River Valley Area Research Articles

Optimizing arable land suitability evaluation using improved suitability functions in the Anning River Basin

Conducting arable land suitability evaluation (ALSE) is essential for identifying agricultural development opportunities and ensuring sustainable production and food security. Traditional ALSE methods, relying on suitability proportion functions, often encounter constraints due to land use structures. Therefore, it is necessary to develop new function methods to avoid the constraints imposed by land use structures, thus making ALSE more convenient. This study aims to propose a novel set of rules for constructing proportion functions, aiming to enhance the applicability of suitability functions in arable land suitability evaluation. The study findings reveal that: (1) In the Anning River Basin, the highly Suitable, Moderately Suitable, and Marginally Suitable current arable land (CAL) respectively account for 45.3%, 29.8%, and 18.9% of the arable land (AL). The proportion of areas deemed Temporarily Unsuitable and Permanently Unsuitable is only 6%. The distribution of suitability levels for the potential arable land (PAL) is relatively uniform, with a proportion of suitable areas reaching 66.1%, indicating substantial development potential. (2) The agricultural production conditions in the arid and warm river valley area of the Anning River Basin are exceptional. Highly Suitable CAL and Highly Suitable PAL cover 93.14% and 82.97% of this region, respectively, making it a focal point for regional agricultural development. (3) The spatial distribution patterns of ALSE results based on the original function and the improved function are essentially consistent. However, there are significant differences among the suitability levels. The correlation analysis results indicate that the evaluation results based on the improved function are closer to reality. This study enhanced the accuracy of ALSE results based on the suitability function. It provided a new approach for evaluating the suitability of AL and offers a beneficial reference for regional arable land resource utilization and sustainable agricultural development.

Global Warming Will Drive Spatial Expansion of Prunus mira Koehne in Alpine Areas, Southeast Qinghai–Tibet Plateau

Global climate change exerts great effects on plant distributions. However, the response of Prunus mira Koehne, one of the most important species for ecological protection in the southeast of the Qinghai–Tibet Plateau, to climate change remains unclear. To explore the ecological factors affecting the distribution of P. mira in the context of global climate change, the MaxENT model is used to predict suitable habitats for P. mira. Our study indicated that the distribution of Prunus mira Koehn is primarily influenced by temperature rather than precipitation, and warming can facilitate the growth of P. mira. When the temperature seasonality (bio4) ranges from 134 to 576 and the mean temperature of the coldest quarter (bio11) ranges from −2.6 °C to 2.7 °C, it is most conducive to the growth of P. mira. Among the four climate scenarios, the optimal habitat for P. mira is predominantly concentrated in river valley areas and is expected to expand into higher altitude regions, particularly in the north and southeast. SSP245 and SSP370 climate pathways are conducive to the growth and spatial expansion of P. mira. Our findings highlight the significant impact of temperature not precipitation on the distribution of P. mira, and this insight is crucial for the stability and conservation of this ecologically significant plant species.

Identification of river valley areas threatening the chemical status of groundwater, in the example of the upper course of the Ner River basin, central Poland

Identification of river valley areas threatening the chemical status of groundwater, in the example of the upper course of the Ner River basin, central Poland

First Reports of Cladosporium tenuissimum Causing Leaf spots on Hydrangea macrophylla in Anhui province in China.

