathered tropical soils. We compared the P availability under extensive land-use (rubber agroforest) and intensive land-use with moderate fertilization (rubber monoculture plantations) or high fertilization (oil palm monoculture plantations) in Indonesia. The P stock was dominated by inorganic forms (60 to 85%) in all land-use types. Fertilizer application increased easily-available inorganic P (i.e., H 2 O-Pi, NaHCO 3 -Pi) in intensive rubber and oil palm plantations compared to rubber agroforest. However, the easily-available organic P (NaHCO 3 -extractable Po) was reduced by half under oil palm and rubber. The decrease of moderately available and non-available P in monoculture plantation means that fertilization maintains only the short-term soil fertility that is not sustainable in the long run due to the depletion of P reserves. The mechanisms of this P reserve depletion are: 1) soil erosion (here assessed by C/P ratio), 2) mineralization of soil organic matter (SOM) and 3) P export with yield products. Easily-available P fractions (i.e., H 2 O-Pi, NaHCO 3 -Pi and Po) and total organic P were strongly positively correlated with carbon content, suggesting that SOM plays a key role in maintaining P availability. Ecologically based management is therefore necessary to mitigate SOM losses and thus increase the sustainability of agricultural production in P-limited, highly weathered tropical soils. [ABSTRACT FROM AUTHOR]

Soil organic matter (SOM) decomposition in response to global change represents a critical uncertainty in coupled carbon (C) cycle-climate models. Much of this uncertainty arises from our limited mechanistic knowledge of the effects of organic C input frequency on SOM decomposition. Based on a three-source-partitioning isotopic approach (14C glucose addition to soil continuously labeled by C 4 plants over 21 years) and literature review of 86 observations, we assessed the priming of fast- and decadal-SOM decomposition after occasional and frequent (every 12 vs 60 days) labile C input in a grassland soil. Frequent glucose input accelerated SOM decomposition over 200 days, but the occasional input reduced this positive priming by 2.6 times. The positive priming by occasional C input resulted in 139 μg C g−1 soil net C sequestration corresponding to 38% of C input. During the 200 days incubation, the primed fast-cycling C (younger than 21 years) under occasional C addition was 52–94% greater compared with frequent addition. Conversely, the priming of decadal SOM (older than 21 years) by frequent C input was 463 μg C g−1 after the 200 days incubation, which represents 5.3% of the initial decadal-cycling soil C pool. This was 1.5 times higher than by occasional input because of the stronger N mining caused by the continuously high activity of microbial K strategists under frequent C input. Our global scale assessment showed that occasional C input reduces the priming of decadal SOM decomposition by 89–127 Tg per year compared to frequent input and thus, sequestrated an additional 102 Tg C per year. Overall, the vulnerability of decadal SOM to increasing C input frequency thus weakening the C sink of grassland, whilst reduced C input frequency (e.g. by drought) suppresses the SOM priming and reduces the positive feedback of SOM decomposition to global change. This points out the necessity to assess the age of soil C when predicting the consequences of altered soil C input frequency under global change. • Frequent C input induces stronger priming of the decadal-than fast-cycling C pool. • Microbial N mining and the dominant growth of K -strategy cause higher priming effect under frequent C input. • Occasional C input reduces the SOM priming by 1.5 times relative to frequent inputs. • The intensity of priming was increased with time under frequent C input. [ABSTRACT FROM AUTHOR]

Tropical regions, such as Sumatra, experiencing extensive transformation of natural ecosystems, are close to complete exhaustion of available land. Agroecosystems strongly modify water and nutrient cycles, leading to losses of soil fertility, C sequestration and biodiversity. Although large companies are the main drivers of deforestation and plantation establishment, smallholders account for 40% of the oil palm and the majority of the rubber production in Indonesia. Here, we assess the extent and mechanisms of soil degradation under smallholder oil palm and rubber plantations in a context of land scarcity. The topsoil properties (C and N contents, C stocks, C/N ratio, bulk density) in 207 oil palm and rubber plantations in the Jambi province of Sumatra were determined beside trees, inside rows and interrows. Soils under oil palms were on average more degraded than under rubber, showing lower C content and stocks, lower N and higher bulk density. While soil properties were homogenous under rubber, two opposite trends were observed under oil palm plantations: the majority of soils had C content <2.2%, but about one fifth of the plantations had >9% C. This resulted from the establishment of oil palms under conditions of land scarcity. Because the oil palm boom started when rubber was already well-established, oil palms were frequently planted in marginal areas, such as peatlands or riparian areas (high C) or soils degraded by previous use (low C). The management of oil palms led to subsequent soil degradation, especially in interrows: C content decreased and bulk density increased in older oil palm plantations. This was not observed in rubber plantations because of a C input from leaf litter spread homogeneously all over the plantation, higher ground cover and a limited use of motorized vehicles. Considering that 10% of soils under oil palms had very low C content (<1%), we conclude that intensive cultivation can lead to intensive soil degradation and expect future degradation of soils under young oil palms. This challenges the sustainability of agricultural intensification in Sumatra. Because Sumatra is a pioneer of tropical land-use change, this should be regarded as potential threats that other tropical regions may face in future. [ABSTRACT FROM AUTHOR]

