Sprinkler Flow Rate Research Articles

Effects of Summer Cooling Strategies on Post-Summer Cow Welfare: Evaluating Lameness and Behavior

The study aimed to compare the effect of different summer cooling strategies on post-summer lameness prevalence and behavior in Holstein Friesian cows. Twenty-one milking cows were randomly subjected to three different cooling strategies including: 1) a traditional approach (TRD), where cows were continuously cooled using a sprinkler during the daytime; 2) a reduced cooling strategy (2CS), which involved two cooling sessions of one hour each; and 3) increased cooling sessions strategy (4CS), with four cooling sessions daily. Each cooling session lasted for 1 h with a 12 min cycle (3 min water on and 9 min off) with a sprinkler flow rate of 1.25 L/min. The cows' lameness scores, lying behavior, standing behavior, and step counts were assessed during the post-summer period. The results revealed that the 4CS group had lower lameness prevalence compared to the TRD and 2CS groups (p = 0.015). Furthermore, the TRD and 2CS groups exhibited higher lying times and lower standing times during post-summer (p < 0.05), potentially indicating lameness pain and discomfort. Additionally, the step counts were lowest in the TRD group, fol-lowed by the 2CS and 4CS groups (p < 0.001). In conclusion, the continuous sprinkling (TRD) as a cooling strategy during summer showed potential negative consequences on post-summer cow welfare. The study highlights the significant influence of cooling strategies on post-summer cow welfare, emphasizing the need for considering long-term effects beyond the summer season.

Evaluating the impact of sprinkler cycle and flow rate on dairy buffalo performance during heat stress.

The aim of this study was to evaluate the effect of the sprinkler cycle and flow rate on physiological, behavioural, and productive responses in dairy buffaloes. Nine Nili Ravi lactating buffaloes were subjected to three sprinkler cycles and two flow rates using a double replicated 3 × 3 Latin square design. The flow rates were 1.25 and 2 l/min, and the sprinkler cycles (minutes water on/off, number of cycles/h) were: 3/3, 10 cycles; 3/6, 7 cycles and 3/9, 5 cycles. The showering was applied from 0800 till 1630 h daily. In the first square of 21 d, each of the three sprinkler cycles was applied using a 1.25 l/min flow rate for 7 d per cycle. In the later square, the same treatments (sprinkler cycles) were applied using the 2 l/min flow rate. The average temperature humidity index during the study period was 85.7 ± 3.8 (Mean ± sd). The result showed that the 3/3 treatment group had lower body temperature and respiration rate than the other groups. The buffaloes in the 3/3 group produced 0.5 and 0.7 kg more milk with 1.4 and 2.4% more fat than the 3/6 and the 3/9 treatment groups, respectively. Similarly, the 2 l/min flow rate had a lower core body temperate and respiration rate and higher milk yield than the 1.25 l/min group. The 3/3 showering cycle with a 2 l/min flow rate appeared effective in improving physiological responses and milk yield in dairy buffaloes.

On-Farm Water Use Efficiency: Impact of Sprinkler Cycle and Flow Rate to Cool Holstein Cows during Semi-Arid Summer

Sprinkler cooling is a common heat abatement method in dairy cows and uses huge quantities of groundwater. Sprinkler flow rate and timing affect cow cooling and water use efficiency, but little is known about how these strategies may influence dairy cow performance under heat stress conditions in Pakistan. The objective of this study was to evaluate the cooling efficiency of different sprinkler cycles and flow rates in Holstein Friesian cows under semi-arid summer conditions in Pakistan. Thirty (30) lactating cows were subjected to 2 sprinkler flow rates and 3 sprinkler cycle strategies in a crossover design. Flow rates were 1.25 and 2 L/min, and the sprinkler cycles (water on|off) were: 3 min on|3 min off, 3 on|6 off, and 3 on|9 off. Results showed that the 1.25 L/min flow rate had a similar performance to the 2.0 L/min group in terms of milk yield and behavior, despite using 37.2% less water. The respiration rate was lowest in the 3|3 sprinkler cycle (SC) group, followed by the 3|6 and the 3|9 SC groups, respectively. Milk yield in the 3|3 group was 2 kg/d higher than the 3|9 group. In conclusion, these findings suggest that the 3|3 sprinkler cycle and 1.25 L/min flow rate may be a more efficient option in terms of water use while maintaining cow performance in semi-arid heat stress conditions.

