Duration Of Dry Period Research Articles

Association of Dry Period Length with Automatic Milking System, Mastitis, and Reproductive Indicators in Cows.

The objective of this study was to evaluate the association between dry period (DP) length and various indicators of productivity, reproduction, and udder health in cows managed with an automatic milking system. We analyzed records from 3861 cows, categorizing them into three groups based on their DP duration: (1) <40 days, (2) 40-70 days, and (3) DP > 70 days. Cows with a DP of 40-70 days had an average energy-corrected milk production that was 8.2 kg greater than that of cows with a short DP and 5.0 kg greater than that of cows with a long DP (p < 0.001). Milk from the 40-70-day DP group exhibited the highest lactose concentration (4.64 ± 0.01%). Additionally, cows with the longest DP had the smallest proportion of animals with a milk fat-to-protein ratio of 1.2 to 1.4. Cows with a DP of 40-70 days also showed the lowest milk electrical conductivity across all udder quarters, whereas cows with the shortest DP had the highest conductivity. The highest conception rates were observed in the group with the shortest DP. These results suggest that a DP of 40-70 days is optimal for maximizing milk production and improving both udder health and reproductive performance under AMS. Proper management of DP duration can be an effective strategy for sustainable dairy herd management.

Determining the Association of the Dry Period Duration with Dystocia and Stillbirths in Dairy Cows by Considering Parity, Season, and Gestation Length.

This study aimed to assess the relationship between the length of the dry period (DL) and the risks of dystocia and stillbirths in Holstein cows. A total of 1072 healthy cows in lactations 1 and ≥2 were categorized based on the DL (mean: 58.07 ± 0.33 days) into three groups: short DL (<40 days; 13.0% of cows), medium DL (40-70 days; 60.1%), and long DL (>70 days; 26.9%). Dystocia occurred in 12.4% of cows, while stillbirths accounted for 4.1% of calves. The medium DL group had the highest number of unassisted calvings. The dystocia rates were 11.4% for cows with gestation (GA) ≤ 274 days; 6.0% for cows with GA = 275-282 days; and 19.9% for cows with GA ≥ 283 days (p < 0.001). In season 1 (November-April), dystocia occurred in 15.0% of cases compared to 8.8% in season 2 (May-October) (p < 0.001). The stillbirth rates ranged from 3.6% to 4.0% for cows with medium and long DLs; while those with a short DL had 5.8% (p < 0.05). The stillbirth rates were 5.2% for cows with GA ≤ 274 days; 3.2% for cows with GA = 275-282 days; and 5.1% for cows with GA ≥ 283 days (p < 0.001). Season 1 had a stillbirth rate of 4.8%, while season 2 had a stillbirth rate of 3.3% (p < 0.001). This research provides insights that could assist the dairy industry in making informed decisions to reduce the incidence rates of dystocia and stillbirths in cows.

Effect of topography and hydrological change on solute transport at the sediment-water interface in seasonal lakes

Study regionThe Poyang Lake is located in northern Jiangxi Province, which is the largest fresh water in China. The upstream connection with rivers and downstream access to the Yangtze River create seasonal hydrological regimes, resulting in over 100 seasonal lakes within the floodplain. These lakes provide important habitats for migratory birds to forage and nest during dry seasons, and contribute to floodwater regulation during wet seasons, maintaining lake ecosystem. Study focusThis study has combined laboratory experiments and numerical simulations to mechanically analyze the effect of the depth, width, slope of seasonal lakes, water level amplitude and dry season periods on water recharge patterns, exchange fluxes and solute transport characteristics at the sediment-water interface. New hydrological insights for the regionReducing the lake area by 33% through adjustments in depth or slope significantly reduces solute transport range (12.81% and 6.5% within 120 min) and high velocity area. The sensitivity of the solute amount in the lakebed to depth is the highest, followed by slope and width. Decreasing water level amplitude during dry seasons increases the flow velocity within the beach, facilitating short-term solute transport towards the lakebed. Extending the duration of dry periods increases cumulative flux of solutes entering the lakebed. These findings contribute to the ecological restoration efforts in floodplains and water pollution control measures.