Tropical forest conversion to agricultural land leads to a strong decrease of soil organic carbon (SOC) stocks. While the decrease of the soil C sequestration function is easy to measure, the impacts of SOC losses on soil fertility remain unclear. Especially the assessment of the sensitivity of other fertility indicators as related to ecosystem services suffers from a lack of clear methodology. We developed a new approach to assess the sensitivity of soil fertility indicators and tested it on biological and chemical soil properties affected by rainforest conversion to plantations. The approach is based on (non-)linear regressions between SOC losses and fertility indicators normalized to their level in a natural ecosystem. Biotic indicators (basal respiration, microbial biomass, acid phosphatase), labile SOC pools (dissolved organic carbon and light fraction) and nutrients (total N and available P) were measured in Ah horizons from rainforests, jungle rubber, rubber ( Hevea brasiliensis ) and oil palm ( Elaeis guineensis ) plantations located on Sumatra. The negative impact of land-use changes on all measured indicators increased in the following sequence: forest < jungle rubber < rubber < oil palm. The basal respiration, microbial biomass and nutrients were resistant to SOC losses, whereas the light fraction was lost stronger than SOC. Microbial C use efficiency was independent on land use. The resistance of C availability for microorganisms to SOC losses suggests that a decrease of SOC quality was partly compensated by litter input and a relative enrichment by nutrients. However, the relationship between the basal respiration and SOC was non-linear; i.e. negative impact on microbial activity strongly increased with SOC losses. Therefore, a small decrease of C content under oil palm compared to rubber plantations yielded a strong drop in microbial activity. Consequently, management practices mitigating SOC losses in oil palm plantations would strongly increase soil fertility and ecosystem stability. We conclude that the new approach enables quantitatively assessing the sensitivity and resistance of diverse soil functions to land-use changes and can thus be used to assess resilience of agroecosystems with various use intensities. [ABSTRACT FROM AUTHOR]

The University of Florida GeoPlan Center has been organizing, standardizing, and distributing geospatial data since 1998 through the Florida Geographic Data Library (FGDL), a collection of Florida geospatial data from various agencies, as well as data developed in-house. With funding from the Florida Department of Transportation (FDOT), FGDL serves as a public distribution mechanism for hundreds of Florida geospatial data layers. Since 2004, FGDL layers have formed the data foundation for FDOT's interagency application known as efficient transportation decision making (ETDM), which facilitates the review and permitting process for proposed transportation projects. Data layers are standardized and inspected to ensure that the data are adequate for use in analysis and decision making. To efficiently manage the geospatial data and workflows, a quality assurance/quality control (QAQC) process and relational database schema was developed to track the standardization procedures, lineage, versioning, and archiving of the data layers. This article details the history of the Florida Geographic Data Library, challenges of managing a large geospatial data repository, development of a QAQC process and database schema, and lessons learned. [ABSTRACT FROM AUTHOR]

Efficient cruising, manoeuvrability and noiseless performance of fish robots have been attracting people in various scientific realms. Accordingly, a number of fish robots are designed and fabricated so far. However, the existing robots are only capable of one gait of locomotion. This deficiency is addressed by UC-Ika 2 with multiple gaits of locomotion including cruising and manoeuvring that are inspired from two different fishes. This paper aims at presenting the design and fabrication process of UC-Ika 2. The swimming performance of the robot is tested and compared with its previous version UC-Ika 1. [ABSTRACT FROM AUTHOR]

Indonesia lost more tropical forest than all of Brazil in 2012, mainly driven by the rubber, oil palm, and timber industries. Nonetheless, the effects of converting forest to oil palm and rubber plantations on soil organic carbon (SOC) stocks remain unclear. We analyzed SOC losses after lowland rainforest conversion to oil palm, intensive rubber, and extensive rubber plantations in Jambi Province on Sumatra Island. The focus was on two processes: (1) erosion and (2) decomposition of soil organic matter. Carbon contents in the Ah horizon under oil palm and rubber plantations were strongly reduced up to 70% and 62%, respectively. The decrease was lower under extensive rubber plantations (41%). On average, converting forest to plantations led to a loss of 10 Mg C ha-1 after about 15 years of conversion. The C content in the subsoil was similar under the forest and the plantations. We therefore assumed that a shift to higher δ13C values in plantation subsoil corresponds to the losses from the upper soil layer by erosion. Erosion was estimated by comparing the δ13C profiles in the soils under forest and under plantations. The estimated erosion was the strongest in oil palm (35 ± 8 cm) and rubber (33 ± 10 cm) plantations. The 13C enrichment of SOC used as a proxy of its turnover indicates a decrease of SOC decomposition rate in the Ah horizon under oil palm plantations after forest conversion. Nonetheless, based on the lack of C input from litter, we expect further losses of SOC in oil palm plantations, which are a less sustainable land use compared to rubber plantations. We conclude that δ13C depth profiles may be a powerful tool to disentangle soil erosion and SOC mineralization after the conversion of natural ecosystems conversion to intensive plantations when soils show gradual increase of δ13C values with depth. [ABSTRACT FROM AUTHOR]

