Low Seasonal Rainfall Research Articles

Assessing Soybean Yield Potential and Yield Gap in Different Agroecological Regions of India Using the DSSAT Model

The study used the DSSAT model to assess potential soybean yields in different regions of India and validated it under diverse agroecological conditions. The average simulated yield under irrigated conditions was 3794 kg ha−1 relative to the simulated average rainfed yield of 2446 kg ha−1, showing a 35.52% reduction in grain yield due to adverse moisture conditions under rainfed conditions. Relative to simulated yield, the average observed (actual) rainfed yield across 43 districts of India was 1025 kg ha−1, which was 2769 and 1421 kg ha−1 lower than irrigated and rainfed potential yield, respectively. A significant positive correlation was observed between simulated water non-limited yield and solar radiation (R2 = 0.55, p ≤ 0.05). The simulated rainfed grain yield (R2 = 0.66, p ≤ 0.05) had a significant, positive, and curvilinear relationship with growing season rainfall. On the other hand, the actual yield (R2 = 0.008) showed a non-significant relationship with mean crop seasonal rainfall across locations. The gap between simulated yield under irrigated and rainfed conditions is huge at locations with low seasonal rainfall and narrows with increasing rainfall. In addition, the gap between actual yield and simulated yield under rainfed conditions was larger, even in high seasonal rainfall areas. The yield gap under rainfed conditions is due to the non-adoption of improved crop management practices and could be reduced with proper interventions. This includes adapting drought-resistant varieties, conserving rainwater, changing land configuration, and adopting waterlogging-tolerant varieties using improved technology to reduce the soybean yield gap.

Water footprint and production of rain-fed saffron under different planting methods with ridge plastic mulch and pre-flowering irrigation in a semi-arid region

Most of the saffron cultivation areas in Iran are irrigated and with pre-flowering irrigation being necessary to facilitate flower emergence. However, the growers face shortage of water. Post- flowering rain-fed (PFRF) saffron cultivation could be a solution, and ridge and furrow rainfall harvesting (RFRH) with plastic mulch could be used to collect runoff in the field planting areas. In this regard, the objectives of this study were to determine the effects of interaction of two different saffron planting methods (basin and furrow planting), using plastic mulch and without plastic mulch on ridge of the furrow planting, using irrigation at pre-flowering and without irrigation on saffron growth, yield, yield components, economic water productivity (EWP) and water footprint of saffron in two growing seasons with low (167 mm) and high (367 mm) seasonal rainfall in a semi-arid region. Without irrigation in pre-flowering (NPFI) produced a saffron yield reduction of 70% compared with pre-flowering irrigation (PFI). It is concluded that 90 mm of irrigation water should be applied as PFI for adequate flowering and yield. In addition, the use of the RFRH system resulted in a runoff coefficient of 0.85 and increased soil water storage (48% at low seasonal rainfall), saffron yield (51%), leaf dry matter, LDM (90%) and EWP (17%). The blue water footprint (BWF) with low rainfall (165 mm) was higher than that with abundant rainfall (367 mm), because saffron yield in the second year was lower due to the older age of saffron in field, which resulted in lower yield and consequently higher BWF. Likewise, green water footprint (GWF) was higher (4810 m3 kg−1) than those that obtained as BWF (739 m3 kg−1) due to the fact that pre-flowering irrigation is necessary for onset of flower and the regional rainfall is insufficient to initiate flowering. The effects of low seasonal precipitation (less than 200 mm) on saffron were manifested in yield and LDM reduction of 70% and 42%, respectively, compared to high seasonal precipitation, decreasing as seasonal precipitation increased. Precipitation reached around 300 mm in rain-fed with pre-flowering irrigation caused no reduction in saffron yield and LDM. Therefore, in PFRF conditions, furrow planting with ridge plastic mulch and pre-flowering irrigation is recommended. The economic water footprint of saffron under PFRF conditions with PFI was 50% of that obtained for irrigated saffron production, which is preferable in virtual water trade.

