Photovoltaic Direct Drive Water-saving irrigation System and Its Optimization Design Method

Photovoltaic irrigation has been widely used in many areas without conventional energy sources. In order to solve the problem of unstable operation and poor irrigation uniformity caused by the diurnal variation of solar radiation, a photovoltaic direct-drive water-saving irrigation system with automatic regulation was proposed. By using automatic control technology and the method of zonal rotation irrigation, all the electric energy generated by solar panels can be converted into irrigation energy under different light intensities, so that the water-saving irrigation equipment can work stably in different regions and the irrigation uniformity is ensured in different regions. According to the characteristics of solar energy resources and photovoltaic water-pumping units, the optimum design method of photovoltaic water-saving irrigation system is put forward. The minimum capacity of solar panels can meet the irrigation demand of a certain area, which can guide the engineering design of solar water-saving irrigation, greatly improve the engineering quality and energy utilization rate. It has the advantages of simple design, low cost, stable operation and energy-saving ring.

Analisisis Kinerja Sprinkler Mini Meganet 24 D Netafim Terhadap Variasi Debit dan Jarak Penempatan Sprinkler

Currently, there are many efficient and effective sprinkler irrigation tools on the market, so it is necessary to be careful in choosing for irrigation. Among them, the Meganet 24D Netafim, including the type of irrigation tool, which still needs testing to know its performance. This study aims to examine the sprinkler irrigation performance of Meganet 24D Netafim, on variations in flow rate and distance between sprinklers, related to irrigation uniformity (CU) and irrigation radius (Rn). This test was carried out on an area of about 1 acre, at a flow rate of Q1=0.42/sec, Q2=0.51 l/sec, Q3=0.52/sec, Q4=0.56 and the test sprinkler distance, r1=2 ,5m, r2=3m,r3 = 3.5m and r4 = 4m. The results of data analysis are presented in the form of tables and graphs and concluded descriptively. The results showed that, in all variations of Q and sprinkler spacing r1, r2, r3 obtained irrigation uniformity (CU) above 85% which was classified as high, while in the r4, Q1 and Q2 tests, CU was obtained below 85% which was considered low. All discharge variations, showing irrigation radius (R) about 5 m. So at r4 sprinkler spacing, it is not recommended in irrigation applications.

Evaluation of the Quality of Irrigation Machinery by Monitoring Changes in the Coefficients of Uniformity and Non-Uniformity of Irrigation

Recently, the development of agricultural technology has been focused on achieving higher reliability and quality of work. The aim of the presented paper was to examine the possibilities of evaluating the quality of work of wide-area irrigation machinery by monitoring the coefficients of uniformity and non-uniformity of irrigation. The object of the research was pivot irrigation machinery equipped with sprinklers with a total length from 230 to 540 m. The commonly applied quality of work parameter for wide-range irrigators is the irrigation uniformity coefficient according to Heermann and Hein CUH. Work quality evaluations were also carried out through other parameters applicable in practice, such as irrigation uniformity coefficients calculated according to Christiansen CU, Wilcox and Swailes Cws, and our introduced parameters, the coefficient ar (derived from the degree of unevenness according to Oehler) and the degree of uniformity γr (derived from the degree of non-uniformity according to Voight). Other applied parameters for determining the quality of work of wide-range irrigation machinery were the coefficients of irrigation uniformity according to Hart and Reynolds CUhr, further according to Criddle CUcr and subsequently according to Beale and Howell CUbr. Next, the parameters of the non-uniformity coefficient according to Oehler a, the coefficient of variation according to Stefanelli Cv, the degree of non-uniformity according to Voigt γ and the degree of non-uniformity according to Hofmeister Ef were evaluated. Field tests were performed during the growing season of cultivated crops (potatoes, corn and sugar beet) in the village of Trakovice (agricultural enterprise SLOV-MART, southwest of the Slovakia) and in the district of Piešťany (Agrobiop, joint stock company). During the research, the inlet operating parameters (speed stage, inlet pressure, irrigation dose), technical parameters (number of sprayers, total length, number of chassis) and weather conditions (wind speed and temperature) were recorded. The obtained results were examined by one-way ANOVA analysis depending on the observed coefficient or input conditions and subsequently verified by Tukey and Duncan tests as needed. Irrigation uniformity values ranged from 67.58% (Cws) to 95.88% (CUbh) depending on the input conditions. Irrigation non-uniformity values ranged from 8.58 (a, Ef) to 32.42% (Cv). The results indicate a statistically significant effect of the site of interest and thus the impact of particular field conditions (p < 0.05). When evaluating the application of different coefficients of irrigation uniformity, the results showed a statistically significant effect only in the first test (p = 0.03, p < 0.05). During further repeated measurements, the quality of work increased due to the performed inspection of all sprayers and the reduction in the influence of the wind.