Dual-Diameter Laterals in Center-Pivot Irrigation System

Design strategies to enhance modern irrigation practices, reduce energy consumption, and improve water use efficiency and crop yields are fundamental for sustainability. Concerning Center-Pivot Irrigation Systems, different design procedures aimed at optimizing water use efficiency have been proposed. Recently, following a gradually decreasing sprinkler spacing along the pivot lateral with constant diameter and sprinkler flow rate, a new design method providing a uniform water application rate has been introduced. However, no suggestions were given to design multiple-diameter laterals characterized by different values of the inside pipe diameter. In this paper, first the previous design procedure is briefly summarized. Then, for the dual-diameter center pivot laterals a design procedure is presented, which makes it possible to determine pipe diameters that always provide sprinkler pressure heads within an admitted range. The results showed that for the assigned input parameters, many suitable solutions can be selected. The lateral pressure head distributions were compared to those derived by the common numerical step by step solutions, validating the suggested simplified procedure. An error analysis was performed, showing that the relative error, in pressure heads, RE, was less than 2.3%. If imposing the mean weight diameter, Dm, equal to its minimum value, the optimal pressure head tolerance of the outer lateral, δI, amounting to about 2%, with the RE in pressure heads being less than 0.4%, which makes the suggested procedure very accurate. Several applications were performed, compared, and discussed.

Sprinkler flow rate affects physiological, behavioural and production responses of Holstein cows during heat stress

Holstein Friesian cows are known for their high milk yield. They are popular in the commercial dairy sector of Pakistan. Heat stress is a major challenge for these animals owing to the longer summer season with high ambient temperatures (35 - 40 °C) and relative humidity (30 - 50%) in the area (Butt et al., 2020). Mitigating the effects of heat stress requires substantial investments in energy and water. Spraying dairy cows with water in the holding pen or at the feed bunk is common practice as it lowers body temperature and respiration rate (Kendall et al., 2007; Chen et al., 2013; 2016), and improves feed intake and milk yield (Keister et al., 2002). Owing to the recent decrease in global groundwater, studies have focused on strategies to reduce the use of water to cool dairy cows (Chen et al., 2016). Sprinkler flow rates of 1.3 and 4.9 L/min had similar effects on physiological responses of cows to heat load but produced a 73% difference in water use (Chen et al., 2016). Similarly, Tresoldi et al. (2019) concluded that a sprinkler flow rate of 4.9 L/min had poor efficiency compared with 3.3 L/min, as the additional water did not result in increased biologically relevant cooling. These studies were conducted in Mediterranean climates with an average temperature humidity index in the range of 76 to 78. A recent study with Nili Ravi buffaloes revealed a sprinkler flow rate 1.25 L/min was more efficient than one of 2.0 L/min during subtropical summers (Bah et al., 2021). Because water is projected to be scarce in Pakistan by 2030 (Mustafa et al., 2013), holistic strategies for water conservation in the dairy sector are important nationally. The objective of this study was to evaluate the effects of various sprinkler flow rates on the performance of lactating Holstein Friesian cows in a typical corporate dairy farm setting during the subtropical summer. Performance of these cows was assumed to be similar, irrespective of the sprinkler flow rates.