Forever Summer Hydrangea (Hydrangea macrophylla) is a common flowering plant in the Yangtze River Valley area of China, and it is widely cultivated globally (Chen et al. 2015). In July 2023, H. macrophylla leaves exhibiting visible diseased lesions were reported in a nursery in Wuhu, Anhui Province, China. The incidence reached 40% in a 0.2 ha area. The primary disease symptom was multiple irregular necrotic spots (0.5 to 1 mm in diameter) appearing on the leaves. These spots on the leaves were faded yellow around the perimeter and grayish brown in the center.). 15 leaf samples were sterilized with 75% alcohol and rinsed three times in sterile distilled water, then transferred to antibiotic-added potato dextrose agar (PDA) for incubation at 27°C. The colonies were fluffy, flocculent, or hairy, dark green, gray-green to gray-brown in color, and spreading or protruding punctate with a colorless halo on PDA. The conidiophores were brown to dark brown, smooth or rough surface, mostly unbranched, clearly differentiated, erect or curved. The conidia displayed a light brown to brown hue, lemon shape, fusiform, elongated ellipsoid or others with obvious spore markings and spore umbilicus. Genomic DNA was extracted from fungal colonies on infected leaves of three collections separately (Braun et al. 2003) and the internal transcribed spacer regions (ITS), actin (ACT) genes and partial translation elongation factor-l-alpha (EF) were amplified and sequenced using the primers ITS1/4 (Yin et al. 2012), ACT-512F/ACT-783R and EF 1-728F/986R (Carbone and Kohn 1999), respectively. DNA sequences of isolates were identical and deposited in GenBank (accession no. OR362754 for ITS, OR611929 for ACT and PP209106 for EF). The consensus sequences from ITS, EF and ACT showed 100%, 98.98% and 100% identical to Cladosporium strains (accession no. OQ186140.1, MT154169.1 and OL322092.1), respectively. To confirm the pathogenicity of the isolates, hydrangeas were planted in 15-cm pots containing commercial potting mix (one plant/pot). Three healthy plants were inoculated at the five to eight leaf stage by spraying 50 μL of the isolate conidial suspension (4 × 106 spores/mL) on healthy leaves. Three plants treated with sterile distilled water were used as controls. After inoculation, all plants were placed in a humidity chamber (>95% relative humidity, 26°C) for 48 h and then transferred to a greenhouse at 22/27°C. All inoculated leaves exhibited symptoms similar to those observed in the nursery 10 days after inoculation, while no symptoms were observed for control leaves. The fungus was re-isolated and confirmed to be C. tenuissimum. Based on the above morphological characterization and molecular identification, the causal agent for this leaf spot disease was identified as C. tenuissimum. Although C. tenuissimum has been reported to cause disease on H. paniculata in northern China (Li et al.2021), this is the first time that C. tenuissimum has been found on H. macrophylla in southern China. This new disease of H. macrophylla caused by C. tenuissimum is a threat to urban greening and is worth further investigation.

Effects of Different Degrees of Xanthium spinosum Invasion on the Invasibility of Plant Communities in the Yili Grassland of Northwest China.

Studying the effects of different degrees of exotic plant invasion on native plants' community structure and plant diversity is essential for evaluating the harm caused to ecosystems by plant invasion. In this study, we investigated the effects of Xanthium spinosum, a widespread invasive species, on plant community species diversity and community stability in the Ili River Valley area of Xinjiang, China, under three invasion levels (no invasion and low, moderate, and heavy invasion), and the competitive advantage index, invasion intensity, and contribution of plant community species diversity to community stability and invasibility were determined for the prickly fungus under different degrees of invasion. The results show that there were significant differences (p < 0.05) in the species diversity and community stability of plant communities caused by different degrees of invasion of X. spinosum. The species diversity and stability of plant communities were negatively correlated with the community invasibility, competitive advantage, and invasion intensity of X. spinosum (p < 0.05); therefore, the competitive advantage and invasion intensity of X. spinosum increase with the increase of its invasion degree. On the contrary, community species diversity and stability decreased with the increase of its invasion degree, ultimately leading to differences in community invasibility under different invasion degrees. The Shannon-Wiener and Simpson's indices were the greatest contributors to community stability and invasibility, respectively. Moderate and heavy levels of invasion by X. spinosum reduced the diversity and stability of local plant communities, increased the invasibility of communities, and substantially affected the structures of plant communities. Therefore, the continued invasion by X. spinosum will have an immeasurable impact on the fragile ecosystems and diversity of indigenous species in Xinjiang. We recommend that this invasive species be controlled and eradicated at the early stages of invasion to prevent further harm.

Research on the Prediction Model of Loess Collapsibility in Xinyuan County, Ili River Valley Area

