Rainy Season Research Articles

Mechanisms of evolution and pollution source identification in groundwater quality of the Fen River Basin driven by precipitation

Groundwater pollution has attracted widespread attention as a threat to human health and aquatic ecosystems. However, the mechanisms of pollutant enrichment and migration are unclear, and the spatiotemporal distributions of human health risks are poorly understood, indicating insufficient groundwater management and monitoring. This study assessed groundwater quality, human health risks, and pollutant sources in the Fen River Basin(FRB). Groundwater quality in the FRB is good, with approximately 87 % of groundwater samples rated as “excellent” or “good” in both the dry and rainy seasons. Significant precipitation elevates groundwater levels, making it more susceptible to human activities during the rainy season, slightly deteriorating water quality. Some sampling points in the southern of Taiyuan Basin are severely contaminated by mine drainage, with water quality index values up to 533.80, over twice the limit. Human health risks are mainly from As, F, NO3−, and Cr. Drinking water is the primary pathway of risk. From 2019 to 2020, the average non-carcinogenic risk of As, F, and NO3− increased by approximately 28 %, 170 % and 8.5 %, respectively. The average carcinogenic risk of As and Cr increased by 28 % and 786 %, the overall trend of human health risks is increasing. Source tracing indicates As and F mainly originate from geological factors, while NO3− and Cr are significantly influenced by human activities. Various natural factors, such as hydrogeochemical conditions and aquifer environments, and processes like evaporation, cation exchange, and nitrification/denitrification, affect pollutant concentrations. A multi-tracer approach, integrating hydrochemical and isotopic tracers, was employed to identify the groundwater pollution in the FRB, and the response of groundwater environment to pollutant enrichment. This study provides a scientific basis for the effective control of groundwater pollution at the watershed scale, which is very important in the Loess Plateau.

LAMTORO FERMENTASI (LaFer): PAKAN PENYANGGA MUSIM KEMARAU

The availability of feed throughout the season is a problem in livestock development in West Nusa Tenggara Province. The abundance of feed sources in the rainy season is inversely proportional to the shortage of forage and other feed sources in the dry season. As a result, the condition of livestock in the dry season is very thin and malnourished, leading to miscarriage and death. To overcome these problems, processing technology and storage of abundant feed sources in the rainy season so that they can be used in the dry season are very necessary. Lamtoro Fermentation (LaFer) is a feed from lamtoro (Leuchaena sp.) that is fermented with other ingredients so that it can be stored for a long time for use in the dry season. The LaFer was made at the Agropreneur Center of the Faculty of Animal Husbandry, University of Mataram in Sambik Elen Village, Bayan District, North Lombok Regency, which is a research center for lamtoro as animal feed. The results of the activity showed that fresh lamtoro that was wilted for 24 hours, chopped and mixed with chopped corn straw, then sprayed with lactic acid bacteria mixture and fermented for at least 1 month in silo with the addition of rice bran can produce silage with good quality characterized by the absence of mold, tape-like smell, greenish color, and has high palatability for goats. The lamtoro silage is a bit dark in color because it loses Mg in chlorophyll when it reacts with organic acids to become brown phaeophytin and as an indicator that lamtoro silage contains a high pigment. Fermentation technology can be used to extend the shelf life of lamtoro so that it becomes a source of feed source protein throughout the season for livestock.

Spatiotemporal variation and teleconnections of extreme precipitation in the Upper Indus Basin: insights for natural hazard assessment

ABSTRACT The study investigates trends and teleconnections of extreme precipitation events in the Upper Indus Basin (UIB) within the Indian region, part of the crucial geo-ecological Hindu Kush Himalayan Mountain system. Utilizing high-resolution (10 km × 10 km) HAR data from 2002 to 2013, we analyzed 11 indices established by the Expert Team on Climate Change Detection and Indices (ETCCDI) to observe variations in extreme precipitation at the monthly, seasonal, and annual time scale. The result shows an increase in dry and wet extreme precipitation frequency and intensity, increasing monsoon precipitation and a shift of winter precipitation, increasing continuous dry days. Using the APHRODITE daily (0.25° × 0.25°) data from 1952 to 2014, continuous wavelet transform and wavelet coherence analysis indicate significant periodicities and correlations with large-scale climate anomalies such as the El Niño-Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO). Wavelet coherence analysis reveals that monthly extreme precipitation events significantly correlate with ENSO at a 3–5 years periodicity, while annual extremes show significant coherence with NAO at 8–10 years and over 16 years periodicities. The study highlights the impact of global climate change on regional precipitation and the need for adaptive water management policies to mitigate flood risks during the rainy season and address water scarcity in the dry season.

