Fertilizer Distribution Uniformity Research Articles

Effect of manifold layout and fertilizer solution concentration on fertilization and flushing times and uniformity of drip irrigation systems

Applying fertilizer through drip irrigation system is a very important method to save fertilizer and labour. Three manifold layouts (water supply in one end for transversal drip tapes (M1), water supply in both ends for transversal drip tapes (M2) and water supply in one end for longitudinal drip tapes (M3)) and four different fertilizer solution concentrations (50.00 g L−1 (C1), 66.67 g L−1 (C2), 100 g L−1 (C3) and 200 g L−1 (C4)) were selected to investigated the effect of the manifold and concentration on water fertigation uniformity. Results showed that the emitter at the extreme end of the manifold needed more time to clean the rudimental fertilizer in the drip tapes. The minimal flushing time increased from 8 to 13, 4 to 7 and 7 to 12 min with increasing the fertilizer concentration from C1 to C4 for M1, M2 and M3, respectively. The drip irrigation system needed more time for flushing to reduce the risk of emitter clogging when a higher fertilizer solution concentration was applied. In order of performance, M2 had the highest water and fertilizer uniformity, followed by M3 and lastly by M1. The fertilizer solution concentration had no significant effect on water distribution. However, it had a significant effect on fertilizer distribution. The mass of the applied fertilizer for the drip tapes close to the inlet increased with increasing fertilizer solution concentration from C1 to C4, which indicated that higher fertilizer solution concentration can result in lower fertilizer distribution uniformity. There was a significant effect of the manifold layout on water uniformity. The fertilizer concentration and the interaction between manifold layout and concentration had no significant effect on the water uniformity. Similarly, both the manifold layout and concentration had a significant effect on fertilizer uniformity. The interaction between manifold layout and concentration had a significant effect on the Christiansen’s uniformity (CU) and distribution uniformity (DU) for fertilizer, whilst, a significant effect on emission uniformity (EU) was not found. The manifold layout and fertilizer solution concentration should therefore be considered in the design and operation of fertigation system.

Numerical simulation of spreading performance and distribution pattern of centrifugal variable-rate fertilizer applicator based on DEM software

Farmers in China have been concerned with the efficiency and utilization rate of fertilizers, because of the rigorous implementation of China’s “dual-reduction” plan, which calls for reducing fertilizer and pesticide usage. This study was aimed to improve the spreading performance and fertilizer distribution uniformity of an independently developed centrifugal variable-rate fertilizer applicator. The spreading performance was evaluated by conducting discrete-element-simulation tests, and the relationship between the variations in the fertilizer particle distribution and the working parameters of the fertilizer spreader was analyzed. The quality of the particles was evaluated using a two-dimensional matrix, and the coefficient of variation of the transverse distribution of the fertilizer particles was determined. The results show that the shape of the distribution varies irregularly with the increase in the vane pitch angle, and the coefficient of variation decreases with the increase in the spreader disc height. Further, when the application flow rate is increased gradually, the coefficient of variation decreases rapidly first but gradually thereafter. In addition, with an increase in the rotational speed of the disc, the distribution gradually changes from a triangular shape to a W shape and ultimately to an M shape. The average coefficient of variation was the lowest (14.39%) for a single-row application flow rate of 300 g/s, a vane pitch angle of 15°, a spreader disc height of 95 cm, and a rotational speed of 600 r/min, with a good spreading uniformity. Field validation tests show that the average coefficient of variation with respect to the effective spreading swath width of the applicator was 16.74%. The relative error was 10.66% with respect to the simulation results, thus validating the simulation model and confirming its accuracy. The results show that the coefficient of variation for the developed variable-rate spreader is reduced, exhibiting a high spreading performance. The results serve as a theoretical basis for farmers for altering their traditional empirical fertilization techniques and should aid design and optimization of centrifugal variable-rate fertilizer applicators.

