Simulated Rain Research Articles

Simulation of Rainfall Intensity and Slope Gradient to Determination the Soil Runoff Coefficient at Microplot Scale

Simulating rainfall is one of the valuable methods of measuring hydrological data and soil erosion processes. Rapid evaluation, high repeatability, and low cost are the reasons of using rain simulators. In this study, a rain simulator was constructed in dimensions of 3.0 × 3.0 × 3.0 m and it was protected on three sides by a plastic cover. An inclined table was used to create slopping surfaces of 5, 10, and 15%. Microplots were used in the dimensions of 0.2 × 0.4 × 1.0 m to collect and measure direct runoff in a bucket outside the device. Nozzles were calibrated to produce two different rainfall intensities 10 and 20 mmh−1 using sprinkler Model 5B at 8 and 12 psi, respectively. Furthermore, three different soil types, namely, clay loam (CL), silty clay (SC) loam, and SC were examined. In general, it was observed that with increasing the rainfall intensity and slope, the rate of runoff and sedimentation increase. SC soil at 15% slop offered the highest performance under the intensity of 20 mmh−1. SC and the CL soils produced the highest and lowest runoff coefficients, respectively. The CL soil produced the highest soil loss (1 kgm2 at 15% and I = 20 mmh−1). Further, it was concluded that a significant change (an average increase of 53%) in soil loss can be achieved as the rainfall intensity increased from 10 to 20 mmh−1.

Effect of leaching events on the fate of polyhalite nutrient minerals used for crop fertilization

Polyhalite is a natural mineral containing potassium (K), calcium (Ca), magnesium (Mg) and sulfur (S) and is proposed as a fertilizer source for these essential nutrients. Application of polyhalite is expected to be most relevant in soils where the availability of these nutrients is low: in sandy soils, in highly leached soils, or in areas where crops are irrigated by water with low content of these nutrients or are rain-fed. A controlled lysimeter experiment investigated the efficacy of surface applied polyhalite as a fertilizer supplying K, Ca, Mg and S compared to soluble sulfate salts in two soils (sandy and loamy) with or without simulated rain leaching events through two cycles of cropping. In the first cycle, carrot response and nutrient uptake, transport, and loss through leaching were studied, while in the second cycle the residual effect of the fertilizer was considered on maize without additional fertilizer application or leaching. Polyhalite plus rain led to increased carrot yield due to augmented Ca uptake in sandy soil. In both soils, polyhalite behaved as a prolonged availability fertilizer with more nutrients retained in the top soil layer and not leached below the root zone. The treatments did not affect maize growth or nutrient uptake except for lower K and S uptake in soils where rain had been simulated for the previous crop. We conclude that polyhalite shows potential as a commercial fertilizer to supply K, Ca, Mg, and S nutrients under conditions of dryland agriculture where occasionally leaching by rainfall occurs.

Effect of Natural and Simulated Rainfall and Wind on Melanaphis sacchari1 on Sorghum

The impact of natural and simulated rainfall and wind on sugarcane aphid, Melanaphis sacchari (Zehntner), on sorghum, Sorghum bicolor (L.) Moench, was studied near Rio Bravo, Tamaulipas, northeastern Mexico. In 11 events, natural rainfall intensity ranged from 15 to 51 mm per hour; average winds from 5 to 37 km per hour; and maximum wind (gusts) from 10 to 107 km per hour. Natural rain caused an average reduction of 32% adults, 13% nymphs, and 14% total (adults + nymphs) after 30 minutes; however, 5 days later, aphid abundance increased an average of 14% (range -55 to +93%). Natural rain caused only an average of 0.6% loss of parasitoid mummies of braconid Lysiphlebus testaceipes (Cresson). A rain simulator was designed to test the effects of artificial rainfall (40 mm per 15 minutes), constant wind (20 km per hour), and wind gusts (70 km per hour, 20 seconds every 2 minutes) during 15, 30, 45, and 60 minutes. After 60 minutes in the rain simulator, 77% of M. sacchari survived with rain alone, 44% with rain + constant wind, 34% with rain + wind gusts, and only 22% with rain + constant wind + wind gusts. Combination of rain and wind was more important than rainfall itself, particularly because M. sacchari feeds underneath the leaves, and disturbance produced by wind greatly reduced aphid survival. Multiple regression models well explained (R2 > 0.95) the association of M. sacchari survival (y) with rain and wind independent variables (xn) for natural, simulated, and combined (natural + simulated) conditions.