Diversity of Calliphoridae and Sarcophagidae (Diptera: Oestroidea) in a forested area in the municipality of Macaé, RJ, Brazil

Sarcophagidae and Calliphoridae are families of Diptera that cover, respectively, about 3,100 and 1,000 species described worldwide. The species of these families have medical and veterinary importance, due to their role as vectors of pathogenic agents. The Diptera fauna is little known in many Brazilian ecosystems, including some phytophysiognomies of the Atlantic Forest. In the present study, two expeditions were carried out, one in the rainy season and the other in the dry season, using four traps baited with fish and exposed for 48 hours in the field in the Parque Natural Municipal Atalaia in the municipality of Macaé. The collected material was sorted and assembled at Instituto de Biodiversidade e Sustentabilidade - NUPEM/UFRJ and transported to Laboratório de Biodiversidade e Sistemática de Diptera - Museu Nacional, UFRJ (MNRJ), for later identification. A total number of 712 specimens of Calliphoridae and 27 of Sarcophagidae were collected. The sampling effort for Sarcophagidae collection was average, since the species accumulation curve continues to rise, unlike the Calliphoridae curve, which remains stable. The study included species considered asynanthropic, as Hemilucilia semidiaphana (Rondani, 1850) (Calliphoridae), but also invasive species, like those of the genus Chrysomya Robineau-Desvoidy, 1830 (Calliphoridae). Therefore, the present study contributed to expand knowledge about both families in the Atlantic Forest, in Rio de Janeiro, and emphasized the importance of continuing studies in the region, as many species are asynanthropic, while others are invasive, which can result in the inhibition of the native ones.

Green synthesis of Cu/CuO nanoparticles using Cuscuta reflexa plant as an innovative organic insecticide

Cu/CuO nanoparticles (NPs) have received extensive attention owing to their tremendous antifungal and antibacterial properties. Cu/CuO NPs are used in diverse fields, viz. electronics, catalysis, photonics, biosensing, optoelectronics and many more. Herein, we described the green synthesis of Cu/CuO NPs using Cuscuta reflexa (Amarvel) plant material at room temperature. The prepared NPs were characterized by routine technique, viz. XRD, UV-Vis, SEM and TEM. The typical size found was merely 7–10[Formula: see text]nm using the TEM technique. The as-prepared solution of NPs was tested against the Diptera larval nymph of mosquitoes. These mosquitoes breed in monsoon (rainy season) in stagnant water. It is observed that NPs were very effective against these larvae, which were killed overnight when just four drops of the as-prepared NPs solution were directly added to a 10[Formula: see text]ml water sample containing mosquito larvae. Overall, the biosynthesized Cu/CuO NPs showed good insecticidal activity against the parasitic disease malaria-causing Anopheles mosquitoes in the larval stage itself. We believe the outcome will lead to a new era in the preparation of innovative organic insecticides.

Assessment of Water Quality and its Risk to Human Health Posed by Drinking Water from Open Sources in Jammu and Kashmir

Globally, the quality of the water has been connected to health outcomes. This study assessed the community practices surrounding water collection and storage, the physicochemical and bacteriological quality of drinking water supplied by the public health division from the point of use to the source in Anatnag, and the risks to human health associated with water consumption. A water quality assessment was performed on one hundred samples. To find out how the community moves water from its source to its point of use and stores it, questionnaires were employed. The majority of the homes (73%) do not purify their water before consumption, and many of them reported frequent interruptions in the water supply. Although total coliform and E. coli were not found in the water samples taken at the reservoir's source, It was discovered that there was significant E. Col and total coliform contamination in the samples taken from the street taps and the domestic storage containers at the point of use. During the rainy season, higher levels of E. Coli and total coliform were found than during the dry season. The amounts of trace metals in the drinking water samples fell below the World Health Organization's and Indian Standards' acceptable limit. Drinking water through ingestion and cutaneous channels has noncarcinogenic effects that are assessed using hazard quotient toxicity potential and cumulative hazard index. These effects are less than unity, which suggests that there may not be a major non-carcinogenic health risk associated with water intake. sporadic disruptions to the water supply as well as specific methods of water storage and transit by residents of the community raise the possibility of contaminated water. We suggest that the province of Kashmir receive a more steady supply of treated water and that its citizens be instructed in hygienic methods for carrying and storing drinking water from the point of origin to the place of use

