Humid Climate Regions Research Articles

Effects of pipeline and well‐pad reclamation on topsoil properties: A meta‐analysis

AbstractThe development of horizontal drilling and hydraulic fracking has led to an increase in oil and natural gas extraction. Development of infrastructure to extract and transport these resources is expected to increase over the next few decades, resulting in extensive land disturbance. Although reclamation aims to sufficiently return disturbed lands to their pre‐disturbance use in an ecological sense, reclaimed rights‐of‐ways (ROW) commonly produce reduced crop yields. The objective of this study was to use meta‐analysis to determine soil disturbance trends across studies found in the peer‐reviewed literature. Papers that reported soil property data on disturbed ROWs and adjacent undisturbed sites were retrieved by searching the Web of Science database. Papers were separated by climate regions, resulting in analyses being conducted for studies in semiarid and humid climate regions. Results indicate that soil bulk density, soil organic matter, and pH are significantly increased on reclaimed ROWs. Soil metrics not incorporated in meta‐analysis due to insufficient observations or the possible presence of publication biases like a desire to publish significant results and poor study design (cation exchange capacity, calcium, phosphorus, magnesium, total nitrogen, electrical conductivity, sodium, sodium adsorption ratio, and texture) are assessed and discussed. Best management practices gleaned from studies incorporated into meta‐analysis are discussed to provide strategies to limit soil property disturbances.

Thermal Performance Assessment of Envelope Retrofits for Existing School Buildings in a Hot–Humid Climate: A Case Study in Chennai, India

This study aims to propose building envelope retrofit packages for existing naturally ventilated school buildings in the hot–humid climatic region of Chennai, India. Indoor thermal parameters were collected through field studies from nine sample classrooms of a selected school building in May 2019, between 9.00 am and 4.00 pm. The thermal performance assessment of the existing building was performed by examining the discomfort hours using the CBE thermal comfort tool. Envelope retrofit strategies gathered from the literature and building standards were applied and studied through simulation. The findings reveal the enormous potential to increase the thermal comfort of existing school buildings through envelope retrofit measures. The results demonstrate that the whole-building temperature can be reduced up to 3.2 °C in summer and up to 3.4 °C in winter. Implementing retrofit measures to the building envelopes of existing buildings will help school owners to increase the comfortable hours of whole buildings by up to 17%. In comparison, annual energy savings of up to 13% for the whole building can be made by enhancing the thermal performance of the building envelope. The findings will also help architects to optimise thermal performance and energy usage with minimal interventions.

Hydrogeochemical Responses of MTMS-Coated Capillary Cover under Heavy Rainfalls

To limit the oxidation of waste rocks that originates from mining operations and the subsequent leaching of acidic solutions with high concentration of metal ions, a tailing–rock–clay triple layer capillary cover system was developed to prevent rainwater infiltration in humid climatic regions. The fine grained soil (FGS) layer consists of mine tailing and a hydrodesulfurization (HDS) clay from waste-water treatment with a 95:5 mass ratio. The coarse grained soil (CGS) layer consists of local waste rock granules with a size of 1–10 mm. Methyltrimethoxysilane (MTMS), an oxidation-inhibiting agent with strong hydrophobicity, was passivated on the rock grains to further reduce water infiltration and leaching of metal ions. Prototype-scale column tests were performed with matric suction and water content measurements under 680 min rainfall of 60 mm/h, the most severe annual precipitation case scenario for the Dexing Copper Mine (Jiangxi Province, China, 28.95° N, 117.57° E, humid climate). Both the uncoated and the coated covers exhibited zero leakage throughout the experiment. The passivation on rock granules in the coated cover increased the water entry value (WEV) of the CGS layer to −0.56 kPa. This led to a 15 mm water storage increment in the overlain FGS layer as compared to that in the uncoated cover, and induced lateral drainage (5% of the precipitation) in the FGS layer, which was not overserved in the uncoated cover. The concentrations of the leached Fe2+, Cu2+, Zn2+, Mn2+ and Mg2+ cations drained from the CGS layers of the uncoated cover were 0, 0.4, 0.8, 73.5, and 590.5 mg/L, which are all within the regulation limits of industrial discharge water standards. The concentrations of Cu2+, Mn2+ and Mg2+ cations drained from the coated CGS layer were reduced by 1–3 orders of magnitude. The abovementioned laboratory studies validated the water retention and leaching prevention abilities of the proposed three-layer capillary covers and the MTMS coating, which hold promises in engineering applications.

