Christiansen Uniformity Coefficient Research Articles

Optimizing irrigation and nitrogen management improves soil soluble nitrogen pools and reduces nitrate residues in a drip-fertigated apple orchard on the Loess Plateau

Appropriate water and nitrogen fertilizer management is crucial for achieving sustainable development in the apple industry. However, the soil nitrogen supply capacity and residual nitrate characteristics under drip fertigation remain poorly understood. Therefore, this study aims to (1) investigate the coupling effects of irrigation and nitrogen levels on the concentrations and distribution characteristics of soil soluble nitrogen fractions and residual soil nitrate; (2) explore the relationships between Christiansen uniformity coefficient (CU) of soil nitrate and apple yield, water productivity (WPc) and nitrogen use efficiency (nitrogen agronomic efficiency, AEn). The field experiment was conducted in a drip-fertigated apple orchard starting in 2017, which included two irrigation levels, 85% (W1) and 100% (W2) of field capacity (FC), and four nitrogen rates, 0 (N1), 120 (N2), 240 (N3) and 360 (N4) kg ha–1. The results showed that nitrogen inputs significantly increased soil soluble inorganic nitrogen and soluble organic nitrogen (SON) contents. However, the SON content significantly decreased when 360 kg N ha–1 was applied, particularly at W1. The maximum nitrate accumulation in the 0–3 m soil layer at N4 reached 2540.97 kg ha–1 in 2021, but the maximum value decreased to 1251.62 kg ha–1 in 2022 due to extreme rainfall. The average CU of residual nitrate across irrigation levels in the 0–3 m soil layer was highest at N3, with values of 0.68 and 0.57 in 2021 and 2022, respectively. High irrigation level increased the diffusion distances of nitrate both vertically and horizontally, resulting in a significant effect on CU. Apple yield and WPc first increased and then decreased with increasing nitrogen rates, while AEn consistently decreased, but they were all greater with a higher CU. The recommended combination of irrigation and nitrogen application was 85% FC and 240 kg N ha–1, which can achieve the dual goals of enhancing soil nitrogen supply capacity and minimizing environmental risks while improving orchard productivity.

Statistical process control in pulsed drip irrigation systems

Pulse drip application is a management option to prevent clogging and improve water-use efficiency. The measurement of distribution uniformity is opportune for pulse irrigation projects to ensure efficiency since the shorter the pulse time, the more negative influence the transition periods have. The objective of the present work was to monitor the quality of a drip irrigation system with different emitter models and different pulse times. The experiment was conducted under laboratory bench conditions, and 25 tests were performed for each pulse application (2, 3, 6 and 12 minutes) and emitter model (non-compensated and auto-compensated). Uniformity was determined using Christiansen's uniformity coefficient (CUC) and distribution uniformity coefficient (DUC) and monitored by Shewhart control charts and exponentially weighted moving average (EWMA). The decrease in pulse time caused a decrease in flow rate and uniformity only in drip irrigation systems with non auto-compensated emitters. However, this decrease is subtle, to the point that uniformity presented an excellent performance for all pulses tested. The use of the Shewhart and EWMA control charts were effective in monitoring the uniformity of the pulsed drip irrigation system. The Shewhart control chart was more robust in identifying isolated non-compensated uniformities, while the EWMA control chart was more sensitive in identifying unstable propensity. In the treatments with the non-compensated emitter, the statistical process control was able to identify that shorter pulse times resulted in greater application instability. As for the auto-compensated emitters, the statistical process control highlighted the concern with application uniformity after maintenance interference.
 Keywords: anti-drain emitter, high-frequency irrigation, irrigation interval, statistical quality control.