Seasonal Patterns and Abiotic Influences on Fall Armyworm Dynamics in Chhattisgarh's Maize Agroecology

The fall armyworm Spodoptera frugiperda (J. E. Smith), an invasive pest in India, exhibits variations in population dynamics and incidence levels compared to its native regions. Understanding these variations is crucial for developing effective management strategies. Given India's diverse agroecosystems and climatic conditions, continuous watch on pest dynamics is essential. In this context a fixed plot experiment for comprehensive analysis of fall armyworm population dynamics, incidence patterns across seasons, and damage potentials in the maize crop ecosystem of the Chhattisgarh plains, India was conducted across three seasons of the year 2022-23. The year-round activity of the pest and its potential to cause huge losses in the early stages of maize was reported. Specifically, the study provided insights into the comparative incidence of fall armyworm in the different maize growing seasons of the area with a maximum incidence in the rainy season (0.58 larvae/plant) followed by winter (0.56 larvae/plant) and summer (0.53 larvae/plant) seasons. Moreover, the incidence trends of fall armyworm in different growing stages of maize were analysed by considering egg laying pattern, leaf damage, larval incidence and plant damage parameters, which highlighted the plant age-dependent response of fall armyworm. The impact of various weather parameters in shaping the damage and population fluctuations was analysed, where the influence of temperature was significant. Results obtained in this study are crucial in devising ETL levels and developing integrated pest management strategies against fall armyworm.

Temporal, spatial, and seasonal variations in airborne PCDD/F and dl-PCB concentrations around Bien Hoa hot spot, Vietnam, and health risk assessments

Passive air samplers were used to monitor polychlorodibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorobiphenyls (dl-PCBs) between 2020 and 2022 in four residential areas around Bien Hoa hot spot (BHS) including Trung Dung (TD), Tan Phong (TP), Quang Vinh (QV), and Buu Long (BL). The total toxic equivalents of PCDD/Fs and dl-PCBs (∑TEQs) were highest in the TD area, from 284 to 642 fg TEQ/PUF day. Next was the QV area, where ∑TEQs ranged from 229 to 569 fg TEQ/PUF day. Then, ∑TEQs varied from 205 to 503 fg TEQ/PUF day in the TP area. The lowest ∑TEQs were between 179 and 385 fg TEQ/PUF day in the BL area. The temporal, spatial, and seasonal variations in concentrations of PCDD/Fs and dl-PCBs were related to the prevailing wind direction and the distance from each area to the dioxin hot spot. The average ∑TEQs for all four areas surrounding BHS in the dry season (423 fg TEQ/PUF day) were 1.4 times higher than in the rainy season (303 fg TEQ/PUF day). Health risk assessments from airborne dioxin exposure were estimated using the average daily doses through inhalation (ADDI). The ADDI for residents surrounding BHS ranged from 14.6 to 208 fg TEQ/kg BW/day. The ADDI values by areas were as follows: 23.2–208 fg TEQ/kg BW/day in the TD, 18.7–184 fg TEQ/kg BW/day in the QV, 16.7–163 fg TEQ/kg BW/day in the TP, and 14.6–125 fg TEQ/kg BW/day in the BL. These ADDI values remained within and below the 10% threshold of the WHO-recommended tolerable daily intake (100–400 fg TEQ/kg BW/day). It is necessary to control the excavation activities inside the BHS and cover the temporary storage sites of dioxin-contaminated materials to minimize the emissions of PCDD/Fs and dl-PCB into the ambient air.

Inventatory of the funga in the Sierra de Cóndiro-Canales, Jalisco Mexico

The Sierra of Cóndiro-Canales is located between the municipalities of Atotonilco elAlto, La Barca and Ocotlán, which forms a polygon declared as a State HydrologicalProtection Area. Within this, three plant comunities are differentiated: deciduoustropical forest (BTC), oak forest (BE) and submontane scrub (MS). Fungi collectionswere carried out during the rainy season from 2021 to 2023, obtaining 123specimens, of which 85 were determined, corresponding to 60 species; of them, 52are Basidiomycota and eight are Ascomycota. Of the taxa collected, 29 from BE and31 are from the BTC and this is the vegetation with the greatest number ofdetermined species. Five new records are cited for the mycobiota of Jalisco:Lactarius uvidus, Paraisaria gracilioides, Peziza cerea, Phaeoclavulina flaccida andPluteus longistriatus.

