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A better understanding of how land management might affect soil respiration can greatly help enhancing the long-term sustainability of agricultural soils. This study investigated the effects of two key management practices, nutrient fertilization and soil tillage, on soil respiration in an intensive grassland system. Data were collected from a long-term grassland experiment established in 1970 in Northern Ireland, UK. The experiment commenced with eight nutrient treatments: an unfertilised control, inorganic fertiliser (NPK), two types of slurry: cattle and pig slurry at three application rates. In September 2019 half of the experimental plots were tilled and reseeded with a multi-species sward mixture. Static automated chambers were used to measure the fluxes of CO 2 between 2018 and 2021. Surprisingly, we did not find any significant nutrient treatment effects on mean hourly or cumulative CO 2 emissions. Likewise, there were no significant differences in CO 2 emissions between the type of slurry, slurry application rate or the interaction of these treatment factors. However, seasonal changes in CO 2 emissions were highly significant while ploughing had a significant decreasing effect on the cumulative daily CO 2 emissions but only during the establishment period (first nine weeks). Significant relationships with CO 2 flux were found for soil temperature and soil water content. We also found no relationship between short-term soil CO 2 emissions and long-term soil organic carbon storage data, which highlights the complexity of soil C source-sink dynamics and C balance. Our study brings evidence that regarding CO 2 emissions the impact of soil tillage is short-lived, and the direct effect of nutrient additions is small. • CO2 emissions from an intensively managed grassland were monitored over 4 years. • Evidence of no nutrient input effects on CO2 emissions. • Evidence of no slurry type or rate of slurry application effects on CO2 emissions. • Soil tillage during reseeding had a short-term decreasing effect on CO2 emissions. [ABSTRACT FROM AUTHOR]

The effect of increasing rates of potassium (K) fertiliser was studied on a soil with base exchangeable K values ≤ 0.1 cmol(+)/ kg by assessing biomass, feed quality, mineral concentration and grain yield for wheat, triticale and canola. The crops showed variable biomass response to K rates at early plant growth stages, however at anthesis there were significant positive biomass responses to increasing rates of K. A positive K rate effect was detected on feed quality with significant increases in metabolisable energy. Irrespective of sampling time, increasing K rate resulted in significant increases in crop K concentration and mineral ratios, such as the Tetany index, but significant decreases in Ca and Mg concentrations. Final grain yield was significantly increased by K rate and there were beneficial effects on grain quality (thousand grain weight). Overall, this study highlights the importance of K to production responses and implications for the health and productivity of grazing livestock. [ABSTRACT FROM AUTHOR]

Precision nutrient management requires accurate assessment of crop nutrient status. This is common for assessing N status, but much less so for other nutrients. Because fluorescence can indicate crop stress, the robustness of different fluorescence indices was assessed to predict crop nutrient status (K, Mg and Ca). The hypothesis was that crop nutrition limitations, especially K, can be detected using fluorescence proximal sensing to quantify crop response with a high degree of spatial resolution. A factorial experiment was imposed with four treatment factors: crop, K fertilizer rate, lime and row management. The soil at the experimental site was K deficient and the crop variables showed significant treatment effects (e.g. yield, protein). Fluorescence sensing identified a significant positive K response for three chlorophyll related indices (SFR_G, SFR_R and CHL), but not for FLAV; while wheat was significantly different from barley. Using a k-fold cross-validation method promising predictive relationships were found. The strongest predictions were for SFR_R to predict crop biomass, for SFR_G to predict crop K content of inter-row wheat, for CHL to predict crop Ca content of inter-row wheat and for FLAV with barley grain protein in the windrow treatment. The fluorescence indices produced more significant crop variable predictions than measuring NDVI using an active sensor. This study illustrates the utility of fluorescence sensing to measure chlorophyll related signals for capturing the nutritional status of barley and wheat crops. These results show encouraging potential to rapidly detect crop nutrient status for non-N nutrients using fluorescence sensing. [ABSTRACT FROM AUTHOR]