Artificial Neural Networks versus Multiple Linear Regressions to Predict the Christiansen Uniformity Coefficient in Sprinkler Irrigation

The Christiansen Uniformity Coefficient (CUC) describes the distribution of water in a sprinkler system. In this study, two types of models were developed to predict the Christiansen Uniformity Coefficient (CUC) of sprinkler irrigation systems: Artificial Neural Network (ANN), specifically the feed-forward neural networks, and multiple linear regression (MLR) models. The models were trained on a dataset of published research on the CUC of sprinkler irrigation systems, which included data on a variety of design, operating, and meteorological condition variables. In order to build the predictive model of CUC, 10 input parameters were used including sprinkler height (H), working pressure (P), nozzle diameter (D and da), sprinkler line spacing (SL), sprinkler spacing (SS), wind speed (WS), wind direction (WD), temperature (T), and relative humidity (RH). Fifty percent (50%) of the data was used to train ANN models and the remaining data for cross-validation (25%) and for testing (25%). Multiple linear regression models were built using the training data. Four statistical criteria were used to evaluate the model’s predictive quality: the correlation coefficient (R), the index of agreement (d), the root mean square error (RMSE), and the mean absolute error (MAE). Statistical analysis demonstrated that the best predictive ability was obtained when the models (ANN and MLR) utilized all the input variables. The results demonstrated that the accuracy of ANN models, predicting the CUC of sprinkler irrigation systems, is higher than that of the MLR ones. During the training stage, the ANN models were more accurate in predicting CUC than MLR, with higher R (0.999) and d (0.999) values and lower MAE (0.167) and RMSE (0.456) values. The R values of the MLR model fluctuated between 0.226 and 0.960, the d values oscillated from 0.174 to 0.979, the MAE values were in the range of 2.458% and 10.792%, and the RMSE values fluctuated from 2.923% to 13.393%. Furthermore, the study revealed that WS and WD are the most influential climatic parameters. The ANN model can be used to develop more accurate tools for predicting the CUC of sprinkler irrigation systems. This can help farmers to design and operate their irrigation systems more efficiently, which can save them time and money.

Prediction of water distribution uniformity of sprinkler irrigation system based on machine learning algorithms

The coefficients of uniformity Christiansen's uniformity coefficient (CU) and distribution uniformity (DU) are an important parameter for designing irrigation systems, and are an accurate measure for water lose. In this study, three machine learning algorithms Random forest (RF), extreme gradient boosting (XGB) and random forest-extreme gradient boosting (XGB-RF) were developed to predict the water distribution uniformity based on operating pressure, heights of sprinkler, discharge, nozzle diameter, wind speed, humidity, highest and lowest temperature for three different impact sprinklers (KA-4, FOX and 2520) for square and triangular system layout based on four scenarios (input combinations). The main findings were; the highest CU value was 86.7% in the square system of 2520 sprinkler under 200 kPa, 0.5 m height and 0.855 m3/h (Nozzle 2.5 mm). Meanwhile, in the triangular system, it was 87.3% under the same pressure and discharge and 1 m height. For applied machine learning, the highest values of R2 were 0.796, 0.825 and 0.929 in RF, XGB and XGB-RF respectively in the first scenario for CU. Moreover, for the DU, the highest values of R2 were 0.701, 0.479 and 0.826 in RF, XGB and XGB-RF respectively in the first scenario. The obtained results revealed that the sprinkler height had the lowest impact on modeling of the water distribution uniformity.

Effect and Mechanism of Micro-Nano Aeration Treatment on a Drip Irrigation Emitter Based on Groundwater