Исследование поведения стеновых сэндвич-панелей, орошаемых дренчерной завесой, при одностороннем тепловом воздействии

In the last ten years, drencher curtains are widely used at the large production facilities to increase fire resistance of the building structures. The length of the drencher curtains used as a compensating measure instead of fire walls can reaches 250 m. A three-dimensional modeling of the operation of a drencher curtain together with a type 1 fire barrier in the form of a sandwich panel was performed. FireCat software package was used for modeling. One of its components is the PyroSim software package designed for fire modeling. A field model was chosen as a mathematical model of fire development. A number of simulations was carried out at a given sprinkler flow rate of 1 l/s, but at different distances between the sprinklers (different number of sprinklers operating in one stream was used) — from 0.5 to 5 m. As a result, it is established that when sprinklers are placed at a distance of no more than 2.5 meters from each other, the model meets the fire resistance requirements for type 1 fire walls. The experiments were carried out in the irrigation intensity range of 0.1–0.5 l/s·m. It is established that in order to achieve fire resistance limit REI 150, the irrigation intensity must be at least 0.37 l/s·m. The studies carried out made it possible to obtain qualitative data on the efficiency of drencher curtains plaсed in one line as a measure to increase the time limits of fire resistance of fire barriers from 45 to 150 minutes.

Performance of Holstein cows subjected to different cooling sessions during subtropical summer.

This study aimed to determine the effect of different cooling sessions (CSs) as a water conservation strategy on physiological, and production responses and welfare in Holstein Friesian cows during subtropical summer in Pakistan. Twenty-one cows were subjected to three CS in a completely randomized design. The treatments were: i) eleven hours continuous cooling with sprinklers - control (CNT), ii) four CS, and iii) two CS. The CNT represented the practices of the commercial dairy farms in the area, while the other CSs were used as water reduction strategies. Each CS lasted for 1 h with a 12 min cycle (3 min water on and 9 min off) with a sprinkler flow rate of 1.25 L/min. The average temperature humidity index of the shed and the outside open area were 81.9 and 82.5, respectively. The results showed that both physiological responses were highest in the 2CS group followed by the CNT and the 4CS (p = 0.001). The CNT and 4CS groups had similar milk yield (p = 0.040). The 4CS group had more lying and eating times than the CNT and 2CS groups (p = 0.000). The cortisol level in the 2CS group was 2.0 and 2.2 μg/dL more than the CNT and the 4CS groups, respectively (p = 0.000). In conclusion, the 4CS was more efficient in cooling the cows and had better welfare, as it yielded similar milk yield, and better physiological responses than the CNT despite using 90% less water.

Hydraulic Design of the Center-Pivot Irrigation System for Gradually Decreasing Sprinkler Spacing

Design strategies that enhance modern irrigation practices, reduce energy consumption, and improve water use efficiency and crop yields are fundamental for sustainability. Although microirrigation is currently a widely applied method, center-pivot irrigation systems have become very popular on large farms, thanks to their automation, wide-coverage, and reliability. Different design procedures have been proposed, even though some aspects have not been solved yet. This paper presents a simple design procedure for center-pivot systems using a gradually decreasing sprinkler spacing along with a pivot lateral, which makes it possible to set favorable and uniformly distributed water application rates. The sprinkler spacing distribution along the radial direction is derived by considering just one dimensionless group accounting for the geometric and hydraulic input parameters. According to this outcome, the results showed that the suggested procedure made it possible to select the sprinkler characteristics and the pipe diameter based on the desired input parameters, i.e., the uniform water application rate and the lateral length. For assigned input parameters, the lateral length is delimited by a threshold value, indicating that lateral lengths longer than that threshold value require the modifications of a sprinkler flow rate or pipe diameter. Finally, applications based on the proposed hydraulic design procedure were performed and discussed for two different cases.

Effects of Sprinkler Flow Rate on Physiological, Behavioral and Production Responses of Nili Ravi Buffaloes during Subtropical Summer.