Seasonal variation in plastic litter pollution in mangroves from two remote tropical estuaries of the Colombian Pacific

Mangroves in estuaries are highly vulnerable to the impacts of plastic litter pollution, because their location at river mouths and the high capacity of mangrove trees to trap plastic items. Here, we present new results on the abundance and characteristics of plastic litter during high and low rainfall seasons in mangrove waters and sediments of the Saija and Timbiqui River estuaries in the Colombian Pacific. In both estuaries, microplastics were the most common size (50–100 %), followed by mesoplastics (13–42 %) and macroplastics (0–8 %). Total abundances of plastic litter were higher during the high rainfall season (0.17–0.53 items/m−3 in surface waters and 764–832 items/m−2 in sediments), with a moderately positive relationship between plastic abundances recorded in both environmental matrices. The most common microplastics were foams and fragments. Continuous research and monitoring are required for a better understanding and management of these ecosystems and their threats.

Statistical Study of Rainfall Variations Across Different Districts of Bundelkhand Region, India

The Bundelkhand region, one of the most vulnerable locations in central India, is prone to severe drought and crop failure attributed to annual rainfall fluctuation. In this study, basic statistics were utilized to determine the variances in rainfall across different districts in the Bundelkhand zone for 30 years (1987-2016) The average annual rainfall was found to be maximum for Damoh district (1169.24 mm) followed by Sagar district (1163.04 mm), Panna district (1118.79 mm), whereas it was minimum for Jalaun district (774.91 mm) followed by Datia district (841.61 mm), Hamirpur district (849.30 mm). In this study period in the year 2010 received low annual rainfall. The average seasonal rainfall was found to be maximum for Sagar district (1075.52 mm) followed by Damoh district (1073.40 mm), Panna district (1008.74 mm) whereas was minimum for Jalaun district (701.11 mm) followed by Datia district (769.1 mm). In this 30 year 1990 real received low seasonal rainfall. This research demonstrates the rainfall pattern over the study region and indicates susceptible locations that are more likely to face water stress as a result of rainfall variability.

Trends in the seasonal cycle of modelled streamflow across Australia, 1980–2018

AbstractAustralian seasonal streamflow cycles represent diverse weather and climate variations and distinctive influences from coupled ocean-atmospheric phenomena, including monsoons, frontal systems, and El Nino-Southern Oscillation. Streamflow strongly modulates the health of ecosystems and is inextricably linked to communities through consumptive use and cultural and spiritual practices. To better understand the potential impacts of a changing climate, a comprehensive trend analysis of streamflow variability resolved at daily scales is pursued for 35 rivers across Australia using a serially complete modelled streamflow dataset (1979–2018) from the GloFAS-ERA5 operational global river discharge reanalysis. Analysis consisted of quantile regression to identify direction and significances of trends in low, median, and high flows, K-means clustering to identify grouping of data with similar features, and Poisson regressions to identify rainfall changes during low and high rainfall seasons. Results present comprehensive decreases at low, median, and high flows in southern continental river streamflow. Northern continental streamflows display increases and decreases throughout the year across flows, with increases more prevalent. Trends within upper and lower portions of the flow distributions reveal unique sub-seasonal time windows in the extremes, thus underscoring that trends across the full distribution of streamflow are necessary to understand vulnerability to human and environmental systems.

Modeling and Performance Assessment of a Hypothetical Stand-Alone Parabolic Trough Solar Power Plant Supported by Climatic Measurements in Ipoh, Malaysia

Abstract This study presents a conceptual design for a concentrated solar power plant by using direct steam generation and a stand-alone power system based on a concentration of solar parabolic troughs. The system is located at the solar research site (SRS) of Universiti Teknologi PETRONAS in Ipoh, Malaysia. The model system uses an integrated turbine with 1.2 kW generators, and steam is generated by a flow loop powered by solar parabolic trough concentrators. An in-situ calculation of normal direct irradiance was conducted in SRS and used as an input for the mathematical model. The model was developed to assess the transient behavior of the system and the behavior of the projected power generation under seasonal variations and daily solar radiation. The parabolic trough power plant achieved the highest average output of 8.85% during the low rainfall season in March.