The problem of emitter clogging has become the main obstacle restricting the application and promotion of drip irrigation technology. Studying the process of emitter clogging helps improve irrigation efficiency and save water resources. A large number of researchers have tried to solve the problem of emitter clogging from many perspectives. However, the influence of micro-nano bubbles as well as generated blockage on the clogging process of drip irrigation systems is less studied. Here, the influence of aeration on emitter clogging was studied by adding micro-nano bubbles to groundwater. Four different emitters were selected. Two treatments, micro-nano aeration and non-aeration, were set up, with a total of eight sets of experiments, running for 1500 h. The degree of emitter clogging was quantitatively characterized using the discharge ratio variation (Dra). The Christiansen uniformity coefficient (Cu) and statistical uniformity coefficient (Us) were used to evaluate the influence of emitter clogging on the performance of the drip irrigation system. Compared with the non-aeration treatment group, the Dra of aerated E1–E4 decreased by 64.74%, 54.22%, 64.20%, and 94.69% in 800 h, respectively. At the same time, the Us of the aerated E1–E4 decreased by 100%, 60.05%, 92.32%, and 100%, while the Cu of aerated E1–E4 decreased by 76.64%, 53.79%, 74.11%, and 100% compared with the unaerated group. The Cu and Us of all emitters under the aeration treatment were smaller than those comparison group. As for the blockage, the main components were typical physical blockage SiO2 and chemical blockage CaCO3. Most of the blockages in the non-aeration treatment group are 5–10 μm in length, while those in the aerated treatment group were generally less than 5 μm. Aeration treatment made the blockage more broken and dense and more likely to accumulate in the flow channel, obstructing the flow of water and thus intensifying the clogging process. As a result, micro-nano aeration treatment increased the risk of emitter clogging, accelerated the development of blockage in the emitter, and disturbed the uniformity of the entire drip irrigation system. This study provides a reference idea for solving the problem of blockage in drip irrigation systems.

Experimental study on clogging of three different types of emitters with similar properties

AbstractThe drip irrigation process has been designed to reduce water losses, and to combine irrigation, with the supply of fertilizers. However, in drip irrigation systems, the clogging of emitters is a major problem that significantly reduces the performance of drip irrigation systems. The water used in these systems is generally loaded with suspended matter, which might cause clogging of the emitters. This work was carried out in order to evaluate the clogging rate in three different types of emitters with roughly similar flow rates, tested in an experimental drip irrigation system, using water pumped from the Sebou River. Thus, a compensating‐pressure emitter named E1 and two non‐compensating‐pressure emitters named E2 and E3 were tested. Each dripper was subjected to 112 irrigations, which lasted 397 h and were spread over a period of 2 months. To evaluate the hydraulic performance of the emitters, the following three coefficients were used to measure the effect of clogging: (i) the variation of the flow ratio (Dra), which reflects the degree of clogging; (ii) the emission uniformity coefficient (EU); and (iii) the Christiansen uniformity coefficient (CU). No emitters became completely clogged during the experiment. However, as the clogging rate increased, the average flow rates measured in some emitters at the end of the test had decreased by 89% compared to the initial flow rates. During the experiment, flow fluctuations were observed during the evolution of the clogging, which could come from a partial recovery of flow.

Effects of saline water with different concentrations of calcium and magnesium ions on emitter clogging in drip irrigation integrated water–fertilizer system

AbstractThe application of saline water in drip irrigation is severely constrained due to its high salt content, which causes precipitation and emitter clogging. Therefore, the effects of calcium and magnesium ions at 100, 150 and 200 mg/L in saline water coupled with humic acid nitrogen fertilizer on emitter clogging were studied. Compared with ground saline water, all treatments significantly increased the emitter clogging risk. In the calcium and magnesium ion treatment groups, clogging fouling increased by 23.94–58.35 and 14.55–51.21 mg/cm2, the discharge variation ratio (Dra) decreased by 22%–59% and 14%–49%, and the Christiansen coefficient of uniformity (CU) decreased by 29%–79% and 15%–74%, respectively. Higher ion concentrations caused more clogging. Saline water with a high calcium content caused more clogging. Under similar concentration conditions, the Dra and CU in high magnesium saline water were 9%–32% and 8%–51% higher, respectively. In addition, the increase in magnesium ion concentration changed the crystal form of carbonate, slowed the formation rate of precipitated dirt and significantly reduced the carbonate content by 19%–40%. Our results provide support for the popularization of saline water drip irrigation systems.

