Low Rainfall Amounts Research Articles

A systematic flood risk assessment of Bloemfontein Watershed, South Africa

Understanding the elements contributing to flood risk can create effective plans and policies for decision-makers to lessen vulnerability and boost resilience. Over the years, Bloemfontein has experienced seasonal flooding, despite the low amount of rainfall it receives compared to other towns in South Africa. This study systematically assessed flood risk in the most vulnerable watershed of Bloemfontein. The analytical hierarchy process (AHP) and GIS-based multi-criteria decision-making were utilized to map and identify potential locations that are vulnerable to floods. The relative weight of each criterion taken into account for the susceptibility mapping was determined using AHP. Geospatial techniques were used to assess the vegetation cover, moisture content, surface water, and land surface temperature (LST) from 1991 to 2023, as well as ten physical environmental factors linked to the occurrence of floods. Findings from this study revealed a decrease in vegetation cover and moisture content and an increase in the LST from 1990 to 2023. The susceptibility to flood map shows that 9.63% of the watershed is low susceptible to flooding, 79.26% is moderate, 11.07% is high, and 0.03% is very high susceptible to flooding. The built areas and major farmlands fall within the high susceptibility zone of 11%.

The influence of climatic factors on the effect of growth regulators in agrocenoses of spring barley

Relevance. In recent years, under the conditions of climate change, there has been a tendency to reduce the acreage of spring barley, reduce the quantity and quality of grain. From the point of view of ensuring the stability of gross grain harvests and ecology, it is necessary to manage the agrocenosis.Methods. The experiments were conducted in 2021–2024 agricultural years in the conditions of the Azov sea zone of the Rostov region. Objects of research: Leon spring barley variety and growth regulators “Artafit” (0.3 l/ha), “Biodux” (3 ml/ha), “Obereg” (60 ml/ha), “Trainer” (3 l/ha), “Fulvohumate” (0.4 l/ha).Results. The climatic conditions in 2024 were extreme in terms of low rainfall and high amounts of spring temperatures. The year 2023 was the most favorable from this point of view. The yield level correlates with the level of moisture in the spring period, the highest indicators were observed in 2023, and the lowest in 2024. In the current market conditions and annual price increases, unit production costs are increasing. Thus, in 2024, the cultivation of spring barley turned out to be unprofitable. Moreover, the use of biological products did not allow us to gain a plus. In 2022 and 2023, the use of the drug “Trainer” turned out to be unprofitable due to the high cost of the drug. “Biodux” and “Obereg” showed the highest profitability.

Correlation between flood couplet-based sediment yield and rainfall patterns in a small watershed on the Chinese Loess Plateau

Understanding how rainfall patterns impact sediment yields during rainfall events is important to explore soil erosion changes and to prevent watershed flood disasters. However, few studies identified sediment yields variation affected by rainfall patterns at continuous deposited flood couplet scale. This study analyzed sediment yields under different rainfall patterns and correlated particle depositional features on the condition that the erosive environment was obviously changed by anthropogenic activities in a check dam-controlled small watershed on the Chinese Loess Plateau. Results showed that erosive rainfall events, having formed 40 flood couplets behind the check dam between 1978 and 2010, can be grouped into three rainfall patterns (i.e., rainfall patterns I, II, and III) according to changes in rainfall amount, erosivity, and duration. Rainfall pattern III, characterized by high rainfall amount and erosivity within a short duration (i.e., rainstorm) accounted for only 15.0 % of erosive rainfall events while yielding 44.7 % of the total sediment. Conversely, rainfall pattern I (the most common, 55.0 %), characterized by its long duration and relatively low rainfall amount and erosivity, only contributed 25.3 % of the total sediment. Both sediment yields and thickness proportions of coarse particle layer in flood couplets exhibited a decreasing trend under all three rainfall patterns. Meanwhile, the main factor that impacted sediment yields changed from rainfall in the 1980s and 1990s to the “Grain for Green” program dominated anthropogenic activities since 1999. For a small watershed with a few terraces and only one check dam at the outlet, artificial vegetation restoration significantly reduced coarse soil particle loss and sediment yield. Findings showed that sediment yield and deposition feature variations in flood couplets under different rainfall patterns are helpful in improving watershed soil and water conservation measures against flood disasters, particularly under rainstorms.

