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Irrigation is an important adaptation to reduce crop yield loss due to water stress from both soil water deficit (low soil moisture) and atmospheric aridity (high vapor pressure deficit, VPD). Traditionally, irrigation has primarily focused on soil water deficit. Observational evidence demonstrates that stomatal conductance is co-regulated by soil moisture and VPD from water supply and demand aspects. Here we use a validated hydraulically-driven ecosystem model to reproduce the co-regulation pattern. Specifically, we propose a plant-centric irrigation scheme considering water supply-demand dynamics (SDD), and compare it with soil-moisture-based irrigation scheme (management allowable depletion, MAD) for continuous maize cropping systems in Nebraska, United States. We find that, under current climate conditions, the plant-centric SDD irrigation scheme combining soil moisture and VPD, could significantly reduce irrigation water use (−24.0%) while maintaining crop yields, and increase economic profits (+11.2%) and irrigation water productivity (+25.2%) compared with MAD, thus SDD could significantly improve water sustainability. Irrigation is the most important use of water. A newly developed irrigation management scheme leads to a significant reduction in water use and increase in economic gains while maintaining crop yields, presenting opportunities for real-world impacts under current and future climate conditions.

Agricultural systems exhibit a large degree of within-field yield variability. We require a better understanding of the drivers of this variability in order to optimally manage croplands. We investigated drivers of sub-field spatial variability in yield for three crops (hard red winter wheat, Triticum aestivum L. variety Langin; corn, Zea mays L.; and proso millet, Panicum milaceum L.) usings a multi-year dataset from a dryland research farm in northeastern Colorado, USA. The dataset spanned 18 2.6–4.3 ha management units, over 4 years, and included high-resolution topographic data, densely sampled soil properties, and on-site weather data. We modeled yield for each crop separately using random forest regression and evaluated model performance using spatially blocked cross-validation. The topographic position index (TPI) and increasing percent sand had a strong negative effect on yield, while the nitrogen application rate (N) and total soil carbon had strong positive effects on yield in both the wheat and millet models. Remarkably, TPI had almost as large of an effect size as N, and outperformed other more commonly used topographic predictors of yield such as the topographic wetness index (TWI), elevation, and slope. Despite the size and quality of our dataset, cross-validation results revealed that our models account for approximately one-quarter of the total yield variance, highlighting the need for continued research into drivers of spatial variability within fields.

Global studies that quantify climate effects on crop yields using top‐down spatial frameworks are invaluable for assessing generalized effects on world food supplies, yet do not contain the resolution necessary to identify local mediating effects of management. Our objectives were to identify (a) what climate factors have historically affected winter wheat (Triticum aestivum L.) yields in eastern Colorado, (b) how management may mitigate climate impacts, and (c) the potential for varietal selection to climate extremes. We paired long‐term yield data for wheat in rotations that varied in management (tillage intensity, with and without fallow) with robust on‐site weather data. We also used data from colocated variety trials to investigate trade‐offs between mean yields and the ability to withstand water and temperature stress. Precipitation in April–June was nearly as predictive of yields as full growing season precipitation. While precipitation and air temperatures are tightly linked in this agroecosystem, temperatures were more predictive of yields than precipitation. Increases in minimum May temperatures positively affected yields, likely because of minimizing freeze damage, but did not offset detrimental effects of warmer daytime spring and summer temperatures. The largest negative temperature effects were caused by extreme maximum temperatures in June. No‐till with fallow maximized yields. Low‐ and high‐yielding varieties did not differ in yield responses to high temperatures, suggesting that future advancements in heat stress resistance will not necessarily require yield trade‐offs. Climate pressures will likely require producers to balance yield goals with maintaining soil cover, underscoring the difficulty of identifying win–win climate adaptations. Core Ideas Precipitation in a 90‐d window (April–June) was nearly as predictive of yields as full growing season precipitation. Information on monthly air temperatures (April–June) was more predictive of wheat grain yields than precipitation. Daytime temperatures in May and June are already above optimum in most years, negatively affecting grain yields. Both no‐till and fallow increased the intercept of the yield response to precipitation and temperature. The slope of the yield responses to high temperatures did not differ between low‐ and high‐yielding varieties.

Soil erosion and loss of soil organic C (SOC) may limit the sustainable harvest of crop residues for biofuels from dryland systems in the semiarid Great Plains. The objective of this study was to evaluate the capabilities and constraints of harvesting residues from dryland systems. The study used observations from a long‐term experiment in Colorado to examine biomass production from wheat (Triticum aestivum L.), corn (Zea mays L.), and grain sorghum [Sorghum bicolor (L.) Moench] at three no‐till sites in a winter wheat–corn–fallow (WCF) or winter wheat–sorghum–fallow cropping system. Modeling evaluated the impact of residue removal on erosion rates and SOC dynamics. The Revised Universal Soil Loss Equation and the Wind Erosion Equation were used to simulate erosion, and the DAYCENT model was used to estimate changes in SOC with residue removal. Biomass yield for WCF averaged 3.8 Mg ha−1, divided into stover and grain yields of 2.2 and 1.6 Mg ha−1. Water erosion was not shown to constrain residue harvest, but modeling indicated unsustainable wind erosion rates after removing 10 to 30% of corn residue. Simulations showed that up to 80% of wheat straw could be harvested without exceeding sustainable wind erosion rates. The major constraint to sustainable residue harvest is a residue return rate of 2.4 Mg ha−1 yr−1 of biomass to maintain SOC.