This note proves a conjecture of Sparling [Germ of a synthesis: space-time is spinorial, extra dimensions are time-like. Proc R Soc Lond Ser A Math Phys Eng Sci. 2007;463(2083):1665-1679; The Ξ-transform for conformally flat space-time. arXiv:gr-qc/0612006; 2006.], that the ultrahyperbolic wave operator and the Ξ transform on form an exact couple. [ABSTRACT FROM AUTHOR]

Better understanding of the relationship between soil properties and soil function is required to minimise nutrient losses from agriculture and protect the environment. There is a need to predict the solute movement through horticultural soils because of the intensive management practices. Thus, the mobile water content ( θ m ), the active fraction of soil water content engaged in solute transport, is a suitable soil property to investigate further. Accurate measurement of such solute transport properties in the field are costly, labour intensive and time consuming but there are opportunities to establish predictive relationships. θ m was measured together with other basic soil properties to test established predictive relationships (known as pedotransfer functions, PTFs) and to develop new PTFs. The field measurements were taken on a diverse range of vineyard soils across New South Wales (NSW), Australia. Poor predictions were found with available PTFs for θ m and the mobile water fraction f (= θ m /θ fm ; where θ fm = volumetric water content at which θ m was measured). Backward stepwise multiple regression analysis produced better PTF model predictions than the multiple linear regression analysis for new PTFs that were calculated. Differences in the analysis methods showed a trade-off between the prediction capacity and the number of predictor variables in each PTF model. A prediction accuracy of between 80 to 90% was found with 3 predictor variables in the PTFs for θ m and f . Both the PTFs developed were in strong agreement with the measured properties (minimum R 2 = 0.82). For the θ m PTF, the % clay content (varied from 11 to 59) was the strongest predictor variable while bulk density (ranged from 1.2 to 1.51 g cm −3 ) contributed the smallest. The PTF for f was similar to θ m except it was the % soil organic carbon which had the smallest contribution. These relationships are useful to predict θ m and f from easily measured soil physical properties of vineyard soils in NSW, but further testing on a wider range of soils is required. [ABSTRACT FROM AUTHOR]

We observe that the standard homogeneous cosmologies, those of Minkowski, de Sitter, and anti-de Sitter, which form the matrix for the Robertson-Walker scale factor, live naturally as isolated points inside a larger family of conformally flat metrics obtained by allowing a tensor containing the information of conformal symmetry breaking to be more general. So the standard cosmological metrics are parametrically unstable in this sense, and therefore unphysical. When we pass to the stable family of perturbed metrics, we immediately encounter a scalar field, which drives the conformal expansion of the universe and which automatically obeys the non-linear sine-Gordon equation. The Lagrangian for the sine-Gordon equation is a cosine potential agreeing to the fourth order with the potential used in the approach to the generation of mass in gauge theories. Accordingly we identify our geometric scalar field-actually of the type of an abelian gauge field-with the recently discovered scalar field. There are two constants in the theory: the first, named $$m$$ , is positive and defines a mass scale for the universe; the second, named $$\varLambda $$ , is the cosmological constant. For the space-time to be everywhere non-singular, equivalently for the (strict) dominant energy condition to hold, these constants must obey the inequality $$\varLambda > m^2/4$$ . [ABSTRACT FROM AUTHOR]

This study investigated the role of peer mentoring and voluntary self-development activities (i.e., capitalization) in anchoring science, technology, engineering, and mathematics students to their college majors. Online data were collected from 214 undergraduate students. As hypothesized, mentoring was positively related to capitalization, and both mentoring and capitalization were positively related to satisfaction with one's major, affective commitment to one's major, involvement in one's major, and willingness to be a mentor. Contrary to expectations, capitalization did not mediate the relationship between peer reentering and student outcomes, suggesting that these constructs contribute independently to positive outcomes. Implications and future research directions are discussed. [ABSTRACT FROM AUTHOR]

