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The existing non-linear flow model does not consider the influence of temperature change on the non-linear flow law. Therefore， based on the capillary flow model， the Hagen-Poiseuille equation， and the boundary layer theory， as well as the influence of the temperature on the thickness of the boundary layer and the yield stress of the fluid， a dynamic non-linear flow model in low-permeability porous media considering the influence of temperature was derived. Then， the fitting verification was carried out according to the experimental data in published literature， and the calculated flow velocity curve and minimum start-up pressure gradient were highly consistent with the experimental data， which revealed the correctness of the dynamic non-linear flow model. Meanwhile， the comparative analysis with the static non-linear flow model and the Darcy flow model illustrated the rationality of the dynamic non-linear flow model. The sensitivity analysis of the flow velocity curve revealed that the increase in coefficients A and B made the flow velocity curve right-shift； the curvature degree of the non-linear flow section was weakened， and the minimum start-up pressure gradient was increased. The increase in the temperature had a much more significant effect on the flow velocity curve， which made the velocity curve move up obviously. The curvature degree of the non-linear flow section weakened， and the minimum start-up pressure gradient increased. The proposal of this dynamic non-linear flow model further enriches the development of the non-linear flow theory and can be extended to the numerical simulation of two-phase flow and high-temperature and high-pressure oil and gas reservoirs.

Aims: The flow of electric current in the root-soil system relates to the pathways of water and solutes, its characterization provides information on the root architecture and functioning. We developed a current source density approach with the goal of non-invasively image the current pathways in the root-soil system. Methods: A current flow is applied from the plant stem to the soil, the proposed geoelectrical approach images the resulting distribution and intensity of the electric current in the root-soil system. The numerical inversion procedure underlying the approach was tested in numerical simulations and laboratory experiments with artificial metallic roots. We validated the method using rhizotron laboratory experiments on maize and cotton plants. Results: Results from numerical and laboratory tests showed that our inversion approach was capable of imaging root-like distributions of the current source. In maize and cotton, roots acted as “leaky conductors”, resulting in successful imaging of the root crowns and negligible contribution of distal roots to the current flow. In contrast, the electrical insulating behavior of the cotton stems in dry soil supports the hypothesis that suberin layers can affect the mobility of ions and water. Conclusions: The proposed approach with rhizotrons studies provides the first direct and concurrent characterization of the root-soil current pathways and their relationship with root functioning and architecture. This approach fills a major gap toward non-destructive imaging of roots in their natural soil environment.

Dynamic fracture propagation significantly affects water flooding efficiency in tight oil reservoirs. This phenomenon, where moderate fracture openings can enhance water flooding volume and alleviate injection challenges, has been underexplored in current literature. Understanding dynamic fracture behavior poses a challenge due to the difficulty in characterizing them within traditional reservoir numerical simulators. In this study, we propose a numerical simulation method that integrates the KGD dynamic fracture model with a two-phase flow model. This approach enables detailed exploration of dynamic fracture evolution in reservoir scenarios featuring one injector and one production well. Our findings reveal that fractures extend from the water injection well to the oil production well, exhibiting rapid initial growth followed by a slower rate. Fluctuations in fracture tip pressure correspond to cycles of opening and closure. We observe that cumulative oil production increases more rapidly when injection pressure exceeds the fracture opening pressure. However, this growth rate diminishes beyond a certain threshold, highlighting the critical role of injection parameters in dynamic fracture efficacy. Optimal water flooding performance is achieved when injecting water slightly above the fracture opening pressure. Furthermore, we compare water cut curves generated by conventional commercial simulators with our fracture propagation model. Our model's water cut curve aligns better with on-site data, indicating improved historical fitting accuracy. In conclusion, our study underscores the importance of dynamic fractures in enhancing water flooding efficiency in tight oil reservoirs and presents a robust numerical simulation framework for better understanding and management of reservoir dynamics. [ABSTRACT FROM AUTHOR]