SAND DAMS AS SOURCES OF WATER AND ITS SUITABILITY FOR RURAL COMMUNITIES DURING DRY SEASON AROUND MAKURDI SEMI ARID ZONE, NIGERIA

Water is one of the most plentiful and essential compound for living organisms and plants all over the world. Millions of people in other parts of the world struggles with problems of water supply during periods of low rainfall and dry season where water supply is extremely low. Rural communities especially in Africa who dwell around seasonal streams rely on sand dams. Sand dams store water in shallow depths along dry stream and river beds, are fetched by scooping out sand. An assessment of existence of sand dams in some communities in the outskirt of Makurdi, Benue State was done. Riverbeds used as viable sand dams were identified; 16 physico-chemical parametres were analyzed to determine the water quality. Turbidity, TC, Fe and Mn, were above the threshold, pH, Cl, Ca, Mg, K, were within the threshold limit and TDS, Nitrate, TH, EC, were within acceptable limits. The overall water quality index was found to be 22.89 which is rated as very poor quality. It is recommended that water from sand dams be treated before it is use for drinking and domestic uses. Sand dams should be constructed using modernized structures to increase water storage which will invariably provide and preserve enough clean water throughout the dry season.

Effects of the Municipal Solid Waste Landfill on the Quality of Water Resources in Khalkhal: A Case Study

Transmission of leachate from municipal solid waste landfills can potentially threaten ecosystems and human societies when the landfill has no system for collecting and treating leachate. Leachate produced from landfills finds its way through the soil to groundwater and surrounding surface waters, leading to pollution of water resources. This study aimed to investigate the effects of leachate from Khalkhal landfill (a city in Ardabil province, northwestern Iran) on the quality of groundwater and surrounding surface water. During 2019-2020, 4 wells (one control well located upstream of the landfill and three wells located downstream of the landfill) and two stations of the surface water resource of the Herochai river were spots for sampling. First, we did sampling during high and low rainfall seasons in accordance with the standards. Second, we analyzed the values of some physical, chemical, and biological quality parameters according to standard methods. The sampling of the soil texture was conducted following ASTM D 422 standards. Then, the soil was analyzed at Reference Laboratory of Water, Soil, and Plant in Ardabil province. The value of most parameters measured in the water of downstream wells was lower than the limit recommended by the Iranian and World Health Organization, indicating no limitation for drinking and agricultural uses. The quality of the Herochai river water was also relatively undesirable in terms of turbidity and total coliform in some samples. Additionally, consistent with the study results, no difference was observed between high and low rainfall seasons. According to the results obtained from different parameters, Schuler and Wilcox diagrams, and landfill water pollution index (LWPI), the quality of upstream and downstream water resources of Khalkhal municipal solid waste landfill was not much different. In other words, the landfill did not affect water.

How temperature shocks impact energy poverty in Vietnam: mediating role of financial development and environmental consideration.

This paper evaluates the energy poverty of Vietnam by mediating the role of financial development and environmental considerations. Across the globe, billions of individuals live in fuel poverty, failing to access inexpensive and sustainable energy, which is necessary for long-term development. An elevation in power consumption due to an overall increase in heat and short periods of extreme heat exacerbates global warming. The goal of this research is to look at how climate change is affecting energy poverty in Vietnam. This finding (1) demonstrates that temperature shocks have a positive and quantitative impact. (2) The same may be said for "poor income/high cost" figures, which include information on power rates. Similarly, if households use the same amount of power but spend less on other items, the influence will not raise their electricity use. (3) Thermal shocks have been shown to reduce agricultural output in studies. During seasons of low rainfall, for example, higher evaporation and plant water demand can worsen drought and raise total irrigation expenses. Labor productivity is also affected by rising temperatures, particularly in weather-sensitive industries like agriculture. As a result, heat shocks will lower agricultural revenues, worsening energy poverty. Surprisingly, overall income appears to be a little mitigating influence. This might be owing to widespread underreporting of stated income, particularly among persons who rely on agriculture for their livelihood.

Ecological assessment of Black Fly (Simuliumdamnosum, Sensulato) breeding sites in two tributaries of Ogun river, Ogun state, Nigeria.