First report of Colletotrichum siamense causing leaf spot on Manglietia decidua in the world.

Manglietia decidua Q. Y. Zheng is a deciduous broad-leaved plant and native to Jiangxi province, China. It is cultivated for its timber and urban landscaping (Xiong et al., 2014). In September 2019, a new foliar disease was observed on approx. 25% of 121 M. decidua trees in Jiangxi Agricultural University (N28°45'56″, E115°50'21″), Nanchang city, Jiangxi Province, China. The disease site belongs to the subtropical monsoon humid climate, with rainfall (1,600-1,700 mm) and red soil region. Initially, infection appeared on the leaf margins or tips as water-soaked, irregular lesions, then expanded to the center, developed into large black-brown, irregular necrotic lesions. Finally, the lesions fall off the leaves. To identify the pathogen, 15 diseased leaves were collected from 5 trees (3 leaves per tree) randomly. Small pieces (5 × 5 mm) cut from the lesion margins were surfaced sterilized (70% ethanol for 30 s, 3% NaOCl for 1 min, rinsed 3 times with sterile water), and placed on potato dextrose agar (PDA) at 25 °C. Among the isolated fungi, Colletotrichum-like colonies were about 91%, and 18 monoconidial isolates were obtained. Isolates HML-1, HML-4, and HML-7 were selected and preserved for further studies. Colonies on PDA were white, cottony, and grayish-white on the reverse side. Setae absent. Acervuli were brown, circular. Conidiophores were clear, septate, non-branching or branching at the base, conidiogenous cells were enteroblastic, phialidic, colorless, cylindrical, ampulliform. Conidia were elliptical, single-celled, straight, hyaline, and measured 13.3-17.9 × 4.3-5.7 µm (14.8 ± 1.2 × 4.8 ± 0.4 µm, n = 100). Appressoria were oval to irregular, dark brown, and ranged from 5.3-9.1 × 4.4-6.3 µm (7.2 ± 0.3 × 5.1 ± 0.2 µm, n=100). Morphological characteristics matched the description of Colletotrichum gloeosporioides sensu lato (Weir et al. 2012). The internal transcribed spacer regions (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), actin (ACT), chitin synthase (CHS-1), calmodulin (CAL), and beta-tubulin 2 (TUB2) were sequenced (Weir et al., 2012), and deposited in GenBank (ITS: OL757565-OL757567; ACT: OL627398-OL627400; CHS-1: OL757358-OL757360; GAPDH: OL757361-OL757363; CAL: OL757355-OL757357; TUB2: OL757364-OL757366). Six loci were concatenated, and the aligned sequences (2056 bp) were 99.9%, 99.8% homologous to C. siamense ICMP 18574 and ex-type ICMP18578, respectively. In the maximum-likelihood phylogenetic tree, the highest log likehihood was -9259.74, and 3 isolates were in the C. siamense clade. Based on the phylogeny and morphology, 3 isolates were identified as C. siamense. The pathogenicity of 3 isolates was tested on 12 M. decidua plants (variety: Yi lin ke) grown in the field. Healthy leaves were wounded slightly with a needle (Φ=0.5 mm) and inoculated with 10 µL of spore suspension (106 conidia/mL). Controls were treated with ddH2O (Si et al. 2021). All the treated leaves were covered with plastic bags to keep a high-humidity environment for 2 days. The experiments were repeated twice. Within 9 days, all the inoculated points showed similar symptoms to those observed in the field, whereas controls were asymptomatic. The same isolate was re-isolated from the lesions, whereas no fungus was isolated from control leaves. Manglietia decidua is an ancient and endangered plant, threatened with southern blight (Sclerotium rolfsii) (Yi et al. 2021a), root rot (Calonectria ilicicola) (Yi et al. 2021b). This is the first report of the newly emerging disease caused by C. siamense in the world. The potential threat should be evaluated for conservation in the future. This study provided crucial information for epidemiological studies and appropriate control strategies.