Effect of Different Tillage Operations on Soil Water Storage, Water Use Efficiency and Productivity of Durum Wheat (Triticum durum Desf.) in Semi-arid Region

Background: The low amount of rainfall and high loss of soil water through evaporation during spring; there are the dominant factors affecting crop production in semi-arid region. Methods: A field study was conducted during two cropping seasons of durum wheat (Triticum durum Desf.) to compare the effect three tillage operations viz., no-tillage, minimum tillage and conventional tillage. Result: There was variation in precipitation between the experimental years (dry and rainfall seasons). All the parameters registered significant differences between the cropping seasons. Soil water storage to a depth of 0.4 m was higher under no tillage (NT) and minimum tillage (MT) in the first year as compared to conventional tillage (CT) in the first year. During the second year, the soil water content was same under different tillages. The thousand-kernel weight registered significant differences among the tillage operations viz., no till (36.09-50.36 g), minimum tillage (30.93-46.81 g) and conventional tillage (28.31-45.05 g) in the two seasons, respectively. Under no till treatment water use efficiency was high from grain production. The no till also recorded high grain yield of 1.07 t/ha and 4.7 t/ha during first and second year, respectively. The lack of rain was more detrimental in conventional tillage system as compared to no till and minimum tillage.

Impact of climate change on the different borders of Iraq's rainy territories

The research concluded that rainfall amounts do not follow a specific spatial pattern in their changes, but rather tend towards an increase in some spatial ranges shown by the modeling maps, which may indicate that it is an extreme increase and not an actual increase. It also became clear that the stations in the north and center of the study area recorded the highest amount of rainfall during the first study period, and decreased during the second, third, fourth and fifth study periods, then it increased again during the sixth period, this is a result of climate change and the decrease in the frequency of rainy weather depressions, especially frontal ones.The high rainfall region occupy an area of %(62.6, 39.8, 53.9, 59.7, 50.0, 0.0, 73.6) for all periods respectively, Thus, the fifth period is the least occupied period in the spatial dimension, so that the high rainfall region category has completely receded. At a rate of (zero) km2 and with a deviation of (%62.6), the research also found that a region with low rainfall amounts was also subject to spatial changes, as it was found that a region with low rainfall occupies an area ratio of (12.8, 20.5, 19.8, 19.8, 17.9, 17.3, 27.1, 4.6) for all periods respectively, this means that the fifth period is the largest spatial extent for a region with low amounts of rain at (27.1) mm, while the sixth period is less extensive at (8.2-) mm.

Maize Production under Drought Stress: Nutrient Supply, Yield Prediction.

Maize yield forecasting is important for the organisation of harvesting and storage, for the estimation of the commodity base and for the provision of the country's feed and food demand (export-import). To this end, a field experiment was conducted in dry (2021) and extreme dry (2022) years to track the development of the crop to determine the evolution of the relative chlorophyll content (SPAD) and leaf area index (LAI) for better yield estimation. The obtained results showed that SPAD and LAI decreased significantly under drought stress, and leaf senescence had already started in the early vegetative stage. The amount of top dressing applied at V6 and V12 phenophases did not increase yield due to the low amount of rainfall. The 120 kg N ha-1 base fertiliser proved to be optimal. The suitability of SPAD and LAI for maize yield estimation was modelled by regression analysis. Results showed that the combined SPAD-LAI was suitable for yield prediction, and the correlation was strongest at the VT stage (R2 = 0.762).