Impact of the Intermittency Movement of Center Pivots on Irrigation Uniformity

A computer model was developed to simulate the varying depths of water applied to the ground due to the intermittent movements of a typical center pivot. The stop–go model inputs include the sprinkler application depth, the sprinkler pattern, that pattern’s wetted radius, the center pivot’s % timer setting, the move cycle time, and the end tower maximum travel speed. The model outputs were the depth of application in the pivot’s movement direction, the distribution uniformity (DU), and the coefficient of uniformity (CU). The results revealed that the pivot circular application uniformity is mostly a function of the move distance as a percent of the sprinklers’ wetted radius. This, in turn, is a function of the percent timer setting, the cycle time, and the end tower travel speed. Due to this, the high-speed center pivots had corresponding lower application uniformities compared to low-speed machines, and sprinklers with larger wetted radii resulted in better uniformity. Shortening the cycle time also resulted in higher uniformity coefficients. Based on these results, it is recommended that the run time be set based on the pivot end-tower’s travel speed and sprinkler wetted radius, such that the end tower move distance is equivalent to the sprinkler wetted radius. This will reduce wear to the tower motors due to the on–off cycling, especially for slow travel settings and for sprinklers with larger wetted radii. The ponding depths at different percent of the move distance, for the potential runoff, were estimated, which were set to be equivalent to the wetted radius.

Aeschynomene spp. Identification and Weed Management in Rice Fields in Southern Brazil

In 2002, a survey carried out in rice paddies in the Rio Grande do Sul (RS) state reported the occurrence of nine species of jointvetch (Aeschynomene). Due to their semi-aquatic habit, some species adapted to irrigated rice fields, which led to their being considered the worst broadleaf weed in RS. Although farmers have successfully implemented weed management practices, Aeschynomene plants have reportedly escaped chemical control. This study aims to identify the species of Aeschynomene that occur in rice fields in RS and to evaluate the reasons why escapes are occurring. A survey was carried out by collecting mature seeds from individual adult plants. A questionnaire on the management practices employed in each field was administered to 54 farmers and 18 extension agents, each of whom was responsible for one of the surveyed rice fields. This survey found four species of Aeschynomene are present in rice fields in RS: A. denticulata, A. indica, A. rudis, and A. sensitiva. The results suggest that the explanation for escapes may lie in the management practices adopted by farmers, which are focused on the control of weedy grasses. Escapes are also associated with problems such as the lack of irrigation uniformity and out-of-stage, late herbicide applications.

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.