StoPET v1.0: a stochastic potential evapotranspiration generator for simulation of climate change impacts

Abstract. Potential evapotranspiration (PET) represents the evaporative demand in the atmosphere for the removal of water from the land and is an essential variable for understanding and modelling land–atmosphere interactions. Weather generators are often used to generate stochastic rainfall time series; however, no such model exists for the generation of a stochastically plausible PET time series. Here we develop a stochastic PET generator, stoPET, by leveraging a recently published global dataset of hourly PET at 0.1∘ resolution (hPET). stoPET is designed to simulate realistic time series of PET that capture the diurnal and seasonal variability in hPET and to support the simulation of various scenarios of climate change. The parsimonious model is based on a sine function fitted to the monthly average diurnal cycle of hPET, producing parameters that are then used to generate any number of synthetic series of randomised hourly PET for a specific climate scenario at any point of the global land surface between 55∘ N and 55∘ S. In addition to supporting a stochastic analysis of historical PET, stoPET also incorporates three methods to account for potential future changes in atmospheric evaporative demand to rising global temperature. These include (1) a user-defined percentage increase in annual PET, (2) a step change in PET based on a unit increase in temperature, and (3) the extrapolation of the historical trend in hPET into the future. We evaluated stoPET at a regional scale and at 12 locations spanning arid and humid climatic regions around the globe. stoPET generates PET distributions that are statistically similar to hPET and an independent PET dataset from CRU, thereby capturing their diurnal/seasonal dynamics, indicating that stoPET produces physically plausible diurnal and seasonal PET variability. We provide examples of how stoPET can generate large ensembles of PET for future climate scenario analysis in sectors like agriculture and water resources with minimal computational demand.

Disentangling runoff generation mechanisms: Combining isotope tracing with integrated surface/subsurface simulation

The majority of runoff studies to date have reported a similar pattern of rapid rain-to-runoff conversion via overland flow and shallow subsurface water flow, as well as the ubiquity of thresholds and hysteresis in rainfall-runoff response. But each of those approaches has limitations in terms of inference and process description. Processes of water transport and mixing and how they influence runoff generation are still not well understood or quantified. In this study, HydroGeoSphere, a fully-integrated surface/subsurface flow model, was used together with stable isotopes for disentangling runoff generation mechanisms in a headwater catchment. The study area (0.21 km2) is the first-level tributary of the Xin’an Jiang River located in a humid climate region of eastern China. Water flow simulation elucidated the spatial water transport process, and isotope tracing quantified the complex water mixing process between the shallow soil and hillslope surface. This study provides insights into the rapid transformation of rainfall infiltration and mixing in soil and exfiltration to a hillslope. Results show that the stream runoff was separated into rainfall-induced overland flow (9 %), exfiltration-induced overland flow (including the 53 % of mixed water from rainfall infiltration and 6 % of the stored soil water), and subsurface flow (32 %). Exfiltration-induced overland flow was the dominant water source in the headwater catchment during a rainfall-runoff event. The mutual influence of rainfall infiltration and soil water exfiltration caused the shallow soil to rapidly become saturated, thus forming saturation excess overland flow. The consistence of estimated soil water velocity based on the integrated isotope and numerical modeling approach, at about 0.4 m/d nearby the stream channel, improved the reliability of model visualizations. Further analysis indicates that water flow paths and velocities responding to the rainfall event were attributed to the soil moisture conditions and topography. This study demonstrates that identifying the rapid mixing processes between the rain and the soil water was crucial for understanding hillslope overland flow and runoff generation in headwater catchments.