Comparisons of Retention and Lag Characteristics of Rainfall–Runoff under Different Rainfall Scenarios in Low-Impact Development Combination: A Case Study in Lingang New City, Shanghai

An increasing focus has been given to stormwater management using low-impact development (LID), which is regarded as a “near-nature” concept and is utilized to manage and reduce surface runoff during the rainfall–runoff process. According to the hydrological monitoring data, we evaluated the retention and lag characteristics of rainfall–runoff in LID combination under three rainfall-intensity scenarios (light–moderate, heavy, and torrential rainfall) in Lingang New City in Shanghai. LID facilities have been constructed for three years in the target study area, including rain gardens, retention ponds, green parking, porous pavement, and grass swales. The average runoff retention was 10.6 mm, 21.3 mm, and 41.6 mm under light–moderate, heavy, and torrential rainfall scenarios, respectively, and the corresponding runoff retention rate was 72.9%, 64.7%, and 76.1% during the study period. By comparing rainfall, runoff retention, runoff retention rate, cumulative rainfall, and lag times, it becomes evident that the ability to retain runoff can be greatly improved in the LID combination. The average runoff retention was significantly enhanced by nearly two times and four times under the heavy and torrential rainfall scenarios compared to the conditions under the light–moderate rainfall scenario. Furthermore, the lag time from the end of rainfall to the end of runoff (t2) and the lag time between the centroid of rainfall and the centroid of runoff (t3) showed a significantly negative correlation with rainfall intensity. Meanwhile, t3 presented an incredibly positive correlation with rainfall duration. In this study, the LID combination demonstrated superior benefits in extending the duration of runoff in rainfall events with lower rainfall amounts, and demonstrated significant overall lag effects in rainfall events with longer durations and lower rainfall amounts. These results confirmed the vital role of the LID combination in stormwater management and the hydrologic impact of the LID combination on rainfall-induced runoff retention and lag effects. This work has provided valuable insights into utilizing LID facilities and can contribute to a better understanding of how runoff retention and lag characteristics respond to different rainfall intensity scenarios.

Modelling the impacts of water harvesting and climate change on rainfed maize yields in Senegal

Senegalese agriculture is threatened by climate change effects, affecting rainfall variability both at interannual and interdecadal timescales. Using FAO’s AquaCrop crop-growth model, we tested the efficiency of an in situ water harvesting technique - tied ridges - for maize cropping in the Fatick region in Senegal, in response to changes in temperature and precipitation with different fertility levels and different soils. Results showed that, considering the current climate and soil fertility, tied ridges did not significantly impact maize yields. The rainfall amount was enough for maize production and to avoid water stress during the cropping season. Under perturbed climates and, especially, in years with low average rainfall amounts, high losses in yield were registered under optimal fertility conditions (up to 80%). The strongest effect was obtained when tied ridges were simulated on clay soil, enhancing yields by 5.6% and 13% at actual and optimal fertility conditions, respectively. Our results highlighted how the current maize production in the Fatick region in Senegal is sustainable in the current climate scenario, while it could be potentially impacted by climate change in the near future. In a pessimistic climate change scenario, in situ water harvesting has the potential to avoid excessive crop losses.

Regional Sources and Seasonal Variability of Rainwater Dissolved Organic and Inorganic Nitrogen at a Mid‐Atlantic, USA Coastal Site

AbstractChanges in anthropogenic activities have altered the speciation and concentration of inorganic reactive nitrogen (Nr) delivered to coastal and oceanic waters with precipitation. Less is known about rainwater dissolved organic nitrogen (DON) despite its quantitative importance (>20% of Nr) and potential contributions to primary and secondary production. We document decreases in rainwater nitrogen and carbon amounts between 1994 and 2019 in Delaware, USA with the major reduction observed for nitrate (64%) reflecting emissions technology improvements. [DON] in 2019 was 55% that of 1994, though only 2 years of data are available precluding any assessment of trends. Season, airmass back trajectory (AMBT), rainfall amount, and meteorology influenced Nr amounts in 2018–2019 rain. [DON], which peaked in Summer, had different seasonal patterns than inorganic Nr and dissolved organic carbon, suggesting a biological source. Marine AMBT events showed the lowest Nr abundances. AMBTs from the southwest had the highest concentrations of Nr and DOC partially due to low rainfall amounts. Characterization of the oxidized fraction of DON revealed abundant highly unsaturated aliphatic and peptide‐like formulas suggesting a combination of secondary organic, biomass burning, and biological sources. The large changes in Nr and DOC loads emphasize the dynamic nature of atmosphere to land/water fluxes due to the influence of anthropogenic processes with potential implications for coastal and oceanic water quality and ecology. Models of atmospheric deposition to watersheds and the ocean should be frequently reevaluated with current data to accurately assess inputs from changing atmospheric sources.