Performance of an Automatic Variable-Rate Fertilization System Subject to Different Initial Field Water Conditions and Fertilizer Doses in Paddy Fields

High-performance fertilization equipment with high uniformity is essential for the improvement of fertilizer use efficiency in paddies. The performance of these fertigation systems might be affected by the initial field conditions and fertilizer doses. In this study, the uniformity of fertilization by an automatic system (SF) was investigated; the investigation had two initial field water conditions and fertilizer doses, and manual fertilization by farmers (FF) was used as the control. After fertilization, the Christiansen uniformity coefficient (CU) in the SF paddies was higher than in the FF paddies, and the SF in the non-flooded paddies (SFN) was the highest. With time, the CU of treatments with poor fertilization uniformity was improved; it was driven by the osmotic potential of fertilizer ions, but it was far from exceeding that of the treatments originally conducted with higher CU. For the SF treatments, the fertilizer dose did not affect fertilization uniformity significantly; so, an SF can match the efficient fertilization strategies more precisely. As water-saving irrigation (WSI) is conducive to the production of non-flooded field conditions and the promotion of the efficient use of topdressing, the use of automatic fertilization systems to implement efficient fertilization management practices in WSI paddy fields is suggested.

Evaluation of new pivoting linear‐move precision irrigation machine

AbstractDue to population growth, freshwater resources around the world are becoming increasingly scarce, and the water supply in agriculture has emerged as one of the limitations of food production. Variable‐rate irrigation (VRI), a type of precision irrigation, allows water‐efficient irrigation techniques to ensure an optimal water supply. The University of Debrecen, in collaboration with Magtár Kft., was the first in Hungary to develop a new laterally mobile irrigation machine equipped with VRI. The subject of our study was the testing of this system. According to the research, high and homogeneous irrigation uniformity was achieved in practice, with a Christiansen uniformity coefficient (CUc%) of 93 ± 2, distribution uniformity (DU%) of 88 ± 2 and coefficient of variation (CV) of 9 ± 2. Irrigation accuracy was also found to be satisfactory (mean absolute error 0.6 ± 0.1, mean bias error 0.2 ± 0.2, normalized root mean square error 8.6 ± 2), and only 1.4% ± 2% was overirrigated and 0.4% ± 0.3% underirrigated. In addition, the uniformity and accuracy of irrigation in different management zones along the pipeline were also investigated, and significant differences (p < 0.05) were found between irrigation water depths. Based on the above, a new laterally mobile irrigation machine equipped with VRI can be used to develop more uniform and accurate irrigation schedules in the future in arable fields as this is critical for water‐saving irrigation management.

Simulador de chuva portátil: avaliação e adequação dageometria da parcela para melhorar a uniformidade da chuva

ABSTRACT Rainfall simulators are an important tool in many areas of geosciences. The authors of most of the studies published with rainfall simulators try to get the most uniform distribution of precipitation as possible. However, since this is very difficult, indexes are used to assess the greater or lesser uniformity of precipitation in the plot area under study. One of the most used indexes is the Christiansen uniformity coefficient. In this work, changes in the geometry of the wetted area of the plot were analyzed to improve the uniformity of precipitation. This was evaluated through the intensity of precipitation and Christiansen uniformity coefficient in the wet area. The tests were carried out using two models of spray nozzles and different operating pressures. The initial plot geometry was 0.7 x 1.0 m (0.7 m2). The Christiansen uniformity coefficient results were classified as low, while the best performance in terms of precipitation uniformity was obtained at a pressure of 48.3 kPa. Non-uniform precipitation was observable near the outer limits of the plot. Based on the best Christiansen uniformity coefficient results, it was proposed to reduce the effective area of the experimental plot from 0.70 to 0.56 m2, leading to a precipitation intensity of 114.07 and 149.20 mm·h−1, and a Christiansen uniformity coefficient of 81.6 and 83.8%, with the two models of spray nozzles. The results showed that adjusting the geometry of the plot can lead, in a simple and fast way, to a better uniformity of artificial rainfall.