Genetic variability of yield and yield-related traits among 27 drought-tolerant maize genotypes

Abstract Maize is a valuable crop with high genetic variability, and understanding this variability is essential for improving crop productivity and resilience to environmental stressors. This study evaluated the genetic variability and heritability of yield and yield-related traits among 27 drought-tolerant maize genotypes in a humid climate region of Southwestern Nigeria. The experiments followed rigorous agronomic, soil, and climatic requirements for maize cultivation. Our findings revealed significant genetic variability among the traits of the maize genotypes, particularly in the number of ears per plant, which had the highest genetic advancement as a percentage of the mean (68.25 % and 67.83 %) under both well-watered and drought conditions, respectively. This suggests that breeding programs targeting this trait could significantly improve maize productivity and resilience to drought stress. Additionally, most of the agronomic traits targeted were highly heritable with heritability values ranging from 0.76 to 0.99 under both environments where the genotypes were evaluated, thus indicating that selective breeding for these traits could lead to consistent improvements in maize yields over time. Overall, this study highlights the importance of evaluating yield-related traits’ genetic variability and heritability in maize breeding programs. Findings suggest that targeting the number of ears per plant in drought-tolerant maize genotypes as revealed in the study could be an effective approach for improving crop productivity and resilience in regions with variable moisture regimes.

Experimental investigations on thermal performance of spray cooling double skin façade in hot humid climate region

Thermal performance of the spray cooling double skin façade in hot and humid climate region are experimentally investigated in this study. Two identical double skin facades are constructed for the comparative analysis. Thermal performance of the spray cooling double skin façade is evaluated by the indicators of cavity air temperature, glass surface temperature, the U-value, and solar heat gain coefficient. The influences of the ventilation mode (open conditions of the top and bottom vents in the double skin façade system), operation time (spray and interval time of the spray system), and spray direction on the cooling effect of the spray cooling double skin façade are experimentally compared and analyzed, and the operation mode of the spray cooling double skin façade with the best thermal performance is obtained. The results demonstrate that the appropriate operation mode of the spray cooling double skin façade is that the top and bottom vents are opened, and the spray direction is from up to down with the operation time of 10/15 min (spray/interval time). The average temperature of the cavity and inner glass decreased by 8.1 °C and 3.7 °C, respectively. The mean U-value and SHGC of the spray cooling double skin façade are 2.13 W/(m2·K) and 0.25, respectively, which are smaller than the most stringent limit values of the current national standard. The spray cooling double skin façade has good thermal performance in hot humid climate region in China.

The Impacts of Urban Configurations on Outdoor Thermal Perceptions: Case Studies of Flat Bandar Tasik Selatan and Surya Magna in Kuala Lumpur

This study assesses the impacts of urban configurations on thermal perceptions in Flat Bandar Tasik Selatan (FBTS) and Surya Magna (SM) in Kuala Lumpur, Malaysia. It aims to understand the impacts of urban configurations on thermal perceptions in outdoor spaces. The study addresses the following research questions: (1) Do urban configurations influence outdoor comfort? (2) Do urban configurations also have significant impacts on thermal perceptions? We mapped out the sites to understand their configurations. The research considered on-site measurements of the environmental conditions and carried out modelling and simulations (ENVI-met V3.1) of the sites. Mathematical models (Wet-Bulb Globe Temperature (WBGT), Universal Thermal Climate Index (UTCI), and Standard Effective Temperature (SET)) were used to determine the thermal indices and the impact of the urban configurations on outdoor comfort. The thermal indices varied from 25.44 to 34.75 °C. In terms of the main contribution of this work, the results show that in hot and humid climate regions, urban configurations plus other design variables (e.g., orientation towards the Sun’s path) and environmental parameters influence occupants’ comfort and perceptions. Our findings show that high solar radiation and the need for a better thermal environment in hot and humid climates are the contributing factors for developing alternative urban configurations.

Relationship of shading devices and its effects on daylight in Commercial buildings in Pune

Day lighting is a critical part of visual environment in workspaces. It creates a sense of well-being and contributes to the efficiency of the occupants. Research has established that solar radiation admitted through the windows have serious effects on visual comfort of the occupants in the indoor spaces. Use of solar shading devices can address glare problems. This signifies the need for design of optimal shading devices that increase daylight levels with desirable control on excessive sunlight with an aim to reduce glare and discomfort for the occupants. In this research various configurations of conventional shading devices used for commercial buildings located in Pune, India was examined. A typical commercial building is modelled using the simulation program Integrated Environmental Solutions (IES) where existing as well as different identified configuration of shading devices was analysed for daylight performance and visual comfort with respect to amount and uniformity of illumination with Radiance rendering tool. The analysis indicated that use of appropriate shading device result in improved visual comfort for occupants. The performance of different shading device presented aimed to help architects to select suitable shading device in order to contribute to sustainability aspects of office buildings in warm and humid climatic regions.