Projections of meteorological drought events in the upper Kızılırmak basin under climate change scenarios

Climate change, whose negative impacts are becoming increasingly apparent as a result of human actions, intensifies the drought problems to dangerous levels. The development of local-scale drought projections is crucial to take necessary precautions for potential risks and possible effects of drought. In this study, drought analysis was conducted in the Upper Kızılırmak Basin using the standard precipitation index (SPI) method for the near future (2020–2049), mid-century (2050–2074), and late century (2075–2099). The precipitation data required for the SPI were gathered from the data sets developed for the SSP climate change scenarios of the four chosen global climate models. Precipitation data has been made more convenient for local analysis studies with the statistical downscaling method. Forecasts have been created for the temporal variation and spatial distribution of drought events. The study findings indicate that, under the SSP 2-4.5 scenario, drought-related effects of climate change will decrease until 2100. On the other hand, the number and severity of drought events, as well as the duration of dry periods, will increase until 2100 under the SSP 5-8.5 scenario. According to the SSP 5-8.5 scenario, consisting of the most pessimistic forecasts, moderate drought will last 0–60 months, severe drought will last 0–30 months, and extreme drought will last 0–20 months in different regions of the area in the late century. The spatial distribution of droughts will differ based on the SPI index and climate change scenarios. Comparison of SPI and CZI data showed that both indices are effective in meteorological drought analyses.

Event-based rainfall analysis in Sinai, Egypt

ABSTRACT This study investigates event-based rainfall characteristics in Sinai (Egypt) using hourly precipitation data from the Global Satellite Mapping of Precipitation (GSMaP). A hierarchical cluster analysis of a 19-year dataset (2003–2021) identified five regions in Sinai. Distinct storms were identified using a minimum inter-event time of 5 h. The analysis of storm characteristics revealed that rainfall events in Sinai last from 1.7 to 3.6 h, with a mean storm volume of 6.4 mm. Rainfall intensity ranges from 1.7 to 4 mm/h, and the average dry period duration is 34 days. The northern region has the highest frequency of storms (25 events/year). The Weibull distribution was found to fit the best for all rainfall characteristics except for intensity, which was best represented by the generalized extreme value distribution. This study provides valuable insights about rainfall events in Sinai that can be applied to improve flood mitigation strategies and water resources management.

Hydrological and geochemical properties of bottom ash landfills

In Switzerland, municipal solid waste incineration bottom ash is deposited in open landfills, which leads to its interaction with rainwater and thus the formation of a polluted leachate. This study attempts to provide a better understanding of the hydraulic and geochemical properties of bottom ash landfills by combining field and laboratory investigations. The results show that a bottom ash landfill can be described as a generally unsaturated body with several layers of different grain sizes. Three different water domains with variable hydraulic and geochemical properties were identified in the landfill: (1) zones of preferential flow, (2) a reservoir of mobile porewater, and (3) an immobile porewater reservoir. Preferential flow systems account for approximately 5–10 vol.%. The landfill layering is primarily responsible for the formation of various flow systems during heavy rainfall events. The domains and reservoirs provide variable volumetric contribution to the leachate, depending on precipitation rates and duration of dry periods. Sampling of leachate during heavy rainfall events revealed dilution effects for Na (− 59–61% compared to concentrations prior to the event), Ca (− 44–47%), Cl (− 57–77%), and SO4 (− 35–47%), while pH (+ 7–8%) and concentrations of Al (+ 368–1416%), Cu (+ 7–58%), Cr (+ 29–48%), V (+ 100–118%), and Zn (+ 289%) increased significantly. The findings of this study serve as a basis for the development of a hydrogeochemical model of a bottom ash landfill, which allows better prediction of the future evolution of leachate quality.