The impact of atmospheric N deposition and N fertilizer type on soil nitric oxide and nitrous oxide fluxes from agricultural and forest Eutric Regosols

Agricultural and forest soils with low organic C content and high alkalinity were studied over 17 days to investigate the potential response of the atmospheric pollutant nitric oxide (NO) and the greenhouse gas nitrous oxide (N2O) on (1) increased N deposition rates to forest soil; (2) different fertilizer types to agricultural soil and (3) a simulated rain event to forest and agricultural soils. Cumulative forest soil NO emissions (148–350 ng NO-N g−1) were ~ 4 times larger than N2O emissions (37–69 ng N2O-N g−1). Contrary, agricultural soil NO emissions (21–376 ng NO-N g−1) were ~ 16 times smaller than N2O emissions (45–8491 ng N2O-N g−1). Increasing N deposition rates 10 fold to 30 kg N ha−1 yr−1, doubled soil NO emissions and NO3− concentrations. As such high N deposition rates are not atypical in China, more attention should be paid on forest soil NO research. Comparing the fertilizers urea, ammonium nitrate, and urea coated with the urease inhibitor ‘Agrotain®,’ demonstrated that the inhibitor significantly reduced NO and N2O emissions. This is an unintended, not well-known benefit, because the primary function of Agrotain® is to reduce emissions of the atmospheric pollutant ammonia. Simulating a climate change event, a large rainfall after drought, increased soil NO and N2O emissions from both agricultural and forest soils. Such pulses of emissions can contribute significantly to annual NO and N2O emissions, but currently do not receive adequate attention amongst the measurement and modeling communities.

Uji Laboratorium Pengaruh Kemiringan Lereng Terhadap Kejadian Longsoran Aliran Debris Pasir Merapi

The debris flow that happen on the of Mount Merapi is really hard to be seen, therefore, it is necessary to conduct laboratory-scale simulations to know when debris flows will happen as regard to rainfall intensity and the slope of Mount of Merapi. This research examines the correlation between the slope and the potential for debris flow at 25 mm/h rainfall intensity. This will be a reference for early warning of landslides on Mount of Merapi. This research uses a tool such as flume that sized 3 x 5 x 0,15 m as a model of slope of Mount of Merapi, and artificial rainfall apparatus as the rain simulator. The simulation is conducted using five years rainfall intensity of 25 mm/h in combination of slope i.e. 15, 20, 25, 30 and 35 degrees whereas the material used to represent the sediment is in form of sand taken from Gendol River upstream with 4,75 mm passing mesh sieves. The result of this simulation is the steeper the slope is, the faster the duration for the rain to cause debris flow. This research can be continued with change variation of rainfall intensity to understand the debris flows behavior. Keywords: Debris flow, Mount of Merapi, laboratory test, rainfall intensity, flume model

Dynamic depth distribution of cesium-133 near soil surfaces in packed soils under multiple simulated rains

Various 137Cs conversion models have been used to predict soil erosion. A knowledge of the initial distribution of 137Cs is vital to improve soil loss prediction. The objectives were to (1) characterize the dynamic distributions of 133Cs near the soil surfaces in multiple rains spiked with 133Cs using a rainfall simulator, and (2) further estimate the relaxation mass depth (H) for use in an improved 137Cs mass balance model. Three silt loam soils were packed to soil boxes (1 × 0.5 × 0.1 m) and rained on at 30 mm h−1 and 10% slope in five consecutive rains. Soil cores (62.5 mm i.d.) were taken following each rain and were sectioned in the 1–10-mm intervals. Event runoff and sediment were collected. Cs+ was extracted with an NH4OAc method using a centrifuge procedure and analyzed with Inductively Coupled Plasma-Mass Spectrometer. The results showed initial Cs distributions near the soil surfaces were approximately exponential, and the mean H value could adequately characterize the initial Cs distributions for each soil for any sequence of rains. The averaged H values were 0.338, 0.304, and 0.354 g cm−2 for the three soils, equivalent to the soil depths of 2.76, 2.20, and 2.58 mm, indicating that majority of Cs was distributed within the top 3-mm depth. Cs+ was strongly adsorbed by the soils as indicated by the large Kd values of >32.6 L kg−1, showing the limited mobility of the freshly deposited Cs+ in the soils. Better H estimation should lead to more accurate soil loss prediction using the improved Cs mass balance model.

