Seasonal Course Research Articles

Applying minirhizotrons to observe spatiotemporal variations in rooting depth and distribution in agroecosystems to improve the performance of hydrological models

AbstractTo understand and explain soil moisture dynamics, the role of the vegetation is crucial. Hydrological processes in agricultural soils are strongly affected by rooting depth and root distribution. We present a new approach to monitor and model root dynamics and its influence on soil moisture using minirhizotrons combined with phenological observations. Field setups consist of a portable root scanner and acrylic glass tubes installed in the soil at the start of the growing season. 360° scans of soil and roots are taken regularly at different depths in the tubes. Root traits are identified automatically for each soil layer and complemented by observations of aboveground plant phenology. Results from minirhizotron data collected at an agrometeorological observatory in Germany show for both cereal and rapeseed (Brassica napus L.) crops a higher root density in deeper soil layers and a lower density near the soil surface when compared to literature data. An opposite picture emerged for maize (Zea mays L.) and potato (Solanum tuberosum L.), whereas vertical root distribution in sugar beet (Beta vulgaris subsp. vulgaris) had a different seasonal course than expected from literature. Applying the new root distribution data in calculations of the soil water balance resulted in differences of more than 3% in absolute volumetric soil water content. A comparison with in situ measurements of volumetric soil moisture at 20‐ and 50‐cm depth revealed a significant improvement of the model results due to the new parameterization. Thus, we argue that minirhizotrons constitute a useful supplement to hydrological observatories and can help understand and predict soil moisture dynamics in the critical zone.

Seasonal dynamics and regional distribution patterns of CO2 and CH4 in the north-eastern Baltic Sea

Abstract. Significant research has been carried out in the last decade to describe the CO2 system dynamics in the Baltic Sea. However, there is a lack of knowledge in this field in the NE Baltic Sea, which is the main focus of the present study. We analysed the physical forcing and hydrographic background in the study year (2018) and tried to elucidate the observed patterns of surface water CO2 partial pressure (pCO2) and methane concentrations (cCH4). Surface water pCO2 and cCH4 were continuously measured during six monitoring cruises onboard R/V Salme, covering the Northern Baltic Proper (NBP), the Gulf of Finland (GoF), and the Gulf of Riga (GoR) and all seasons in 2018. The general seasonal pCO2 pattern showed oversaturation in autumn–winter (average relative CO2 saturation 1.2) and undersaturation in spring–summer (average relative CO2 saturation 0.5), but it locally reached the saturation level during the cruises in April, May, and August in the GoR and in August in the GoF. The cCH4 was oversaturated during the entire study period, and the seasonal course was not well exposed on the background of high variability. Surface water pCO2 and cCH4 distributions showed larger spatial variability in the GoR and GoF than in the NBP for all six cruises. We linked the observed local maxima to river bulges, coastal upwelling events, fronts, and occasions when vertical mixing reached the seabed in shallow areas. Seasonal averaging over the CO2 flux suggests a weak sink for atmospheric CO2 for all basins, but high variability and the long periods between cruises (temporal gaps in observation) preclude a clear statement.

Pediatric anesthesiology in Brazil, Chile, and Mexico.