Physio-Chemical Properties Responses of Six Fonio Genotypes (Digitaria exilis and D. iburua) Subjected to Drought Stress Conditions

Abstract The cultivation of fonio in the Western Africa has been greatly hindered by the low amount of rainfall. Crop failure due to drought has been widely reported in Nigeria, which has led to research on different crops with paucity of information on fonio. The present study evaluated six drought genotypes of fonio to determine their physiological and biochemical responses under drought stress conditions. Fonio seeds were planted for a period of 3 weeks and subjected to drought. WUE decreased under drought stress particularly in the P21 genotype, while the RSR significantly increased for all evaluated genotypes. Drought stress seems to enhance the lipid peroxidation and free amino acid activities in the 6 evaluated genotypes, whereas it reduced the proline activities in 4 out of the 6 genotypes. At the early and the late stage, the highest lipid peroxidation was recorded in P25 and P21 respectively. The SOD activities varied at the early and the late stage under drought stress conditions, particularly for the P25, which showed higher level of SOD activities (= 10 folds higher than the control group at the late stage). The activities of CAT and GR for all genotypes studied were not affected by these stressful conditions. However, the APX activity was preferentially reduced in some genotypes, while the remaining ones were unchanged. In conclusion, difference in the physiochemical responses to drought reflects the differences in the ability of the genotypes to withstand varying degrees of drought. The increase in SOD activities might be a frontline defence to counter the increase observed in lipid peroxidation content caused by the reduction in CAT activities under droughtconditionsn.

Prediction of future climate in semi-arid catchment under CMIP6 scenarios: A case study of Bahi (Manyoni) catchment in Internal Drainage basin (IDB), Tanzania

Prediction of future climate is vital, especially for areas with low rainfall amounts, rapid population growth and high groundwater dependency. Bahi (Manyoni) is among the driest catchment hosting the new capital city of Tanzania which depends heavily on groundwater resources. Therefore, future climate prediction was done using the Coupled Model Intercomparison Project Phase 6 (CMIP6) scenarios of SSP126, SSP245 and SSP585. Linear Scaling (LS) bias-corrected on European center Reanalysis 5th generation (ERA5) was used to supplement temperature data. Out of 15 Global Climate Models (GCMs), CNRM-CM6-1-HR, INM-CM4-8 and INM-CM5-0 for rainfall and AWI-CM-1-1-MR, MRI-ESM2-0, EC-Earth3 and EC-Earth3-Veg for temperature were selected based on their highest performance in Taylor Skill Score (TSS) and subsequently their ensemble used. TSS of 0.83, 0.90, and 0.65 were obtained for rainfall, minimum temperature (Tmin), and maximum temperature (Tmax) ensembles respectively. LARS-WG 6.0 was applied for downscaling climatic data. Findings predicted that in 2080s for SSP126 and SSP585 scenarios, catchment mean annual rainfall to decrease between 13.8% and 4.3% in northern part, and to increase between 14.5% and 25.4% in southeast with an overall average Tmin increase between 0.2 °C and 4.5 °C and Tmax between 0.8 °C and 2.8 °C. This indicated relatively warmer and drier climate in northern compared to southern part of the catchment. These differences in microclimates could not be captured in large-scale studies such as IPCC, 2021. These findings highlighted potential climate change impacts on crop production and groundwater recharge, which contributes to Tanzania's Nationally Determined Contributions and National Adaptation Plans against future climate change.