Global convection-permitting model improves subseasonal forecast of plum rain around Japan

Abstract In 2020 early summer, a historically severe rainy season struck East Asia, causing extensive damage to life and property. Subseasonal forecast of this event challenges the limits of rainy season predictability. Employing the integrated Atmospheric Model Across Scales (iAMAS) and the Sunway supercomputer, we conducted ensemble one-month forecasts at global 3 km, variable 4-60 km, and global 60 km resolutions. The global convection-permitting forecast accurately captures the rainband, while other forecasts exhibited northward and weaker shifts due to the northward shifts of the atmospheric rivers (ARs) over Japan, attributed to intensified Western North Pacific Subtropical High (WNPSH). Further, the double-ITCZ-like tropical rainfall pattern in Western Pacific (D-ITCZ-WP) in global convection-permitting forecast contributes to a more accurate WNPSH and rainband. In contrast, other forecasts show a single-ITCZ-like pattern in Western Pacific (S-ITCZ-WP), leading to a northward-shifted WNPSH and rainband, advocating the importance of accurately representing tropical convections, as they can significantly affect mid-/high-latitude weather and climate.

Growth rates of five coral species across a strong environmental gradient in the Colombian Caribbean

Coral calcification is critical for reef growth and highly dependent on environmental conditions. Yet, little is known about how corals calcify under sub-optimal conditions (e.g., turbid waters, high nutrients, sedimentation) or coral growth in understudied regions such as the Colombian Caribbean. We therefore assessed the calcification and linear extension rates of five coral species across an inshore-to-offshore gradient in the Colombian Caribbean. A suite of environmental variables (temperature, light intensity, visibility, pH, nutrients) measured during the rainy season (May – November 2022) demonstrated more sub-optimal conditions inshore compared to offshore. Across all species, calcification rates were 59% and 37% lower inshore compared to the offshore and midshore sites, respectively. Across all sites, massive corals calcified up to 92% more than branching species but were more susceptible to heat stress and sub-optimal inshore conditions. However, branching species had reduced survival due to extreme climatic events (i.e., bleaching, hurricanes). A comparison with published rates for the wider Caribbean revealed that massive species in the Colombian Caribbean grow up to 11 times more than those in the wider Caribbean while branching species generally have similar growth rates, but this finding may have been influenced by fragment size and/or heat stress. Our findings indicate that present-day environmental conditions, coupled with more frequent extreme climatic events, will favor massive over branching species in midshore areas of the Colombian Caribbean. This suggests a possible shift towards faster calcifying massive species in future coral communities, possibly exacerbating the ongoing regional decline in branching species over the last decades.

Trend Analysis of Total Suspended Solids in Inland Waters Using the BFAST Algorithm on MOD09GA Products in Porto Primavera Reservoir – Brazil

Satellite remote sensing, particularly using the MODIS orbital platform, is crucial for large-scale lake monitoring, allowing the observation of optically active components with suitable spatial and temporal resolution for lakes with surfaces greater than 40 hectares. In this context, the objective of this article was to propose a methodology that improves the retrieval and monitoring of data related to Total Suspended Solids (TSS) in large lakes. The methodology employed involved defining a baseline to map the spatiotemporal dynamics of TSS using MODIS band 1, which generates information in the infrared spectrum and is centered at 645 nm. The method was tested in the Porto Primavera Reservoir (PPR), Brazil. To validate the model, two fieldwork campaigns were conducted in the PPR, where radiometric and water quality data were collected. An empirical model was fitted between reflectance and the TSS data set (r = 0.93, R2 = 0.85, p < 0.01, n = 25). This empirical model was applied to a time series of MODIS images from May 2000 to April 2020. Using the spatial distribution maps, a time series was created from an average pixel of the sampling stations, and then this time series was analyzed to separate the trend and seasonality. The results showed that the average TSS values observed in the time series were 5.79 mg/L. The seasonality of the time series revealed that the highest concentration is recorded in the austral summer (December-February), the rainiest season. The trend component indicates that variations in TSS concentration coincide with exceptional events of increased precipitation and with a homogenization interval of the waters following the reservoir's construction.