Latin America comprises an extensive and diverse territory composed of 33 countries in the Caribbean, Central, and South America where Romance languages-languages derived from Latin are predominantly spoken. Economic disparities exist, with inequitable access to pediatric surgical care. The Latin American Surgical Outcomes Study in Pediatrics (LASOS-Peds), a multi-national collaboration, will determine safety of pediatric anesthesia and perioperative care. Below, we provide a descriptive initiative to share how pediatric anesthesia in Brazil, Chile, and Mexico operate. Theses descriptions do not represent all of Latin America. Brazil an upper middle-income country, population 203 million, has a public system insufficiently resourced and a private system, resulting in inequitable safety and accessibility. Surgical complications constitute the third leading cause of mortality. Anesthesiology residency is 3 years, with required rotations in pediatric anesthesia; five hospitals offer pediatric anesthesia fellowships. Anesthesiology is a physician-only practice. A Pediatric Anesthesia Committee within the Brazilian Society of Anesthesiology offers education through seasonal courses and workshops including pediatric advanced life support. Chile is a high-income country, population 19.5 million, the majority cared for in the public system, the remainder in university, private, or military systems. Government efforts have gradually corrected the long-standing anesthesiology shortage: twenty 3-year residency programs prepare graduates for routine pediatric cases. The Chilean Society of Anesthesiology runs a 1-month program for general anesthesiologists to enhance pediatric anesthesia skills. Pediatric anesthesia fellowship training occurs in Europe, USA, and Australia, or in two 2-year Chilean university programs. Public health policies have increased the medical and surgical pediatric specialists and general anesthesiologists, but not pediatric anesthesiologists, which creates safety concerns for neonates, infants, and medically complex. Chile needs more pediatric anesthesia fellowship programs. Mexico, an upper middle-income country, with a population of about 126 million, has a five-sector healthcare system: public, social security for union workers, state for public employees, armed forces for the military, and a private "self-pay." There are inequities in safety and accessibility for children. Pediatric Anesthesiology fellowship is 2 years, after 3 years residency. A shortage of pediatric anesthesiologists limits accessibility and safety for surgical care, driven by added training at low salary and hospital under appreciation. The Mexican Society of Pediatric Anesthesiology conducts refresher courses, workshops, and case conferences. Insufficient resources and culture limits research.

Seasonal Variability of Cultivable Nitrate-Reducing and Denitrifying Bacteria and Functional Gene Copy Number in Fresh Water Lake.

This study describes the seasonal course of denitrifying and nitrate-reducing bacteria in a dimictic mesotrophic lake (Lake Scharmützelsee, Brandenburg, Germany) within a three-year period from 2011 to 2013. The bacterial cell numbers were quantified by the fluorescence microscopy, most probable number (MPN) and PCR-dependent quantification of the chromosomal 16S rDNA and of the nirS and nirK gene copy number. The highest seasonal differences (up to three orders of magnitudes) have been measured using MPN in the epilimnion. This variation was not reflected by PCR-dependent approaches or direct microscopical enumeration. At adverse conditions (low temperature and/or low nitrate concentrations), the differences between MPN and gene copy numbers increased by up to five orders of magnitudes and decreased to one magnitude at favourable environmental conditions. These results can be explained best by an increasing ratio of viable but not cultivable (VBNC) cells or dead cells at impairing conditions. In the hypolimnion, the courses of MPN and nir gene copy numbers were similar. This can be explained by a higher feeding pressure and therefore smaller amounts of dormant cells. In the pelagial in general, the total cell numbers enumerated by either microscopical or molecular approaches were similar. In the sediment, more than 99% of the DNA was obviously not related to viable bacteria but was rather DNA in dead cells or adsorbed to particle surfaces.

Temporal downscaling of glaciological mass balance using seasonal observations

Abstract Glaciological mass-balance measurements have been the backbone of internationally coordinated glacier monitoring. The resulting annual observations have been used to understand glacier reactions to climate change, and to assess both regional and global glacier mass changes and related contributions to runoff and sea-level rise. However, the comparability of annual observations is hampered by differences in survey periods and mass-balance amplitudes between glaciers, regions and hemispheres. This study presents a simple approach to temporally downscale glaciological mass balance using seasonal observations and sine functions. The proposed analytical model allows reconstruction of the seasonal course of glacier mass balance at weekly to monthly resolution from only annual or seasonal observations. Strengths and limitations of this analytical approach are discussed and compared with results from numerical mass-balance modelling. Potential applications include seasonal corrections of glaciological and geodetic observations and comparisons to monthly results from spaceborne gravimetry and altimetry.

Recommendations for growing young Australian red-clawed crayfish (Cherax quadricarinatus) in industrial conditions

The Australian thermophilic red-clawed crayfish (Cherax quadricarinatus) is characterized by a number of qualities that ensure its effective cultivation in commercial aquaculture. At the same time, the year-round cultivation of this species in natural reservoirs of Russia is limited by the seasonal course of temperatures. In this regard, the cultivation of tropical crayfish in certain periods of life in regulated conditions is a necessary stage of full-cycle technology. In particular, the successful maintenance of ARCC juveniles until they are transferred to natural conditions (after reaching a mass of 5 g) in installations with a controlled temperature regime is due to a number of factors. First of all, this is the planting density, which naturally depends on the area and capacity of installations with a closed water supply cycle, the size, mass and age characteristics of the object. The physiological and biological state of crayfish, the intensity and quality of feeding, and the duration of cultivation play an important role. The purpose of this work is to determine the main technological indicators of growing juveniles Australian red-clawed crayfish in industrial conditions up to 5 g. Data on the results of growing juveniles Australian red-clawed crayfish under controlled temperature conditions showed the main differences in mass indicators and survival of groups of juveniles Australian crayfish depending on the initial average weight, planting density, order of offspring. The terms of growing juveniles up to 5 g have been established, the feed costs for this period have been calculated, the chemical composition of the body of juvenile crayfish has been determined.