Storm types in Bangladesh: duration, intensity and area of intra‐daily wet events

AbstractWe explore the characteristics of 96,190 wet events (WEs) defined as consecutive 3‐hourly rainfall ≥ 1 mm/3 hr from a network of 34 stations across Bangladesh. Nearly 60% (5%) of WEs last ≤ 3 (≥ 15) hr. The WEs are dynamically clustered into four “canonical” storm types (STs), mostly discretized by their duration, but also their mean and maximal intensity. While durations, total amounts and wet contiguous areas of WEs are positively related, their mean intensity is nearly independent of them. Approximately 60% of WEs are associated with ST#1, characterized by short and small WEs and very low rainfall amounts (usually <10 mm), ~30% of WEs are associated with either (ST#2) short/small WEs but with intense rainfall, probably mostly related to scattered thunderstorms or (ST#3) longer/larger WEs but with less intense rainfall. The last ST (ST#4) is rare (~6%), related to very long durations and large wet areas and includes the wettest WEs. It is especially frequent over southeastern Bangladesh. ST#2–ST#4 contribute almost equally to the local‐scale total amount of rainfall (27–29% each in mean) while ST#1, despite its individual low rainfall amount, still includes ~15% of it. ST#2 (ST#4) is related to the highest probability of occurrence of 3‐hourly (daily) extremes. ST#4 occurrence is the most impacted by synoptic Indian lows/depressions as well as the main modes of intra‐seasonal variation, while ST#1 and ST#2 are also significantly impacted by intra‐seasonal modes but in reverse manner than ST#4.

The Production of Dual-Purpose Triticale in Arid Regions: Application of Organic and Inorganic Treatments under Water Deficit Conditions

Most of the arid and semi-arid regions, particularly in the Mediterranean area, suffer from the lack of a sufficient quantity of high-quality feed, as well as a low amount of rainfall that is unevenly distributed, resulting in the region being highly vulnerable to drought. A field experiment was carried out at the experimental station of the Faculty of Desert and Environmental Agriculture, Fuka, Matrouh University, Egypt during the winter seasons of 2018/19 and 2019/20 to study the performance of triticale (X Triticosecale Wittmack), grown under water deficit conditions, in terms of productivity and quality. The study investigated the influence of five levels of potassium fertilization (PF; 0, 43.2, 86.4, 129.6, and 172.8 kg ha−1) and ascorbic acid (AA; 0, 25, 50, 75, and 100 mg L−1) that was applied to the triticale grains before sowing and humic acid (HA; 0, 2.4, 4.8, 7.2, and 9.6 kg ha−1) that was applied as powder to the soil 21 days after sowing followed by sprinkler irrigation on triticale forage and grain production when forage was removed at variable ages at cutting (AC), determined as days after sowing (AC; 40, 65, 90, 115, and 140 DAS) on forage yield and nutritive value, in addition to the final grain yield of triticale. The experimental design was a central composite design with one replicate. Results indicated that the PF*AC interaction was significant, and it gave values of 84.78 and 238.00 g kg−1 for crude protein (CP) and degraded neutral detergent fiber (DNDF). In addition, the interaction between AA and AC was significant for CP, acid detergent fiber (ADF), 100-grain weight (100 GW), number of spikes m−2 (NSM−2), and plant height (PH). Moreover, the AC*HA interaction was significant with values of 175.17 and 247.00 g kg−1 for CP and DNDF, respectively, and 0.55 t ha−1 for grain yield (GY). Age at cutting exerted the strongest effect on the studied characteristics. It was observed that the contents of neutral detergent fiber (NDF), ADF, acid detergent lignin (ADL), and non-fiber carbohydrates (NFC) in the triticale forage significantly increased when the crop was cut at an advanced age, unlike CP, DNDF, GY, NSM−2, 100 GW, and PH that decreased with advanced AC. The highest values of 271.00, 256.00, and 268.00 g kg−1 for DNDF were obtained with higher levels of either PF, AA, or HA, respectively. However, the highest value of GY (0.97 t ha−1) was obtained with higher levels of PF*HA averaged over the two seasons. The interaction between AA*HA resulted in 393.39, 311.00, 27.13 g kg−1, and 0.94 t ha−1, for NDF, DNDF, ADL, and GY, respectively. The highest significant NDF (413.11 g kg−1) and DNDF (307.50 g ka−1) values were obtained with the application of high levels of either AA or HA. In the dual-purpose production system, it is recommended to cut the triticale crop at 65 DAS to achieve the optimum balance between forage yield and quality on the one hand, and final grain yield on the other hand. In the arid regions, application of PF, AA, and HA could help in reducing the damage caused by water deficit.