Effect of harvesting time on root yield and nutritional composition of orange-fleshed sweet potato [Ipomoea batatas (L.) Lam] varieties in East Hararghe

In eastern Ethiopia, sweet potato is a vital food and nutrition security crop; moreover, orange-fleshed sweet potato (OFSP) varieties are rich in beta-carotene content and have the potential to alleviate chronic Vitamin A malnutrition in the region. However, the unavailability of adaptable varieties and lack of information on production and post-harvest handling practices have limited its production and utilization in eastern Ethiopia. The research was conducted to identify the proper harvesting stage of OFSP varieties for optimum yield and nutritional compositions at Rare and Babile research stations of Haramaya University during the main rainy season of 2022. Three varieties (Alamura, Kabode, and Bakule) and four harvesting periods (120, 150, 180, and 210 days after planting (DAP) in factorial combinations were evaluated in randomized complete block design with three replications. Data were collected for growth, yield, and physicochemical composition-related parameters. Combined analysis of variance revealed the interaction effect of harvesting time and varieties had a significant (p < 0.05) effect on yield, yield-related parameters, and physicochemical components. Alamura variety produced comparable above-ground biomass (28.99 t ha−1) and the highest marketable root yield of 36.40 t ha−1 at 150 DAP, with dry matter content of 33.01 and 30.58 % at 150 and 120 DAP, respectively. Harvesting Alamura at 150 DAP also had the highest ꞵ-carotene, zinc, and iron contents of 11809 μg/100 g, 3.79, and 14.47 mg/100 g, respectively. It was concluded that growing the Alamura variety and harvesting at 150 DAP was better for obtaining higher root yield with good nutritional compositions in the study area.

Assessing the role of technology transfer and participatory technology development on farmers crop yield and income in Shawa village of Zalingei, Central Darfur State

This study is aiming at assessing the role of technology transfer and participatory technology development on farmers’ crop yield and income in Shawa village of Zalingei locality during 2022/2023 cropping rainy season. Clustered random sampling technique applied. Demonstration farm was established in an area of 1.5 feddan. Farmers field schools (FFSs) of 25 men and women farmers selected. Participatory Technology Development (PTD) for men and women farmers was also developed in an area of 1.5 feddan. Improved seeds will be grown versus local check. Each treatment comprising NPK fertilizer micro dose (0. 0.3, 0.6 and 0.9 gram/ hole) randomly practiced. Fertilizer micro dose with percentage of 17-17-17 was added and mixed with seeds per hole at planting method. All farmers experienced to practical and theoretical farming of FFSs training in all research technical packages of land preparation, sowing date, seed preparation, seed dressing, thinning, weeding, water harvesting, soil conservation, pests and diseases control, seed production technologies, harvest and post harvest technologies. Results of partial crop budget revealed that all crops finically gave positive net returns. The highest yield kg/ha was obtained by Sorghum Wad-Ahmed 3500, Sorghum Butana with 3250, 3000 kg/ha for sorghum local and G/nut Gibaish, while the lowest yield/ha shown by sesame local (776 kg/ha). Therefore, the highest net returns was recorded by sorghum Butana (SDG 329048), sorghum wad-Ahmed (SDG 295477), sorghum local (SDG 269048) and G/nut Gibaish (SDG 108990). While the lowest net returns was computed by G/nut local with SDG 21,381. Results of marginal analysis revealed that sorghum Butana gave the highest MRR 1230. Results of Participatory Technology Development (PTD) of improved yields against local indicated that, the highest yield obtained by sorghum Wad-Ahmed and G/nut Gibaish (1100 and 950 kg/feddan), respectively. While the lowest yield obtained by sesame local (195 kg/feddan). The increased over decreased of improved versus local showed that sorghum wad-ahmed exceed local by 11%, millet Ashana 36%, sesame Promio 13% and groundnut Gibaish exceed local by 25%. The study recommended strengthening research extension farmers and enhancing farmers’ participatory technology development.

