Pulsed Irrigation Research Articles

Variable Pulsed Irrigation Algorithm (VPIA) to Reduce Runoff Losses under a Low-Pressure Lateral Move Irrigation Machine

Due to restrictions and limitations on agricultural water worldwide, one of the most effective ways to conserve water in this sector is to reduce the water losses and improve irrigation uniformity. Nowadays, the low-pressure sprinkler has been widely used to replace the high-pressure impact sprinklers in lateral move sprinkler irrigation systems due to its low operating cost and high efficiency. However, the hazard of surface runoff represents the biggest obstacle for low-pressure sprinkler systems. Most researchers have used the pulsing technique to apply variable-rate irrigation to match the crop water needs within a normal application rate that does not produce runoff. This research introduces a variable pulsed irrigation algorithm (VPIA) based on an ON–OFF pulsing technique to conserve irrigation water through (1) decreasing the runoff losses by considering the soil infiltration rate, surface storage capacity, and sprinkler wetting diameter; and (2) ensuring a high level of water distribution uniformity in the direction of machine movement. From a wide range of pulse numbers and widths tested applying a certain water depth to a sandy loam soil, the best solution that gives the lowest runoff and highest uniformity while delivering an acceptable water depth was selected. A MATLAB code was written to simulate the soil infiltration rate, the sprinkler application rate, and to apply the proposed algorithm. The simulation results showed a runoff reduction of at least 90.7% with a high level of distribution uniformity in the direction of movement while delivering the highest possible irrigation depth using the lowest number of pulses.

Moisture in the soil profile with water applications using pulse drip irrigation

The wet bulb, as a result of local application of irrigation water, is the soil volume that presents higher water content in relation to the surrounding soil. Due to increased moisture in the soil, successive irrigation events tend to form bigger wet bulbs and superficial water accumulation area (AWSS). The objective was to verify the distribution of water in the soil profile, with intermittent application of water, considering the hypothesis that antecedent soil water content modifies the wet bulb characteristics after water pulse application, and to evaluate the effect of increasing AWSS on the lateral dimensions of the bulb. The water applications were performed using 1, 2 and 4 pulses in the flows of 4 and 8 L h-1, totalizing six treatments, which were carried out in four replications for each treatment. The evaluations of AWSS were performed with the continuous application of water at the mentioned flow rates. The results indicate increasing AWSS does not affect the wet bulb, differences in the distribution of soil water are visible only in the first moments after last pulse application. It was concluded water tends to distribute in the soil regardless of the amount of irrigation pulses and pulse irrigation tends to result in similar distribution of moisture inside the wet bulb in relation to continuous irrigation.

Using Pulsed Water Applications and Automation Technology to Improve Irrigation Practices in Strawberry Production

Quebec, Canada, is the third largest strawberry (Fragaria ×ananassa) producer in North America, behind Florida and California. In view of increasing global water scarcity and the high water requirements of strawberry production, there is a critical need for growers to optimize irrigation practices to improve crop water productivity (CWP). In Quebec, pulsed irrigation has been shown to increase yields in strawberry crops while using the same volume of water as standard (nonpulsed) irrigation, thus improving CWP. However, more frequent and shorter-duration water applications (pulsed irrigation) might be more complex to manage manually; therefore, it could be of interest to automate the irrigation process at the farm scale. The first objective of our study was to assess the economic impact of pulsed irrigation compared with the standard irrigation procedure (nonpulsed irrigation) in a strawberry crop grown in a highly permeable clay loam soil in Quebec. The second aim was to determine whether pulsed irrigation would generate enough benefits to offset the cost of an automated irrigation system. We used data from three sites to determine the effect of pulsed irrigation on marketable yields and gross revenues compared with nonpulsed irrigation. We conducted a cost–benefit analysis to assess the cost-effectiveness of an automated irrigation system based on net gains associated with pulsed irrigation. Our results showed that pulsed irrigation was appropriate in strawberry crops grown in a highly permeable soil because it led to significant gross revenue increases relative to the standard irrigation procedure. Our results also revealed that pulsed irrigation generated enough additional benefits to cover the cost of an automated irrigation system, with a short payback period of about 1 year.