Pods as sails but not as boats: dispersal ecology of a habitat-restricted desert milkvetch.

Adaptive seed dispersal mechanisms are fundamental to plant fitness, but dispersal advantage is scale-dependent. We tested the hypothesis that informed dispersal in response to an environmental cue enables dispersal by wind on a local scale for Astragalus holmgreniorum, a desert species restricted to swales and wash skirts with overland flow, but prevents longer-distance dispersal by water into unfavorable wash habitats. Pod biomechanics in A. holmgreniorum lead to major shape modifications with changes in moisture content. We performed laboratory experiments to examine the interaction of pod shape with wind and water, and conducted field experiments in A. holmgreniorum habitat evaluating the roles of wind, water, and seed predators on dispersal. Dry pods exhibit a flattened crescent shape with partial dehiscence that facilitated wind dispersal by ground tumbling and seed scattering in laboratory experiments. Rain simulation experiments showed that even small precipitation events returned wetted pods to their cylindrical shape and opened the dorsal suture, exposing the seeds. In the field experiments, dry pods were moved locally by wind, whereas rain caused pod opening and washing out of seeds in place. Seed predators had minimal effect on pod movement. Astragalus holmgreniorum exhibits pod structural remodeling in response to environmental change in a striking and novel demonstration of informed dispersal. Wind-driven movement of dry pods facilitates local seed dispersal, but rain causes pods to open and release seeds, ensuring that they are not transported out of suitable habitats and into active washes where they would be lost from the seed bank.

Micromorphological alterations induced by simulated acid rain on the leaf surface of Joannesia princeps Vell. (Euphorbiaceae)

Acid rain has been detected in natural protected areas of the Atlantic Rainforest in Brazil. We evaluated the effects of simulated acid rain on the leaf blade surface of Joannesia princeps, aiming to assess the species potential as biosensor of acidic precipitation. Seedlings were subjected to simulated rain prepared with pH 4.5 H2SO4-acidulated water and, in the control treatment, pH 6.0 deionized water. Severe microstructural damage was detected in the youngest leaves, consisting in wilting of epidermal common cells, which resulted on alteration of the epidermal relief due to formation of grooves among these wilted cells. Stomatal guard cells were also structurally altered, no longer presenting the turgid aspect which was visible in the control treatment. Epidermal microrelief is characterized by the presence of cuticular striae, which might have been crucial to determine the species susceptibility due to increased roughness and decreased wettability. The implications of this hypothesis are further discussed in light of recent research addressing the responses of native tree species to acid rain. The micromorphological alterations found occurred prior to the onset of visible symptoms, and therefore suggest the use of J. princeps as a biosensor of the impact by acid precipitation.

Ecophysiology with barley eceriferum (cer) mutants: the effects of humidity and wax crystal structure on yield and vegetative parameters.