Quality of Snow Cover Characteristics Derived from ERA 5-Land Reanalysis for the Territory of Perm Krai

Received March 31, 2023; revised June 6, 2023; accepted June 27, 2023Agreement between values of the mean monthly snow depth provided by the ERA 5-Land reanalysis and similar characteristics of snow cover calculated on the basis of the extended hydrometeorological monitoring performed in the Perm Region for 1990–2020 is analyzed. It was found that ERA 5-Land in 73% of cases reproduces the presence/absence of snow during the onset period, and in 53% – during the period of snow loss. The conclusions made in the authors' previous studies based on more limited material were generally confirmed. It is shown that the reanalysis values of the snow depth are overestimated in relation to instrumental measurements for most of the hydrometeorological stations of the Perm Region. In space, the magnitude of the reanalysis error increases from the southwest to the northeast of the region, with the exception of its central part, where the influence of the Kama water reservoir is perceptible. But the interannual variability of the average snow depth in the Perm Region was reproduced by the ERA 5-Land reanalysis adequately. For 30 years, the magnitude of the reanalysis error decreased as it was compared with 61% observation points. The analysis of seasonal variability showed that in ERA 5-Land time of the maximum snow depth was shifted to earlier onset. The complete coincidence of the seasonal course was recorded only in 5% of hydrometeorological monitoring sites. The value of the average monthly discrepancies between the data of the reanalysis and the information of the posts as a whole exceeds the similar characteristic for the stations, which is especially evident during the period of active snowmelt.

0382 Age at Onset in Adults with Insomnia: A Latent Profile Analysis

Abstract Introduction Research has sought to understand insomnia through identification of subtypes, yet age at onset (AAO) has received limited empirical attention. Across psychiatric disorders, early AAO is associated with higher clinical severity and burden, more persistent course, and greater familiality, whereas late AAO is associated with comorbid psychiatric and physical illness. We sought to detect clinically distinct AAO subgroups in adults with insomnia utilizing latent profile analysis (LPA). Methods Participants were 618 adults aged 18 to 71 years (M=28.94, SD=11.06) with insomnia, recruited through Prolific Academic. Participants completed an internet survey of demographics, medical/psychiatric history, family history, insomnia onset acuity, and course, causal attributions surrounding insomnia onset, and current insomnia severity and sleep-related impairment. LPA was performed on AAO of clinically significant insomnia (i.e., causing distress or daytime impairment and occurring 3 days per week for at least 3 months). Independent samples t-test and chi-squared test of independence were performed to compare resulting AAO subgroups on clinical outcomes. Results A two-class model (Class 1: n=547, 88.5%, Monset=19.2 years; Class 2: n=71, 11.5%, Monset=43.5 years) was optimal for forming insomnia AAO subgroups. The late onset group had higher relative insomnia severity, t=-2.78, p=.006, and sleep-related impairment, t=-3.75, p<.001. There were no group differences in lifetime prescription sleep medication, p=.569, lifetime diagnosis of psychiatric disorder(s), p=.189, family history of insomnia, p=.159, or insomnia onset acuity (i.e., sudden vs. gradual), p=.140. Late onset was associated with higher relative endorsement of hormonal factors, Χ2=12.81, p<.001, bodily arousal, Χ2=8.57, p=.003, scheduling, Χ2=9.08, p=.003, and childhood experiences and traumatic events, Χ2=5.67, p=.017). There were group differences in insomnia course, Χ2=16.35, p<.001, such that early onset was associated with higher relative endorsement of persistent insomnia and late onset was associated with higher relative endorsement of seasonal insomnia. Conclusion Findings suggest the presence of an early onset group with higher persistence, but not increased severity and impairment as anticipated, and a late onset group with more seasonal course, numerous causal attributions, and higher insomnia severity and impairment. Future replication is needed to determine the validity and treatment applications of these subgroups. Support (if any) NIMH K23MH113884