Assessing Wet and Dry Periods Using Standardized Precipitation Index Fractal (SPIF) and Polygons: A Novel Approach

In the open literature, there are numerous studies on the normal and extreme (flood and drought) behavior of wet and dry periods based on the understanding of the standard precipitation index (SPI), which provides a series of categorizations by considering the standard normal (Gaussian) probability distribution function (PDF). The numerical meaning of each categorization assessment is quite lacking in terms of future predictions of wet and dry period duration based on historical records. This paper presents a new approach for calculating possible formations of future wet and dry period durations based on historical records through an effective fractal geometric forecasting approach. The essence of the proposed methodology is based on the number of dry periods (steps) of non-overlapping monthly duration along consecutive broken line paths in the SPI classification for wet and dry period durations. It has been observed that the plot of periods on double logarithmic paper falls along a straight line against the number of such periods, implying a power function, which is the essence of fractal geometry. Extending the empirically derived straight line provides the number of periods that may occur in the future over a range of SPI levels. This methodology is referred to as SPI fractal (SPIF), and the classic SPI classification is converted into SPIF wet and dry polygons, which provide additional information about the drought period number within a valid polygonal area, compared to the classic SPI results. The wet and dry period features of any hydro-meteorology time series are constrained in SPIF polygons. The application of the methodology was carried out on monthly rainfall records on the European side of the Istanbul Florya meteorological station in Turkey.

Variation in protein metabolism biomarkers during the transition period and associations with health, colostrum quality, reproduction, and milk production traits in Holstein cows

The aims of this study were to assess (1) the variation of protein metabolism biomarkers and factors affecting them during the transition period, (2) the association of each biomarker with skeletal muscle reserves and their changes, and (3) the association of these biomarkers with postpartum health, colostrum quality, reproduction, and milk production. For this purpose, 238 multiparous Holstein cows from 6 herds were used in a prospective cohort study. Plasma concentrations of 3-methylhistidine (3-MH) and 1-methylhistidine (1-MH) and serum concentrations of total protein (TP), albumin (ALB), urea nitrogen (BUN), and creatinine (SCR) were determined for each cow at -21, -7, 7, 21, and 28 d relative to calving. Clinical diseases were recorded during the first 28 d postcalving, and presence of subclinical ketosis (scKET) was investigated at 7 and 21 d. Colostrum quality was estimated by Brix refractometry. Reproduction data by 150 d in milk (DIM) and milk production records were also available. Linear mixed models including the fixed effects of time point, herd, parity, body condition score (-21 d), duration of dry period and postparturient diseases were fitted to assess the variation in each biomarker's concentration. The association between the biomarkers' concentration during the prepartum period with the odds for each postparturient disease and for a combined trait (CD_1-28), defined as the presence of at least one clinical condition during the first 28 d after calving, were assessed with separate binary logistic models for time points -21 d and -7 d. The relationship of each biomarker's concentration with longissimus dorsi thickness (LDT) and the changes in LDT (ΔLDT) was assessed with pairwise correlations. Separate general linear models were used to assess the association of each biomarker with colostrum Brix values and milk production traits. Finally, the associated hazard for first artificial insemination (AI) and for pregnancy by 150 DIM (PREG_150DIM) was assessed with Cox proportional hazard models, whereas odds for pregnancy to the first AI (PREG_1stAI) were assessed with binary logistic models. The level of 3-MH was affected mainly by herd, time points, and their interaction. Higher 3-MH was associated with increased odds for metritis and CD_1-28, increased hazard for PREG_150 DIM and with increased milk production. 1-Methylhistidine was affected mainly by herd, scKET and occurrence of displaced abomasum. Higher 1-MH was associated with better colostrum quality, increased odds for scKET, increased hazard for first AI by 150 DIM and with decreased milk production. Both 3-MH and 1-MH were weakly to moderately negatively correlated with LDT and moderately to strongly negatively correlated with ΔLDT at the corresponding time periods. Additionally, higher TP was associated with increased odds for metritis and CD_1-28 and increased milk production, while higher ALB was associated with increased odds for scKET and increased milk production. Moreover, higher BUN was associated with decreased odds for scKET, increased odds for PREG_1stAI and increased milk production. Higher SCR was associated with decreased odds for retained fetal membranes, metritis, and CD_1-28. Periparturient protein metabolism is significantly associated with postpartum health, colostrum quality, reproduction, and milk production; mechanisms involved require further investigation.