Effects of continuous and pulse irrigation with different nitrogen applications on soil moisture, nitrogen transport and accumulation in root systems

Pulse and continuous irrigation can affect water distribution in the soil, thereby affecting the growth and distribution of root systems. Different base and topdressing fertilizers can affect nitrogen transport in the soil and root distribution, thus affecting root water and nitrogen uptake. This study used pot experiments to set up four different nitrogen levels, including two different irrigation methods, to research the effects of soil moisture, nitrogen transport, nitrogen accumulation and root systems under the conditions of continuous and pulse irrigation, as well as different nitrogen applications. Result showed that continuous irrigation can increase the moisture content around the drip emitter position and reduce the soil moisture content in the horizontal spreading compared with pulse irrigation, especially reducing the horizontal spreading in the deep soil layers. One treatment in this study did not apply base fertilizer, and then supply topdressing fertilizer at a ratio of 2:4:4 in the seedling stage, jointing stage and tasseling stage, respectively. This treatment is beneficial for improving nitrogen utilization efficiency. Furthermore, this treatment can increase the root length density and root surface area in the deep soil layers, especially in the 20-35 cm soil depth, and to some extent increase the deep growth of the root system. Keywords: pulse irrigation, continuous irrigation, fertilization, irrigation, soil DOI: 10.25165/j.ijabe.20181105.3674 Citation: Huang L M, Yang P L, Ren S M, Cui H B. Effects of continuous and pulse irrigation with different nitrogen applications on soil moisture, nitrogen transport and accumulation in root systems. Int J Agric & Biol Eng, 2018; 11(5): 139–149.

Applicability of time-of-flight-based ground and multispectral aerial imaging for grapevine canopy vigour monitoring under direct root-zone deficit irrigation

ABSTRACTThis study investigates the applicability of ground-based 3D time-of-flight (ToF) imaging and small unmanned aerial system (UAS) integrated multispectral imaging as a rapid grapevine canopy vigour mapping tool for decision support during crop production management. Direct root-zone deficit irrigation was applied to grapevines with continuous and pulse irrigation techniques at 15%, 30%, and 60% rates as that of standard irrigation rate (100%) established by the grower in a commercial production. The control block was irrigated continuously at 100% standard irrigation rate. Field plots were imaged using ground platform integrated with 3D ToF imaging sensor and small UAS-integrated multispectral camera at 128 and 65 days before the harvest to estimate the canopy vigour variability associated with irrigation treatments. Customized as well as standard methods (convex hull and voxel grid) were utilized to extract canopy attributes (e.g. volume) from the 3D ToF imaging sensor data. The multispectral images were processed to extract normalized and green normalized difference vegetation index images. Resulting data were used to estimate canopy area ratio i.e. the ratio between the grapevine canopy area with respect to the total area in selected region of interest. A significant correlation (r = 0.34) between canopy volume estimated by customized algorithm and aerial canopy area ratio was observed. Custom canopy volume estimates were also highly correlated (r = 0.79) with voxel grid derived canopy volume data. Overall, 60% continuous direct root zone deficit irrigation appeared to produce canopy volume/vigour comparable with those under control treatment. Results also suggest that grower can utilize either or both (ground and aerial) grapevine canopy mapping techniques for effective management.