Background and aims: Uptake of Sr and Cs in plants varies widely between soil types and between plant species. It is now recognized that the radionuclide uptake in plants is more influenced by site-specific and plant-specific parameters rather than the bulk radionuclide concentration in soil. We hypothesized that the stress which Alpine plants experience because of the short growing season may enhance the phylogenetic effect on the Cs and Sr transfer factors as well as the dependency of the uptake by plant to the concentrations of exchangeable Ca and K of soils. Methods: We carried out a field study on the Sr and Cs uptake by 11 species of Alpine plants growing on 6 undisturbed and geochemically different soils in the Alpine valley of Piora, Switzerland. Results: Results show that a strong correlation exists between the log TF and the log of exchangeable Ca or K of the soils. Conclusions: Cs uptake by Phleum rhaeticum (Poales) and Alchemilla xanthochlora (Rosales) is more sensitive to the amount of exchangeable K in the soil than the corresponding uptake by other orders. Moreover, the Sr results indicate a phylogenetic effect between Non-Eudicot and Eudicots: the order Poales ( Phleum rhaeticum) concentrating much less Sr than Eudicots do. [ABSTRACT FROM AUTHOR]

• The role of land-use change, crop rotation and site conditions were elucidate. • SOC was depleted in croplands compared to grasslands and mountain pastures. • SOC dynamics was more influenced by land-use changes than management practices. • P excess in soils enables C sequestration without additional P sequestration. • SOC balancing budget is a realistic approach to encourage C sequestration practices. Increasing soil organic carbon (SOC) in agroecosystems enables to address simultaneously multiple goals such as climate change adaptation and mitigation as well as food security. As croplands are depleted in SOC, they offer a great potential to sequester atmospheric carbon (C). Nonetheless, croplands are still losing SOC under most of the current agricultural systems. Although many factors driving SOC dynamics have already been identified, their relative importance has not been quantified yet. Using one of the densest European soil monitoring networks with 250 sites established in western Switzerland, in the present study we (i) assessed long-term (over 30 years) SOC dynamics in croplands (CR), permanent grasslands (PG) and mountain pastures (MP), and (ii) prioritized the importance of land use, soil characteristics and sites conditions in driving SOC dynamics. The SOC levels in PG and MP were similar when clay content was accounted for, whereas CR were depleted in SOC by 3.9 mg C mg−1 clay as compared to PG. The majority (61 %) of CR had SOC:clay ratio below 1:10, but only 16 % of PG and MP sites reached this threshold. By contrast, soil organic matter stoichiometry (C:N:Porg ratios) was similar in CR and PG for comparable SOC content. The increase of C:Porg ratio with SOC content (dilution effect) and the high total P in CR and PG (legacy effect) indicate the possibility to sequester atmospheric C at reduced nutrient sequestration costs. SOC changes ranged from -0.61 to 1.32 mg g-1 soil yr−1 and were the highest in sites that experienced land-use changes. No PG were losing SOC, while CR sites exhibited both SOC gains and losses. Because of the predominance of the initial SOC content on SOC dynamics, land-use history must be accounted for when assessing the effect of management practices. The main manageable factors driving SOC dynamics were the time under temporary or permanent grasslands along with the soil total P. As PG already are rich in SOC and total P, organic amendments should be partly redirected to CR. [ABSTRACT FROM AUTHOR]