THE TIMES keeps me in touch with the metropolis, and frequent items concerning the upper west side interest me especially. Two years in that part of town have given me some understanding of the popular jokes about the police force and the Street Cleaning Department. May I add a word as to Saturday's complaint from that region?

The goal of this paper is to introduce the hypothesis that white matter (WM) and vascular injury are long‐term consequences of repetitive head impacts (RHI) that result in a novel T2 fluid attenuated inversion recovery (FLAIR) magnetic resonance imaging pattern. A non‐systematic literature review of autopsy and FLAIR studies of RHI‐exposed adults was first conducted as a foundation for our hypothesis. A case series of RHI‐exposed participants is presented to illustrate the unique FLAIR WM hyperintensities (WMH) pattern. Current literature shows a direct link between RHI and later‐life WM/vascular neuropathologies, and that FLAIR WMH are associated with RHI, independent of modifiable vascular risk factors. Initial observations suggest a distinctive pattern of WMH in RHI‐exposed participants, termed RHI‐associated WMH (RHI‐WMH). RHI‐WMH defining features are as follows: (1) small, punctate, non‐confluent, (2) spherical, and (3) proximal to the gray matter. Our hypothesis serves as a call for research to empirically validate RHI‐WMH and clarify their biological and clinical correlates. Highlights Repetitive head impacts (RHI) have been associated with later‐life white matter (WM) and vascular neuropathologies. T2 FLAIR MRI of RHI‐exposed participants reveals a potentially unique WM hyperintensity (WMH) pattern that is termed RHI‐associated WMH (RHI‐WMH). RHI‐WMH are characterized as (1) small, punctate, and non‐confluent, (2) spherical, and (3) proximal to the gray matter at an area anatomically susceptible to impact injury, such as the depths of the cortical sulci.

ObjectivesPrevious studies demonstrated associations between reduced serum 25-hydroxyvitamin D (25OHD), inflammation and disease activity in paediatric systemic lupus erythematosus (pSLE). The goal of this study was to assess parathyroid hormone (PTH) in its relationship to vitamin D and inflammation, as well as to better understand the role of human cathelicidin (LL-37) in pSLE.MethodsFrozen serum samples collected at baseline of the Atherosclerosis Prevention in Paediatric Lupus Erythematosus (APPLE) study were assayed to determine 25OHD, PTH and LL-37 levels. Pearson’s correlations and Χ2 tests were used to evaluate the relationships between 25OHD, PTH, LL-37, inflammation, disease activity and infection using baseline values collected as part of the APPLE study.Results201/221 APPLE participants had serum available for analysis. Serum 25OHD was inversely associated with serum PTH, but not LL-37. Serum PTH was not associated with high sensitivity C-reactive protein, carotid intima media thickness or high-density lipoprotein (HDL) or low-density lipoprotein (LDL) cholesterol, but was negatively associated with lipoprotein(a) levels. Despite no association with serum 25OHD, LL-37 was negatively associated with total cholesterol, HDL and LDL cholesterol and positively associated with age. There was no significant difference in mean LL-37 levels in participants with reported infection as an adverse event during the 3-year APPLE study.ConclusionsDespite links to vitamin D levels in other studies, LL-37 levels were not associated with baseline serum 25OHD concentrations in paediatric patients with pSLE. Despite the lack of correlation with 25OHD, LL-37 levels in this study were associated with cholesterol levels. Some subjects with pSLE have significantly elevated levels of LL-37 of unknown significance. These exploratory results addressing the role of LL-37 levels in pSLE appear worthy of future study.

Objective Epidemiological associations suggest that vitamin D status may play a role in inflammation and progression of atherosclerosis. Using frozen serum, carotid intima medial thickness (CIMT) measurements and other existing data from the Atherosclerosis Prevention in Pediatric Lupus Erythematosus (APPLE) trial, we assessed interactions between serum 25-hydroxyvitamin D (25(OH)D), atorvastatin randomisation and CIMT progression rate. Methods Participants in the 3-year APPLE trial were randomised to placebo or atorvastatin and CIMT progression rate was measured. Baseline frozen serum was used to measure 25(OH)D concentrations. Mixed effect longitudinal models for CIMT progression at 3 years were used to evaluate interaction between vitamin D deficiency (serum 25(OH)D <20 ng/mL) at baseline and atorvastatin or placebo treatment, adjusting for key systemic lupus erythematosus disease variables and cardiovascular risk factors. Results 201/221 APPLE participants had available samples and were included in this analysis; 61/201 (30%) had vitamin D deficiency at baseline. In adjusted longitudinal modelling, there was significant interaction between baseline vitamin D deficiency and atorvastatin randomisation in 3-year progression of mean-max CIMT. In four out of six carotid segments, there was a greater decrease in mean-max CIMT progression rate in subjects who were treated with atorvastatin compared with placebo if they had baseline serum 25(OH)D levels ≥20 ng/mL. Conclusions Subjects with serum 25(OH)D ≥20 ng/mL had less mean-max CIMT progression following 3 years of atorvastatin treatment. Results from secondary analyses must be interpreted cautiously, but findings suggest that underlying vitamin D deficiency may be involved in response to atorvastatin in atherosclerosis prevention. Trial registration number NCT00065806.