The full potential for using DNA barcodes for profiling functional trait diversity has yet to be determined in plants and animals; thus, we outline a general framework for quantifying functional trait diversity of insect community DNA and propose and assess the accuracy of three methods for achieving this. We built a novel dataset of traits and DNA barcodes for wild bees in China. An informatics framework was developed for phylogeny‐based integration of these data and prediction of traits for any subject barcodes, which was compared with two distance‐based methods. For Phylogenetic Assignment, we additionally conducted a species‐level analysis of publically available bee trait data. Under the specimen‐level dataset, the rate of trait assignment was negatively correlated with distance between the query and the nearest trait‐known reference, for all methods. Phylogenetic Assignment was found to perform best under several criteria; particularly, it had the lowest false‐positive rate (rarely returning a state prediction where success was unlikely; where the distance from query to the nearest reference was high). For a wider range of compiled traits, conservative life‐history traits showed the highest rates of assignment; for example, sociality was predicted with confidence at 53%, parasitism at 44% and nest location at 33%. As outlined herein, automated trait assignment might be applied at scale to either barcodes or metabarcodes. With further compilation and databasing of DNA barcode and trait data, the rate and accuracy of trait assignment is expected to increase to the point of being a widely viable and informative approach. [ABSTRACT FROM AUTHOR]

The microbiomes associated with bee nests influence colony health through various mechanisms, although it is not yet clear how honeybee congeners differ in microbiome assembly processes, in particular the degrees to which floral visitations and the environment contribute to different aspects of diversity. We used DNA metabarcoding to sequence bacterial 16S rRNA from honey and stored pollen from nests of 4 honeybee species (Apis cerana, A. dorsata, A. florea, and A. laboriosa) sampled throughout Yunnan, China, a global biodiversity hotspot. We developed a computational pipeline integrating multiple databases for quantifying key facets of diversity, including compositional, taxonomic, phylogenetic, and functional ones. Further, we assessed candidate drivers of observed microbiome dissimilarity, particularly differences in floral visitations, habitat disturbance, and other key environmental variables. Analyses revealed that microbiome alpha diversity was broadly equivalent across the study sites and between bee species, apart from functional diversity which was very low in nests of the reclusive A. laboriosa. Turnover in microbiome composition across Yunnan was driven predominantly by pollen composition. Human disturbance negatively impacted both compositional and phylogenetic alpha diversity of nest microbiomes, but did not correlate with microbial turnover. We herein make progress in understanding microbiome diversity associated with key pollinators in a biodiversity hotspot, and provide a model for the use of a comprehensive informatics framework in assessing pattern and drivers of diversity, which enables the inclusion of explanatory variables both subtly and fundamentally different and enables elucidation of emergent or unexpected drivers. [ABSTRACT FROM AUTHOR]

Summary: Determining whether isotope fractionation occurs during root water uptake is a prerequisite for using stem or xylem water isotopes to trace water sources. However, it is unclear whether isotope fractionation occurs during root water uptake in gramineous crops.We conducted prevalidation experiments to estimate the isotope measurement bias associated with cryogenic vacuum distillation (CVD). Next, we assessed isotope fractionation during root water uptake in two common agronomic crops, wheat (Triticum aestivum L.) and maize (Zea mays L.), under flooding after postdrought stress conditions.Cryogenic vacuum distillation caused significant depletion of 2H but negligible effects on 18O for both soil and stem water. Surprisingly CVD caused depletion of 2H and enrichment of 18O in root water. Stem and root water δ18O were more than soil water δ18O, even considering the uncertainty of CVD. Soil water 18O was depleted compared with irrigation water 18O in the pots with plants but enriched relative to irrigation water 18O in the pots without plants.These results indicate that isotope fractionation occurred during wheat and maize root water uptake after full irrigation and led to a heavy isotope enrichment in stem water. Therefore, the xylem/stem water isotope approach widely used to trace water sources should be carefully evaluated. [ABSTRACT FROM AUTHOR]