Milk productivity and reproductive capacity in Holstein cows of Moscow region

The article presents the reproductive quality indicators of the Holstein herd of APA (C) “Kuzminsky” (Moscow region) with different milk productivity levels. Some patterns have been identified for the herd, reflecting associations between reproductive and productive traits. The coefficient of the reproductive capacity ranges in the herd from 0.976 to 0.986, and the highest average rate was noted among cows with the highest milk yields in the herd. It’s noteworthy that the largest group (n=100) with an average level of milk yield per herd was characterized by the lowest coefficient. The average calving interval is 372 days, which can be explained by an extended service period; the dry period duration in cows with high milk yields is the maximum among the studied livestock.

ВЛИЯНИЕ СОЧЕТАЕМОСТИ ЛИНИЙ НА ВОСПРОИЗВОДИТЕЛЬНУЮ СПОСОБНОСТЬ КОРОВ ГОЛШТИНСКОЙ ПОРОДЫ

The paper presents the results of determining the influence of line compatibility on the reproductive ability of cows. Scientific and economic experiment was carried out on the basis of LLC "Plemzavod im. Lenin" Koverninsky district, Nizhny Novgorod region. It was found that groups 1 and 7 had the greatest influence on the reproductive ability of cows, because the duration of lactation, dry period, calf yield and reproduction rate were close to optimal values. It was found that the yield of calves in these groups was 86 % and 91 %, respectively.

Humidification resources of the Tomsk region

To determine the standards of anthropogenic load on the water resources of the territory, as well as to carry out their geo-ecological assessment, the question arises of quantitative determination of the characteristics that influence the conditions for the formation and functioning of water resources of geographical systems. The ability of an ecosystem to withstand external stress depends on its resident resilience and ability to recover after a reduction in stress. Among the many factors in assessing the geoecological state of a territory, an important place is occupied by the availability of water resources and their quantitative characteristics, as well as the distribution of moisture resources throughout the territory at different periods of time. Analysis of the water supply of the territory is necessary, both from the point of view of determining the natural capabilities (potential) of aquatic ecosystems, and determining the qualitative state of water bodies. In the presented article, based on observational data over a long-term period, the average durations of wet and dry periods, as well as the percentage of precipitation at weather stations in the study area, are determined. Based on the data on humidity and heat resources, the heat and energy resources of the climate, evaporation and their water equivalents were calculated. The calculations made made it possible to determine characteristics important for water availability, such as the ratio of heat and moisture resources and the humidification coefficient. Based on a study of the main directions of economic development of the territory, industries that place a significant burden on water resources were identified and recommendations were given for restoring impaired functions.

INFLUENCE OF CALVING SEASON OF COWS ON THEIR PRODUCTIVITY UNDER ORGANIC AND CONVENTIONAL MILK PRODUCTION

The aim of the research was to study the impact of the first calving season of Simmental cows on their future milk productivity and reproductive capacity in conditions of both organic and conventional milk production.&#x0D; Research materials and methods. The research was conducted in Simmental breed herds of PE "Galex-Agro" (organic milk production, n = 272) and STOV "Myroslavel-Agro" (conventional milk production, n = 120) in the Zviahel district of Zhytomyr region, Ukraine. First-calving cows in the two farms were categorized into four groups based on the calving season: Group I – Winter (n = 83 and 42 cows in PE "Galex-Agro" and STOV "Myroslavel-Agro" respectively); Group II – Spring (59 and 26);Group III (45 and 12); Group IV (85 and 40 cows).&#x0D; Research results. First-calving cows in organic production demonstrated a higher expression of quantitative traits of milk productivity, regardless of the calving season, compared to their counterparts in conventional conditions, albeit with slightly lower qualitative traits. However, statistically significant differences were found only in 305-day milk yield between autumn-calving cows in favor of first-calving cows from PE "Galex-Agro."&#x0D; It is worth noting that, in both farms, the first calving in the autumn season was found to be the most favorable, while the summer season was the least favorable, which provides grounds for planning calving in the autumn period. Our research results indicate that animals under organic management, regardless of the calving season, exhibited statistically significantly (P &lt; 0.01–0.001) older age at first calving and longer calving intervals. No statistically significant intergroup differences were found in other reproductive traits.&#x0D; The season of first calving in both organic and conventional milk production conditions accounted for 0.3 to 4.7% and 0.2 to 3.3% of the total phenotypic variability in milk productivity traits, as well as 1.0 to 2.9% and 0.6 to 2.5% of the reproductive capacity. Statistically significant effects of the calving season were only observed in PE "Galex-Agro" and exclusively on productivity traits, including lactation duration (3.2%), 305-day milk yield (4.3%), milk fat content (4.7%), milk protein content (4.3%), milk fat, and protein content (4.7%), as well as the duration of dry period (2.9%) (P &lt; 0.05–0.001).&#x0D; Conclusion. Our research results highlight the importance for specialists in both farms to pay attention to the seasonality of first calving in cows and, if possible, take these aspects into account when planning breeding and technological measures in the farms.