Collapsibility is a unique engineering geological property of loess. Choosing appropriate parameters to build the prediction model of loess collapsibility is an essential step toward solving the loess collapsibility problem. A case study was performed for the loess in Xinyuan County of the Yili River Basin, China. A large amount of data was collected from preliminary geotechnical tests in this region. Mathematical statistics were applied to analyse the correlations between the loess collapsibility and soil parameters. Multiple linear regression and neural network theories were adopted to build this region’s prediction model of loess collapsibility. The results showed that microscopically, the soils in this region were predominantly flocculated structures. The soil particles were flaky and in bracket contact, and the pores were round or irregularly shaped. Regarding the material composition, the soils were primarily composed of quartz and albite, with a low hematite content. In the study area, the correlation coefficients between the collapsibility coefficient of the loess vs. the density, dry density, saturation, porosity ratio, and porosity varied between 0.628 and 0.857, indicating a strong or very strong correlation. In terms of predicting loess collapsibility, the effectiveness of neural networks based on RBF (radial basis function) and multiple linear regression models was contrasted. The latter was discovered to be more appropriate, dependable, and accurate, with an accuracy percentage of 94.42%. Simultaneously, the model’s assessment index is 0.014 for the root mean squared error (RMSE), 0.962 for the correlation coefficient (CC), 0.919 for the Nash–Sutcliffe efficiency coefficient (NSE), and −1.494 percent for the percent bias (PBIAS). It works well for estimating whether local loess may collapse. Therefore, the RBF neural network model built in the present study has adequate precision and meets the engineering requirements. Our research sheds new light on loess collapsibility assessment in this region.

Numerical Study on the Influence of Aquitard Layer Distribution and Permeability Parameters on Foundation Pit Dewatering

Evaluating the influence of geologic features on dewatering efficiency, particularly within strata of varying permeability, is critical to optimizing dewatering designs for deep excavations. In river valley areas, river sedimentation results in a discontinuous distribution of relatively aquitard layers (clay layers). The evaluation and calculation of the distribution and permeability parameters for foundation pit dewatering are very important when on-site geological data are insufficient. For this purpose, the deep excavation pit on the right bank and floodplain of Chongjiang River is taken as an example in this article. A three-dimensional groundwater flow model was constructed using the Unstructured Grid (MODFLOW-USG) software package version 1. The model was carefully calibrated using hydrogeologic features and observed groundwater levels to ensure its reliability. The simulation results effectively reproduce actual dewatering processes. The study reveals the following findings: (1) Increased aquitard layers (clay layer) enhance the barrier effect, thereby improving dewatering efficiency. (2) Increased clay layer permeability and storage coefficients reduce dewatering efficiency, while the specific yield of the clay layer has less pronounced effects. (3) Due to the discontinuous nature of the clay layer, dewatering rates are higher when the clay layer is below the riverbed than when it is in the flow boundary area (foothills).

Collaborative Life Protection Plan for the Lower Lhasa River Valley Area in China Based on Animal Release Behaviors

Collaborative Life Protection Plan for the Lower Lhasa River Valley Area in China Based on Animal Release Behaviors

Citizen science and land use data provide insight into the invasive riparian plant composition of the Hudson River Valley watershed

AbstractInvasive plants in the riparian zone can negatively affect the characteristics and quality of a watershed. To support the development of a watershed management plan and foster public appreciation of the value of the riparian zone, Mohonk Preserve established a volunteer monitoring program surveying sites for invasive species. Between 2017 and 2019, citizen scientists repeatedly surveyed 20 sites in the Hudson River Valley in New York for 10 invasive plant species: purple loosestrife (Lythrum salicaria L.), common reed [Phragmites australis (Cav.) Trin. ex Steud], multiflora rose (Rosa multiflora Thunb.), garlic mustard [Alliaria petiolata (M. Bieb.) Cavara &amp; Grande], dame’s rocket (Hesperis matronalis L.), Japanese knotweed (Polygonum cuspidatum Siebold &amp; Zucc.), wineberry (Rubus phoenicolasius Maxim.), barberry (Berberis spp.), Japanese stiltgrass [Microstegium vimineum (Trin.) A. Camus], and Asiatic bittersweet (oriental bittersweet, Celastrus orbiculatus Thunb.). We found that the number of target species detected was higher on sites closer to paved roads and with increasing drainage area size, while lower with higher percentages of forested land in the basin. Our analysis results highlight variation in the presence of target invasive species across the Hudson River Valley region, highlighting sites and areas to monitor for future introductions and take action to prevent species’ invasions. Our results highlight differences in the most relevant abiotic factors for hydrophytes and non-hydrophyte species, underscoring the importance of considering species’ life-history traits before the development of management plans for invasive plant species in the riparian zone. Our case study of community-collected data in the Hudson River Valley region using a relatively simple monitoring protocol can provide a road map for other regions fostering volunteer engagement with invasive plants.