Simple SummaryWater buffaloes wallow in water to combat heat stress during summer. With the decreasing reservoirs for wallowing, the farmers use hosepipes and sprinklers to cool the buffaloes in Pakistan. The sprinklers use a large quantity of groundwater, which is becoming scarce. In the current study, different flow rates in sprinklers were evaluated as a strategy to optimally use groundwater to cool water buffaloes. The sprinkler flow rates 1.25 and 2.0 L/min both had better physiological response, more feed intake, and higher milk yield compared to the 0.8 L/min. However, the flow rate 1.25 L/min was more efficient in cooling the buffaloes because it yielded similar physiological, production, and the behavioral responses despite using 37.5% less groundwater compared to 2.0 L/min. The current findings will help farmers to reduce the amount of groundwater used in cooling dairy buffaloes.Water buffaloes wallow in water to combat heat stress during summer. With the decreasing reservoirs for wallowing, the farmers use sprinklers to cool the buffaloes in Pakistan. These sprinklers use a large quantity of groundwater, which is becoming scarce. The objective of the current study was to determine the effect of different sprinkler flow rates on the physiological, behavioral, and production responses of Nili Ravi buffaloes during summer. Eighteen buffaloes were randomly subjected to three sprinkler flow rate treatments in a double replicated 3 × 3 Latin square design. The flow rates were 0.8, 1.25, and 2.0 L/min. During the study, the average afternoon temperature humidity index was 84.6. The 1.25 and 2.0 L/min groups had significantly lower rectal temperature and respiratory rates than the 0.8 L/min group. Water intake was significantly higher in the 0.8 L/min group. Daily milk yield was higher in the 1.25 and 2.0 L/min groups than in the 0.8 L/min group. These results suggested that the sprinkler flow rates > 0.8 L/min effectively cooled the buffaloes. The sprinkler flow rate of 1.25 L/min appeared to be more efficient, as it used 37.5% less water compared to the 2.0 L/min.

A Simulation Model for Sprinklers Irrigation System

Center pivot irrigation (CPI) system is one of the most efficient methods of applying irrigation water. It is a form of overhead sprinklers irrigation supported by trusses. The sprinkler flow rate out of each sprinkler orifice is based on the water pressure supplied to the sprinkler inlet. The objective of this paper is to build a simulation model for CPI to optimize performance of system estimating the expected number of a sprinklers and diameter of nozzle according to the required water quantities.

Effects of Plate Structure and Nozzle Diameter on Hydraulic Performance of Fixed Spray Plate Sprinklers at Low Working Pressures

HighlightsThe hydraulic performance of fixed spray plate sprinklers (FSPS) was evaluated at low working pressures.The effects of geometric structure on the hydraulic performance of FSPS were studied.A model was developed for estimating the application depth and uniformity of FSPS under a linear-move system.The recommended values of the most effective sprinkler combination spacing for FSPS are given.Abstract. Reducing the working pressure of sprinklers can effectively reduce the energy consumption of sprinkler irrigation systems. Fixed spray plate sprinklers (FSPS) have a simple structure, and their working pressure has potential to be reduced to 40 kPa. To evaluate the hydraulic performance of FSPS at low pressure, an experiment was conducted to investigate the effects of working pressure, plate structure, and nozzle diameter on sprinkler flow rate, wetted radius, and water application distribution. Two plates (FSPSB and FSPSY) and five nozzles were used in the tests. The cumulative water application depth and irrigation uniformity coefficient were calculated under a linear-move system. The results show that sprinklers with larger nozzle diameters and higher working pressures produce greater coefficients of discharge. The wetted radius gradually increases with the increase in working pressure and nozzle diameter. Two empirical equations for estimating the wetted radius of the two plates are proposed. The FSPSB has a concave trajectory structure that produces a longer wetted radius than the FSPSY, which has a flat trajectory structure. Along the wetted radius, the water application rate increases and then decreases, with a peak value at a certain distance. For the FSPSB, the peak rate of water application decreases with increasing working pressure. However, the FSPSY shows the opposite trend, with the maximum peak value occurring at the highest working pressure of 250 kPa. The water distribution for a single FSPSB sprinkler is discrete due to the greater water dispersal caused by the deeper grooves in the plate. In contrast, a single FSPSY sprinkler provides a more uniform water distribution. The irrigation uniformity of the FSPSY is higher than that of the FSPSB. The recommended values for the most effective sprinkler combination spacings for FSPSB and FSPSY are given in this article. The results may be useful for selecting appropriate sprinklers in hydraulic design procedures. Keywords: Cumulative spray water depth, Irrigation uniformity, Sprinkler irrigation, Water distribution, Working condition.