Lateral roots and root hairs are essential portions of cotton roots. However, the morphology and lifespan of cotton (Gossypium hirsutum L.) lateral roots and root hairs in response to nitrogen stress have remained unknown. Two cotton cultivars were assessed when no nitrogen and normal nitrogen (138 mg N·kg−1 soil) were added. The daily acquisitions of root phenotype information including the lateral root angle, lateral root density, lateral root diameter, lateral root lifespan, root hair length, root hair density, and root hair lifespan, were obtained in situ by a self‐designed platform of RhizoPots equipped with high‐resolution scanners. Nitrogen starvation significantly reduced the growth of shoots and roots, although there was less reduction of roots than shoots. Root hairs were the first organ to respond to nitrogen deficiency through morphological changes. The lateral root diameter and angle as well as the root hair lifespan decreased significantly under nitrogen stress. However, nitrogen deficiency dramatically increased the lateral root lifespan, root hair density and length. Our results demonstrate that low nitrogen can induce notable changes in lateral roots and root hairs, which may play a crucial role in the adjustment to nitrogen uptake, particularly in species that can adapt to low nitrogen availability. [ABSTRACT FROM AUTHOR]

Roots strongly influence the growth and yield of field crops. We characterized root morphological traits of 10 winter wheat varieties in order to determine the extent they were influenced by the environments and impacted grain yield under two irrigation regimes at Bushland (a cooler, drier site with clay loam soil) and Uvalde (a warmer, wetter site with clay soil) in Texas, USA, from 2015 to 2017. Major root traits, including root diameter, specific root length (SRL), root surface area (SSA), tissue mass density (TMD), root length density (RLD), and root weight density, were measured and related to one another and to grain yield. RLD of wheat decreased but SRL and SSA increased with soil depth. Irrigation was second to environment in affecting root traits. Compared with Uvalde, the environment of Bushland promoted deeper root growth, higher TMD, but reduced SRL and SSA. Water deficit inhibited RLD and root: shoot ratio at Bushland, but moderately promoted them at Uvalde. Both SRL and RLD were positively associated with grain yield, with the former relation stronger under drought. The dichotomy of "conservative" versus "acquisitive" root strategy partially explained the variations of root traits of winter wheat in contrasting environments. [ABSTRACT FROM AUTHOR]

Bulk leaf carbon isotopic composition (δ13Cbulk) has been widely used to investigate leaf level water use efficiency (WUEl) in efforts to boost grain yield relative to crop water use. Although widely used for isotopic analyses, the bulk leaf represents a complex mixture of compounds. Single‐compound isotopic analyses carry diagnostic advantages over bulk analyses in a range of applications and may also serve as surrogates for WUEl and grain yield in crops. This study tests whether compound‐specific carbon and hydrogen isotopes of leaf wax n‐alkanes (δ13Calk and δDalk) and n‐alcohols (δ13Calc) could be used as surrogates for WUEl and grain yield using conventional δ13Cbulk as a reference. Ten winter wheat (Triticum aestivum L.) cultivars were planted under two irrigation treatments (full and deficit irrigation) at Uvalde (wet location) and Amarillo (dry location), TX, during two growing seasons. There were significant relationships between δ13Calk or δDalk and δ13Cbulk, indicating they can all serve as surrogates for WUEl in most cases. Compared with δ13Cbulk, we found stronger relationships between δ13Calk at Uvalde or δDalk under deficit irrigation at Amarillo and grain yield. The δ13Calk also had higher broad‐sense heritability than δ13Cbulk, indicating larger cultivar effects in δ13Calk than in δ13Cbulk. In contrast, the δ13Calc was not consistently related with δ13Cbulk or grain yield. Our study introduces the idea that δ13Calk and δDalk may supplement conventional δ13Cbulk with potential to assist in the breeding process when selecting for high‐WUE and high‐yielding cultivars. [ABSTRACT FROM AUTHOR]