Study of white onion (Alium cepa L.) on yield and economics under pulse irrigation (drip) for different irrigation levels

The field experiment was conducted during two Rabi seasons from 12 th November, 2014 to 26 th April, 2015 and 23 rd November, 2015 to 4 th May 2016, on sandy clay loam soil at Instructional Farm of Department of Irrigation and Drainage Engineering, College of Agricultural Engineering and Technology, Dr. Balasaheb Sawant Konkan Krishi Vidypeeth, Dapoli, India (latitude 17 0 45’ N and longitude 73 0 10’ E and altitude of 250 m). The experiment was arranged in twelve treatment combinations with strip plot design as horizontal factor (main treatment) one continuous irrigation (P 1 ), two pulses (P 2 ), three pulses (P 3 ) and four pulses (P 4 ), while vertical factor (sub treatment) as irrigation levels viz., I 1 (0.80 ET C ), I 2 (1.0 ET C ) and I 3 (1.20 ET C ) treatments. It was revealed that the average seasonal water applied to white onion under pulse irrigation (drip) through different irrigation levels varied from 276.8 mm for I 1 (0.8 ET C ) to 429.0 mm for I 3 (1.2 ET C ) irrigation levels. Among the different treatment combination I 2 P 4 (irrigation level I 2 (1.0 ET C ) with four pulse treatment P 4 ) was found 38.52 t.ha -1 and significantly superior over I 1 P 1 (irrigation level I 1 (0.8 ET C ) with continuous irrigation P 1 ). The production cost of Rs. 4,47,366 and Rs. 4,42,962 ha -1 , gross returns of Rs. 9,63,000 and Rs. 9,31,500 ha -1 , net returns of Rs. 5,15,634 and Rs. 4,88,538 ha -1 and B C ratio of 2.15 and 2.10, were observed for I 2 P 4 and I 3 P 4 treatment combinations, respectively. Average water use efficiency was found maximum for I 1 P 4 (11.93 q ha -1 cm -1 ) treatment combination followed by I 1 P 3 (11.33 q ha -1 cm -1 ) and I 2 P 4 (10.99 q ha -1 cm -1 ) treatment combinations, respectively.

Effect of Pulse Irrigation on Prevention of Incision Infection in Tibiofibular Fracture

We aimed to describe the effect of pulse irrigation in preventing incision infection in tibiofibular fracture and to explore the effectiveness of pulse irrigation on the prevention of the infection, providing a theoretical basis for its clinical application. Clinical data of 158 patients with tibiofibular fracture admitted in our hospital between Jan. and Dec. 2015 and 158 with tibiofibular fracture admitted between Feb. and Nov. 2016 were reviewed, and the patients were divided into the observation group and the control group. Wound was flushed by conventional method before incision suture for the patients in the control group, and pulse irrigation was applied for those in the observation group before suture. Postoperative incision infection rate, primary healing rate and the level of incision healing were compared. Rates of incision infection and wound healing in patients of the control group were 9.5% and 90.5%, respectively, and the corresponding rates in the observation group were 1.3% and 98.7%. The differences between the two groups were statistically significant (c2=10.51, p<0.05); level-A healing was observed in 132 patients of the control group and 150 in the observation group, with a statistically significant difference between groups (c2=10.68, p<0.05).Pulse irrigation effectively reduces the incidence of incision infection in tibiofibular fracture and improves the incision healing level.

Heap Leaching: Modelling and Forecasting Using CFD Technology

Heap leach operations typically employ some form of modelling and forecasting tools to predict cash flow margins and project viability. However, these vary from simple spreadsheets to phenomenological models, with more complex models not commonly employed as they require the greatest amount of time and effort. Yet, accurate production modelling and forecasting are essential for managing production and potentially critical for successful operation of a complex heap, time and effort spent in setting up modelling tools initially may increase profitability in the long term. A brief overview of various modelling approaches is presented, but this paper focuses on the capabilities of a computational fluid dynamics (CFD) model. Advances in computational capability allow for complex CFD models, coupled with leach kinetic models, to be applied to complex ore bodies. In this paper a comprehensive hydrodynamic CFD model is described and applied to chalcopyrite dissolution under heap operating conditions. The model is parameterized against experimental data and validated against a range of experimental leach tests under different thermal conditions. A three-dimensional ‘virtual’ heap, under fluctuating meteorological conditions, is simulated. Continuous and intermittent irrigation is investigated, showing copper recovery per unit volume of applied leach solution to be slightly increased for pulse irrigation.