Uniformity of water distribution in sprinkler irrigation mini-cannons in a high Andean community in Peru

The objective of the present work was to determine the uniformity of water distribution through mini-irrigation cannons in conditions of the Peruvian altiplano, applying the formulas for the Christiansen Uniformity Coefficient (CUC) and the Distribution Coefficient (DU) and to interpret the incidence of wind on water distribution at three different times during the day (5:30-7:30, 12-14 and 16-18 hours). Necessary climatological information, field rainfall tests, emitter pressure, and flow, wind speed were collected to evaluate their influence on water application. Variable CUC and distribution uniformity results were obtained at the level of four demonstration plots, the maximum and minimum CUC was 87.42% and 55.34%, while the DU resulted with a maximum of 80.79% and 26. 88% minimum; it is worth mentioning that in the last two schedules, results were obtained that show a poor water distribution; while winds less than 2 m/s favored the uniform distribution of water applied through the sprinklers, affirming that it was possible to obtain an acceptable water distribution uniformity at the plot level considering the irrigation schedule.

Implementación y evaluación del sistema de riego por borbolleamiento en el cultivo de café (Coffea canephora) en la Estación Experimental de Sapecho

The present research work was developed in the Sapecho Experimental Station belonging to the Faculty of Agronomy - UMSA, located 239 km from the city of La Paz, it presents an average temperature of 26 ° C with an annual rainfall of 1500 mm, the objective was to implement and evaluate the sprinkling irrigation system in the coffee crop (Coffea canephora). For the implementation of the system, the agronomic and hydraulic design was carried out that allowed the calculation of the water needs of the crop as well as the components of the system, the installation was made on a surface of 720 m2, it consists of a 2300-liter tank that works as constant load device, a 38.1 mm diameter bypass line with a length of 21 m, four laterals of 19.5 mm in diameter and 28.5 m in length each and distribution hoses of 5 mm in diameter and 2.5 m in length, it was installed to irrigate 80 coffee plants of the robusta variety. Subsequently, the operation evaluation of the irrigation system was carried out in which it was found that the Christiansen uniformity coefficient (CUC) is 83% and the distribution coefficient (CD) is equal to 76%, these results indicate that the implemented system is between good and acceptable. The evaluation on the effect of irrigation showed us that the application of optimal irrigation is positive in vegetative growth, being 30% higher in the development of the foliar area, 30.1% in number of nodes, 38.4% in length of bandola and it was reduced by 17% in the loss of fruits compared to the control.

Construction and calibration of a portable rain simulator designed for the in situ research of soil resistance to erosion

Land degradation caused by erosion processes is a widespread global problem. Rain simulators are one of the tools often used to determine the resistance of soils to erosion processes. The aim of this publication is to present the process of the construction and calibration of a small, portable field simulator which would be implemented in research studies designed to determine the changes in the soils’ shear strength parameters in forested areas (in situ) caused by a change in soil moisture content achieved by the rain simulation. The constructed simulator consists of a metal frame, sprayers (with specific nozzles), a sediment funnel/tray made of metal, water and a sediment collector unit, a water tank and pump, and a set of rubber hoses, manometer, valves, reducers, adapters and other supplementary equipment. The calibration was carried out by using the pluviometric method. The choice of nozzles was based on the criteria of low water consumption (losses), the Christiansen uniformity coefficient (CU) and the possibility of achieving specific downpour intensities for the investigated area. The further calibration of the device consisted of determining the raindrop diameter and the distribution of the rainfall when the simulator is positioned on the slopes (7° and 15°). The achieved rain intensity was 1.7–1.9 mm/min, with a CU of 92.23–93.70% for the raindrop diameters (D<sub>50</sub>) equal to 1.2 mm. The kinetic energy of the simulated rain (Ke) was 2.82∙10<sup>–6</sup> J. The constructed simulator proved itself to be in accordance with all of the given criteria, and it can successfully be implemented in research studies aimed at determining the resistance of forest soils to erosion processes, infiltration, and sediment yield.