Variable-Rate Irrigation Uniformity Model for Linear-Move Sprinkler Systems

HighlightsUsing different nozzle sizes on a linear-move sprinkler irrigation system is a simple method for implementing VRI.This study established a variable-rate sprinkler irrigation model for a linear-move system with different nozzles.Uniformity parameters were predicted for different tests, and prediction accuracy ranged from 1.6% to 13.0%.The simulation model can be applied to other sprinkler systems with variable-rate irrigation.Abstract. Variable-rate irrigation (VRI) can vary the application rate by either changing the amount of water flowing through sprinkler nozzles (zone control) or varying the speed of a moving irrigation system across parts of a field, referred to as speed/sector control. The uniformity of sprinkler irrigation in each management zone under VRI directly affects crop growth and yield. The use of different nozzle diameters on a linear-move sprinkler irrigation system is a simple and affordable method for achieving VRI. There are few studies on modeling the uniformity of VRI on linear-move sprinkler irrigation systems. In this study, a cubic spline difference-value model was used to simulate the variable-rate water distribution and uniformity of a linear-move system. Nine tests were designed to evaluate VRI uniformity with different nozzle diameters. A simulation and corresponding field experiments were carried out. The application rate of the simulation model was higher than the experimental values because of wind drift. The uniformity coefficients of the simulation with nozzle diameters of 1.98, 2.97, and 4.17 mm in tests 1, 2, and 3 were 86.56%, 85.24%, and 79.94%, respectively. The uniformity coefficients of the VRI simulations with combinations of nozzle diameters in tests 4 through 9 were 76.89%, 80.70%, 76.67%, 69.58%, 76.64%, and 81.87%, respectively. The smallest error between the simulation and experiment was 1.6%, and the largest error was 13.0%. The simulation model and prediction method can be applied to other sprinkler irrigation systems. Keywords: Linear move, Simulation model, Sprinkler irrigation, Uniformity, VRI.

Determination of qualitative indicators of the work of the wide sprinkling machine

The aim of the research is to select the diameters of the nozzles of the deflector nozzles and to determine the quality indicators of the operation of a new wide-grip sprinkler of circular action, developed at the Federal State Budgetary Scientific Institution «RosNIIPM». The selection of the diameters of the nozzles of the deflector nozzles was carried out from the conditions of passing three different flows through the DM water pipeline: 15, 30 and 60 l/s. The scheme of their arrangement – rain-forming devices have different flow rates and diameters of nozzles at the same distance between them along the DM water-conducting pipeline. The analysis of the results obtained showed small deviations in the actual flow rate of the deflector nozzles through the water pipeline (cf. deflector nozzles with calculated nozzle diameters. Investigations of irrigation uniformity were carried out, as a result of which the following results were obtained: effective irrigation coefficient – 0.67–0.78; the coefficient of insufficient irrigation is 0.10–0.12, the coefficient of excessive irrigation is 0.12–0.15. At the same time, a decrease in the uniformity of irrigation is associated with an increase in wind speed and thereby an increase in the drift of artificial rain drops, the worst condition for the use of a WDM is a wind speed of more than 5 m/s, and therefore it is recommended to use this DM in the morning and evening, characterized by a more reduced wind load.

A simplified method to improve water distribution and application uniformity for sprinkler irrigation on sloping land: adjustment of riser orientation

To improve the water application uniformity for sprinkler irrigation on sloping land, indoor tests were conducted on an artificial slope (slopes of 0, 0.05, 0.10 and 0.15) to evaluate the effects of two riser orientations, vertical (VO) and perpendicular (PO) to the slope, on the uniformity of sprinkler rotation, radius of throw, water distribution of an individual sprinkler and the overlapped water application uniformity (WAU). Compared with the VO, the PO could effectively improve the water distribution on sloping land and minimize the risk of soil erosion. Additionally, the PO was superior in the WAU, and a rectangular arrangement could dramatically enhance the WAU at smaller sprinkler spacing, while larger acceptable sprinkler spacing was accepted in a triangular arrangement. The riser orientation and sprinkler spacing had the most significant effect on the WAU, followed by the slope and sprinkler arrangement, suggesting that the adjustment of riser orientation or sprinkler spacing was helpful in improving the WAU. However, from the aspects of investment cost and installation convenience for irrigation projects, the method of PO was recommended. Therefore, when designing the sprinkler irrigation systems on the slope, choosing PO is the simplest and most effective way to achieve good irrigation uniformity.