Efficient Design of Drip Irrigation System using Water and Fertilizer Application Uniformity at Different Operating Pressures in a Semi‐Arid Region of India

AbstractPerformance evaluation of irrigation has been an important area of research for better management of water resources. The present study was conducted to evaluate the effect of drip lateral lengths and system operating pressures on water and fertilizer application uniformity at the Indian Agricultural Research Institute (IARI), New Delhi, India. The following parameters of nutrients and water were studied to design and evaluate the performance of drip irrigation systems: (i) uniformity coefficient; (ii) discharge variation; (iii) distribution uniformity; (iv) statistical uniformity. Drip‐line lengths and system operating pressures (P < 0.05 and P < 0.01) significantly affect the different parameters of fertilizer and water application. The highest values of uniformity coefficient (99.2%), statistical uniformity (99.2%) and distribution uniformity (97.4%) for irrigation water were observed at a pressure of 1.5 kg cm−2 with a 25 m long drip‐line. Lower values of discharge variation (2.65%) and coefficient of variation (0.04) were observed at the same operating pressure (1.5 kg cm−2) and drip‐line length. However, the lowest value of the uniformity coefficient (88.1%), statistical uniformity (93.7%) and distribution uniformity (93.2%) for irrigation water were recorded at 0.5 kg cm−2 pressure with a 100 m long drip‐line length. The highest values of urea, potassium and phosphorus distribution uniformity were found to be 97.8, 97.1 and 98.2%, respectively, at 1.5 kg cm−2 pressure with 25 m long drip‐line, and lower values of urea, potassium and phosphorus distribution uniformity (93.1, 92.6 and 93.2%, respectively) were recorded at 0.5 kg cm−2 pressure with a 100 m long drip‐line. Water and fertilizer distribution uniformity decreased with increase in drip‐line length, and increased with increase in system operating pressure. Copyright © 2017 John Wiley & Sons, Ltd.

Water and Nitrogen Distribution Uniformity for Different Drip-lengths under Drip Irrigation System

A field experiment was conducted at the research farm of Water Technology Centre, Indian Agricultural Research Institute, New Delhi during 2010 to study the effect of different drip-lengths (lateral) (25, 50, 75 and 100 m) and system operating pressures (0.5, 1.0 and 1.5 kg.cm-2) on water and nitrogen distribution uniformity under drip irrigation system. The varying drip lengths and system operating pressures significantly (P<0.01) affected coefficient of variation and distribution uniformity of the drip irrigation system. Highest distribution uniformity for both irrigation water (97.4%) and urea (97.8%) were observed at 1.5 kg.cm-2 operating pressure with 25 m long laterals. The lower values of urea distribution uniformity (93.0%) were recorded at 0.5 kg.cm-2 pressure with 100 m long drip line. Considering the system uniformity coefficient with drip lengths at different system operating pressures and an engineering approach towards the performance of the system for using drip-line, 50 m length was found appropriate for operation at 0.5 kg.cm-2 pressure. However, better performance of the drip up to 100 m lateral length was obtained at pressures of 1 and 1.5 kg.cm-2. Water and fertilizer distribution uniformity decreased with increase in lateral length, while it increased with increase in system operating pressure.

Effect of different vane combinations on fertilizer distribution uniformity with various flow rates in spinning disc broadcasters

Vanes throwing the particles of fertilizer or granular material onto a field are one of the most important machine parts influencing the fertilizer distribution pattern in spinning disc broadcasters. Manufacturers prefer mostly straight-shaped vanes in spinning disc broadcasters, probably because their production is easy. In previous studies, therefore, many researchers studied the spinning disc broadcaster with the straight-shaped vanes only. In this study, the effect of the combinations of the straight-shaped vane with different shaped vanes on the fertilizer distribution uniformity in single-spinning disc broadcaster was investigated with various flow rates using triple superphosphate. The combinations used in the study were the straight-shaped vane in combination with forward-curved-5, forward-curved-10, back-curved-5, and back-curved-10 vane, and ‘no combination’ consisted of the straight-shaped vane only. The circular orifices of 30, 40, and 50 mm diameters were used at the bottom of hopper to obtain the different flow rates of the fertilizer. The results of the study showed that the combination of the different shaped vanes on the spinning disc had a significant effect on fertilizer distribution uniformity. ‘No combination’ used commonly in practice did not give the best fertilizer distribution uniformity. The best fertilizer distribution uniformity was obtained from the combination of the straight-shaped vane with forward-curved-5 vane shape for all the flow rates. The CV values obtained from this combination were 10.31%, 15.49%, and 19.92% for the orifices with diameters of 30, 40, and 50 mm, respectively.