Effect of Pulsating Pressure on Water Distribution and Application Uniformity for Sprinkler Irrigation on Sloping Land

Crops are highly susceptible to drought in sloping land. Due to its good adaptability to complex terrain, sprinkler irrigation is one of the commonly used methods for sloping land. To improve water application uniformity for sprinkler irrigation on sloping land, an experiment was conducted on an artificial slope to determine the effects of pulsating versus constant pressure on sprinkler flow rate, radius of throw, water distribution pattern, and water application uniformity. Compared with sprinkler flow rate and water distribution uniformity at constant pressure, sprinkler flow rate was not reduced, but water distribution uniformity for a single sprinkler was improved due to the decreased uphill throw, downhill throw and the ratio of downhill throw to uphill throw at pulsating pressure. The Christiansen Uniformity Coefficient (CU) value of water distribution for a single sprinkler at pulsating pressure was about 10% higher than that of constant pressure. When water distribution of single sprinkler overlapped with rectangular arrangement, CU values for pulsating pressure were on average 4.06% higher than those for constant pressure with different sprinkler spacings. Thus, pulsating pressure is recommended for use in sprinkler irrigation on sloping land to improve water application uniformity.

Sprinkler flow rate affects dairy cattle preferences, heat load, and insect deterrence behavior

Sprinklers provide benefits for cattle, such as reducing heat load and possibly deterring insects. However, the use of this resource by cows varies across studies. Some of this variation may, in part, be explained by sprinkler flow rate. Higher flow rates provide greater heat abatement (desirable in warmer conditions, but perhaps not in milder weather) and generate greater spray impact, which cattle may avoid. Our objective was to evaluate the effects of flow rate on dairy cows’ preferences for sprinklers and shade. We tested cows (n=18) in a shaded arena (air temperature=29±3.8°C, mean±SD). To ensure they made informed choices and to measure insect deterrence behavior, we exposed cows to each treatment (flow rate=0, 0.4, and 4.5L/min, spray impact=0, 1.1, and 8.9kPa, respectively) ≥10 times in 12-min sessions. We then offered pairwise choices between 12-min treatments once daily for 8 consecutive d/pair. Cows preferred 0.4L/min over shade alone [probability of choosing 0.4L/min=0.87; 95% confidence interval (CI)=0.53–0.98]. Although cows did not prefer 4.5L/min overall (probability of choosing 4.5 vs. 0L/min=0.62, CI=0.27–0.87; vs. 0.4L/min=0.37, CI=0.11–0.73), their likelihood of choosing it over shade alone tended to increase with respiration rate, body temperature, air temperature, and Temperature Humidity Index (odds ratios=1.04, 3.57, 1.13, and 1.16, respectively). Relative to shade alone, both 0.4 and 4.5L/min sprinklers provided the benefits of reducing insect deterrence behavior (tail flicks by 28 and 35%, respectively, and skin twitches by 32 and 48%), localized air temperature (by 0.6 and 1.1°C, respectively, SE=0.2°C), and respiration rate (by 11 and 14 breaths/min, respectively, SE=1.6 and 1.5 breaths/min). In addition, when cows chose 4.5 over 0.4 or 0L/min, body temperature decreased by an additional 0.14°C during treatment and stayed below starting values for 34 and 47min longer afterward. Cows did not prefer 0.4L/min over 4.5L/min sprinklers, suggesting they do not avoid higher impact spray. Nonetheless, greater spray impact and heat loss may outweigh the benefits of 4.5L/min in mild conditions, perhaps explaining why preference for this sprinkler flow rate over shade alone increased with heat load. As 0.4L/min did not have these potential costs, this may explain why cows preferred the lower flow rate sprinkler to shade alone across all conditions tested.