Background and AimsIn addition to preventing water loss, plant cuticles must also regulate nutrient loss via leaching. The eceriferum mutants in Hordeum vulgare (barley) potentially influence these functions by altering epicuticular wax structure and composition.MethodsCultivar ‘Bonus’ and five of its cer mutants were grown under optimal conditions for vegetative growth and maturation, and nine traits were measured. Nutrient and water amounts going through the soil and the amount of simulated rain as deionized water, affecting phyllosphere humidity, delivered during either the vegetative or maturation phase, were varied. Cer leaf genes and three wilty (wlt) mutations were characterized for reaction to toluidine blue and the rate of non-stomatal water loss.Key ResultsVegetative phase rain on ‘Bonus’ significantly decreased kernel weight and numbers by 15–30 %, while in cer.j59 and .c36 decreases of up to 42 % occurred. Maturation phase findings corroborated those from the vegetative phase. Significant pleiotropic effects were identified: cer.j59 decreased culm and spike length and 1000-kernel weight, .c36 decreased kernel number and weight, .i16 decreased spike length and .e8 increased culm height. Excepting Cer.zv and .ym mutations, none of the other 27 Cer leaf genes or wlt mutations played significant roles, if any, in preventing water loss. Cer.zv and .ym mutants lost non-stomatal water 13.5 times faster than those of Cer.j, .yi, .ys and .zp and 18.3 times faster than those of four cultivars and the mutants tested here.ConclusionsUsing yield to measure the net effect of phyllosphere humidity and wax crystal structure revealed that the former is far more important than the latter. The amenable experimental setup described here can be used to delve deeper. Significant pleiotropic effects were identified for mutations in four Cer genes, of which one is known to participate in wax biosynthesis. Twenty-seven Cer leaf genes and three wlt mutations have little if any effect on water loss.

Lane Departure Warning and Lane Keep Assist Assessment based on Southeast Asian Environmental Conditions: Preliminary Investigation


 
 
 Lane Departure Warning (LDW) and Lane Keep Assist (LKA) systems are part of the Advanced Driver-Assistance Systems (ADAS), which are equipped in the latest passenger vehicles sold in the Southeast Asia (SEA) countries. Both technologies are very beneficial to gain improved safety performance for vehicle occupants and benefiting other road users such as pedestrians and cyclists by alerting the driver and making automatic trajectory correction when the vehicle is deviating away from the correct path while in motion. Nevertheless, there is yet any test protocol established by the New Car Assessment Program for Southeast Asian Countries (ASEAN NCAP) to evaluate both technologies tailored to the SEA’s environmental conditions. Hence, this is a preliminary investigation of the new test protocol developed for LDW and LKA based on SEA’s environmental conditions. The proposed protocol incorporated the effect of both dry and wet conditions, which is unique to simulate the main weather elements in the region. On-road tests using actual passenger vehicles were conducted using a rain simulator to simulate the rainy weather. The preliminary tests were performed on straight road conditions. Results show that the proposed protocol was able to assess the effectiveness of LDW and LKA in both dry and wet conditions. Further actions shall be carried out in the later stage of this project to validate the proposed protocol using other vehicle models sold in SEA that equipped with similar technologies.
 
 

Urban induced land-use change impact during pre-monsoon thunderstorms over Bhubaneswar-Cuttack urban complex

The effect of urbanization over the Bhubaneswar-Cuttack urban complex, a twin city of eastern India, is investigated in this study. For this purpose, the realistic representation of urban land use (LU) from the ‘Indian Space Research Organization (ISRO)’ and the older ‘United States Geological Survey’ is considered. The sensitivity experiment was performed to choose microphysics that was suitable for the study location. The recent LU simulations improved the amount and spatio-temporal distribution of rainfall over the city. Results suggested that the underlying impervious layer has a remarkable impact on the precipitation, temperature, and other meteorological variables during thunderstorms. Most of the simulated rain is found in the downwind direction of the city core and over the suburban periphery. The variation of the rainfall, showing dual peak characteristics during late evening hour, has excellent correspondence with the associated atmospheric moisture transport and dynamics and thermodynamics. The near-surface temperature and urban heat island found to be well simulated, covering the entire urban core from 12 UTC onward.

Are there environmental or agricultural benefits in using forest residue biochar in boreal agricultural clay soil?