New growth locations of Artemisia sieversiana Willd. in the Western Pamir

The article presents data on the place of growth of Artemisia sieversiana Willd. in the Western Pamirs, previously unpublished. This medicinal plant is well known to the locals of the area and is widely used in folk medicine. Some literature shows a limited distribution of this species, however, the plant has a wider distribution in the Western Pamirs. During our studies on the study of the habitat of A. sieversiana in the Western Pamirs, 11 new localities of this species were found, 6 of which belong to the Shugnan and 5 to the Ishkashim regions. During expeditionary research, we found that A. sieversiana is widespread in many villages of Porshinev. It can be found in the villages of Barchid, Midenshor, Tishor, Ji-ruj, etc. In the Gund valley of the Shugnan region, it can be found in the villages of Charsem and Sardem. Also in the Ish-kashim region, the plant grows in the villages of Kozideh, Yakhshvol, Boypar, Ratm and Yamchun. which refers to the new localities of this species in the Western Pamirs. In the Roshtkala district of the A. sieversiana, it grows from 2100 to 3840 m above sea level in the river valley, in gardens and near residential areas.

Liquefaction and Reliquefaction Characteristics of Aeolian Sand Foundation Reinforced by Precast Cement Piles Based on Shaking Table Test

With the continuous development of traffic construction, road engineering inevitably crosses the aeolian sand river valley area. Compared with general sandy soil and silty soil, cohesionless aeolian sand foundation has similar properties with fluid and higher liquefaction potential. Precast cement pile can greatly improve the vertical bearing capacity of foundation, but this paper finds that it also has antiliquefaction effect when it is used to reinforce aeolian sand foundation. In addition, there may be more than one liquefaction of aeolian sand foundation in areas with frequent earthquakes. Therefore, this paper explores the liquefaction and reliquefaction characteristics of aeolian sand foundation reinforced by precast cement piles through shaking table test. The test results show that under the excitation of 0.4 g EL Centro wave: (1) the increase of pore pressure in aeolian sand foundation will have multiple instantaneous peaks, which will promote the surface to float or sink. The phenomenon will be weakened by multiple earthquakes or pile reinforcement. (2) The prefabricated cement pile can improve the liquefaction and reliquefaction resistance of aeolian sand foundation. The effect is the best in the shallow layer of the foundation, which is increased by more than 30%, and the deeper the buried depth, the lower the effect. (3) The antiliquefaction ability of foundation will be improved after strong earthquake, but the dynamic response will be significantly increased in the next earthquake. (4) When the aeolian sand foundation reinforced by precast cement piles is reliquefied, the main frequency of the foundation will migrate to low frequency. The liquefied layer will inhibit the low frequency (2 ~ 15 Hz) energy transfer and promote the high frequency (25~30 Hz) energy transfer. The results provide reference for antiliquefaction design of aeolian sand foundation and improve the application of precast cement pile in liquefied foundation.

One-off basal application of nitrogen fertilizer increases the biological yield but not the economic yield of cotton in moderate fertility soil

Basal and topdressing split application of nitrogen (N) fertilizer is widely used in cotton in many cotton-growing countries, including China. Recently, in the Yellow River valley of China, one-off basal application of N fertilizer has been applied to meet the challenge of increasing labor costs. However, how one-off basal application of N fertilizer affects cotton yields and N use efficiency and by what mechanisms are not clear. Therefore, an experiment was conducted using full-season (K836) and short-season (LM532) cotton cultivars in a moderate fertility field in the Yellow River valley in 2019 and 2020. A split-plot design was established for each variety with the main plots assigned to a mulching pattern (with or without plastic film mulching) and the subplots assigned to an N rate (0 or 195 kg N ha −1 , abbreviated as N0 and N195). Cotton yield and yield components, biomass accumulation and distribution, and total N and 15 N absorption and utilization were determined each year. Compared with N0, one-off basal application of N fertilizer (N195) did not increase boll density, boll weight, lint percentage or seedcotton yield regardless of cultivar or mulching. Biomass and total N uptake of cotton increased significantly in N195 compared with N0, but the increases occurred primarily in vegetative organs, leading to reductions in the harvest index and N yield efficiency index. With one-off basal application of N fertilizer, more than 80 % of the N in cotton plants derived from soil. Approximately 28 % of 15 N-labeled urea was absorbed by cotton plants, of which only approximately 35 % was used in forming seedcotton yield. Therefore, cotton plants with one-off basal application of N fertilizer only recovered a small amount of fertilizer N, and even less of the fertilizer N was used in yield formation. As a result, the harvest index of cotton decreased, and thus, one-off basal application of N fertilizer failed to increase seedcotton yield. Cultivar and plastic film mulching did not alter the effects of one-off basal application of N fertilizer. Therefore, although one-off basal application of N fertilizer in cotton is a labor-saving approach, it should not be encouraged in moderate fertility soil in the Yellow River valley or other areas with similar ecology. • One-off basal N application did not increase the seedcotton yield compared with no-N fertilization. • One-off N application led to a low proportion of plant N derived from 15 N and even less for yield formation. • Both N uptake and N distribution to vegetative organs was improved by one-off basal N application. • Cultivar and plastic mulching did not alter the effects of one-off basal application of N fertilizer.