Effects of continuous and pulse irrigation with different nitrogen applications on soil moisture, nitrogen transport and accumulation in root systems

Pulse and continuous irrigation can affect water distribution in the soil, thereby affecting the growth and distribution of root systems. Different base and topdressing fertilizers can affect nitrogen transport in the soil and root distribution, thus affecting root water and nitrogen uptake. This study used pot experiments to set up four different nitrogen levels, including two different irrigation methods, to research the effects of soil moisture, nitrogen transport, nitrogen accumulation and root systems under the conditions of continuous and pulse irrigation, as well as different nitrogen applications. Result showed that continuous irrigation can increase the moisture content around the drip emitter position and reduce the soil moisture content in the horizontal spreading compared with pulse irrigation, especially reducing the horizontal spreading in the deep soil layers. One treatment in this study did not apply base fertilizer, and then supply topdressing fertilizer at a ratio of 2:4:4 in the seedling stage, jointing stage and tasseling stage, respectively. This treatment is beneficial for improving nitrogen utilization efficiency. Furthermore, this treatment can increase the root length density and root surface area in the deep soil layers, especially in the 20-35 cm soil depth, and to some extent increase the deep growth of the root system. Keywords: pulse irrigation, continuous irrigation, fertilization, irrigation, soil DOI: 10.25165/j.ijabe.20181105.3674 Citation: Huang L M, Yang P L, Ren S M, Cui H B. Effects of continuous and pulse irrigation with different nitrogen applications on soil moisture, nitrogen transport and accumulation in root systems. Int J Agric & Biol Eng, 2018; 11(5): 139–149.

Mechanical colon cleansing for screening colonoscopy: A randomized controlled trial.

Effective screening colonoscopy depends on the quality of colon preparation. This study aimed to compare pulsed irrigation evacuation (PIE), polyethylene glycol (PEG) and sodium phosphate colon preparations. Outpatients at a VA hospital were randomized using sealed envelopes. Preparations consisted of polyethylene glycol 4L, Fleet sodium phosphate 90 mL with four to six glasses water twice daily and 296 mL of magnesium citrate in the evening with PIE prior to colonoscopy. Colon cleansing was assessed blindly using a five-point scale: 0 (very poor) to 4 (excellent). Altogether 391 patients participated in the study (129 in the PEG group, 127 in the sodium phosphate and 135 in the PIE group), with a mean age of 62 years, of whom 75% were men. PIE and sodium phosphate were superior to PEG: median cleansing scored 4 (excellent) versus 3 with PEG (P < 0.01). Inadequate preparations were more common with PEG than PIE (18% vs 5%) (P < 0.01). Side-effects included vomiting: 37% in the sodium phosphate group versus 5% in the PEG and 2% in the PIE groups (P < 0.01). The three preparations were judged intolerable in ≤ 5%. PIE and sodium phosphate are superior to PEG for colon preparations. PIE is the preferred preparation for those at high risk of unsatisfactory preparations or with unsatisfactory traditional preparations.

High Resolution Multispectral and Thermal Remote Sensing-Based Water Stress Assessment in Subsurface Irrigated Grapevines