Часова динаміка морфометричних характеристик фітопланктону в прибережній акваторії Криму (Чорне море, Україна)

The morphometric characteristics of algae at different levels of hierarchical organization – cells, species, functional complexes of species, taxa (diatom algae, dinoflagellates) and phytoplankton as a whole were analyze. Study based on the results of monitoring carried out near the shores of Sevastopol (the Black Sea) in different periods (2004−2006 and 2009−2014), using the cells shape sphericity index (CSSI). It is shown that for each period there is a certain range of fluctuations of average values, both in seasonal and interannual dynamics. A comparison of the two investigated periods by the average CSSI showed a statistically significant decrease in diatoms and a slight increase in dinoflagellates, which may be associated with a shift in the species composition of diatom algae towards more elongated forms, and more rounded in dinoflagellates. Based on the example of two species with elongated cell forms: the diatom Proboscia alata (Brightwell) Sundström and the dinoflagellate Tripos furca (Ehrenberg) F.Gómez, as well as on the 3rd complex as a whole, a significant positive correlation with the water density on the surface was found with the 99% confidence level, which quantitatively confirms their seasonal polymorphism. The analysis of the seasonal dynamics of CSSI of diatoms as a whole showed statistically significant differences and a wide range of fluctuations by month. In the seasonal dynamics, three waves with an interval of four months were found, which corresponded to the seasonal course of the population quantity, except for the March bloom of the 2nd complex representatives belonging to the genus Pseudo-nitszchia H.Peragallo, as a result of which the CSSI was minimal. The May and September maxima of numbers corresponded to the maxima of the CSSI due to bloom and the development of the 1st complex representatives, mainly of the genus Chaetoceros Ehrenberg. For dinoflagellates seasonal differences were not significant and varied within a narrow range, with high mean values (above 0.94) for most of the year. The CSSI minima coincided with the population maxima in May and October. The range of CSSI fluctuations in the seasonal dynamics of diatoms (34.7%) was an order of magnitude higher than that of dinoflagellates (3.7%), which indicates a more stable grouping structure of the latter. Therefore, the average form depends to a large extent on species diversity. At the same time, diatoms are characterized by greater plasticity in adapting to environmental conditions. All phytoplankton are characterized by high CSSI values for most of the year due to the predominance of small flagellates and Prymnesiophyceae algae, with an episodic decrease during the period of diatom bloom in spring and autumn. The rounding of the grouping of both diatoms and dinoflagellates in 2010 May be a response to an abnormally high temperature of water, which led to the intensification of trophic processes in the marine environment. The obtained results can be used as a baseline for comparison in case of resumption of monitoring in this area in the future. The proposed method can be used as a basis for carrying out similar monitoring in any other water area of any type of reservoir.

Tracking vegetation phenology of pristine northern boreal peatlands by combining digital photography with CO2 flux and remote sensing data

Abstract. Vegetation phenology, which refers to the seasonal changes in plant physiology, biomass and plant cover, is affected by many abiotic factors, such as precipitation, temperature and water availability. Phenology is also associated with the carbon dioxide (CO2) exchange between ecosystems and the atmosphere. We employed digital cameras to monitor the vegetation phenology of three northern boreal peatlands during five growing seasons. We derived a greenness index (green chromatic coordinate, GCC) from the images and combined the results with measurements of CO2 flux, air temperature and high-resolution satellite data (Sentinel-2). From the digital camera images it was possible to extract greenness dynamics on the vegetation community and even species level. The highest GCC and daily maximum gross photosynthetic production (GPPmax) were observed at the site with the highest nutrient availability and richest vegetation. The short-term temperature response of GCC depended on temperature and varied among the sites and months. Although the seasonal development and year-to-year variation in GCC and GPPmax showed consistent patterns, the short-term variation in GPPmax was explained by GCC only during limited periods. GCC clearly indicated the main phases of the growing season, and peatland vegetation showed capability to fully compensate for the impaired growth resulting from a late growing season start. The GCC data derived from Sentinel-2 and digital cameras showed similar seasonal courses, but a reliable timing of different phenological phases depended upon the temporal coverage of satellite data.