Cooling cows efficiently with water spray: Behavioral, physiological, and production responses to sprinklers at the feed bunk

Dairies commonly mount nozzles above the feed bunk that intermittently spray cows to dissipate heat. These sprinklers use potable water—an increasingly scarce resource—but there is little experimental evidence for how much is needed to cool cows in loose housing. Sprinkler flow rate may affect the efficacy of heat abatement, cattle avoidance of spray (particularly on the head), and water waste. Our objectives were to determine how sprinkler flow rate affects cattle behavioral, physiological, and production responses when cows are given 24-h access to spray in freestall housing, and to evaluate heat abatement in relation to water use. We compared 3 treatments: sprinklers that delivered 1.3 or 4.9L/min (both 3min on and 9min off, 24h/d) and an unsprayed control. Nine pairs of high-producing lactating Holstein cows received each treatment at a shaded feed bunk for 2d in a replicated 3×3 Latin square design [air temperature (T): 24-h maximum=33±3°C, mean ± SD]. Cows spent 5.8±0.9h/24h (mean ± SD) at the feed bunk overall, regardless of treatment. With few exceptions, cows responded similarly to the 1.3 and 4.9L/min flow rates. Sprinklers resulted in visits to the feed bunk that were on average 23 to 27% longer and 13 to 16% less frequent compared with the control, perhaps because cows avoided walking through spray. Indeed, when the sprinklers were on, cows left the feed bunk half as often as expected by chance, and when cows chose to walk through spray, they lowered their heads on average 1.7- to 3-fold more often than in the control. Despite possible reluctance to expose their heads to spray, cows did not avoid sprinklers overall. In warmer weather, cows spent more time at the feed bunk when it had sprinklers (on average 19 to 21min/24h for each 1°C increase in T), likely for heat abatement benefits. Compared with the control, sprinklers resulted in 0.3 to 0.7°C lower body temperature from 1300 to 1500h and 1700 to 2000h overall and attenuated the rise in this measure on warmer days (for each 10°C increase in T, body temperature increased by on average 0.5 to 0.7°C with sprinklers vs. 1.6°C without). Sprinkler access also resulted in milk yield that was, on average, 3.3 to 3.7kg/24h higher than in the control treatment. In this hot and dry climate, 1.3L/min cooled cows more efficiently than 4.9L/min, as the lower flow rate achieved equivalent reduction in body temperature and increase in milk yield relative to no spray, despite using 73% less water.

Sprinkler flow rate affects dairy cattle avoidance of spray to the head, but not overall, in an aversion race

Spraying cattle with water elicits behavioral responses ranging from willing use to avoidance of wetting the head or entire body. This variation may be partly explained by sprinkler flow rate, as higher flow rates result in greater heat abatement and spray impact. An aversion race can be used to evaluate the emotional valence cows associate with treatments, based on the prediction that they will approach negative (vs. positive) stimuli more slowly and require greater pressure from a handler. Our objective was to evaluate how heat load affects the degree to which dairy cattle show reluctance to approach sprinklers with different flow rates in an aversion race. We compared unsprayed treatments (n=8 with feed, n=16 without) to 0.4L/min (n=14) and 4.5L/min (n=17) sprinklers, which differed eight-fold in spray impact (1.1 vs. 8.9kPa, respectively). Over 10 trials, cows were required to approach treatments in a covered, narrow raceway (average outdoor air temperature, mean±SD, 31±3.8°C). We compared time to complete the race (transit time), the pressure handlers applied, and head posture. Overall, handlers applied pressure half as often when feed was offered but there were no other treatment differences in handling pressure or transit time. Thus, we excluded the feed treatment when examining interactions with heat load and sprinkler flow rate. In warmer weather, transit time increased (by 13s per 10°C increase). As their respiration rate increased, unsprayed cows moved more slowly (by 7s per 10 breaths/min increase), whereas sprayed cows did not. Handling pressure was not affected by heat load or spray application, but head posture depended on sprinkler flow rate. When cows approached 4.5L/min, they lowered their heads nearly five times as often compared to 0.4L/min or no spray (proportion of trials±SE, 0.81±0.05, 0.17±0.06, and 0.15±0.05, respectively). This may have been an attempt to reduce exposure of sensitive body parts to higher-impact spray. Indeed, when we applied von Frey monofilaments to the ear and shoulder (n=56), the ear had a lower response threshold (greater sensitivity) than the shoulder [mean (95% confidence interval), 0.2 (0.1 to 0.4) vs. 1.2 (0.5 to 2.5) g of force, respectively, back transformed from natural log values]. In conclusion, each measure provided different insights about reluctance to approach treatments. Transit time increased in response to heat load rather than aversion. Handling pressure reflected willingness, as it was needed less often when cows were offered a feed reward, but this measure did not differ among sprinkler treatments. Therefore, although cows lowered their heads to avoid exposing sensitive areas to 4.5L/min spray, they did not show overall aversion to higher-impact spray.