Short-term agronomic and environmental benefits are fundamental factors in encouraging farmers to use biochar on a broad scale. The short-term impacts of forest residue biochar (BC) on the productivity and carbon (C) storage of arable boreal clay soil were studied in a field experiment. In addition, rain simulations and aggregate stability tests were carried out to investigate the potential of BC to reduce nutrient export to surface waters. A BC addition of 30 t ha−1 increased soil test phosphorus and decreased bulk density in the surface soil but did not significantly change pH or water retention properties, and most importantly, did not increase the yield. There were no changes in the bacterial or fungal communities, or biomasses. Soil basal respiration was higher in BC-amended plots in the spring, but no differences in respiration rates were detected in the fall two years after the application. Rain simulation experiments did not support the use of BC in reducing erosion or the export of nutrients from the field. Of the C added, on average 80% was discovered in the 0–45 cm soil layer one year after the application. Amendment of boreal clay soil with a high rate of BC characterized by a moderately alkaline pH, low surface functionalities, and a recalcitrant nature, did not induce such positive impacts that would unambiguously motivate farmers to invest in BC. BC use seems unviable from the farmer's perspective but could play a role in climate change mitigation, as it will likely serve as long-term C storage.

Rain cracking in sweet cherries is caused by surface wetness, not by water uptake

Rain cracking limits sweet cherry production worldwide. Cracking is often assessed in laboratory assays, where detached fruit is submerged in water. The objective of this study was to compare cracking of detached fruit that were submerged in water, with fruit that remained attached to the tree, but were exposed to simulated rain or fruit that were detached, placed in a wire cage and positioned in the canopy and were exposed to simulated rain.Water uptake and cracking were determined. For attached fruit, water uptake was calculated from diameter changes measured using linear variable displacement transducers. For detached fruit, uptake was quantified gravimetrically. Cracking was determined by inspecting fruit (detached and attached) at regular intervals.Water uptake into attached and detached fruit increased linearly indicating approximately constant rates of water uptake. Rates of water uptake were highest in detached, submerged fruit, were intermediate in attached fruit exposed to simulated rain and least in detached fruit in a wire cage exposed to simulated rain. The percentage of cracked fruit increased sigmoidally with time. Cracking was markedly faster in detached, submerged fruit, than in still attached fruit, than in detached fruit in a cage. Expressing the percentage of cracked fruit as a function of the amount of water taken up, again revealed a sigmoidal relationship. Cracking of detached, submerged fruit generally required less water uptake than attached fruit or detached fruit in a wire cage. Attached fruit cracked mostly in the pedicel cavity region whereas detached submerged fruit cracked mostly in the stylar scar region.Our study demonstrates that cracking is primarily a function of wetness duration and area wetted. Wetness duration was longest and area wetted largest in detached, submerged fruit, followed by attached or detached fruit exposed to simulated rain.

Surface modification of PLA nets intended for agricultural applications

Exclusion nets create a physical barrier between pests and crops, serving as a practical tool to reduce pesticide use in a wide variety of crops, and their negative impacts on the environment. While the efficiency of this method has been recently assessed, protection from pests is incomplete, as microorganisms such as fungi are not hindered by netting. In order to avoid favorable conditions for microbial development (e.g. wet leaf surfaces), the present study discusses two hydrophobic surface treatment approaches, each applied to two PLA substrates that can be used as exclusion nets to reduce water ingress on protected fruit trees. Both a commercial exclusion net and a fused deposition modelled (or 3D printed) mesh were treated via solvent-free and solvent-induced modifications. Photo-initiated chemical vapor deposition (PICVD) allowed organic thin film growth on the substrate at near-ambient conditions. Dip-dip-dry (DDD) exploited solvent-induced topology modification to yield hydrophobic PLA samples, showing various microstructures (crazes or hierarchical topology) depending on the substrate properties. Both substrates were efficiently rendered hydrophobic after surface treatments, with water contact angles climbing from 73° to 101° (PICVD) or 143° (DDD) for printed PLA samples, and to 131° (PICVD) or 135° (DDD) for commercial exclusion nets. The hierarchical features present on DDD-treated printed PLA substrates showed potential for molecular adsorption, paving the way for a method to increase the phytosanitary effect of agricultural textiles by active ingredient incorporation (limonene is used here as a test case). Surface properties were characterized with SEM imaging, contact angle measurements, tensile tests and drop penetration assessments (rain simulation).