Evaluation of Indoor Thermal Comfort Conditions of Residential Traditional and Modern Buildings in a Warm-Humid Climate

Achieving optimal levels of indoor thermal comfort in a warm, humid climate continues to pose a challenge to building occupants in such climatic regions. Buildings are either being retrofitted or designed differently to cater to thermal comfort. As a result, a variety of tactics have been deployed to guarantee optimal thermal comfort for occupants. Some scholars have highlighted the salient contributions of various types of construction materials toward the delivery of different housing types which perform differently under a diverse range of climatic conditions. A plethora of studies suggesting better indoor thermal comfort performance of traditional buildings as compared to contemporary dwellings due to various reasons have been observed. However, limited studies have sought to investigate this suggestion within warm, humid climatic regions. As such, this study engages in an evaluation of indoor thermal comfort qualities of traditional and modern buildings during the dry season with the goal of developing design guidelines for a thermally pleasant environment in a town, Okigwe, which is situated in a warm, humid climatic region in Southeastern Nigeria. Data were collected utilizing a field measurement technique. Throughout the survey period, variables of the indoor environment such as relative humidity and air temperature were recorded concurrently in nine selected buildings, two traditional and seven modern buildings. The fluctuations and differences in relative humidity and air temperature between the two building types were investigated using Z-test statistical techniques. The study’s results revealed that the contemporary structures’ indoor air temperature (29.4 °C) was 0.6 °C higher than traditional buildings’ indoor air temperature (28.8 °C). Therefore, the study recommends that architects and planners should make concerted efforts to integrate methods of passive design into the provision of a comfortable indoor thermal environment rather than relying solely on active design strategies, which whilst lacking in traditional buildings, nonetheless did not prevent such buildings from recording lower air temperature readings compared to modern buildings.

A field study on indoor environmental quality and energy savings of an office building integrated with underfloor air conditioning system in India

This study aimed to examine the real-time indoor environmental quality (IEQ) factors in an office space environment with a dedicated underfloor air conditioning system. Nevertheless, underfloor air distribution (UFAD) system buildings in India do not have reliable studies to record the impact of occupant perception and IEQ factors. This study was conducted in the UFAD office building during the peak monsoon period of 16th – 25th October 2019 in a warm and humid climate region of Mumbai, India. IEQ factors of indoor thermal, air quality, lighting, and noise comfort were examined using an occupant questionnaire survey for sensation, preference and overall acceptability, as well as physical measurements. Furthermore, energy consumption and energy utilization coefficient were determined at different room set-point temperatures. Four hundred and thirty-five responses were collected during the field study. The comfort zone temperature was obtained between 22.24–25.3 °C with near-zero (±0.5) tolerance range. Moreover, 80-95% of the occupants felt comfortable and acceptable within the thermal environment of the room set-point at 22-25 °C. Results showed that the real-time IEQ score was perceived between 0.663-0.846. The real-time IEQ score can be used as a building management strategy that simultaneously improves thermal comfort and indoor air quality.

Impacts of residential fertilizer ordinances on Florida lacustrine water quality

AbstractDespite the assumption that residential fertilizer ordinances improve regional water quality, their impacts across space and time largely remain unknown. Here, we analyze changes in water quality of lakes throughout the State of Florida from 1987 to 2018, comparing trends in water quality parameters before and after implementation of county‐wide fertilizer ordinances. We used a large dataset of publicly collected water quality data and linear mixed models to analyze ordinance impacts on total nitrogen, total phosphorus, chlorophyll a, and Secchi depth across 160 lakes throughout Florida. We further analyze water quality impacts relative to the type of ordinance (winter fertilizer ban, summer ban, nonseasonal ban, no ban). We found fertilizer ordinances favorably impacted lacustrine water quality, and winter (dry season) fertilizer bans had the greatest effect across all water quality metrics. Results of this study can be used to support the effectiveness of fertilizer ordinances across humid tropical and subtropical climate regions.