Onchocerciasis is a disease transmitted by blackfly vector of the genus Simuliumdamnosum complex having public and socio-economic consequences. The abundance of blackfly is directly linked to fluvial ecosystems in both tropical and non-tropical countries of the world. This study assessed the ecology of blackfly breeding sites in two tributaries of River Ogun located in Olokemeji and Lisa villages, Ogun State. A total of eighteen water samples were collected for physicochemical analysis during high rainfall (May, June and July), low rainfall (August, September and October) and dry season (November and December) with mean rainfall values of 163.17, 88.03 and 8.95mm, respectively, in both tributaries. Physicochemical parameters such as temperature (oC), electrical conductivity (EC), pH, total solids (TS), dissolved oxygen (DO), biochemical oxygen demand (BOD), total suspended solids (TSS), hardness (H), sulphate (SO4), phosphate (PO4), alkalinity, acidity, nitrate (NO3) and total dissolved solids (TDS) were analysed using standard laboratory methods. Digestive enzymes were analysed using 1g of frozen gut of Simulium larvae grounded with 20ml of 0.067g of potassium hydrogen and 20ml of 0.1M sodium reagent. A total of 766 and 482 samples of Simulium larvae were collected from Olokemeji and Lisa tributaries using Eppendorf tubes. The zooplanktons collected from Olokemeji and Lisa tributary were 904 and 802, while phytoplanktons collected from Olokemeji and Lisa tributary were 635 and 582 during the study period. Data obtained were analysed using both descriptive analysis and T-test. The results obtained for the physicochemical parameters were 28.7°C, 137.5 µS/cm, 6.3, 248.1mg/L, 58mg/L, 108.8mg/L, 90.8mg/L, 2.24mg/L, 2.24mg/L, 30.76mg/L, 42.35mg/L, 1.99mg/L, 2.07mg/L and 2.55mg/L for Temperature, EC, pH, TS, DO, BOD, TSS, H, SO4, PO4, alkalinity, acidity, NO3 and TDS, respectively. There were significant (p < 0.05) differences between the means of EC, pH, TS, TDS, TSS and hardness of Lisa tributary, and water samples were also viewed under an electron microscope for zooplanktons and phytoplanktons. The values of species diversity which were greater than 0.5 indicated that the species were abundant and evenly distributed. There were significant (p < 0.05) differences between the tributaries in all the digestive enzymes except amylase content. The regression analysis between TSS, nitrate, sulphate, phosphate, acidity, hardness, TS, pH and Simulium larvae abundance showed a positive correlation, R2 with values of 0.828, 0.994, 0.948, 0.933, 0.986, 0.997, 0.889 and 0.981, respectively. The R2 values between Simulium larvae abundance with phytoplanktons and rainfall have values of 0.868 at p < 0.01 and 0.911 at p < 0.05.

Drought index for the region experiencing low seasonal rainfall: an application to northwestern Bangladesh

Drought index for the region experiencing low seasonal rainfall: an application to northwestern Bangladesh

Combinations of in-field moisture conservation and soil fertility management reduce effect of intra-seasonal dry spells on maize under semi-arid conditions