Christiansen uniformity revisited: Re-thinking uniformity assessment in rainfall simulator studies

Rainfall simulators have been used extensively for a variety of research applications. The uniformity and spatial distribution of simulated rainfall is an important metric to consider when conducting rainfall simulator experiments. Over the past 80 years, several methods of assessing rainfall distribution and uniformity over the plot surface below a rainfall simulator have been developed. However, the Christiansen Uniformity Coefficient (CU; Christiansen, 1942) is most frequently used. Here, we provide a critique of this established methodology and metric for quantifying rainfall distribution characteristics. Uniformity coefficients express the distribution of rainfall across the plot surface as a single percentage value. Therefore, if all collection beakers receive equal volumes of water during an experimental run, the rainfall simulator or irrigation system would be applying water with 100% uniformity. There are shortcomings with using a single percentage value to represent rainfall simulator rainfall distribution, especially over a larger plot surface, and CU is highly dependent on the sampling methodology employed. This paper assesses rainfall uniformity by conducting a series of controlled uniformity experiments and resampling different grid layouts of collection containers. Results demonstrate that the coarseness of the sampling methodology affects rainfall uniformity coefficient values. CU values of 45 – 51% were recorded under a dense (17 × 17) sampling grid layout, compared to CU values of 81% using a coarser (8 × 8) sampling methodology, despite being subjected to comparable rainfall events. This paper explores the sensitivity of CU to the resolution and spatial layout of the sampling methodology used and assesses whether the CU captures repeatability and localised variability of uniformity between experimental runs. A complementary statistical approach expressing variations in relation to their standard deviation from the mean is presented. Understanding how experimental setup (i.e. number, density, spatial configuration of collection containers) affects CU is critical when interpreting results from different rainfall simulator studies and an understanding of the factors which influence CU is critical to benchmark the results of uniformity testing across different rainfall simulator setups.

Automatic variable rate fertilisation system for improved fertilisation uniformity in paddy fields

China currently relies on manual labour to fertilise paddy fields, hindering the improvement of fertilisation uniformity, management efficiency, and fertiliser use efficiency. Following a drastic decrease in the availability of agricultural labour, fertilisation operations are facing increasing labour costs and low reliability rates and this is threatening food security. This study developed an automatic fertilisation system suitable for pipe and canal irrigation systems in paddy fields, which measures the irrigation flowrate every second and adjusts the variation of the fertiliser flowrate to maintain a steady water-fertiliser ratio ( WFR ). An inexpensive single-chip microcomputer was used as the core of the system for precise control and tests were conducted to check its performance in concentration control. Results show that the fertilisation system developed in this study steadily controlled fertiliser concentration with a normalised mean absolute error ( NMAE ) ranging from 0.15% to 0.58% and from 0.22% to 0.63% for the tested pipe and canal irrigation systems, respectively. The fertiliser flowrate was adjusted to the irrigation flowrate instantly and accurately, with a maximum deviation of 0.56% in the WFR . This system drastically improved fertilisation uniformity compared to manual fertilisation, and had a Christiansen uniformity coefficient of 96.30%; a distribution uniformity of 0.93, and a coefficient of variation of 0.05. It also decreases labour costs, reduces potential pollutions and increases management efficiency. Thus, it can improve fertiliser use efficiency and contribute to the development of precision agriculture. • Automatic fertilisation system for paddy fields developed based on an SCM. • System is suitable for both pipe and canal irrigation systems. • Fertilisation is controlled by irrigation flowrate and responds to its change. • Fertiliser was applied with great precision and distributed uniformly in the field. • Proposed system can improve fertiliser use efficiency and reduce manual labour.