Assessing heavy metal pollution in mangrove ecosystems of the Kribi-Campo sub-basin, Cameroon

Mangrove ecosystems provide crucial ecological services, yet they are increasingly threatened by anthropogenic pollution, particularly from heavy metals. This study investigated heavy metal contamination (Pb, Fe, Ni, Cu) in four mangrove sites within the Kribi-Campo sub-basin, Cameroon, during the dry and rainy seasons of 2023. Physicochemical parameters (temperature, pH, conductivity, dissolved oxygen, salinity) were measured in situ, and heavy metal concentrations in water samples were determined using X-ray fluorescence spectrometry. Results revealed spatial variations in physicochemical parameters, with the Mpolongwé site showing excessive mineralization (conductivity &gt; 1000 µS/cm) likely attributed to industrial and domestic effluents. Lead contamination was restricted to Londji (0.05 - 0.21 mg/L), potentially linked to fishing activities. Iron concentrations were highest at Londji (0.67 mg/L) and Nziou (0.61- 0.68 mg/L), while nickel was absent only at Eboundja. Notably, copper was ubiquitous across all sites (2.68 - 3.31 mg/L), highlighting its widespread distribution. Londji emerged as the most contaminated site, harboring detectable levels of all analyzed metals. These findings underscore the vulnerability of Kribi’s mangroves to heavy metal pollution, emphasizing the need for continuous monitoring and implementation of mitigation measures to ensure the sustainable management of this valuable ecosystem.

Determination of critical crop-weed competition period: Impact on growth, nutrient dynamics and productivity of green gram (Vigna radiata)

The critical period of crop-weed competition (CPCWC) varies by cultivars, management strategies, cropping seasons, soil, and climate. Hence, a study was done to assess CPCWC in green gram under different cropping seasons and its impact on nutrient mining, agro-physiological characteristics, and productivity of green gram during the summer and rainy seasons. The experiment comprised of 12 treatments (weed interference until 10, 20, 30, 40, 50 days after sowing (DAS) and crop maturity, weed-free until 10, 20, 30, 40, 50 DAS and crop maturity). The treatments were placed in a randomized complete block design (RCBD) with three replications. Results revealed that, summer green gram outperformed rainy green gram by boosting nutrient uptake, growth and productivity. Weed interference up to crop harvest lowered the green gram dry matter accumulation by 34.11 %, seed index by 8.98 %, grain yield by 76.21 % and biological yield by 31.06 %. However, weed-free until crop harvest boosted nitrogen content by 50.4 %, phosphorus by 87.7 % and potassium by 42.9 %. Similarly, weed-free environment until harvest of the crop raised chlorophyll-a content by 2.9–6.6 fold and 2.7–7.0 fold, chlorophyll-b by 3.8–5.8 fold and 3.8–6.5 fold over season-long weedy plots during summer and rainy season, respectively. This study suggested that the critical duration for crop-weed competition under 5 % relative yield loss (RYL) was 11–43 DAS in summer and 4 to 36 DAS in rainy. Whereas, critical duration for the crop-weed competition at 10 % RYL was 21–36 DAS in summer and 8 to 27 DAS in rainy seasons.

Pemberdayaan Petani Padi Sawah dalam Meningkatan Efisiensi Usaha Tani dengan Pembuatan dan Aplikasi Herbisida Organik di Desa Botolempangan Kabupaten Maros

Botolempangan Village in Bontoa Sub-district is one of the centers of paddy rice production in Maros Regency, with characteristics of rain-fed paddy fields that have many obstacles to weed infestation, especially if the dry season is abandoned from rice farming activities, before being planted during the rainy season where farmers are very dependent on the use of herbicides. Dependence on the use of synthetic (inorganic) herbicides occurs from the pre-growth period of seeds, seedlings to the maintenance process. High costs result in considerable inefficiencies in rice farming. Training in technology transfer efforts to make Organic Herbicide Formulations, and their applications are carried out to increase the Empowerment and Efficiency of rice farming on Rainfed Rice Fields. With the efficiency target is to increase the profit of paddy rice farming, minimizing inorganic herbicide inputs. The output of this activity ultimately produces products that can be applied to at least reduce or reduce the use of inorganic herbicides. At the end of the activity, farmer business groups are able to produce and apply Organic Herbicide Formulations on Demoplots on Farmer-Owned Land.