Despite increasing demand for workers in fields that arc grounded in science, technology, engineering, and math (STEM), retention rates are low among relevant college majors. Using Web-based survey data from 290 STEM majors, the authors investigated links among personality, coping strategics, and STEM major commitment. Proactive personality was positively related to STEM major commitment and to the active planning coping strategy and negatively related to behavioral disengagement. Active planning was positively related to commitment to STEM majors and behavioral disengagement was negative!} related to the outcome. Coping strategies fully mediated the relationship between proactive personality and commitment to STEM majors. [ABSTRACT FROM AUTHOR]

• Over winter cover crops support spring barley rotations in northern latitudes. • Brassica dominated cover crops increased barley grain yield and grain N. • Economic benefits to spring barley after cover crops required subsidy payments. • Soil health was maintained with over winter cover crops for spring barley. A three-year field experiment investigated the potential yield benefits and soil effects from over winter cover crops in Scotland, U.K. Brassica composition of cover crops significantly increased the grain yield and grain nitrogen (N) concentration of the following spring barley crop. The increased yield with cover crops was outweighed by increased costs and thus without subsidy (Ecological Focus Area) payments there was decreased profitability for the following spring barley crop. Cover crop effects were mostly neutral on soil properties, but surface shear strength was significantly lower than in the stubble control. This indicates that even direct drilling of cover crops will loosen the surface soil. Cover crops varied in their effect on slug populations but in all cases slug numbers were below treatment thresholds. No cover crop effects were detected for total nematode and earthworm abundance or the total soil organic carbon concentration. This study indicates that cover crops can improve cereal production in a region with a short growing season with no negative impact on soil health or the agronomic sustainability. [ABSTRACT FROM AUTHOR]

Nitrogen fertilization is the most critical agronomic input affecting barley production and farm profitability. The strict quality requirements for malting barley are challenging to achieve for farmers. In addition, soil variability and weather conditions can affect barley yield and quality. Thus, the objectives of this study are to (a) quantify the variability of soil properties, and (b) use spatial data in a crop simulation model, quantifying the impacts of climate−soil interactions on the barley crop yield and grain quality. Based on historical yield maps, a commercial field was divided into different yield stability zone levels. The Decision Support System for Agrotechnology Transfer model was used to evaluate soil and crop spatial data. The bulk density affected the soil water content and soil mineral N and hence the crop-growing conditions in each yield stability zone. Our observed and simulated results showed that 120 kg N ha−1 is the optimal rate to increase grain yield while still keeping within the grain N% requirements for malting quality. This study shows the great value of integrating crop modeling with on−farm experimental data for improving understanding of the factors which affect site−specific N fertilization of barley. [ABSTRACT FROM AUTHOR]

The generic null geodesic of the Schwarzschild-Kruskal-Szekeres geometry has a natural complexification, an elliptic curve with a cusp at the singularity. To realize that complexification as a Riemann surface without a cusp, and also to ensure conservation of energy at the singularity, requires a branched cover of the space-time over the singularity, with the geodesic being doubled as well to obtain a genus two hyperelliptic curve with an extra involution. Furthermore, the resulting space-time obtained from this branch cover has a Hamiltonian that is null geodesically complete. The full complex null geodesic can be realized in a natural complexification of the Kruskal-Szekeres metric. [ABSTRACT FROM AUTHOR]