Research on the Impact of Rural Population Structure Changes on the Net Carbon Sink of Agricultural Production-Take Huan County in the Loess Hilly Region of China as an Example

People are the fundamental purpose and driving force of agricultural development. The changes in population structure can directly affect social and economic development of rural areas and the entire process of agricultural production. This paper takes Huan County in the Loess Hilly Region of China as the evaluation object, the townships as the evaluation unit, the change of rural population structure as the key point, and the agricultural production as the mediating factor, to study the mechanism of agricultural net carbon sinks. The results show: 1) From 2009 to 2018, the number of rural labor force in Huan County was seriously lost, the quality of the labor force was steadily improved, and the age of the labor force was increased. The number of agricultural employees dropped from 72.6 to 49.4%. The number of people with high school education or above increased from 9.7 to 15.1%. Those over working age who participated in the labor force rose from 5.2 to 8.3%. 2) The Loess Hilly Region in the northwest of Huan County was “grain-trending,” and the River Valley and Plain Area in the southeast was “grain-removing.” The input structure index both increased first and then decreased. and the Loess Hilly Region was more dependent on the fertilizer. 3) The rural population structure affects the agricultural net carbon sink by affecting the planting structure index and the input structure index. The rural population quantity and quality structure have a significant positive effect on the agricultural net carbon sink, while the population age structure has a significant negative effect on the agricultural net carbon sink. 4) From the mediating effect, the loss of population can cause fluctuations in the agricultural net carbon sink. The improvement of population quality will promote the growth of the agricultural net carbon sink, and the aging of the population will cause the decline of the agricultural net carbon sink. 5) The return of the labor force, the improvement of labor force quality, the improvement of production methods, technological innovation, and skill training are the main ways to increase agricultural net carbon sinks and reduce emissions. This paper can lay a solid foundation for realizing the overall emission reduction target of agricultural production in the Loess Hilly Region.

Leishmanial Lymphadenopathy in a Native Patient from the Nonendemic Region of Himachal Pradesh, India

A case of leishmanial lymphadenopathy in an immunocompetent native from a nonendemic area of the Ravi River valley area (altitude 996 m above the mean sea level) of Chamba, Himachal Pradesh, India, is reported. Diagnosis of visceral leishmaniasis by demonstration of Leishman–Donovan bodies in lymph nodes by fine-needle aspiration cytology has been rarely reported.

Особенности заселения средней и нижней Печоры в древности и средневековье (на примере археологических микрорайонов)

Using the example of several archaeological microregions located in various natural and climatic zones of the Pechora River basin, the patterns of settling of ancient collectives in various land-scapes of the Pechora and Izhma river valleys for several thousand years are considered. The analy-sis of archaeological sources, data of paleogeographic reconstructions and the spatial distribution of ancient sites is given. It is concluded that the concentration of archaeological sites in the river valley areas within which the life support systems of the ancient population was most effective was an im-portant part of the settlement system in different epochs. A relatively high population density in the archaeological microregions of the Middle Pechora basin was revealed in the Mesolithic, Eneolithic-Bronze and Early Iron Age epochs, which corresponds to the Boreal and Subboreal periods of the Holocene. The archaeological microregions of the Lower Pechora of the Middle Ages were inha-bited during the climatic optimum of the sub-Atlantic period. Hunting and fishing formed the basis of the life support systems of the population of the microregions of the Middle Pechora basin. For the Mesolithic sites of the Izhma-Tom microregion, the seasonality of habitats was revealed for the first time. On the Lower Pechora, the formation of medieval archaeological microregions occurred in places with an advantageous military-strategic position. Medieval settlements of archaeological microregions of the Pechora Polar region are characterized by the presence of fortifications, a variety of economic activities of their population, including metallurgy and metalworking; trade and ex-change relations with the ancient Russian population have been traced.