Agroclimatological Characteristics of Rainy Seasons in Southwestern Burkina Faso during the 1970-2013 Period

The different drought phases observed during the 1970-2010 period have underlined important weaknesses of West African agricultural systems. The droughts resulted in important decreases in crop production, triggering a significant deficit in food availability. Many studies have identified changes in rain events seasonal patterns as the key drivers of agricultural production failure during these drought phases. In this study, seven agriculturally-relevant intra-seasonal rainfall characteristics (i.e., annual rainfall amount, onset and cessation of the rainy season, dry spells, extreme rain events, hot spells, and strong winds) and associated constraints to crop growth are described for the main cereals (maize, millet, and sorghum) in southwestern Burkina Faso. These characteristics are calculated or determined using daily climate data from a local network of 16 weather stations spanning the 1970-2013 period. A computation of the intensity and the occurrence of these phenomena during the rainy seasons helped to draw the rainy seasons’ nomenclature. Findings suggest that the rainy seasons during the drought phases are characterized by low annual rainfall amount, late onset, early cessation and more frequent long dry spells (>7 days). Furthermore, the long dry spells mostly occurred during the most sensitive phases of crop development: germination at the beginning of the rainy season and flowering at the end of the rainy season. Also, the intensity and the probability of occurrence of the other extreme events (hot spells and strong winds) during rainy seasons are very high in the establishment phase. Thus, adaptation strategies to mitigate these unfavorable climate conditions include a selection of short-cycle crop varieties combined with supplementary irrigation systems during long dry spells.

Short- and Long-Term Effects of Lime and Gypsum Applications on Acid Soils in a Water-Limited Environment: 3. Soil Solution Chemistry

Aluminum (Al) toxicity imposes a significant limitation to crop production in South Western Australia. This paper examines the impact of surface-applied lime and gypsum on soil solution chemistry in the short term (1 year) and the long-term (10 years) in water limited environments. In the experiments, we measured soil solution chemistry using a paste extract on soil profile samples collected to a depth of 50 cm. We then used the chemical equilibrium model MINTEQ to predict the presence and relative concentrations of Al species that are toxic to root growth (Al associated with Al3+ and AlOH2 or Toxic-Al) and less non-toxic forms of Al bound with sulfate, other hydroxide species and organic matter. A feature of the soils used in the experiment is that they have a low capacity to adsorb sulfate. In the short term, despite the low amount of rainfall (279 mm), sulfate derived from the surface gypsum application is rapidly leached into the soil profile. There was no self-liming effect, as evidenced by there being no change in soil solution pH. The application of gypsum, in the short term, increased soil solution ionic strength by 524–681% in the 0–10 cm soil layer declining to 75–109% in the 30–40 cm soil layer due to an increase in soil solution sulfate and calcium concentrations. Calcium from the gypsum application displaces Al from the exchange sites to increase soil solution Al activity in the gypsum treatments by 155–233% in the short term and by 70–196% in the long term to a depth of 40 cm. However, there was no effect on Toxic-Al due to Al sulfate precipitation. In the long term, sulfate leaching from the soil profile results in a decline in soil solution ionic strength. Application of lime results in leaching of alkalinity into the soil profile leading to a decreased Toxic-Al to a depth of 30 cm in the long term, but it did not affect Toxic-Al in the short term. Combining an application of lime with gypsum had the same impact on soil solution properties as gypsum alone in the short term and as lime alone in the long term.

COVID-19: Do weather conditions influence the transmission of the coronavirus (SARS-CoV-2) in Brasília and Manaus, Brazil?