Energy, economic, and environmental (3 E) examinations of the indirect-expansion solar heat pump water heater system: A simulation-oriented performance optimization and multi-objective decision-making

In this paper, a simulation-oriented optimization integrated with the multi-objective decision-making (MODM) model for an indirect-expansion solar-assisted heat pump (IDX-SAHP) water heater is proposed and the energy, economic, and environmental (3 E) aspects of the system are examined. The developed model is verified and its performance is scrutinized in a humid continental climate region of China. Next, the sensitivity analysis is conducted via the one-way analysis of variance (ANOVA) approach. Then, the single-objective optimization (SOO) and multi-objective optimization (MOO) are conducted via the migrating birds optimization (MBO) method to maximize the coefficient of performance (COP) and the collector efficiency (CE), singly and concomitantly. The SOO results indicate the IDX-SAHP design as per the COP-oriented optimization causes the system to operate less for about 120 hours a year in contrast to the system design as per the CE-oriented optimization. Also, the results of MOO integrated with MODM indicate that MOO gives better performance in contrast to the SOOs so that although the CE of the maximized IDX-SAHP reduces a little from 51% to 46%, its COP increases greatly from 2.5 to 7. Therefore, the overall power consumption of the system decreases about 269 hours in contrast to the initial IDX-SAHP. Besides, the environmental examination illustrates the use of IDX-SAHP in Beijing buildings can prevent the burning of 2,877, 000, 000 cubic meters of natural gas per year in the fossil fuel power plants and prevent the release of 8,055,600 tons of CO2 per year into the environment. Furthermore, the economical examination illustrates that Beijing residents may save approximately one billion USD per year on the purchase of electricity if they use the IDX-SAHP. Besides, the Chinese government can achieve about 109 billion USD per year if the equivalent electricity is exported instead of domestic consumption for Electric Water Heaters (EWHs). Moreover, the external costs decrease by 928 million USD per year if the IDX-SAHP is replaced with the EWHs. This paper discloses the significance of energy, economic, and environmental (3 E) examinations, optimization, and MODM during the IDX-SAHP design to increase the system efficiency and decrease the costs and environmental impacts by opting the most appropriate design parameters of the system.

Isotopic fingerprinting of dual monsoon moisture sources, evapotranspiration process and microclimate manifestation over the tropical rainforest region, western part of the Western Ghats, India

The changes in precipitation pattern provide an understanding on the hydroclimatic response to global warming during the Anthropocene. The present study investigates sources of precipitation moisture for the Indian Monsoon and the local environmental mechanisms controlling its distribution over the southwest coast of India. This is achieved by the characterization of stable isotope ratios of oxygen (δ18O) and hydrogen (δ2H) in rainwater samples collected from a high humid tropical setting (Swarna-Madisal river basin) of the Western Ghats, South India and another station further south (Bakrabail, southern edge of Nethravati river basin). This study contributes to the detailed investigation on rainwater isotopic composition and microclimate characteristics which is lacking in the humid west coast region. The rainwater isotopic composition of coast was close to that of the Arabian Sea water and reflected the first condensate of vapours which were originally formed under fast evaporation at the nearby ocean. In inland location, the higher d-excess values reflect continental moisture recycling. Evapotranspiration has led to higher kinetic fractionation effect in the inland region. The isotopic storm effect during winter monsoon season suggested the rain distribution from saturated air masses formed under deep convective effect in the Bay of Bengal. The overall local meteoric water line (LMWL) in the Swarna-Madisal basin was found to be δ2H = {(7.2 × δ18O) + 7.5}, R2 = 0.98. Further south, the LMWL of Bakrabail was, δ2H = {(8.19 × δ18O) + 16.1}, R2 = 0.98 for annual observation and displayed minimal variability for inter-seasonal slopes (7.73 for summer monsoon, 8.48 for winter monsoon and 8.36 for pre-monsoon) and intercepts (15.6 for summer monsoon, 17.8 for winter monsoon and 15.5 for pre-monsoon). In regions of vegetation dominance and humid climate, the prevailing local air mass masked the rain-out effect of marine air mass as well as the amount effect which support microclimatic settings at the local precipitation sites in southwest India. The time and space variability of regional moisture circulation in controlling atmospheric water balance has been deduced in this study. Thus, the high efficacy of stable isotopes in tracing the manifestation of microclimate in the humid tropics has been demonstrated.