Precision irrigation management is based on the accuracy and feasibility of sensor data assessing the plant water status. Multispectral and thermal infrared images acquired from an unmanned aerial vehicle (UAV) were analyzed to evaluate the applicability of the data in the assessment of variants of subsurface irrigation configurations. The study was carried out in a Cabernet Sauvignon orchard located near Benton City, Washington. Plants were subsurface irrigated at a 30, 60, and 90 cm depth, with 15%, 30%, and 60% irrigation of the standard irrigation level as determined by the grower in commercial production management. Half of the plots were irrigated using pulse irrigation and the other half using continuous irrigation techniques. The treatments were compared to the control plots that received standard surface irrigation at a continuous rate. The results showed differences in fruit yield when the control was compared to deficit irrigated treatments (15%, 30%, 60% of standard irrigation), while no differences were found for comparisons of the techniques (pulse, continuous) or depths of irrigation (30, 60, 90 cm). Leaf stomatal conductance of control and 60% irrigation treatments were statistically different compared to treatments receiving 30% and 15% irrigation. The normalized difference vegetation index (NDVI), green normalized difference vegetation index (GNDVI), and canopy temperature were correlated to fruit yield and leaf stomatal conductance. Significant correlations (p &lt; 0.01) were observed between NDVI, GNDVI, and canopy temperature with fruit yield (Pearson’s correlation coefficient, r = 0.68, 0.73, and −0.83, respectively), and with leaf stomatal conductance (r = 0.56, 0.65, and −0.63, respectively) at 44 days before harvest. This study demonstrates the potential of using low-altitude multispectral and thermal imagery data in the assessment of irrigation techniques and relative degree of plant water stress. In addition, results provide a feasibility analysis of our hypothesis that thermal infrared images can be used as a rapid tool to estimate leaf stomatal conductance, indicative of the spatial variation in the vineyard. This is critically important, as such data will provide a near real-time crop stress assessment for better irrigation management/scheduling in wine grape production.

USING ARDUINO BOARD FOR AUTOMATIC PULSE IRRIGATION SYSTEM

Nowadays the scarcity of water is a source of great concern for agriculture and using technology to control irrigation systems has become an essential requirement. A laboratory and outdoor work were carried out at Agricultural Engineering Department, Faculty of Agriculture, Kaferelsheikh University during summer 2016. The aim of this work is designing a system which is capable of on/off the water pump for pulse irrigation system in time. Arduino board and other hardware is programmed at 20 min.on/20min.off (possible to change) with the Arduino software. The proposed prototype can help in reducing hard work of pulse irrigation system due to on/off valves manually, cost and save time. The uses of moisture sensor and solenoid valve make a smart irrigation system. Arduino based automatic watering system has been designed and tested successfully by part of second.

Effect of Irrigation Systems, Pulse Irrigation Technique and Cobalt Application on Productivity and Water use Efficiency of Tomato Plants Grown in New Reclaimed Soil

Effect of Irrigation Systems, Pulse Irrigation Technique and Cobalt Application on Productivity and Water use Efficiency of Tomato Plants Grown in New Reclaimed Soil

Intraoperative Disinfection by Pulse Irrigation with Povidone-Iodine Solution in Spine Surgery.

Background Deep wound infection in spine surgery is a debilitating complication for patients and increases costs. The objective of this prospective study was to evaluate the efficacy of wound pulse irrigation with a dilute povidone-iodine solution in the prevention of surgical site infection. Methods 50 patients undergoing spinal surgery were randomly divided into two groups (A and B) of 25 patients each. In group A, wounds were irrigated with dilute (3%) povidone-iodine solution through a low-pressure pulsatile device. In group B, wounds were irrigated with saline solution through a bulb syringe. In both groups, specimens for bacterial culture were harvested from surgical site before and after irrigation. Results In group A, no surgical site infection occurred; in group B, deep wound infection was observed in 3 patients. In both groups, before irrigation some cultures have been found positive for bacterial contamination. Conclusion Our study seems to support the idea that low-pressure pulsating lavage of surgical wounds with povidone-iodine diluted to a nontoxic concentration of 3% is an effective therapeutic adjunct measure to prevent surgical site infection in spine surgery. However, the number of the enrolled patients is small and a significant statistical analysis is not practicable. This trial is registered with NCT03249363.