Chelated copper reduces yet manganese fertilizer increases calcium-silica fouling in brackish water drip irrigation systems

Water scarcity and deficiency of trace elements (e.g., Cu and Mn) in soils of arid and semi-arid areas are major constrains to crop growth and development. The application of brackish water drip irrigation system (BWDIs), coupled with trace elements, is probably an effective way to solve this problem. However, fouling problems caused by trace elements in BWDIs were inevitable. Therefore, this paper evaluates the mechanism of different types of trace element chelated fertilizers on the fouling of emitters in BWDIs by using long-period, high-frequency periodic flow monitoring and mineral fraction analysis. The influence of chelated fertilizers such as copper (EDTA-Cu) and manganese (EDTA-Mn), and traditional micro-fertilizers copper sulfate (CuSO4) and manganese sulfate (MnSO4) on emitter fouling in BWDIs were investigated. Results suggested, compared with CK, the EDTA-Cu effectively alleviated the emitter fouling, increasing the average discharge ratio (Dra) and Christiansen coefficient of uniformity (CU) by 21.0%− 28.9% and 36.7%− 67.6%, respectively. Due to the strong adsorption ability, EDTA-Cu adsorb the Ca2+ and Mg2+ in BWDIs, which enhanced the structural stability, reduced the flocculation and deposition ability in the fouling, and indirectly reduced the content of calcium and silica fouling. In addition, compared with CK, the EDTA-Mn significantly aggravated the emitter fouling in BWDIs, decreasing the Dra and CU by 18.2%− 22.5% and 24.5%− 43.1% respectively. EDTA-Mn directly increased the content of Ca2+ and Mg2+ in BWDIs due to strong flocculation, which destroyed the morphology of EDTA-Mn chelates and indirectly increased the content of calcium silica fouling (calcite, muscovite, k-feldspar, dolomite and chlorite), thus reduced the anti-clogging ability of BWDIs. Considering these results, this study does not recommend the application of EDTA-Mn for manganese fertilizer in BWDIs. This study provides a new perspective on the rapid application of micronutrient fertilization in BWDIs, with potential implications for sustainable development in arid and semi-arid areas.

Developed for Hose Reel Irrigation Machines Determining Working Success of TURPO CLK FS Hardware

The aim of this study is determining of the working performance of the a new fertigation system (TURPO CLK FS) that developed for hose reel irrigation machines (HRIM). As a liquid fertilizers nitrogen and phosphorus were used. The HRIM was operated under two different irrigation water pressures (5 and 2.5 bar) conditions. The dosing pump was operated for two different frequencies (150 and 300 pulse/min). Field experiments were realised by using two different liquid chemical fertilizers and measured of pH, electrical conductivity (EC), and total dissolved solids (TDS) values. According to evaluation when using nitrogen fertilizer pH values ranged between 8.40 - 8.59, EC values 602.92 - 915.83 µS/cm, and the TDS values 294.17 - 451.25 mg/L at all sets. When using phosphorus fertilizer, pH values ranged between 7.13 - 8.03, EC values 485.42 - 519.58 µS/cm, and TDS values 236.25 - 252.92 mg/L. And then the Christiansen Coefficient of Uniformity (CCU) was calculated over 24 samples in each set. The CCU values were founded between 95.02% - 99.95%. As the result it has been concluded that the TURPO CLK FS could be used together with HRIM during fertigation applications.

Development of green energy based micro-sprinkler irrigation system for small holdings of SAT region

The Indian agriculture in the region of semi-arid tropics (SAT), characterized by small holders, small water harvesting and recycling system assumes a significant potential to sustain agricultural productivity by providing supplemental as well aslifesaving irrigation and mitigating mid-season drought. In Indian Agriculture, major energy consuming activities include on-farm water management. Efficient and cost-effective irrigation system matching the small-scale water harvesting and storage, are anot available in this region. In view of this, a carry-and-irrigate type micro-sprinkler irrigation system was designed and developedin order to achieve the holistic utilization of water resources and niche-potential of solar energy and gravity. The performance was measured on various parameters of application rate, Christiansen uniformity coefficient and pattern efficiency and were quantified as 14.2 mm/h, 91.3% and 89.01% respectively. The develop irrigation system qualified the performance criteria as standardized by ASAE, 1996. Given the characteristics of low cost and portability, it can considerably substantiate the vegetable production at household scale. Though, this system is developed exclusively for the location representing typical dryland agriculture of India, it can be easily and effectively replicated in other part of the world having similar agro-ecosystem. This simple water management technique utilizing the niche potential of gravity and solar energy can significantly contribute to the various objectives of sustainable development goal.