Soil physical attributes in an integrated crop-livestock system with pasture managed under different sward canopy heights and different timings of nitrogen application

This study aimed to evaluate the physical attributes of soil in an integrated crop-livestock system with winter pastures managed under different N fertilization timings and canopy heights after winter and the soybean crop. The experimental design used was randomized blocks with the treatments in a 2 × 2 factorial arrangement (two canopy heights and two N application timings), with three area replications. The canopy heights were 11 and 24 cm kept by continuous stocking grazing method since May to November (175 days). Fertilization timings as N-pasture fertilization and N-corn fertilization (phase before the winter pasture). Treatments characterized as N fertilization inversion were applied with fertilization timings as N-pasture fertilization and N-corn fertilization (phase before the winter pasture). Soil density, total porosity, and moisture content were evaluated after winter pasture (black oat + annual ryegrass) and after the subsequent summer soybean crop. The sampling spots were georeferenced and analyzed using geostatistics, considering the position in the slope of landscape. Soil physical attributes were not influenced by canopy height nor N fertilization timing (P>0.05). Soil density was reduced by 13.3% (from 1.11 to 0.98 g cm-3), whereas total porosity (from 0.58 to 0.62%) and moisture content (from 32.73 to 35.73%) increased by 6.9% and 9.2% after the soybean crop in relation to the values obtained in the winter pasture. The higher elevation areas had higher moisture content, total porosity, and lower density than the lower elevation areas, regardless of the time of evaluation. Well-drained soils were more resistant to compaction by animal trampling than moderately drained soils. In well-managed integrated crop-livestock systems in humid subtropical climate regions, the surface compaction of clayey soils in winter pastures is light, non-limiting, and disappears after the subsequent summer crop.

Image Classification and Land Cover Mapping Using Sentinel-2 Imagery: Optimization of SVM Parameters

Land use/cover (LU/LC) classification provides proxies of the natural and social processes related to urban development, providing stakeholders with crucial information. Remotely sensed images combined with supervised classification are common to define land use, but high-performance classifiers remain difficult to achieve, due to the presence of model hyperparameters. Conventional approaches rely on manual adjustment, which is time consuming and often unsatisfying. Therefore, the goal of this study has been to optimize the parameters of the support vector machine (SVM) algorithm for the generation of land use/cover maps from Sentinel-2 satellite imagery in selected humid and arid (three study sites each) climatic regions of Iran. For supervised SVM classification, we optimized two important parameters (gamma in kernel function and penalty parameter) of the LU/LC classification. Using the radial basis function (RBF) of the SVM classification method, we examined seven values for both parameters ranging from 0.001 to 1000. For both climate types, the penalty parameters (PP) showed a direct relationship with overall accuracy (OA). Statistical results confirmed that in humid study regions, LU/LC maps produced with a penalty parameter >100 were more accurate. However, for regions with arid climates, LU/LC maps with a penalty parameter >0.1 were more accurate. Mapping accuracy for both climate types was sensitive to the penalty parameter. In contrast, variations of the gamma values in the kernel function had no effect on the accuracy of the LU/LC maps in either of the climate zones. These new findings on SVM image classification are directly applicable to LU/LC for planning and environmental and natural resource management.

Effect of drought stress on the formation and lignification of eucalyptus wood cells

Summary Environmental adaptation and cell differentiation processes are factors that influence the anatomical elements of wood. The objective of this study was to investigate the effect of water deficit on lignin composition in anatomical elements and on the characteristics of vessel-neighboring cells. Six-year-old clones of Eucalyptus urophylla and Eucalyptus grandis × Eucalyptus camaldulensis from wet and dry regions were used. All regions received a rainfall exclusion treatment. Cell wall width, cell wall thickness, and form factor of fibers close to and far from vessels were measured. In the same cells, lignin was measured in the middle lamella and vessels by a fluorescence technique. The vessel differentiation process affected cell wall thickness and lignin composition in neighboring cells. Lignin composition was increased in vessels compared to fibers or vasicentric tracheids. Middle lamella lignin was not affected by vessel differentiation or water deficit in either eucalyptus clone. E. grandis × E. camaldulensis is originally from a dry climate region and, therefore, did not suffer alterations in lignin when subjected to water stress conditions; however, this clone exhibited a higher number of vasicentric tracheids. E. urophylla is originally from a humid climate region and, when subjected to water deficit, showed increased wood lignin composition, which seems to be a strategy for better use of water resources. Alterations in lignin composition of vessel, vasicentric tracheid, and fiber cell walls resulting from exposure to water deficit conditions vary according to eucalyptus species.