Physical property characterization of the Nakdong River valley sediments in relation to depositional units

The core samples collected from the Nakdong River valley area were used to characterize physical properties in relation to depositional units. The physical property data were readily classified in good agreement with the depositional units: Units I, II, III, and IV in ascending order. In other words, the variations in the physical properties reflected well the relative characteristics of the depositional units. Overall, Unit I was characterized by high values of physical properties such as compressional wave velocity (1683 m/s on average), wet bulk density (2.17 g/cm3 on average), and shear strength (41.2 kPa on average), whereas the porosity of Unit I was the lowest (approximately 35%). Moreover, the physical properties other than grain density reflected well the characteristics of each unit, characterized by gradual change from Units I to IV. Nevertheless, based on the physical property data, the lithology, rather than compaction with burial depth, likely played an important role in the variation of physical properties of each unit. These results suggest that the physical properties were mainly controlled by depositional processes at the time of deposition. The velocity anisotropies were mostly negative without a significant effect of compaction with burial depth. Nevertheless, the cracks occurring along bedding planes after coring were responsible for low horizontal velocities and negative anisotropies.

Effects of plant density and nitrogen rate on cotton yield and nitrogen use in cotton stubble retaining fields

Increasing nitrogen (N) rate could accelerate the decomposition of crop residues, and then improve crop yield by increasing N availability of soil and N uptake of crops. However, it is not clear whether N rate and plant density should be modified after a long period of cotton stubble return with high N rate. This study seeks to assess the effects of N rate and plant density on cotton yield, N use efficiency, leaf senescence, soil inorganic N, and apparent N balance in cotton stubble return fields in Liaocheng, China, in 2016 and 2017. Three plant densities 5.25 (D5.25), 6.75 (D6.75) and 8.25 (D8.25) plants m−2 and five N rates 0 (N0), 105 (N105), 210 (N210), 315 (N315), and 420 (N420) kg ha−1 were investigated. Compared to the combination used by local farmers (D5.25N315), a 33.3% N reduction and a 28.6% increase in plant density (D6.75N210) can maintain high cotton yield, while a 66.7% N reduction at 6.75 plants m−2 (D6.75N105) can only achieve high yield in the first year. Biological yield increased with the increase of N rate and plant density, and the highest yield was obtained under 420 kg N ha−1 at 8.25 plants m−2 (D8.25N420) across the two years under investigation. Compared to D5.25N315, N agronomic efficiency (NAE) and N recovery efficiency (NRE) in D6.75N210 increased by 30.2 and 54.1%, respectively, and NAE and NRE in D6.75N105 increased by 104.8 and 88.1%, respectively. Soil inorganic N decreased sharply under 105 kg N ha−1, but no change was found under 210 kg N ha−1 at 6.75 plants m−2. N deficit occurred under 105 kg N ha−1, but it did not occurr under 210 kg N ha−1 at 6.75 plants m−2. Net photosynthetic rate and N concentration of leaves under N rate ranging from 210 to 420 kg ha−1 were higher than those under N rate of 0 or 105 kg N ha−1 at all three densities. The findings suggest that D6.75N210 is a superior combination in cotton stubble retaining fields in the Yellow River Valley and other areas with similar ecologies.

Mixed carbonate–siliciclastic sedimentation at the margin of a late Miocene tidal strait, lower Colorado River Valley, south‐western USA

AbstractThe processes and deposits of tide‐dominated river deltas and estuaries are well‐understood, but the sedimentary dynamics of tide‐dominated straits and seaways are relatively little studied. Although recent depositional models have started to fill this gap, many aspects of tidal strait sedimentation such as interaction with strait‐margin alluvial fans and marginal marine systems remain poorly understood. This paper presents a study of the late Miocene basal carbonate member of the Bouse Formation exposed along the lower Colorado River, where prior studies have suggested a tidal influence on deposition. This study explores the applicability of tidal strait models in a continental oblique‐rift setting, and tests hypotheses for depositional processes and environments through detailed analysis of sedimentary facies, cross‐bedding architecture and palaeocurrent data. Mixed carbonate–siliciclastic facies on the west margin of the southern Blythe Basin record sedimentation in alluvial fans and fan‐fringing tidal flats at the retreating margin of a transgressive tidal strait. Pre‐Bouse normal faults established a narrow, tectonically confined basin architecture that led to amplification of tidal currents. Basin‐margin deposits pass laterally and up‐section into high‐energy cross‐bedded grainstone facies that record southward migration of compound dunes in the dune‐bedded strait zone of a shallow (ca 25 m) tidal strait. These findings provide the basis for recognition of strait‐margin facies in other settings where complex facies associations result from along‐strike variations in palaeobathymetry and current velocity. The results support a tidal origin for the southern Bouse Formation and provide new evidence for post‐Miocene uplift of the lower Colorado River Valley and adjacent areas.