Effect of Different Irrigation Systems, Pulse Irrigation Technique and Silicon Application on Maize Growth, Yield and Water Relations under Toshka Climatic Conditions

Effect of Different Irrigation Systems, Pulse Irrigation Technique and Silicon Application on Maize Growth, Yield and Water Relations under Toshka Climatic Conditions

English

Water is the most important production factor in agriculture, since even small restrictions to the water supply can result in decreased productivity. Due to climatic reasons, water supply is limited in many parts of the world, resulting in a need to develop techniques that increase the water use efficiency. Pulse irrigation consists of the application of an irrigation depth, relative to the actual irrigation needed, split throughout the day. The objective of this study was to verify the effects of pulse irrigation on cucumber plants that were either subjected to a water deficit or were sufficiently supplied with water, considering the hypothesis that the application of water during times of greater evapotranspiration demand will promote benefits to the crop in comparison with the continuous irrigation in the early hours of the day. A completely randomised design was used and the treatments were distributed in 3×4 and 4×4 factorial scheme in the first and second cycles respectively. The first factor was the replenishment of the irrigation depth relative to the crop evapotranspiration, while the second factor was the number of pulses; there were a total of 48 and 64 plots in the first and second cycles, respectively. The application of the treatments was started in the vegetative phase and in the reproductive phase for the first and second cycles respectively. It was concluded that smaller irrigation depths than the crop requires can be applied by pulses without resulting in a reduction in the vegetative growth in Japanese cucumber. Key words: Drip irrigation, water savings, reduced irrigation depth, Cucumis sativus, protected environment.

Numerical investigations on pesticide fate and transport in an unsaturated porous medium for a coupled water and pesticide management

The pesticides applied on the soil surface can be transported vertically downwards through the unsaturated porous system and lead to groundwater contamination. Proper agricultural management practices such as selection of appropriate irrigation techniques, choosing proper irrigation rates, and application of optimum pesticide dosages are necessary to prevent leaching of pesticides to greater depths thus preventing groundwater contamination. A simulation study is conducted based on the one-dimensional numerical model considering Richard’s equation for unsaturated water flow and solute transport which takes into account the effect of both adsorption and biodegradation with inhibitory effect to understand pesticide transport in an unsaturated porous medium. The study addresses the influence of irrigation rate, type of irrigation, and pesticide dosage on soil moisture and pesticide concentration distribution. The numerical results suggest that higher water application rates can carry the pesticides to greater depths. Pulsed irrigation can slightly reduce water losses through the root zone when compared to continuous irrigation. The comparison of the wetting patterns and the pesticide distribution obtained in continuous and pulsed irrigation helps to decide the use of a particular irrigation strategy in order to achieve suitable goals. In addition, the results from this study bring out better understanding of the effect of pesticide concentration and dosage on the resultant pesticide distribution in the unsaturated zone and the pesticide potential to cause groundwater contamination. The better analysis of outputs from this study can help in improving and designing better agricultural management strategies, carrying out risk assessment and bioremediation studies.

Local Treatment of Penile Prosthesis Infection as Alternative to Immediate Salvage Surgery.

IntroductionPenile prosthesis (PP) is the established treatment for patients with erectile dysfunction (ED) who do not respond to phosphodiesterase inhibitors and intracavernosal injections. In general, these devices have been largely successful but there are not free of serious complication such as PP infection (PPI). PPI requires immediate surgical removal or salvage rescue of the PP.AimIn this report, we present two clinical cases with inflatable PP (IPP) treated locally with antibiotic and high pressure irrigation and then avoid the PP removal or salvage rescue.MethodsWe present two patients with PPI in our institution and literature review.Main Outcome MeasuresResolution of the two cases.ResultsPatient A (A) was 44 years old and patient B (B) 51 years old presented PPI after three weeks (A) and eight weeks (B). Both patients were diabetic. Physical exploration revealed an open scrotal incision at its margin with a clear discharge. The rest of the incision and scrotum were clean and dry. They had not scrotum pain/tenderness or systemic/septic symptoms. The bacterial culture of the incisional drainage revealed a Staphylococcus aureus (A) and Staphylococcus epidermidis (B). In both cases, we performed an excision of the tissue around the pump with a high pressure pulsed irrigation (Interpulse; Stryker Corp, Kalamazoo, MI, USA). For the irrigation we used three different solutions that included povidone-iodine, antibiotics (gentamicin plus vancomicin), and hydrogen peroxyde. Finally, we performed a multilayered surgical closure with the use of aspirate drainage over 24 hours and intravenous antibiotics. The patients had a total resolution of its symptoms after 20 months (A) and 36 months (B), and the IPP worked properly.ConclusionThis treatment could be an option for to perform specific patients with local IPP infection without systemic symptoms instead of surgical removal.