Integrated Flow-based System Displaying an In-line Mini Soil Column to Monitor Iron Species in Soils Leachates

ABSTRACT Contamination of ground water as a consequence of soil leaching processes is an issue of major concern. In this context, a simulation of the soil leaching process was designed. A sequential injection (SI) method to monitor the soil leaching of iron complexes with in-line rain simulation for leachate production is described. The developed methodology comprises the SI determination of both iron(III) and 3-hydroxy-4-pyridinones iron(III) complexes, coupled to a mini soil column (mSC) for displaying in-line rain simulations. The described SI method enabled iron(III) determination within the range 2.0–35 µmol L−1, with a detection limit of 0.42 µmol L−1, and determination of iron(III) complexes in the range 1.0–45 µmol L−1. It was successfully applied to leachates from laboratory scale soil columns (LSSC), with good precision for both iron(III) and iron complexes determinations: calculated relative standard deviation (RSD) of 5% and 6%, respectively. A step further in automation and miniaturization was attained with the incorporation of a mini soil column for the in-line leachate production. The system enabled the soil leachate production and assessment in less than 5 min, including determinations in triplicate.

Litter decay in rangeland sites with varying history of human disturbance: a study with Hazargangi Chiltan mountain

Hazarganji Chiltan National Park in Balochistan, Pakistan was established in 1980 and the protected area was further extended in 1998. Large area of this mountain is still open for unmanaged human disturbances such as collection of wood for fuel purpose and livestock grazing. Removal of vegetation of rangelands has a significant negative impact on soil organic matter (SOM). This research evaluates litter decomposition in three sites of Hazarganji Chiltan mountain with varying history of human disturbances (unprotected site, young protected site and old protected site). Twigs of Pistacia khinjuk with approximately equal weight and length were placed in litter bags of mesh size 2 mm and were buried in 0-5 cm depth in three sites in January. Half of the twigs of each site received rain simulation in April, August, October, November and January while the other half of the twigs were subjected under natural conditions for 15 months. Twigs from each plot of each treatment of each site were collected from soil after every rain simulation in the previous month of experiment and were processed for weight loss assessment. Results showed that weight loss of twigs by decomposition was significantly higher in the soil of unprotected site as compared to other two sites and there was no difference between rain simulation and control treatments except that loss of weight of twigs of unprotected site was higher under control than rain simulation condition. To confirm that SOM was the major controlling factor for the decomposition of litter decay, soils of each site were collected and burned to remove SOM; thereafter, burned soil samples were mixed with homogenous powder of oven-dried native plants, incubated for 6 months and were provided with dissolved organic matter of the soils of each site. Results showed that there was no difference in the decomposition of litter between soils under controlled laboratory condition, which confirmed that SOM was a major controlling factor for the litter decay in soil under field conditions. The pyrosequencing analysis of the DNA of soils collected from three sites revealed the presence of bacterial species Thermovum composti.

Spondias mombin, a potential bioindicator of potassium fluoride pollution

Ecological contamination by air pollutants is a worldwide problem. Fluoride-based compounds are released in large proportions into the atmosphere, soil and water from various industrial sources. These compounds are more phytotoxic to various plants than are other pollutants. The objective of this work was to determine the effects of fluoride in the form of potassium fluoride (KF)-simulated rain, on morphological and physiological responses, macronutrient content and fluoride accumulation in Spondias mombin leaves. S. mombin seedlings were transplanted to 5-liter pots containing Bioplant® substrate in a greenhouse. After acclimatization, the plants were subjected to KF, through simulated rain, at concentrations of 0, 10, 20 and 30 mg L−1, for a period of 9 days. Subsequently, visual and anatomical evaluations, chlorophyll a fluorescence variables, gas exchange, fluoride accumulation and macronutrient content were performed in all plants. KF-treated S. mombin developed necrosis on leaf surfaces with damage of up to 70%, followed by parenchymal tissue alterations characterized by cellular collapse and accumulation of phenolic compounds. We observed photochemical and macronutrient content changes that may compromise development of these plants. The correlation between the analyses suggested that noninvasive characteristics are important tools for detecting environmental pollution, and that S. mombin is an important bioindicator of KF-contaminated environments.