• Combining CT and mulching significantly increased soil water retention. • Maize yield was best under a combination of CT, mulching and mineral fertilizer + manure during a low rainfall season. • Under high rainfall, combining RT, mulching and mineral NPK fertilizer + manure gave the best maize yield on sandy soil. • On clay, maize yield was highest under CT, mulching and mineral NPK fertilizer + manure during both low and high rainfall. The high frequency of prolonged intra-season dry spells since the turn of the 21st century continues to heighten risk of crop failure in rainfed cropping systems of Southern Africa including Zimbabwe. This study explored the effects of combining in-field moisture conservation techniques and soil fertility management on maize ( Zea mays L.) productivity under rainfed conditions in semi-arid eastern Zimbabwe. Treatment combinations were co-designed with farmers through participatory approaches, and tested on-farm on sandy and clayey soils over three consecutive seasons (2015/16–2017/18). Two tillage practices namely conventional (CT) and reduced tillage (RT), with 30 % mulch cover of dried thatching grass ( Hyparrhenia filipendula (L.) Stapf) applied either at planting or tasseling or at both stages, were combined with low (35 kg N ha −1 , 14 kg P ha −1 and 3 t ha −1 of manure) and high (90 kg N ha −1 , 26 kg P ha −1 and 7 t ha −1 of manure) fertilizer application rates in a split-split plot design. Intra-seasonal dry spells were more frequent during the first two seasons (i.e. 2015/16 and 2016/17), while the 2017/18 season was rather wet with well-distributed rains. Soil water content varied significantly (p < 0.05) across treatments when a dry spell length was between 3 and 15 days, and 3 and 20 days on sandy and clayey soil, respectively. Conventional tillage retained 9–27% more soil water compared to RT, particularly when combined with mulching. During 2015/16 and 2016/17, seedling emergence occurred earlier by 2 days when mulching was applied at planting, while anthesis-silking interval (ASI) was shorter by 4 days following mulching at tasseling. On the sandy soil, the combination of CT + mulching (at both stages) + high fertilizer rate achieved the highest maize grain yield of 2.6 and 2.8 t ha -1 during the 2015/16 and 2016/17, respectively. However, during the wet 2017/18 season, the combination of RT + mulching at planting + high fertilizer rate yielded the best (3.5 t ha -1 ). On clayey soil, CT + mulching (at both stages) + high fertilizer rate gave the highest yields of 2.4, 2.9 and 3.4 t ha -1 in 2015/16, 2016/17 and 2017/18, respectively. Water use efficiency (WUE) was greatest under CT + mulching (at both stages) + high fertilizer rate especially during seasons that had high occurrence of intra-seasonal dry spells. Overall, the combination CT + mulching (at both stages) + high fertilizer rate increased maize yield by over 200 % and 300 % compared to the non-mulched treatments on sandy and clay soil, respectively, particularly during seasons with high incidences of intra-seasonal dry spells. Consequently, the treatment combination achieved the best economic returns during the drier seasons although income returns were reduced during the wetter season because of considerable yield loss due to waterlogging, particularly on the sandy soil. We thus conclude that mulching at strategic crop growth stages in combination with tillage and judicious addition of organic and inorganic fertilizers is a promising agronomic technique for reducing effects of intra-seasonal dry spells on maize productivity in rainfed smallholder cropping systems. Increasing farmer access to organic and inorganic fertilizers is, however, key to accelerated adoption of such agronomic techniques.

Spatiotemporal variability and trends of rainfall and its association with Pacific Ocean Sea surface temperature in West\xa0Harerge Zone, Eastern Ethiopia

BackgroundRainfall variability exceedingly affects agriculture in Ethiopia, particularly in the eastern region where rainfall is relatively scarce. Hence, understanding the spatiotemporal variability of rainfall is indispensable for planning mitigation measures during high and low rainfall seasons. This study examined the spatiotemporal variability and trends of rainfall in the West Harerge Zone, eastern Ethiopia.MethodThe coefficient of variation (CV) and standardized anomaly index (SAI) were used to analyze rainfall variability while Mann-Kendall (MK) trend test and Sen’s slop estimator were employed to examine the trend and magnitude of the rainfall changes, respectively. The association between rainfall and Pacific Ocean Sea Surface Temperature (SST) was also evaluated by Pearson correlation coefficient (r).ResultsThe annual rainfall CV during 1983–2019 periods is between 12 and 19.36% while the seasonal rainfall CV extends from 15–28.49%, 24–35.58%, and 38–75.9% for average Kiremt (June–September), Belg (February–May), and Bega (October–January) seasons, respectively (1983–2019). On the monthly basis, the trends of rainfall decreased in all months except in July, October, and November. However, the trends were not statistically significant (α = 0.05), unlike in November. On a seasonal basis, the trends of mean Kiremt and Belg seasons rainfall decreased while it increased in Bega season although it is not statistically significant. Moreover, the annual rainfall showed a non-significant decreasing trend. The findings also revealed that the correlation between rainfall and Pacific Ocean SST was negative for Kiremt while positive for Belg and Bega seasons. Besides, annual rainfall and Pacific Ocean SST was negatively correlated.ConclusionsHigh spatial and temporal rainfall variability was observed at the monthly, seasonal, and annual time scales. Seasonal rainfall has high inter-annual variability in the dry season (Bega) than other seasons. The trends in rainfall were decreased in most of the months. Besides, the trend of rainfall decreased in the annual, Belg and Kiremt season while increased in the Bega season. The study also indicated that the occurrence of droughts in the study area was associated with ENSO events like most other parts of Ethiopia and East Africa.

Tidally Forced Saltwater Intrusions might Impact the Quality of Drinking Water, the Valdivia River (40° S), Chile Estuary Case.