Adaptation of pressurized irrigation networks to new strategies of irrigation management: Energy implications of low discharge and pulsed irrigation

This paper analyzes the consequences of adopting new on-farm irrigation management strategies (low discharge rates, long irrigation times and high frequencies) in an existing on-demand and sectorized pressurized irrigation system in eastern Spain. The sectorized behavior of the network was analyzed using two criteria: (i) the operating sectors obtained in a first stage by arranging the hydrants depending on their altitude respecting the pumping station and (ii) the operating sectors obtained by means of an optimization process. The Simulated Annealing combinatorial metaheuristic optimization technique was employed to find the best solution. Random on-demand patterns were generated using a Montecarlo simulation. The hydraulic requirements of the network were analyzed in every scenario by the Epanet 2.0 engine. The effect on energy consumption, power requirements and energy costs was assessed taking into account the electricity tariff billing structure. It was found that reductions in emitter discharge (qe) and Energy consumption (E)-Energy Cost (EC) savings are not inherently related to each other. Certain amounts of E and EC could be saved when the number of sectors and operating time parameters were properly selected. Pulsed irrigation in the current scenario showed an energy saving potential of 10.67, 6.43 and 6.99% for power capacity, E and EC, respectively.

Bulb Syringe and Pulsed Irrigation

Retrospective study. The aim of this study was to investigate the difference of efficacy between bulb syringe irrigation and pulsed irrigation in spinal surgeries. Pulsed irrigation has been used for more than half a century, especially in trauma surgeries. However, to the best of our knowledge, there has been no study as to the efficacy of pulsed irrigation in spinal surgeries so far. The consecutive patients who underwent posterior lumbar interbody fusion for 6 months were investigated. Those who underwent surgeries during the first 3 months were irrigated by bulb syringe (group I) and those who underwent surgeries during the next 3 months were irrigated by pulsatile irrigator with 17 psi (group II). Sex, age, surgery time, amount of blood loss, whether associated with diabetes mellitus, smoking, and amount of irrigation solution were compared between the 2 groups to identify homogeneity. Normal saline was used. Intraoperative irrigations were performed 3 times as time elapsed. After the last irrigation, culture specimens were obtained from the muscle layer and intervertebral space. The culture results were compared between the 2 groups. There were 79 cases in group I and 59 cases in group II. In the homogeneity test, surgery time was longer (P=0.011) and amount of irrigation saline was larger (P=0.042) in group II. From the posterior muscle layer, bacteria were cultured in 8/79 cases (10.1%) in group I and 1/59 cases (1.6%) in group II. There was a significant difference between the 2 groups (P=0.046). And from the intervertebral space, it was cultured in 6/79 cases (7.6%) in group I and 5/59 cases (8.5%) in group II. There was no difference between the 2 groups (P=0.546). Staphylococcus epidermidis, Staphylococcus aureus, Staphylococcus hominis, and Staphylococcus saprophyticus were cultured in order of the frequency. Pulsed irrigation was more effective compared with bulb syringe irrigation in the posterior muscle layer. In the intervertebral space, however, both methods were insufficient to eradicate contaminated bacteria.