Selecting high-yielding cultivars under drought is an important practice to improve crop production. Canopy temperature (T) shows a relative reliable association with grain yield. In this study, we compared the suitability of canopy T and other agronomic as well as physiological traits associated with grain yield under different water regimes. Field experiments over two seasons (2011–2012 and 2012–2013) were carried out under three water regimes, represented about 64, 76 and 89% of potential evapotranspiration, with 16 local winter wheat (Triticum aestivum L.) cultivars in each season. Results showed that cultivars with higher yield usually performed consistently lower canopy T under three water regimes, while the relationships of grain yield with other agronomic or physiological traits were more influenced by soil moisture. In addition, the relationship between canopy T and grain yield varied with different growth stages: From the time of heading to early grain filling stages, a more significant negative linear relationship (p < 0.001) existed under the three irrigation levels. [ABSTRACT FROM PUBLISHER]

The major wheat production region of China the North China Plain (NCP) is seriously affected by air pollution. In this study, yield of winter wheat (Triticum aestivum L.) was analyzed with respect to the potential impact of air pollution index under conditions of optimal crop management in the NCP from 2001 to 2012. Results showed that air pollution was especially serious at the early phase of winter wheat growth significantly influencing various weather factors. However, no significant correlations were found between final grain yield and the weather factors during the early growth phase. In contrast, significant correlations were found between grain yield and total solar radiation gap, sunshine hour gap, diurnal temperature range and relative humidity during the late growing phase. To disentangle the confounding effects of various weather factors, and test the isolated effect of air pollution induced changes in incoming global solar radiation on yield under ceteris paribus conditions, crop model based scenario-analysis was conducted. The simulation results of the calibrated Agricultural Production Systems Simulator (APSIM) model indicated that a reduction in radiation by 10% might cause a yield reduction by more than 10%. Increasing incident radiation by 10% would lead to yield increases of (only) 7%, with the effects being much stronger during the late growing phase compared to the early growing phase. However, there is evidence that APSIM overestimates the effect of air pollution induced changes on radiation, as it does not consider the changes in radiative properties of solar insulation, i.e. the relative increase of diffuse over direct radiation, which may partly alleviate the negative effects of reduced total radiation by air pollution. Concluding, the present study could not detect a significantly negative effect of air pollution on wheat yields in the NCP. [ABSTRACT FROM AUTHOR]

An adjusted irrigation regime may help to minimize the risk of soil compaction, which is a major yield constraining factor in global crop production, constituting a serious issue in the winter wheat–summer maize double cropping system of the North China Plain. Thus this study aimed to evaluate the natural changes of soil penetration resistance (PR) and soil bulk density (BD) caused by freezing/thawing (FT) and wetting/drying (WD) cycles. This was tested under full irrigation (FI) and deficit irrigation (DI) over three double cropping seasons from 2011 to 2014, following a conventional tillage sequence of shallow, deep and shallow tillage before the first, second and third season, respectively. The results showed that in the deeper soil layer FT during winter reduced the PR by 22.9%, 34.7% and − 18.7% under FI for the three seasons, respectively. The values under DI were 4.5%, 8.0% and − 33.8% for the three seasons, respectively. However the compaction alleviating effects due to FT were only of temporary nature. Furthermore FI caused a stronger recompaction after deep tillage compared to DI, mainly attributed to increased slumping of soil. On the contrary DI reduced the BD by 8.4% in the deep soil layer by fostering intensive cycles of WD over the three double cropping seasons. Results also showed that DI resulted in a higher physical quality of subsoil, expressed by the value of S, compared to FI. It was concluded that irrigation intensity should be reduced after deep tillage to minimize and slow down subsequent recompaction. [ABSTRACT FROM AUTHOR]