The Valdivia River estuary (VRE) located in south-central Chile is known as one of the largest estuarine ecosystems on the Pacific coast. This research aims to determine the intra-tidal and sub-tidal variability of saline intrusions into the VRE between November 2017 and March 2019 derived from salinity sensors located along the VRE. Complementary hydrographic measurements were conducted during flood and ebb conditions of the spring and neap tides for each of the four seasons of the year along the central axis of the VRE. The results of the salinity time series showed that saline intrusions (values greater than 0.5 Practical Salinity Units) occurred ~20 km from the estuary mouth, when the total flow of the Cruces and Calle-Calle rivers (main tributaries of the estuary) was low, around 280–300 m3 s−1. During the same period, the best co-variability was observed between the saline intrusions and the mixed-semidiurnal tide and the fortnightly and monthly periods of the tide. Regression analyses indicated that salinity intrusion length (L) is best correlated to discharge (D) with a fractional power model L α D−1/2.64 (R2 = 0.88). The decreasing discharge trend, found between 2008–2019, implies that saline water intrusions would negatively impact the Valdivia’s main drinking water intake during the low rainfall season under future climate conditions.

Epidemiology and Management of Bacterial Spot of Almond Caused by Xanthomonas arboricola pv. pruni, a New Disease in California.

Bacterial spot caused by Xanthomonas arboricola pv. pruni was first detected on almond in California in 2013, and it is reported herein as a new disease in California based on fulfilling Koch's postulates and identification of the pathogen using species-specific PCR primers. Infected mummified fruit from the previous growing season and their peduncles were identified as primary overwintering sites of the bacterium on the tree. Twig cankers were not observed, and the pathogen was not recovered from dormant buds. Isolation from flowers and emerging leaves was only successful when they were collected within 20 cm of an infected, mummified fruit on the tree. Inoculation of flowers and immature fruit as well as immature and mature leaves resulted in disease development, indicating a long period of host susceptibility in the spring, but disease incidence was highest in fruit inoculations. In split-plot trials over 3 years, dormant applications in December or January with copper or copper-mancozeb significantly reduced the disease compared with untreated controls in seasons with high rainfall, but they had no effect in seasons with low rainfall. In-season applications of copper-mancozeb at petal fall or at full bloom and petal fall were also effective in reducing the disease. Phytotoxicity was observed after repeated applications of copper bactericides, especially in low-rainfall seasons. Dormant and in-season treatments of copper-mancozeb mixtures integrated with removal of mummified fruit are currently the best management strategies for bacterial spot of almond in California.

Enduring El Niño: impact of market access programmes on livelihood outcomes during drought conditions in Haiti

ABSTRACT This paper evaluates a set of programmes that aimed to help Haitian farmers overcome access barriers to technology adoption and output markets during a low rainfall season. The study relies on inverse probability weighting (IPW) methods to estimate the effectiveness of three interventions separately against the counterfactual of traditional maize intercropping. Of the multiple interventions, estimated impacts indicate that the intensive peanut programme was the most effective in mitigating risk and improving overall outcomes. The findings highlight the importance of focusing on resilience as a means of improving livelihoods for effective development initiatives in disaster-prone areas.

Softening of tap water via calcium removal using sphagnum peat moss sorbent by batch and flow-through approaches

ABSTRACTThe Gaza Strip experiences a water crisis of persistent qualitative and quantitative deterioration in regard to groundwater. There is a low recharging rate of the aquifer because of the low seasonal rainfall, the fast expansion of the urban area, and the high seawater intrusion along the narrow coastal Gaza Strip. Thus, the extremely hard water reduces the performance of the reverse osmosis desalination household units and causes membrane fouling. Sphagnum peat for removal of calcium from water was investigated applying batch and flow-through approaches. Fast calcium removal was demonstrated.