An automated machine learning methodology for the improved prediction of reference evapotranspiration using minimal input parameters

AbstractAn accurate and minimal meteorological parameter‐based reference evapotranspiration (ETo) computational model is highly essential to design a cost‐effective and automated solution for precise water allocation in various agricultural and hydrological applications. Automated machine learning (AutoML), a substantially progressive machine learning (ML) paradigm, expedites the data science applications in these domains by automating and alleviating the tedious tasks of developing ML pipelines, particularly in non‐linear hydrological process modelling. This paper proposes an AutoML solution for daily EToprediction in a limited input parameter scenario, for the first time in EToestimation research. Two AutoML frameworks, AutoGluon‐Tabular (AGT) and H2O AutoML were implemented using daily meteorological data of a humid tropical climatic region of Kerala, India and evaluated its performance with the radiation‐based empirical methods and traditional ML methods. The developed AutoML models imitated the input parameter combinations of radiation‐based empirical models such as Priestley‐Taylor, Makkink, Turc and Ritchie, with the Penman‐Monteith EToserving as the target for modelling process. An improvement of mean absolute error from 0.119 to 0.078 mm/day, mean squared error from 0.035 to 0.017 mm/day, root mean squared error from 0.186 to 0.129 mm/day, root mean squared logarithmic error from 0.078 to 0.026 mm/day, and coefficient of determination (R2) from 0.971 to 0.985 observed in the AutoML model, AGT relative to the empirical model, Turc describes its enhanced performance capability. For demonstrating the superiority of AutoML to traditional ML techniques, another set of AutoML models were also developed based on California Irrigation Management Information System datasets and evaluated them with existing study results in literature. The overall result analysis demonstrated the superiority of AGT model in EToprediction in all the weather stations considered in this study. The results of the study confirm that AutoML techniques can be applied to any hydrological dataset and provide an effective automated solution for hydrological process modelling.

Simulating annual runoff retention performance of extensive green roofs: A comparison of four climatic regions in China

The hydrologic performance of green roofs can be notably influenced by local climatic conditions. The majority of studies have focused on event-based retention performance of particular green roof configuration and climatic condition, making it difficult to predict green roof retention and formulate an efficient green roof configuration in a new location. To date, limited studies have assessed and compared annual or long-term runoff retention performance of green roofs in different climatic regions, and the impacts of climatic conditions on reduction effectiveness of green roofs remain unclear. In this study, a water balance model of green roofs coupling evapotranspiration rate estimation was developed to simulated the annual retention performance of green roofs. Four cities located in different climatic regions of China were selected to compare their average annual and seasonal runoff retention performances of extensive green roofs using 11 years of meteorological data, and assess the impacts of substrate storage capacity, vegetation types parameters and rainfall patterns on runoff retention performance among climatic regions. Results showed that average annual runoff retention in the dry continental climate of Lanzhou was 73.8%, which was higher than that in the humid climatic regions of Beijing (48.9%), Chongqing (45.2%) and Shenzhen (30.0%). Average runoff retention performance of extensive green roofs was the highest in spring for Beijing and Lanzhou, and in winter for Chongqing and Shenzhen. In Lanzhou and Beijing, the enhancement of increases in substrate water storage capacity on runoff retention was higher; and in Chongqing and Shenzhen, the impact for increases in crop coefficients (i.e. higher water use plants) was more efficient. Runoff retention performances of extensive green roofs were significantly decreased as rainfall depth increased. Longer antecedent dry weather period significantly lowered antecedent substrate moisture and resulted in higher runoff retention performances of extensive green roofs. These results can assist to formulate an efficient green roof configuration in local climatic condition and spatially allocate appropriate sites to optimize retention performance of green roofs.