EFFICIENCY AND UNIFORMITY OF AN SUBSURFACE DRIP IRRIGATION SYSTEM IN SUGARCANE CROP

Agricultural productivity in irrigated areas depends on several factors, including the design and maintenance of irrigation systems. Excessive or insufficient applications of water affect plant growth and development, hence agricultural productivity. For this reason, the evaluation of the irrigation system is essential to avoid water loss during application. This study aimed to evaluate the efficiency and uniformity of a subsurface drip irrigation system in sugarcane crops in an area of the company Usina Coruripe, Alagoas, Brazil. For data collection, the flow rates were obtained in four points along the lateral line, in the first dripper, in the drippers located at 1/3 and 2/3 of the lateral line length, and in the last dripper of each operational unit of the irrigation project. In each row, four emitters were evaluated, totalizing 16 emitters, using a chronometer, collectors, and a measuring cylinder for data collection. In these emitters, the volume of water was collected for 3 minutes, with three repetitions. Christiansen's uniformity coefficient, distribution uniformity coefficient, statistical uniformity coefficient, Hart's uniformity coefficient, and application efficiency were estimated. The irrigation system was considered excellent for distribution uniformity. The application efficiency was classified as acceptable, with an average value of 88.9%. However, despite the application efficiency being classified as acceptable, periodic evaluations of the system are recommended.

Different Irrigation Pressure and Filter on Emitter Clogging in Drip Phosphate Fertigation Systems

Irrigation pressures and filters have a significant influence on emitter clogging in drip fertigation systems. Exploring the anti-clogging performance of emitters at different irrigation pressures (80, 90, 100 kPa; 40, 50, 60 kPa) and filters (the disc filter with an aperture of 125 μm, the screen filter with an aperture of 125μm, and the screen filter with an aperture of 200 μm) can provide suitable guidance for the design and operation of drip fertigation systems. The average relative discharge (Dra), the Christiansen uniformity coefficient (CU), and the differential pressure (DP) were analyzed to study the anti-clogging performance of flat emitters (FE) and labyrinth emitters (LE). Meanwhile, the scanning electron microscope and energy dispersive spectrometer were used to observe the surface morphology and chemical composition of clogging substances in filters and emitters. Results showed that the irrigation pressure of 90 and 50 kPa did not cause a significant decrease in Dra, and the Dra of two types of emitters were all great than 95.22%. When the irrigation pressure was 80 and 40 kPa, the Dra decreased significantly (73.48–78.71%, 81.3–83.6% for FE and LE). The CU values of emitters were all greater than 90% except for the irrigation pressures of 80 and 40 kPa. The relative Dra and CU of LE were greater than those of FE, indicating that the LE had a better anti-clogging performance compared with the FE. The decrease in DP reflected an increase in the emitter clogging degree. Meanwhile, irrigation pressures and the interaction between irrigation pressures and filters imposed a significant effect on the CU at a significance level of p < 0.05, p < 0.01, respectively. The clogging process was mainly affected by physical and chemical factors, and the generated clogging substances included phosphate fertilizer, silicate, carbonate, and phosphate precipitations. In conclusion, the best operation mode of phosphate fertilizer in drip fertigation systems was to use the disc filter with an aperture of 125 μm and the LE at the irrigation pressure of 50 kPa. An appropriate irrigation pressure combined with effective filters can reduce emitter clogging while saving water and fertilizer.