Occurrence of plant-parasitic nematodes in sugarbeet fields of North Dakota and Minnesota

Plant-parasitic nematodes (PPNs) are an important group of pathogens on sugarbeet. Surveys were conducted in the Red River Valley (RRV) area of North Dakota (ND) and Minnesota (MN) to determine the incidence, abundance, and distribution of PPNs in sugarbeet fields. A total of 217 soil samples were collected in 2016 and 2017 from fields with sugarbeet or a history of sugarbeet production. In addition, 48 samples were collected in 2016 from tare soils in sugarbeet piling stations, and two samples were collected in 2017 from sugarbeet production fields in eastern Montana (MT) and western ND border area. The incidence and abundance of major genera of PPNs identified from sugarbeet production fields in 2016 and 2017 were: Heterodera (incidence = 15%, abundance = 1,351/200 gm of soil); Helicotylenchus (38%, 157); Tylenchorhynchus (37%, 121); Paratylenchus (28%, 108); Pratylenchus (6%, 38); Paratrichodorus (7%, 37); Xiphinema (3%, 32); and Hoplolaimus (0.4%, 20). Helicotylenchus, Tylenchorhynchus, Paratylenchus, and Heterodera were the most frequent and widely distributed nematode genera whereas, Paratrichodorus and Pratylenchus were found less frequently and at low densities. Xiphinema and Hoplolaimus were rarely detected at lower densities. Paratylenchus and Tylenchorhynchus were widely distributed in most of the sampled counties (n = 11), followed by Helicotylenchus (10), Heterodera (8), Pratylenchus (8), Xiphinema (4), Paratrichodorus (3), and Hoplolaimus (1). Species-specific PCR assays and direct sequencing of ribosomal DNA were conducted to identify species. Species identification revealed that the cyst nematodes from one of the counties in eastern MT were Heterodera schachtii and the cyst nematodes analyzed from 31 samples in 12 counties in ND and MN were H. glycines. We have not identified any H. schachtii thus far from surveyed samples in eastern ND and western MN. Other nematode species identified include Paratrichodorus allius, Pratylenchus neglectus, Tylenchorhynchus sp., Paratylenchus nanus, Helicotylenchus microlobus, and H. pseudorobustus. Accurate identification of these nematodes and awareness of their occurrence across the region is essential for developing effective pest management strategies for improved sugarbeet production.

Secondary open-angle glaucoma in presumed ocular histoplasmosis syndrome

Purpose: Secondary glaucoma refers to any form of glaucoma in which there is an identifiable cause of increased eye pressure, resulting in optic nerve damage and vision loss. Presumed ocular histoplasmosis syndrome (POHS) is an infection caused by the fungus Histoplasma capsulatum. There are diverse ocular and systemic manifestations of POHS, ranging from influenza-like illness, cavitary lung disease to life threatening dissemination affecting multiple major organ systems. Once considered to be a public health threat mainly to Ohio, Mississippi River valley areas of the United States and South America, this case represents a new epidemiological report. Results: Initial presentation of a young patient to our clinical service revealed several punched-out-chorioretinal lesions evident in the left eye. Secondary glaucoma was diagnosed in the left eye after Avastin injection to treat a choroidal neovascular membrane secondary to histoplasmosis. The patient was treated successfully with a topical simbrinza for the glaucoma. Conclusion: The clinical presentation of histo-spots, peripapillary atrophy, and choroidal neovascularization represents a confirmed triad for POHS. Choroidal neovascular membranes can be a complication of POHS and anti-VEGF is a standard treatment. Certain anti-VEGF injections have been linked to sustained elevated intraocular pressure. From a public health perspective, we can look for POHS in other areas of the world where it is not usually and customarily found as well as monitor patients for prolonged increase in eye pressure after Avastin injection.