Drought trends projection under future climate change scenarios for Iran region.

The study highlights the potential characteristics of droughts under future climate change scenarios. For this purpose, the changes in Standardized Precipitation Evapotranspiration Index (SPEI) under the A1B, A2, and B1 climate change scenarios in Iran were assessed. The daily weather data of 30 synoptic stations from 1992 to 2010 were analyzed. The HadCM3 statistical model in the LARS-WG was used to predict the future weather conditions between 2011 and 2112, for three 34-year periods; 2011-2045, 2046-2079, and 2080-2112. In regard to the findings, the upward trend of the potential evapotranspiration in parallel with the downward trend of the precipitation in the next 102 years in three scenarios to the base timescale was transparent. The frequency of the SPEI in the base month indicated that 17.02% of the studied months faced the drought. Considering the scenarios of climate change for three 34-year periods (i.e., 2011-2045, 2046-2079, and 2080-2112) the average percentages of potential drought occurrences for all the stations in the next three periods will be 8.89, 16.58, and 27.27 respectively under the B1 scenario. While the predicted values under the A1B scenario are 7.63, 12.66, and 35.08%respectively. The relevant findings under the A2 scenario are 6.73, 10.16, 40.8%. As a consequence, water shortage would be more serious in the third period of study under all three scenarios. The percentage of drought occurrence in the future years under the A2, B1, and A1B will be 19.23%, 17.74%, and 18.84%, respectively which confirms the worst condition under the A2 scenario. For all stations, the number of months with moderate drought was substantially more than severe and extreme droughts. Considering the A2 scenario as a high emission scenario, the analysis of SPEI frequency illustrated that the proportion of dry periods in regions with humid and cool climate is more than hot and warm climates; however, the duration of dry periods in warmer climates is longer than colder climates. Moreover, the temporal distribution of precipitation and potential evapotranspiration indicated that in a large number of stations, there is a significant difference between them in the middle months of the year, which justifies the importance of prudent water management in warm months.

Estimation of Heterotrophic Soil Respiration Response to the Summer Precipitation Regime and Different Depths of Snow Cover in a Temperate Continental Climate

Regime of precipitation and temperature conditions are key factors that regulate the rate of decomposition of soil organic matter in terrestrial ecosystems. The aim of this work was to assess the effect of the duration of dry periods in summer and different depths of snow cover in winter on heterotrophic soil respiration. The studies were carried out as part of a 2–year field manipulation experiment organized on gray soil (Haplic Luvisol) in the temperate continental climate conditions (southern Moscow region). Three variants were organized: (1) simulation of mild weather with uniform watering of the soil in summer and the absence of freezing in winter, (2) simulating two summer dry periods lasting 1–2 months with natural winter snow cover, (3) simulation of extreme weather with one long (~3 months) dry period in summer and complete removal of snow cover in winter. Heterotrophic soil respiration was measured by the closed chamber method on bare fallow during 2 years of continuous experiment and 1 more year after its completion. Medians of heterotrophic soil respiration for the entire period of the experiment in the three above–mentioned variants of the experiment were 38, 27 and 19 mg C/(m2 h), respectively. Two short dry periods led to an increase in heterotrophic soil respiration by 7–10%, which is associated both with the drying and rewetting cycles of the soil and with an increase in the average summer temperature of a 20–cm soil profile by 1.5°C. The prolonged dry period caused a decrease in heterotrophic soil respiration by 12–16% as a result of low soil moisture. Soil freezing led to a strong decrease in winter CO2 emission from soil, which reached 34–55% in the control variant and 57–72% when the snow cover was removed. The frost period (November–March) contributed from 25–34% without of soil freezing to 14–19% when its presence to the annual CO2 flux. We conclude that the change in the winter temperature regime of the soil due to manipulations with the snow depth led to a more significant change in the annual heterotrophic soil respiration than the lack of precipitations in the summer season.