• The premium for malting barley has been highly variable over the past 14 years. • The optimal N rate varied from 120 to 140 kg /ha for malting barley quality. • The marginal net return ranged between 500 and 2000 GBP/ha. • Crop modelling showed large trade-off differences for N leaching. Barley is one of the most important Scottish crops with major economic implications for the Scottish economy because of its use in whisky and beer production. Managing nitrogen (N) fertilizer at field scale for barley is difficult because of the complexity to simultaneously achieve profitability, malting quality and reducing N losses to groundwater. The aim of this study was to model spatial and temporal optimal N fertilizer rates to reduce nitrate leaching while improving grain yield and quality in malting barley. A calibrated and validated crop growth model (DSSAT) was used to identify the optimal amount of N fertilization rates to be applied in the field. The optimal amount of N fertilizer varied between 120 and 140 kg N ha−1 (as average over the 34 years) to maximize the economic return, grain N% and minimize environmental impact. The malting barley premium paid to farmers varies with N content thus affecting marginal net return, with variation ranging from 500 to 2000 GBP ha−1. The use of long-term weather data for the simulations allowed the calculation of outcomes from 34 different growing seasons. This information combined with the different premium levels paid to farmers can be helpful in identifying the possible combinations between grain quality premium-N fertilizer-weather conditions. Modelling the long-term data showed that the simulated N leaching (kg N ha−1) was highly variable between years and the greatest trade-off was for the amount of N leached. The overall the applied N fertilizer rate had a strong effect on the risk of a trade-off developing over the 34 different growing seasons. [ABSTRACT FROM AUTHOR]

Background:Alu elements are highly researched due to their useful nature as markers in the study of human population genetics. Recently discovered Major Histocompatibility Complex (MHC) polymorphic Alu insertions (POALINs) have not been examined extensively for genetic variation and their HLA associations. Aims: The aim of this study is to assess the genetic variation between three populations using five recently discovered POALINs. Methods and subjects: The study examined 190 healthy, unrelated subjects from three different populations in the East Midlands (UK) for the presence or absence of five Alu elements (AluHG, AluMICB, AluHJ, AluTF and AluHF) via the polymerase chain reaction followed by gel electrophoresis. Data were analysed for genetic variation and phylogenetic analyses. Results: All Alus were polymorphic in study populations. Appreciable allele frequency variation was observed at a number of loci. The British population was significantly different from both the Punjabi Jat Sikh and Gujarati Patel populations, although showing a closer genetic relationship to the Punjabi Jat Sikh population than the Gujarati Patel population (Nei's DA = 0.0031 and 0.0064, respectively). Conclusions: MHC POALINs are useful markers in the investigation of genetic variation and the assessment of population relationships, and may have some bearing on disease associations due to their linkage disequilibrium with HLA loci; this warrants further studies. [ABSTRACT FROM AUTHOR]

• Rainfall is the dominant driver of spring barley yield in Scotland. • Grain quality for distilling is not affected by rainfall. • Maximum crop growth expansion is in May and this is becoming drier. Barley is one of the most important cereals worldwide and is a key crop for Scotland's agriculture due to its use in distilleries to produce whisky. Climatic variability, especially significant changes in rainfall patterns are a present challenge for barley production. Thus, the objectives of this study were: i) to evaluate the performance of a crop model to simulate water and N stresses in spring barley in the east of Scotland; ii) to quantify the impacts of rainfall and temperature on barley grain yield and quality; and iii) to understand how grain nitrogen concentration varies in relation to climate variability. Three field experiments were undertaken at the James Hutton Institute near Dundee, UK. The 2018 experiment consisted of two levels of N (0 N and 120 N) and two levels of water (rainfed and irrigated). Data from two experiments were used as additional evaluation. The Decision Support System for Agrotechnology Transfer (DSSAT v4.7) model was used to evaluate the crop performance. The evaluation of the crop model using the different years, locations and water by nitrogen stress levels, using the same cultivar (Concerto), showed that the cultivar parameters were well calibrated. There was a weak negative and non-significant (p = 0.14) relationship between air temperature and simulated yield, but a strong (p < 0.05) positive relationship between growing season rainfall and simulated yield. During the spring barley growing season (Apr-Aug), the last two decades were drier than the long-term average, with May (time of expansive growth) having about 25 mm less rainfall than the long-term average. The results of this study highlight how rainfall is more important than the temperature for the production of spring barley in Scotland. Our simulated results showed that the premium grain for distilling is reached 41 out of 45 years investigated in this study. [ABSTRACT FROM AUTHOR]