The global outbreak of coronavirus SARS-CoV-2 (COVID-19) disease is affecting every part of human lives. Several researchers investigated to understand how temperature, humidity and air pollution had an influence on COVID-19 transmission. Transmission of COVID-19 due to temperature and humidity is a pertinent question. There is a lack of study of Covid-19 in tropical climate countries. This study aims to analyze the correlation between weather and Covid-19 pandemic in Brasília and Manaus, two states of Brazil. The research topic is important to know how the climate affects or predisposes the spread of COVID-19. This knowledge will provide elements to decision-makers regarding health and public health standards and decisions. This study employed a secondary data analysis of surveillance data of Covid-19 from the Ministry of Health of Brazil and weather from the National Institute of Meteorology of Brazil. These are Brazilian public organizations that, on a daily basis, record this information on a systematic basis of dates. They are central federal organizations, responsible for data analysis and public policy planning to combat Covid-19. The data are reliables and obtained from reliable government sources. We systematically record all information for 51 days, during a period of high disease growth in the country. The components of weather include low temperature (°C), high temperature (°C), temperature average (°C), humidity (%), and amount of rainfall (mm). Pearson-rank correlation test showed that high temperature (r=.643; p<.001), low temperature (r=.640; p<.001) and humidity (r=.248; p<.005) were significantly correlated with deaths caused by Covid-19 pandemic used for data analysis. Social isolation rate (β = -.254; p<.001) and daily record of new cases (β = .332; p<.001), with adjusted R-squared of .623, were the predictors of deaths acummuled by Covid-19. The finding serves as an input to reduce the incidence rate of Covid-19 in Brazil. Statistical results show evidence of the relationship between climate elements and COVID-19 indicators, such as the number of deaths, spread of contamination and social isolation rate. The study of dimensions of climate as a seasonal pattern and its relationship to COVID-19 benefits epidemiological surveillance. The more geographic spaces are known, more will help to understand the differences in disease behavior in different places. The results of this research showed that environmental conditions influence the contagion and speed of transmission of Covid-19. Policies that contribute to benefits to health and sustainability need to be planned. The contribution of climate and other factors, such as air pollution, for example, require additional studies. Environmental changes, such as climate change and biodiversity, must also be investigated for their impact on human health. Acting in prevention, including the promotion of socially acceptable behaviors on the part of the population, seems to be the best way to deal with Covid-19.

Responses of Runoff and Soil Loss to Rainfall Regimes and Soil Conservation Measures on Cultivated Slopes in a Hilly Region of Northern China.

Cultivated land plays an important role in water and soil loss in earthy/rocky mountainous regions in northern China, however, its response to soil conservation measures and rainfall characteristics are still not fully understood. In the present study, 85 erosive rainfall events in 2011–2019 were grouped into three types, and the responses of runoff and soil loss to soil conservation measures and rainfall regimes on five cultivated plots with different slopes in the upstream catchment of the Miyun Reservoir were evaluated. Results found that mean event runoff depths and soil loss rates on the five plots ranged from 0.03 mm to 7.05 mm and from 0.37 t km−2 to 300.51 t km−2 respectively, depending on rainfall regimes, soil conservation measures, and slope gradients. The high frequency (i.e., 72.94%) rainfall regime A with a short rainfall duration (RD), low rainfall amount (P), and high mean rainfall intensity (Im) yielded a lower runoff depth and higher soil loss rate. Rainfall regime B with a longer RD, and a higher P and Im, however, produced higher a runoff depth and lower soil loss rate. Terraced plots had the highest runoff and soil loss reduction efficiencies of over 96.03%. Contour tillage had comparable sediment reduction efficiency to that of the terraced plots on gentle slopes (gradient less than 11.0%), while its runoff reduction efficiency was less than 13.11%. This study implies that in the Miyun Reservoir catchment and similar regions in the world, contour tillage should be promoted on gentle slopes, and the construction of terraced plots should be given ample consideration as they could greatly reduce water quantity and cause water shortages in downstream catchments.