Projecting Hydroclimatic Extremes: Climate Change Impacts on Drought in a German Low Mountain Range Catchment

Germany’s increasing temperatures and droughts are significantly impacting the hydrological realm. This study examines the implications of climate change on future droughts in a representative catchment within Germany’s low mountain range. Findings of this research shed light on potential impacts on future seasonal water availability, aiding decision makers and stakeholders in managing regional climate change risks. Climate and drought indices, as well as the climatic water balance, are computed and analyzed until 2100, relative to a reference period. A high emission scenario (RCP8.5) and a climate protection scenario (RCP2.6) are considered to address uncertainties. Results reveal above-average warming in the study area compared to the national average. Under the RCP8.5 scenario, the far future exhibits an average of 44 annual heat days. Despite wetter winters, extended droughts persist. Water stress intensifies in summer and autumn, with a projected 68% increase in dry period duration. The findings emphasize the necessity of adaptation strategies, as even ambitious global warming mitigation efforts require regional adaptation. The study represents the first application of a Germany-wide, bias-adjusted, and regionalized dataset at catchment level. It contributes novel insights for regional water resources management and advances understanding of climate change impacts in German low mountain range regions.

Milk production of dairy cow at PT. Ultra Peternakan Bandung Selatan

This study aims to determine the effect of body condition score (BCS), lactation length, and dry period on milk production of dairy cows at PT. Ultra Peternakan Bandung Selatan (UPBS). The research was conducted at PT. UPBS, Pengalengan, West Java, the following method used is survey method, where the data of primary and secondary data using 130 lactating dairy cows 3. Complete milk production records as variable y and BCS, lactation length, and dry period as variable x. The effect of BCS, duration of lactation, and dry period were analyzed using multiple linear regression analysis. The results of this study discovered that each factor of BCS, lactation length and dry period duration a very significant effect (P<0,01) with a coefficient of determination (R2) of 76.2%, average milk production 7835±631,33 kg, BCS score 3,25 ±0,26; lactation length is 346±65,26 days, and dry period (R2) is 77±33,18 days. The conclusions of this study; to optimize milk production, the implementation of dairy cows maintenance needed on BCS, lactation length, and optimal dry period according to the recommendations.

Spatiotemporal Application of the Standardized Precipitation Index (SPI) in the Eastern Mediterranean

The ever-increasing need for water, the alteration in the climate, and its observed changes over recent years have triggered a lot of research studies associated with the phenomenon of drought. Within the wider geographical region of the Mediterranean, the relevant scientific subject seems to be of great interest, since it is undoubtedly related to a number of severe socio-economic consequences. This present effort focuses on the evolution of this particular phenomenon over time, within the borders of nine different countries in the Eastern Mediterranean (Athens, Greece—Europe; Constantinople, Turkey—Asia; Nicosia, Cyprus—Europe; Jerusalem, Israel—Asia; Amman, Jordan—Asia; Damascus, Syria—Asia; Beirut, Lebanon—Asia; Cairo, Egypt—Africa; and Tripoli Libya—Africa). By applying the Standard Precipitation Index (SPI), examining precipitation data at the month level (January 1901 to December 2020), and utilizing the Inverse Distance Weighted (IDW) method, the spatio–temporal variability of drought events in the Eastern Mediterranean area was studied. In Jerusalem, long-term droughts presented a higher than usual volume, in accordance with applying the 12- and 24-month SPI, starting from the mid-20th century. Similarly, the region of Damascus presented a similar pattern to those in Beirut, Amman, and Jerusalem. An upward trend in the frequency of extreme drought events was observed for the last thirty years. The same trend seems to be true in terms of the duration of dry periods. Drought events have also been observed in the central, southern, and eastern regions of Turkey. A downward trend was observed in Cairo based on a trend analysis of its monthly precipitation.