What drives forest carbon storage? The ramifications of source-sink decoupling.

This article is a Commentary on Martínez‐Sancho et al. (2022), 236: 58–70.

Вклад мезомасштабных вихрей Лофотенской котловины в ее энергетику

A comparative assessment of the contribution of eddies and other dynamic structures to the energy of the Lofoten Basin is carried out. The basis of the study is the data of global ocean reanalysis GLORYS12V1 for 1993–2019. We estimate the total kinetic and potential energy as well as the corresponding contribution of eddy energy for a region bounded by an isobath of 3000 m. We use the method of automatic identification of vortices for the analysis which allows us to calculate the eddy kinetic and potential energy in the automatically selected areas of the eddies. We establish that the potential energy of both cyclones and anticyclones is on average 2–3 times higher than the kinetic
 energy values, and the energy values of kinetic and potential for anticyclones dominate relative to the energy of cyclones. We also consider the interannual variability and seasonal course of eddy kinetic and potential energy. The seasonal course revealed an increase in both types of energy in the winter months. It is established that the contribution of eddies to the total energy of the basin is small. The contribution of eddy kinetic energy to the total energy of the basin is 7.3%, and the contribution of eddy potential energy is 8.4%. This means that the main contribution to the energy of the basin is made not by mesoscale eddies, but by other dynamic structures i.e. filaments and background flow.

CLM5-FruitTree: a new sub-model for deciduous fruit trees in the Community Land Model (CLM5)

Abstract. The inclusion of perennial, woody crops in land surface models (LSMs) is crucial for addressing their role in carbon (C) sequestration, food production, and water requirements under climate change. To help quantify the biogeochemical and biogeophysical processes associated with these agroecosystems, we developed and tested a new sub-model, CLM5-FruitTree, for deciduous fruit orchards within the framework of the Community Land Model version 5 (CLM5). The model development included (1) a new perennial crop phenology description, (2) an adapted C and nitrogen allocation scheme, considering both storage and photosynthetic growth of annual and perennial plant organs, (3) typical management practices associated with fruit orchards, and (4) the parameterization of an apple plant functional type. CLM5-FruitTree was tested using extensive field measurements from an apple orchard in South Tyrol, Italy. Growth and partitioning of biomass to the individual plant components were well represented by CLM5-FruitTree, and average yield was predicted within 2.3 % of the observed values despite low simulated inter-annual variability compared to observations. The simulated seasonal course of C, energy, and water fluxes was in good agreement with the eddy covariance (EC) measurements owing to the accurate representation of the prolonged growing season and typical leaf area development of the orchard. We found that gross primary production, net radiation, and latent heat flux were highly correlated (r>0.94) with EC measurements and showed little bias (<±5 %). Simulated respiration components, sensible heat, and soil heat flux were less consistent with observations. This was attributed to simplifications in the orchard structure and to the presence of additional management practices that are not yet represented in CLM5-FruitTree. Finally, the results suggested that the representation of microbial and autotrophic respiration and energy partitioning in complex, discontinuous canopies in CLM5 requires further attention. The new CLM5-FruitTree sub-model improved the representation of agricultural systems in CLM5 and can be used to study land surface processes in fruit orchards at the local, regional, or larger scale.

Daily-Seasonal Variation in the Number of Remotely Observed, Pulsed, ULF Electromagnetic Earthquakes and the Spatial Distribution of Their Generation Zones on the Earth’s Surface

Based on data from long-term observations at two geophysical observatories, Borok and College, distantly spaced in latitude and longitude, the results of remote observation of pulsed electromagnetic, ultralow-frequency (ULF) signals detected from distant earthquakes are analyzed withinminutes of the seismic event. The daily and seasonal dependences of the frequency of occurrence of precursors in observatories and the nature of the spatial distribution of their generation zones on the Earth’s surface are studied. Two maxima are distinguished in the daily distribution of the recurrence frequency: in the evening and morning hours of local time. In the seasonal course, there is a maximum in the spring and an increase in the winter months. In the spatial distribution, there is an uneven location of sources around the globe: they are grouped into separate zones and cells that reflect separate regions on the map with manifestations of seismoelectromagnetic activity. Examples are given to illustrate the appearance of precursors. It is noted that the dynamic spectra of signals from earthquakes occurring in different regions of the Earth’s surface were similar. They were repeated at different magnitudes and focus depths and were observed in one time interval allocated relative to the moment of the earthquake. The results of the analysis indicated the universality of the processes of the generation of impulsive precursors preceding an earthquake, as well as the fundamental possibility of a short-term warning (of a few minutes) of an approaching earthquake.