Engineering rhizobacterial community resilience with mannose nanofibril hydrogels towards maintaining grain production under drying climate stress

Ongoing impacts of climatic change especially moisture stress remain a global challenge to agricultural production and food security. Such abiotic effects directly influence soil microbial communities. Previously we demonstrated that polymeric hydrogels, able to provide specific interactions with soil microbial communities, enhance the dynamics and selectivity of ingress and colonisation of plant beneficial bacteria at soil microcosm scales. We now show that small quantities of osmotic hydrogels containing mannose nanofibrils specifically situated in close proximity to developing root zones provide enhanced microbial ingress, colonisation and continuous wetting pathways when contacting developing wheat root systems. These effectively create extensions to the natural rhizosphere sustaining significant beneficial rhizobacterial communities when under moisture stress. Sequencing studies, on wheat production soils undergoing a season of low average rainfall clearly showed microbial abundance increases and taxa selectivity in the rhizosphere-hydrogel regions compared to controls. Here wheat yields increased by about 20% with hydrogel addition compared to controls, which represented a 15% increase in the overall average yield in the region. This represents the first reported demonstration that developing rhizospheres may be readily engineered to consistently select their own distinct microbiome as nodes of functional microbial abundance significantly benefiting grain yield during abiotic stress. Thereby suggesting new opportunities to maintain grain yields during periods of drying climate via these fibrillar hydrogels.

Spatial and temporal characteristics of rainfall over a forested river basin in NW Borneo

The spatial and temporal patterns of rainfall over the Baram River Basin (BR) in Sarawak (Malaysian Borneo) were characterised through cluster analysis and multivariate statistics for the 25 year period from 1990 to 2014. Baram River Basin recorded an average annual rainfall of 3654 mm with high spatial and temporal variations. Ward’s method based analytical hieratical clustering (AHC) identified three homogeneous clusters (HC’s) of rain gauging stations (HC-I, HC-II, and HC-III). Rain gauges in HC-I are located in high rainfall domain, HC-II gauges are in moderate rainfall domain and HC-III gauges are in low rainfall domains. The moderate elevation regions in the Baram basin recorded the highest amounts of rainfall compared to lower and upper elevated regions. Multivariate statistics show variation in the distribution of monthly and annual rainfall within and between individual HC’s. Mean annual rainfall recorded at individual HC’s varies by around 1000 mm. Though the mean monthly rainfall distribution in HC’s varies by more than 70 mm, all clusters show a common pattern of high and low rainfall seasons related to monsoon characteristics of the region. The northeast monsoon (NEM) is the wettest period with highest mean rainfall falling in the months of November and December at all stations. In comparison, the southwest monsoon (SWM) is the driest season with the lowest mean rainfall falling in July. It was also noted that the inter-monsoon periods are actually wetter than the SWM season. Overall, rainfall in the Baram shows high inter-annual variability with dominant low rainfall domain in the lower (coastal) and upper (plateau) reach with highly localised high rainfall domain surrounded by fluctuating moderate rainfall areas in the middle reaches of the river basin. The localised nature of high rainfall domain in the central (south and southwest) part of the basin suggests that the surrounding elevated mountains and hills in that region influence the high rainfall recorded. The findings of the present research will aid in formulating water resource management plans, large scale plantation and agricultural practices and any other hydrological development projects in the region.

Temporal Variation of the Presence of Rhodnius prolixus (Hemiptera: Reduviidae) Into Rural Dwellings in the Department of Casanare, Eastern Colombia.

Rhodnius prolixus (Stål, 1859) is the major vector of Trypanosoma cruzi in Colombia and Venezuela. The species is strongly associated with high-altitude ecotopes, such as sylvatic palms (Attalea butyracea), where spatially and temporally stable infestations are established. We investigated temporal variation in regards to the presence of R. prolixus in rural dwellings in the department of Casanare (eastern Colombia) over a period of 12 mo. Thirty houses were sampled from January to December 2017 by installing Maria sensors, collecting triatomines through community entomological surveillance, and conducting a monthly search in each house. The collection of specimens from the houses varied significantly by month with the higher number of collections occurring in the low-rainfall season and the lower number of collections occurring in the months of increased precipitation. The proportions of males, females, and nymphs also varied significantly throughout the time period: nymphs (fifth instar only) were reported only during May, July, and September and significantly greater numbers of females than males were reported in the inspected dwellings in all months. Density, crowding, and colonization indices varied according to the season. A bloodmeal analysis revealed 17 different hosts. A total of 42 randomly selected R. prolixus specimens were subjected to molecular analyses for detection of T. cruzi DNA with 22 found positive (infection prevalence of 52%). In conclusion, we observed a high presence of R. prolixus (infected with T. cruzi) in dwellings close to native palm plantations. These findings indicate a high risk of vector transmission of T. cruzi for people in the study areas and challenges for the current vector control schemes in the region.