Influence of Design Variables on the Financial Feasibility of Rainwater Harvesting Systems

Extensive implementation of rainwater harvesting (RWH) systems can promote substantial improvement in urban water resource management. Therefore, establishing the financial feasibility of RWH systems is imperative for their dissemination. This study evaluated the influence of rainfall time series indicators (average annual rainfall, seasonality index and behaviour of periods without precipitation) and design variables (catchment area, rainwater demand, number of inhabitants, potable water demand and rainwater tank size) on the financial feasibility of RWH systems in eight Brazilian cities. Correlations between rainfall indicators and financial feasibility were introduced, along with sensitivity analysis of design variables. Financial feasibility was obtained in 30% to 70% of the simulated scenarios. Initial investment and operating costs varied significantly among the eight cities according to local prices. Systems with a catchment area of 200 m2 were capable of supplying, on average, 90.5% of the maximum rainwater consumption observed in this study. Local variation of potable water tariff schemes affected the financial feasibility of RWH systems. The number of inhabitants was the most influential design variable on the financial feasibility of RWH systems, followed by the rainwater tank size. Places with lower rainfall seasonality indexes and lower incidence and duration of dry periods are likely to lead to greater financial feasibility.

Small increases in stream drying can dramatically reduce ecosystem connectivity

AbstractHabitat fragmentation drives biodiversity loss in rivers around the world. Although the effects of anthropogenic barriers on river connectivity are well known, there has been little research on the ways in which stream drying may alter connections among habitats and resources. Given that stream drying is increasing in many regions, there is a pressing need to understand the effects of drying on habitat fragmentation. Here, we quantify spatiotemporal drying patterns under current and future climate scenarios in the Upper Blue River Basin, Oklahoma. We used a hydrologic model to simulate daily streamflow for nine climate scenarios. For each scenario, we calculated metrics of streamflow temporal continuity (dry days, dry periods, and dry period duration) and spatial connectivity (wetted length, number of dry stream fragments, length of dry stream fragments, and dendritic connectivity index) from simulated daily streamflow. We found that stream drying is likely to increase in all future climate scenarios and that increases in stream drying reduce connectivity. However, the effects of stream drying on connectivity were highly nonlinear. Specifically, we observed a threshold around which a small increase in stream drying led to a rapid drop in connectivity. We also found that the greatest increases in stream drying were not associated with the highest emission scenarios, underscoring the complex linkages among climate, water availability, and connectivity. Given that connectivity is essential to ecosystem structure and function, we discuss water management strategies informed by impacts of stream drying.

Postharvest transient water deficit limits longevity of cut Dendrobium ‘Khao Sanan’ orchid

A negative water imbalance due to a temporary water deficit (WD) after harvest can stimulate early flower senescence and reduce flower quality and vase life of orchids. To clarify the physiological responses of cut Dendrobium ‘Khao Sanan’ inflorescences under WD stress and early responses during water recovery, relative water content (RWC), water potential, reactive oxygen species (ROS), ethylene production, lipid peroxidation, antioxidant enzymes, and osmolyte were determined. The inflorescences were exposed to WD for 0, 24, 48, and 72 h after harvest, then placed in water for recovery and vase life determination. The results showed that WD significantly reduced RWC in petals, and over 24 h of WD adversely affected postharvest quality including vase life of cut inflorescences by increasing flower abscission, flower bud opening, and decreasing flower quality score. Moreover, ethylene production was induced early by 72 h of WD. Exposure of cut flowers to WD also increased hydrogen peroxide (H2O2) content, malondialdehyde (MDA) content, proline content, and lipoxygenase (LOX) activity. Additionally, ascorbate peroxidase (APX) and catalase (CAT) activities fluctuated with durations of dry and recovery periods. After rewatering, RWC, water potential, MDA content, and LOX activity of all WD periods recovered at non-WD control levels while H2O2 and proline content remained higher than control. On the other hand, ethylene production of the inflorescences exposed to WD over 24 h remarkably increased after rewatering. Our findings suggested that Dendrobium ‘Khao Sanan’ could tolerate transient WD up to 24 h with negligible reduction in longevity, probably corresponding to the lowest ethylene production during the WD period and the accumulation of antioxidant enzymes and osmolytes.