Increasing soil organic carbon (SOC) in agroecosystems is a promising solution to simultaneously address climate change mitigation, adaptation, and food security. Yet, the best management practices that could achieve these goals remain to be identified. Here, we analyze the long-term effects of application of green manure, cereal straw, farmyard manure, and cattle slurry on SOC in a 37 year long field experiment in Switzerland. The treatment effects were compared against control conditions that received only optimal mineral fertilization. More specifically, this study aimed at evaluating the effect of organic amendments on SOC accumulation and distribution in different soil particle-size fractions by means of a set of indicators about organic matter quality (biological reactivity, humification index) and microbial activity (extracellular enzyme activities). In the absence of organic matter input, application of mineral fertilizers alone resulted in the lowest SOC content and the highest humification index of the bulk soil organic matter. Among the organic amendments, cereal straw, farmyard manure, and cattle slurry promoted a higher SOC content and a lower humification index due to an increase of SOC in the clay-size fraction. The annual C accrual reached 4.4‰ per year over 37 years with farmyard manure. The higher biological reactivity measured for the green manure and cereal straw amendments was associated with higher soil enzymatic activities, while C retention coefficients decreased by at least 2.5 times compared to animal-derived amendments. The low availability of nutrients in green manure and straw amendments as suggested by the high phosphatase and N-acetylglucosaminidase activities may indicate a reduction in C retention of organic matter inputs due to nutrient microbial mining with plant-derived amendments. [ABSTRACT FROM AUTHOR]

The density variations in thin stellar streams may encode important information on the nature of dark matter. For instance, if dark matter aggregates into massive subhalos, these perturbers are expected to scatter stars out of dynamically cold stellar streams, possibly leading to detectable gaps in those structures. Here, we reexamine the density variations in the GD-1 stream, using Gaia Data Release 2 (DR2) astrometry and Panoramic Survey Telescope and Rapid Response System photometry, together with high-precision radial velocities measured with the Canada–France–Hawaii Telescope/ESPaDOnS and Very Large Telescope/Ultraviolet and Visual Echelle Spectrograph instruments and complemented with public radial velocity catalogs. We show that after correcting for projection effects, the density profile exhibits high contrast periodic peaks, separated by 2.64 ± 0.18 kpc. An N-body simulation is presented that reproduces this striking morphology with simple epicyclic motion in a smooth Galactic potential. We also discuss the reliability of measuring density variations using ground-based photometric surveys, and for the particular case of GD-1 we highlight some of the artifacts present in the Gaia DR2 catalog along its track. Massive dark subhalos do not appear to be required to explain the density clumping along GD-1. [ABSTRACT FROM AUTHOR]

Increasing soil organic carbon (SOC) in agroecosystems is necessary to mitigate climate change and to improve soil fertility. Management practices designed to reach this goal call for a deeper understanding of the processes and drivers of carbon input localization and stabilization. Predicting impacts of land-use change and land management on SOC dynamics and its stabilization faces major difficulties as many factors affect both SOC stabilization and mineralization processes. Here, we identify main drivers of SOC stabilization in oil palm plantations using the well-defined spatial patterns of nutrients and litter application resulting from the usual management scheme. The stabilization of oil palm-derived SOC (OP-SOC) was quantified from a shift of C4 (savanna) to C3 (oil palm) vegetations and related to oil palm fine root biomass. Fertilization and frond stacking influenced the stabilization of OP-SOC stocks, which already reached after nine years up to 45 % of the total SOC stocks in the top 10 cm, but had no effects on the decomposition of savanna-derived SOC. Depending on management zones, OP-SOC stocks equalled up to 27% of the fine root biomass accumulated during 9 years. This proportion was not affected by the presence of frond pile in zones where mineral fertilization is identical, indicating that carbon inputs from dead fronds did not stabilize in SOC. SOC mineralization was proportional to SOC content and was independent on phosphorus availability. A path analysis confirmed that the OP-SOC distribution was largely explained by the distribution of oil palm fine roots, which itself is influenced by management practices. We conclude that SOC stabilization was driven by C inputs from fine roots and not by an alteration of SOC mineralization due to management. [ABSTRACT FROM AUTHOR]

We present two spectroscopic surveys of the tidal stellar stream of the Palomar 5 globular cluster undertaken with the VLT/FLAMES and AAT/AAOmega instruments. We use these data in conjunction with photometric data presented in the previous contribution in this series to classify the survey stars in terms of their probability of belonging to the Palomar 5 stellar stream. We find that high-probability candidates are only found in a very narrow spatial interval surrounding the locus of the stream on the sky. PanSTARRS RR Lyrae stars in this region of the sky are also distributed in a similar manner. The absence of significant “fanning” of this stellar stream confirms that Palomar 5 does not follow a chaotic orbit. Previous studies have found that Palomar 5 is largely devoid of low-mass stars, and we show that this is true also of the stellar populations along the trailing arm out to . Within this region, which contains 73% of the detected stars, the population is statistically identical to the core, implying that the ejection of the low-mass stars occurred before the formation of the stream. We also present an updated structural model fit to the bound remnant, which yields a total mass of and a tidal radius . We estimate the mass of the observed system including the stream to be 12,200 ± 400 M⊙, and the initial mass to have been ~47,000 ± 1500 M⊙. These observational constraints will be employed in our next study to model the dynamics of the system in detail. [ABSTRACT FROM AUTHOR]