Cooling cows efficiently with sprinklers: Physiological responses to water spray

Dairies in the United States commonly cool cattle with sprinklers mounted over the feed bunk that intermittently spray the cows’ backs. These systems use potable water—an increasingly scarce resource—but there is little experimental evidence about how much is needed to cool cows or about droplet size, which is thought to affect hair coat penetration. Our objectives were to determine how sprinkler flow rate and droplet size affect physiological measures of heat load in a hot, dry climate, and to evaluate cooling effectiveness against water use. The treatments were an unsprayed control and 6 soaker nozzles that delivered four 3-min spray applications of 0.4, 1.3, or ≥4.5 L/min (with 2 droplet sizes within each flow rate) and resulting in 30 to 47% of spray directly wetting each cow. Data were collected from high-producing lactating Holsteins (n=19) tested individually in ambient conditions (air temperature=31.2±3.8°C, mean ± standard deviation). Cows were restrained in headlocks for 1h and received 1 treatment/d for 3d each, with order of exposure balanced in a crossover design. When cows were not sprayed, physiological measures of heat load increased during the 1-h treatment. All measures responded rapidly to spray: skin temperature decreased during the first water application, and respiration rate and body temperature did so before the second. Droplet size had no effect on cooling, but flow rate affected several measures. At the end of 1h, 0.4 L/min resulted in lower respiration rate and skin temperature on directly sprayed body parts relative to the control but not baseline values, and body temperature increased to 0.2°C above baseline. When 1.3 or ≥4.5 L/min was applied, respiration rate was lower than the control and decreased relative to baseline, and body temperature stayed below baseline for at least 30min after treatment ended. The treatment that best balanced cooling effectiveness against water usage was 1.3 L/min: although ≥4.5 L/min reduced respiration rate relative to baseline by 4 more breaths/min than 1.3L/min did (−13 vs. −9 breaths/min, respectively), each additional liter of water decreased this measure by only ≤0.1 breaths/min (≤1% of the total reduction achieved using 1.3 L/min). We found similar water efficiency patterns for skin temperature and the amount of time that body temperature remained below baseline after treatment ended. Thus, when using this intermittent spray schedule in a hot, dry climate, applying at least 1.3 L/min improved cooling, but above this, additional physiological benefits were relatively minor.

Effect of water drop energy of sprinkler irrigation on clay and silt particles transporation in different gypsifereous soils

A laboratory study have been conducted to investigate the influence of sprinkler water droplets energy generated from nozzles with two flow rates (9 and 15 mm.hr-1) on soil aggregates and the displacement of soil particles in some gypsifereous soil samples. Five soil samples with different gypsum contents were prepared by mixing between low and high gypsum content soil samples. These soils were sampled from AP and C of profile horizons. The prepared soil samples of different gypsum contents were G0 (83), G1 (133), G2 (211), G3 (472) and G4 (592) gm.kg-1. After the incubation of the prepared for two months, the soil samples were passed through sieves of 2 and 4 mm openings to obtain soil aggregates ranged between 2- 4mm diameters. The soil aggregates were packed with a 6 mm thickness (13 gm) in a plastic tube underlined by pure sand with 26 cm length and an inner diameter of 5 cm. The tubes were placed in a moveable circular base with a 60 cm diameter and a circumference of 188.4 cm. The soil sample tubes were distributed randomly with a 37.6 cm separating distance separating. Each tube sets were subjected to 9 and 15 mm.h-1 sprinkler flow rates. The droplets size distribution for each sprinkler flow rate was studied as well as the droplets energy.The results showed that the droplets energy were increased with increasing droplets size and sprinkler flow rate. Maximum droplet energy was obtained with 1.5 mm droplet diameter, while the minimum droplet energy was obtained with 0.18 mm. Silt and clay transportation were decreased with increasing soil gypsum content under the two sprinkler flow rates. The high flow rate sprinkler was more effective on silt and clay transporting.