Quantifying seasonal variations in pollution sources with machine learning-enhanced positive matrix factorization

As the pace of industrialization and urbanization accelerates, water quality management faces increasing challenges, with traditional methods for pollutant source apportionment often proving inadequate in handling complex environmental data. This study enhances the precision and reliability of pollutant source identification by integrating Positive Matrix Factorization (PMF) models with diverse machine learning techniques. Utilizing data from 17 water quality monitoring stations along the Wuding River from 2017 to 2021, we employed Random Forest (RF), Support Vector Machine (SVM), Elastic Net (EN), and Extreme Gradient Boosting (XGBoost) models to predict the Water Quality Index (WQI) during dry and wet seasons. Results indicate that the RF model exhibited optimal performance in the dry season (R2 = 0.93), while the SVM was superior in the wet season (R2 = 0.94). SHAP (SHapley Additive exPlanations) value analysis identified CODMn and NH3-N as significant influencers on WQI in the dry season, whereas COD, BOD, and TP gained prominence during the wet season. SHAP values reveal the contribution of each feature to the model output, thereby enhancing the model’s transparency and interpretability. Additionally, feature importance identified by machine learning was utilized as weights to optimize the contribution rates predicted by the PMF model. The optimised model was able to identify the contribution of domestic and farm effluent discharges more accurately in the dry season, with a significant increase in the percentage of identification from 19.4 % to 45.4 %, and an increase in the percentage of contribution from agricultural non-point sources and domestic effluent in the rainy season. This research offers a novel perspective on the characteristics of river water pollution and holds significant implications for formulating data-driven environmental management strategies.

A potential cause for extensive dieback of Acacia mearnsii plantation in highland districts of Awi zone, northwestern Ethiopia

Although Acacia mearnsii De Wild has rapidly expanded for economic and ecological purposes in the highland districts of the Awi zone, northwestern Ethiopia, recent plantations have suffered from severe defoliation, dieback, and stunted growth. We conducted this study in four districts that hold potential for A. mearnsii plantations. The study examined the identification of the causal agent, its occurrence, and local community perceptions of the plantation's significant dieback. Most respondents (75.8 %) indicated that the substantial dieback began in the rainy season of 2020 and spread rapidly. They also noted that close spacing of plantings and limited silvicultural measures exacerbated the damage. We discovered in this study that the wattle rust disease caused by the Uromycladium acacia fungus was the root cause of significant dieback for A. mearnsii plantations. The incidence and severity of this wattle rust varied significantly (p = 0.001) between districts, seasons, and plantation age groups. In Fegita-Lekuma district, the maximum disease severity was over 72 % in plantations up to two years after planting during the rainy season. The progression of the wattle rust disease caused by U. acacia has led to the loss of A. mearnsii plantations in the Awi zone, resulting in a severe economic and environmental crisis. Consequently, we should apply fungicides to seedlings at nursery sites in the short term. Eventually, however, the focus should shift towards prioritizing disease-resistant species and implementing proper forest management practices. This should be achieved through scientific initiatives that engage key stakeholders in areas where this tree species could potentially grow.

Impact of Urbanization-Driven Land Use Changes on Runoff in the Upstream Mountainous Basin of Baiyangdian, China: A Multi-Scenario Simulation Study

Urbanization in the Haihe River Basin in northern China, particularly the upstream mountainous basin of Baiyangdian, has significantly altered land use and runoff processes. The runoff is a key water source for downstream areas like Baiyangdian and the Xiong’an New Area, making it essential to understand these changes’ implications for water security. However, the exact implications of these processes remain unclear. To address this gap, a simulation framework combining SWAT+ and CLUE-S was used to analyze runoff responses under different land use scenarios: natural development (ND), farmland protection (FP), and ecological protection (EP). The model simulation results were good, with NSE above 0.7 for SWAT+. The Kappa coefficient for CLUE-S model validation was 0.83. The further study found that from 2005 to 2015, urban construction land increased by 11.50 km2 per year, leading to a 0.5–1.3 mm rise in annual runoff. Although urban expansion continued, the other scenarios, which emphasized farmland and forest preservation, slowed this growth. Monthly runoff changes were most significant during the rainy season, with annual runoff in ND, FP, and EP varying by 8.9%, 10.9%, and 7.7%, respectively. While the differences in annual runoff between scenarios were not dramatic, these findings provide a theoretical foundation for future water resource planning and management in the upstream mountainous area of Baiyangdian and offer valuable insights for the sustainable development of Xiong’an New Area. Additionally, these results contribute to the broader field of hydrology by highlighting the importance of considering multiple land use scenarios in runoff change analysis.