Clinical characteristics, sociodemographic profile, and treatment pattern of bipolar disorder - A multicenter study from India

Bipolar disorder (BPD) is a chronic debilitating psychiatric illness, which is episodic in nature. Considering the paucity of evidence from an Indian real-world setting, the objective of the study was to assess the clinicoepidemiological profile of BPD patients and management practices in India. This multicenter, cross-sectional, single-visit study was conducted across 37 centers in India. Patients aged 18–65 years diagnosed with BPD type I or II, with a duration of ≥2 years, were evaluated by using semi-structured questionnaires and standard tools for socio-demographic profile, clinical outcomes, and management practices. A total of 574 patients were enrolled. Socio-demographic data suggest that majority of the patients were men, educated, employed, and belonging to upper-middle class. Mean age at the time of diagnosis of BPD was 33.7 (10.98) years. In all, 348 (60.6%) and 226 (39.4%) patients presented with mania and depression as the first episode of BPD. Total number of seasonal courses (n ​= ​59) and rapid cycling episodes (n ​= ​48) were 2.4 (4.48) and 1.0 (1.74), respectively. The duration of BPD symptoms and duration from diagnosis were 11.9 (32.66) months, and 67.3 (59.73) months, respectively. Mood stabilizers like lithium were recommended in majority of the patients. Findings from this study will help design accurate and personalized treatment plans for the Indian setting. Nevertheless, further studies with extended follow up are warranted for optimal treatment course and outcomes. • In this large, Indian cohort study, bipolar disease was more frequent among men. • Most patients presented with mania as the first episode of bipolar disease. • Mood stabilizers like lithium were the most frequently recommended treatment option. • Other key findings were average QoL, mild disability, and moderate caregiver burden.

Evapotranspiration estimates in a traditional irrigated area in semi-arid Mediterranean. Comparison of four remote sensing-based models

Quantification of actual crop evapotranspiration (ETa) over large areas is a critical issue to manage water resources, particularly in semi-arid regions. In this study, four models driven by high resolution remote sensing data were intercompared and evaluated over an heterogeneous and complex traditional irrigated area located in the piedmont of the High Atlas mountain, Morocco, during the 2017 and 2018 seasons: (1) SAtellite Monitoring of IRrigation (SAMIR) which is a software-based on the FAO-56 dual crop coefficient water balance model fed with Sentinel-2 high-resolution Normalized Difference Vegetation Index (NDVI) to derive the basal crop coefficient (Kcb); (2) Soil Plant Atmosphere and Remote Sensing Evapotranspiration (SPARSE) which is a surface energy balance model fed with land surface temperature (LST) derived from thermal data provided from Landsat 7 and 8; (3) a modified version of the Shuttleworth–Wallace (SW) model which uses the LST to compute surface resistances and (4) METRIC-GEE which is a version of METRIC model (“Mapping Evapotranspiration at high Resolution with Internalized Calibration”) that operates on the Google Earth Engine platform, also driven by LST. Actual evapotranspiration (ETa) measurements from two Eddy-Covariance (EC) systems and a Large Aperture Scintillometer (LAS) were used to evaluate the four models. One EC was used to calibrate SAMIR and SPARSE (EC1) which were validated using the second one (EC2), providing a Root Mean Square Error (RMSE) and a determination coefficient (R) of 0.53 mm/day (R=0.82) and 0.66 mm/day (R=0.74), respectively. SW and METRIC-GEE simulations were obtained respectively from a previous study and Google Earth Engine (GEE), therefore no calibration was performed in this study. The four models predict well the seasonal course of ETa during two successive growing seasons (2017 and 2018). However, their performances were contrasted and varied depending on the seasons, the water stress conditions and the vegetation development. By comparing the statistical results between the simulation and the measurements of ETa it has been shown that SAMIR and METRIC-GEE are the less scattered and the better in agreement with the LAS measurements (RMSE equal to 0.73 and 0.68 mm/day and R equal to 0.74 and 0.82, respectively). On the other hand, SPARSE is less scattered (RMSE = 0.90 mm/day, R = 0.54) than SW which is slightly better correlated (RMSE = 0.98 mm/day, R = 0.60) with the observations. This study contributes to explore the complementarities between these approaches in order to improve the evapotranspiration mapping monitored with high-resolution remote sensing data