The combined effects of soil moisture and physical parameters are important concerns in crop production. A three-season field experiment and a two-season tube experiment were performed to examine the effects of subsoil bulk density (BD) on the performance of winter wheat associated with irrigation regimes. Tubes (19.2 cm in inner diameter and 1 m in depth) were compacted with soil to create different BD ranging from 1.4 to 1.8 g/cm 3 at a subsoil layer (20–40 cm). The field study was conducted under deep tillage (DT) and rotary tillage (RT) that created two different BD at the subsoil layer (1.57 and 1.67 g/cm 3 , respectively). Two irrigation regimes (deficit and adequate) were applied to both the field and the tube experiments. Results from the tube tests showed that total root weight (TRW) was reduced with the increase in the BD, especially the root weight under the subsoil pan. TRW was positively related to the total shoot weight; whereas the final grain yield was not linearly related to the shoot weight, due to the different effects of BD and irrigation on harvest index. Moderate subsoil BD (1.5–1.6 g/cm 3 ) produced the highest harvest index and grain yield. Results from the field experiment showed that the lower subsoil BD under DT improved the root growth in the deep soil layer, resulting in more soil water utilization under deficit irrigation, as compared with the higher subsoil BD under RT. Thus the yield under DT was improved under deficit irrigation. No significant difference in yield under adequate irrigation was found between the two tillage methods. The results testified that the effects of subsoil compaction on crop performance were associated with soil water conditions. Under relative dry condition, higher than optimum subsoil BD would negatively affect crop performance more significantly than that under sufficient water supply. The subsoil BD should be maintained below 1.6 g/cm 3 under the growing conditions of this study. The long-term RT had increased the subsoil BD over this limit. Optimizing the subsoil BD by tillage management would benefit crop production. [ABSTRACT FROM AUTHOR]

Highlights: [•] Pan evaporation from type of E601 was similar to the calculated ET0. [•] Irrigation application could be decided by the net pan evaporation and a coefficient. [•] Yield of winter wheat was optimized with a coefficient of 1.25. [•] Seasonal root zone drainage was related to the irrigation amount per application [ABSTRACT FROM AUTHOR]

It is well acknowledged that due to the polymer component, the oil–water relative permeability curve in polymer flooding is different from the curve in waterflooding. As the viscoelastic properties and the trapping number are presented for modifying the oil–water relative permeability curve, the integration of these two factors for the convenience of simulation processes has become a key issue. In this paper, an interpolation factor Ω that depends on the normalized polymer concentration is firstly proposed for simplification. Then, the numerical calculations in the self-developed simulator are performed to discuss the effects of the interpolation factor on the well performances and the applications in field history matching. The results indicate that compared with the results of the commercial simulator, the simulation with the interpolation factor Ω could more accurately describe the effect of the injected polymer solution in controlling water production, and more efficiently simplify the combination of factors on relative permeability curves in polymer flooding. Additionally, for polymer flooding history matching, the interpolation factor Ω is set as an adjustment parameter based on core flooding results to dynamically consider the change of the relative permeability curves, and has been successfully applied in the water cut matching of the two wells in Y oilfield. This investigation provides an efficient method to evaluate the seepage behavior variation of polymer flooding. [ABSTRACT FROM AUTHOR]

Frequent geological disasters based on a range of precipitating factors occur in areas with fragile geological environments, and the traditional artificial geological disaster survey method is often too dangerous to be carried out effectively. In order to achieve more efficient influence factors and refine the evaluation of micro-scale geological disaster susceptibility, this paper used UAV tilt photography and image processing technology to construct a 3D model of the geological environment. Geological disaster influence factors were extracted from a typical geological disaster area within Qingchuan County, Sichuan Province. A weighted certainty factor method and information model method were used to evaluate geological disaster susceptibility. The geological disaster susceptibility index of different characteristic variables was calculated using a certainty factors method, while factor weight was determined using an information model. The geological environment "potentiality parameter" for each grid unit, taken as the basis of geological disaster susceptibility zoning in the area, was calculated by coupling factor weight and CF value. Finally, the ROC test method was used to verify evaluation results of geological hazard susceptibility. This study found that: (1) UAV tilt photogrammetry data can be an effective method for geological disaster susceptibility evaluation. (2) The areas under the ROC curve calculated using the two methods were 66.20% and 81.71%, respectively, showing that accuracy of the weighted certainty factor method was higher than that of the information method. Image 1 • High-resolution images were got by UAV. • A 3D model was used to select factors. • Disaster susceptibility was evaluated finely. [ABSTRACT FROM AUTHOR]