SEMEN CHARACTERISTICS OF RHODE ISLAND RED AND WHITE BREEDER COCKS

One hundred and three adult cocks of two different strains (Rhode Island White, 59 semen quality with concomitant effect on and Rhode Island Red, 44) were subjected to weekly semen collection for four weeks. The Rhode Island White cocks had gross sperm motility of 80.76± 1.45% while the value for the significant effects of low relative humidity, high Red cocks is 79.43+1.68% but the difference was temperatures, low rainfall and peak amount of insignificant. The Rhode Island White cocks had a higher (P<0.001) sperm concentration (1.93 0.10x10'/ml) than the Red cocks (1.27±0.12x10 /ml) while semen volume (0.58±0.04ml) and colour (1.96±0.14) for the Rhode Island White cocks were lower and (P<0.001) than the corresponding values of 0.80+0.05ml and 2.820.16 for Rhode Island Red cocks. Colour was found to be positively correlated (r= 0.89) with concentration and rate of genetic progress. Breeding soundness total sperm (r=0.61). The correlation between sperm concentration and volume, and evaluation of the breeding cocks is concentration and total sperm, were 0.72 and of 0.67 respectively.

Uncertainty of drought information in a data-scarce tropical river basin

Study regionThe Wami River basin in east-central Tanzania features the Eastern Arc Mountains and dichotomous climate regimes. Study focusDrought characteristics are vital in planning and managing water resources in river basins. However, the estimation of drought characteristics from the evapotranspiration deficit index (ETDI) is susceptible to the uncertainty associated with alternative datasets from hydrological models and remote sensing images. Thus, this study investigated scenario uncertainty in ETDI-based drought characteristics in the river basin using evapotranspiration and potential evapotranspiration data from a classical Soil and Water Assessment Tool (SWAT) and the Moderate Resolution Imaging Spectroradiometer (MODIS) images between the years 2000 and 2010. New hydrological insightsThe findings showed a substantial scenario uncertainty in drought duration, severity, and intensity at various locations in the river basin. Localized severe MODIS-based overall drought intensity (MODIS-ODI) in the middle of the basin was attributed to prolonged low rainfall amounts. In the downstream, localized severe SWAT-based overall drought intensity (SWAT-ODI) was attributed to an imperfection of the SWAT model in simulating the true hydrologic cycle of the river basin. However, at the basin level, both SWAT-ODI and MODIS-ODI between the years 2000 and 2010 were moderate. These findings can be used as the baseline information in improving drought estimation in the river basin. Moreover, this study also demonstrates the importance of assessing scenario uncertainty in drought characterization.

Convection Parametrization and Multi-Nesting Dependence of a Heavy Rainfall Event over Namibia with Weather Research and Forecasting (WRF) Model

Namibia is considered to be one of the countries that are most vulnerable to climate change due to its generally dry climate and the percentage of its population that rely on subsistence agriculture for their livelihoods. Early-warning systems are an important aspect of adapting to climate change. Weather forecasting relies on the use of numerical weather prediction models and these need to be configured properly. In this study, we investigate the effects of using multi-nests and a convection scheme on the simulation of a heavy rainfall event over the north-western region of Kunene, Namibia. The event, which was associated with a cut-off low system, was short-lived and resulted in over 45 mm of rainfall in one hour. For the multi-nest, a 9 km grid-length parent domain is nested within the Global Forecast System (GFS) simulations, which in turn forces a 3 km grid spacing child domain. A different set of simulations are produced using a single nest of 3 km grid spacing, nested directly inside the GFS data. The simulations are produced with the convection scheme switched on and off. The impact of a single versus multi-nest is found to be small in general, with slight differences in the location of high rainfall intensity. Switching off the convection schemes results in high rainfall intensity and increased detail in the simulations, including when a grid spacing of 9 km is used. Using a grid spacing of 3 km with the convection scheme on, results in a loss of detail in the simulations as well as lower rainfall amounts. The study shows a need for different configurations to be tested before an optimum configuration can be selected for operational forecasting. We recommend further tests with different synoptic forcing and convection schemes to be conducted to identify a suitable configuration for Namibia.