Application of remote sensing data for monitoring eutrophication of floodplain water bodies

The aim of this article was to investigate the influence of structural features of the floodplain water network on the spatial and temporal dynamics of chlorophyll-a concentration as an indicator of eutrophication. The research was conducted in the waters of the “Dnipro-Orilskiy” Nature Reserve. The geographic information base with polygonal objects which represented water bodies of the reserve was created on the basis of detailed geographical maps and the high resolution space images. The water bodies were characterized using such parameters as the distance of the water body centroid from the nearest shore of the Dnipro River, the area of the water body, the order of the water body and the connectivity of the water body. Chlorophyll-а concentration was estimated based on the surface algal bloom index. The information was obtained about 148 water bodies, 141 of which are water bodies in the floodplain of the Dnipro River. The area of floodplain water bodies within the reserve was 3.28 million m2. The area of floodplain water bodies ranged from 300–232,500 m2. Trophic State Index allows us to estimate the trophic level of Dnipro River waters as mesotrophic, water bodies of first and second order as eutrophic, and water bodies of third and fourth order as hypereutrophic. The dynamics of chlorophyll-a content in water followed the seasonal course of temperatures. The concentration was lowest in the cold period of the year and reached its maximum in the second half of summer. The autumn decrease occurred at the end of September. The seasonal course of air temperature was superimposed on the peculiarities of the temperature regime of a particular water body, which depended on its depth and flow rate. The time, water body area, distance from the Dnipro River channel, connectivity and order of water bodies were the statistically significant predictors of chlorophyll concentration in water and were able to explain 85% of the variation of this indicator. The increase in chlorophyll-a concentration with increasing order of a water body is due to a decrease in the intensity of water exchange and a decrease in the depth of water bodies of higher order. An increase in the order of a water body is accompanied by a branching network of water bodies, the ability of water bodies to clear sediments decreases. Sediment accumulation leads to a decrease in their depth. Warming of shallow ponds and accumulation of organic matter in them are factors of intensive growth of blue-green algae. The evacuation of surplus organic matter, which results from mass vegetation development with excessive nutrient inputs, is a key driver of the eutrophic regime of water bodies. The increasing importance of regulatory processes develops in agreement with an increase in chlorophyll-a concentration in a water body. The importance of the considered factors reaches the highest level in summer time, when simultaneous maximum warming of water bodies and minimum water level in them take place. Accordingly, the differences between deep and relatively cool water bodies and shallow water bodies that warm up quickly, which significantly stimulates the growth of organic mass, reach the greatest contrast. The spatial patterns of variation in chlorophyll-a concentration have a complex multiscale structure, indicating the multiple nature of the acting factors. The spatial variability was represented as a composition of broad-scale and medium-scale spatial processes. The broad-scale process is most dependent on connectivity, whereas for the medium-scale process the leading one is the effect of water body order.

Amplified Drought and Seasonal Cycle Modulate Quercus pubescens Leaf Metabolome.

The intensification of summer drought expected with climate change can induce metabolism modifications in plants to face such constraints. In this experiment, we used both a targeted approach focused on flavonoids, as well as an untargeted approach, to study a broader fraction of the leaf metabolome of Quercus pubescens exposed to amplified drought. A forest site equipped with a rainfall exclusion device allowed reduction of natural rainfall by ~30% over the tree canopy. Leaves of natural drought (ND) and amplified drought (AD) plots were collected over three seasonal cycles (spring, summer, and autumn) in 2013 (the second year of rain exclusion), 2014, and 2015. As expected, Q. pubescens metabolome followed a seasonal course. In the summer of 2015, the leaf metabolome presented a shifted and early autumnal pattern because of harsher conditions during this year. Despite low metabolic modification at the global scale, our results demonstrated that 75% of Quercus metabolites were upregulated in springs when trees were exposed to AD, whereas 60 to 73% of metabolites (93% in summer 2015), such as kaempferols and quercetins, were downregulated in summers/autumns. Juglanin, a kaempferol pentoside, as well as rhododendrin derivatives, were upregulated throughout the year, suggesting an antioxidant ability of these metabolites. Those changes in terms of phenology and leaf chemistry could, in the end, affect the ecosystem functioning.