Do rainfall and tick burden affect the efficacy of pour-on formulations against Rhipicephalus (Boophilus) microplus?

Rhipicephalus (Boophilus) microplus is the most important livestock tick, causing economical losses especially in tropical and subtropical regions. Pour-on formulations using synthetic chemicals, remain the most farmer friendly conventional form of tick control method. Misuse of acaricides can lead to the emergence of resistance, residual chemicals in animal products, the poisoning of vertebrates and environment contamination. Despite the increase in the use of pour-on formulations, little is known regarding the therapeutic and residual efficacy of these products after the treated animals are exposed to rainfall. Moreover, information is scanty on whether efficacy is modulated by different levels of tick burden. Three studies were conducted. In the two first experiments, we evaluated the therapeutic and residual efficacies of commercial pour-on products (fluazuron 2.5 mg/kg and fipronil 1.0 mg/kg, respectively) on cattle naturally infested with R. (B.) microplus under the condition of simulated rainfall. In the third study, we investigated whether tick burden affects the efficacy of the drugs used a chemical control method involving three different formulations (Day 0: cypermethrin 5.0 mg/kg + chlorpyrifos 7.0 mg/kg + citronellal 0.5 mg/kg; Day 7: fluazuron 3.0 mg/kg + abamectin 0.5 mg/kg and Day 56: fipronil 1.0 mg/kg + fluazuron 3.0 mg/kg). Tick counts were performed on different days to assess efficacy. It was observed that the residual efficacy of the commercial formulations was lower on animals that received simulated rain. In addition, therapeutic and residual efficacies of the products were reduced in the group of animals with a high tick burden of R. (B.) microplus. In conclusion, rainfall decreases the efficacy of acaricides. Also, the tick burden must be considered when selecting a pour-on formulation.

Estimation of Water Balance Components of Watersheds in the Manjira River Basin using SWAT Model and GIS

This study mainly focus on hydrological behavior of watersheds in The Manjira River basin using soil and water assessment tool (SWAT) and Geographical information system (GIS). The water balance components for watersheds in the Manjira River were determined by using SWAT model and GIS. Determination of these water balance components helps to study direct and indirect factors affecting characteristics of selected watersheds. Manjira River contains total 28 watersheds among them 2 were selected having watershed code as MNJR008 and MNJR011 specified by the Central Ground Water Board. The SWAT input data such as Digital elevation model (DEM), land use and land cover (LU/LC), Soil classification, slope and weather data was collected. Using these inputs in SWAT the different water balancing components such as rainfall, baseflow, surface runoff, evapotranspiration (ET), potential evapotranspiration (PET) and water yield for each watershed were determined. The evaluated data is then validated by Regression analysis, in which two datasets were compared. Simulated rain data from SWAT simulation and observed rain data from Global Weather Data for SWAT was selected for comparison for each watershed.

Evaluation of a Bacillus thuringiensis isolate-based formulation against the pod borer, Helicoverpa armigera H\xfcbner (Lepidoptera: Noctuidae)

The present study focuses on the evaluation of the potential of a Tunisian Bacillus thuringiensis (Bt) isolate named Hr1, isolated from dead and diseased pod borer, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) larvae under laboratory and field semi-controlled conditions. The bacterial strain Hr1 showed an insecticidal activity against the pest’s neonates in comparison to the spinosad-based insecticide (Tracer 240 SC®) during bioassays under laboratory conditions. A carboxymethyl cellulose-talc (CMC-talc)-based formulation of the Bt isolate was prepared to evaluate the potential of the bacterium on tomato plants infested with H. armigera under semi-controlled field conditions with and without rain simulation. The results showed the efficacy of the formulation than the spinosad-based insecticide and the treatment with unformulated bacterium. The results also showed the persistence of Bt isolate activity even after rain-wash than the treatment with unformulated bacterium.