Transient Soil Surface Sealing and Infiltration Model for Bare Soil under Droplet Impact

The marked reduction in infiltration rate caused by formation of a soil surface seal due to water droplet impact on bare soil is a well known phenomenon but is rarely considered in infiltration models, especially under center-pivot irrigation. Water application rates under center-pivot irrigation commonly exceed the infiltration rate, especially near the end of the system lateral. This can lead to off-site runoff and erosion, but more importantly results in field-scale non-uniform water infiltration that can substantially reduce water use efficiency of these irrigation systems. The objective of this study was to develop a sealing soil infiltration model that considers transient soil seal formation on a 30 min or less time scale and can potentially be applied to center-pivot sprinkler irrigation systems. A sealing soil infiltration model was developed using an explicit finite difference solution scheme with a transient soil seal formation model, which is unique from other studies in that it explicitly uses droplet specific power as the driving factor for formation of a soil surface seal. The form of the transient seal formation model is also unique in that it is expressed as a rational function of specific power rather than an exponential decay function of droplet kinetic energy. The model was applied to published runoff data from two rainfall simulation studies with varying droplet kinetic energies and application rates on three soils. The sealing soil infiltration model represented the measured infiltration rates very well for all rainfall simulator tests. The transient soil seal formation model uses three parameters, one of which is an empirical parameter representing the susceptibility of the soil to aggregate breakdown that was constant for a given soil. A second model parameter, final saturated hydraulic conductivity of the surface seal, was well correlated to droplet specific power for a given soil. Application of the model to center-pivot irrigation will require the development of a model for estimating droplet specific power and application rate profiles from center-pivot sprinklers for a range of sprinkler designs, flow rates, operating pressures, spacings, and heights.

Evaluation of Potential Runoff and Erosion of Four Center Pivot Irrigation Sprinklers

The operational characteristics of center pivot sprinklers are well documented but few studies have been conducted to evaluate the effects that operating characteristics of a particular sprinkler have on infiltration, runoff, and erosion for specific soil types. The objective of this study was to evaluate potential runoff and erosion from four commercial center pivot sprinklers on four widely distributed, south central Idaho soils. A modified commercial irrigation boom system was used to simulate center pivot irrigation on experimental runoff plots. Sprinklers used in the study were: 1) Nelson R3000 with brown plate, 2) Nelson R3000 with red plate, 3) Nelson S3000 with purple plate, and 4) Senninger I-Wob with standard 9-groove black plate. Significant differences in runoff and erosion between sprinkler types were observed but were not consistent across all runoff tests or soil types. However, on occasions sprinkler types that visually appear to more evenly distribute sprinkler droplets over the wetted area with respect to time produced the greatest soil erosion for bare soil conditions. This functional difference in spatial distribution of water application with respect to time may have caused sediment to remain in suspension in overland flow for a longer duration allowing sediment to be more readily transported down slope and removed from runoff plots. A 50% reduction in sprinkler flow rate reduced runoff and soil erosion 60% to 80% for the same volume of water applied in six irrigations. The practice of reducing sprinkler flow rate early in the growing season prior to crop canopy development could be an effective management tool for reducing center pivot sprinkler irrigation runoff and erosion.

Actual Delivered Density Fire Test Apparatus For Sprinklers Protecting High Commodity Storage

Due to increasing challenges in protecting high commodity storage, sprinkler designers need improved predictive tools. Actual Delivered Density (ADD) fire test data can be used to screen automatic sprinkler designs. An improved ADD fire test apparatus was developed at Underwriters Laboratories for use in developing new sprinklers for protecting high storage facilities. This paper presents the development of the apparatus and initial measurements. Calibration of the fire plume of the ADD apparatus to measurements in four tier rack storage fires indicate that fire plume temperatures and velocities are generally within 10% of those measured in specific rack storage fires. Measured ADD values typically increase with higher sprinkler flow rates, although some sprinkler designs and ignition locations show diminishing returns.