Effects of coated slow-release fertilizers on nitrous oxide emission from winter wheat field in a cool-temperate region in Japan

ABSTRACT To elucidate the effects of slow-release fertilizers on nitrous oxide (N2O) emission from fields with winter wheat cultivation in cool-temperate regions, we conducted a two-year field experiment in Hokkaido. Four types of fertilizer treatment, i.e., urea (U), coated urea (CU), coated calcium nitrate (CC), and no nitrogen fertilizer (NN) were investigated. In the U treatment, urea was applied at 40 and 90 + 60 kg N ha−1 in autumn and in spring, respectively. In the CU and CC treatments, all the nitrogen (190 kg N ha−1) was applied using coated fertilizers in autumn for the first cultivation, whereas nitrogen was applied at 130 kg N ha−1 using the coated fertilizers in autumn and the remaining 60 kg N ha−1 was applied using urea in spring for the second cultivation. The magnitudes and seasonal courses of N2O flux did not largely differ among the treatments (i.e., types of fertilizer), including the NN treatment in most of the experimental periods except that the N2O fluxes were higher in the U and CU treatments than in the CC and NN treatments at the beginning of the second wheat cultivation. In all the treatments, the N2O flux showed the highest peak immediately after basal fertilization, followed by other small peaks in autumn. After the next spring, the N2O flux consistently remained low until the wheat harvest including immediately after the end of snowmelt and after supplemental fertilizations. Cumulative N2O emissions tended to be lower in the CC treatment than in the U and CU treatments, although these differences in the emissions were not statistically significant. Although the wheat grain yields were lower in the CU and CC treatments than in the U treatments, the differences were small for the second wheat cultivation. These results indicate that reduction in N2O emission with no decrease in the wheat yield can be achieved by the basal application of slow-release nitrate fertilizer combined with the supplemental application of conventional fertilizer in winter wheat cultivation in Hokkaido, although further studies are still necessary to determine the optimum allocation levels of the basal and supplemental nitrogen applications.

Crop Identification Using Radar Images

One of the most important tasks in practical agricultural activity is the identification of agricultural crops, both those growing in individual fields at the moment and those that grew in these fields earlier. To reduce the complexity of the identification process in recent years, data from remote sensing of the Earth (remote sensing), including the values of vegetation indices calculated during the growing season, have been used. At the same time, processing optical satellite images and obtaining reliable index values is often difficult, which is due to cloud cover during the shooting. To solve this problem, the article suggests using the seasonal course curve of the radar vegetation index with double polarization (DpRVI) as the main indicator characterizing agricultural crops. In the period 2017-2020, 48 radar images of the Khabarovsk Municipal District of the Khabarovsk Territory from the Sentinel-1 satellite were received and processed to identify crops in the experimental fields of the Far Eastern Research Institute of Agriculture (FEARI) (resolution 22 m, shooting interval - 12 days). Soybeans and oats were the main identified crops. Pixels of fields not occupied by these crops (forage grasses, abandoned fields) were also added. The series of values of DpRVI were obtained both for individual pixels and fields, and approximated series for three classes. The approximation was carried out using the Gaussian function, the double logistic function, the square and cubic polynomials. It is established that the optimal approximation algorithm is the use of a double logistic function (the average error was 4.6%). On average, the approximation error of the vegetation index for soybeans did not exceed 5%, for perennial grasses – 8.5%, and for oats - 11%. For experimental fields with a total area of 303 hectares with a known crop rotation, the classification was carried out by the weighted method of k nearest neighbors (the training sample was formed according to the data of 2017-2019, the test sample -2020). As a result, 90% of the fields were correctly identified, and the overall pixel classification accuracy was 73%, which made it possible to identify the discrepancy between the actual boundaries of the fields declared to identify abandoned and swampy areas. Thus, it is established that the DpRVI index can be used to identify agricultural crops in the south of the Far East and serve as the basis for the automatic classification of arable land.