Evaluation of furrow fertigation and model validation on maize field

In new agricultural practices, joint application of water and fertilizer has been become common. Uniform distribution of fertilizer in soil and in plant growth duration is possible by this procedure. The main objective of this study was to investigate furrow fertigation management effects on distribution uniformity and runoff losses of nitrate in a cornfield, and validate a numerical fertigation model. A field experiment was carried out with seed corn at 12 experiments with a complete randomized block design during 2 years. Nitrogen requirement was determined by soil analysis and accomplished in four stages of the growth: before cultivation, in seven leaves, shooting and earring stages which first section (before cultivation) was applied by manual distribution and others by fertigation. Potash and super phosphate fertilizers (based on soil analysis) were sprayed on soil before planting. Water requirement was estimated by using class a evaporation pan multiplied by plant (Kc) and pan coefficients. Nitrogen fertilizer was solved in irrigation water and injected at the last minutes of irrigation. The results showed that fertilizer distribution uniformity of the low quarter (DULQ) ranged from 85.7% to 91.5% in first year, and 69.9% to 95.5% in second year. While water DULQ ranged from 74.1 to 98.2% in 2 years. Nitrate losses of surface runoff have ranged between 5.7 and 42.0% in first year according to the application time and the outflow flux. In second year, the nitrate losses decreased by adopting appropriate management based on the experiences of first year. The fertigation model was subsequently applied to the experimental data and results showed good agreement with field data.

Fertigation techniques for use with multiple hydrozones in simultaneous operation

Site-specific delivery of fertilizer is a useful tool to address differences in crop need. Modern systems with wirelessly networked sensors and valves allow multiple hydrozones to be created more easily than traditional wired systems. This allows irrigation and fertigation rates to be varied across small portions of a field. However, fertigation to multiple hydrozones with different fertilizer requirements may be complex if each zone cannot be fertigated in an independent set. Instead, it might be necessary to operate several fertigation zones simultaneously. This raises a concern over the ability to deliver fertilizer uniformly within each zone. Four fertigation strategies were tested. The conventional method was to fertigate multiple hydrozones at different times. Three site-specific strategies were considered, involving overlapping fertigation phases in multiple hydrozones. Fertilizer distribution uniformity tests were conducted with a 64-emitter drip line to determine which strategy gave the most uniform distribution of fertilizer within a hydrozone. All fertigation techniques performed well, with fertilizer distribution uniformities between 0.88 and 0.96. Selection of the optimum site-specific fertigation strategy will depend on crop needs, scheduling limitations, and system design parameters such as emitter type, fluid travel time, and slope. Similar to conventional fertigation, the main factor in fertilizer distribution uniformity for this study was drip emitter variability. In the presence of sloped terrain, the site-specific control strategy that involved a delay between fertilizer injection and flushing had the least uniform fertilizer application.

Analysis, assessment, and improvement of fertilizer distribution in pressure irrigation systems

The transformation of traditional irrigation systems into pressure irrigation networks allows water users associations to use central fertigation systems. For efficient fertigation management, however, it is essential to obtain uniform distribution of the injected fertilizer through the system and to understand the hydraulic processes that take place in the central fertigation system. This will allow users to implement strategies that improve fertilizer distribution. In this work we develop a new methodology to improve fertilizer distribution uniformity and apply it to a case study. The results show how fertilizer distribution can be improved by means of proper scheduling of irrigation deliveries. The best results are obtained when fertigating sectors operate without non-fertigating sectors and there are not intermediate irrigations without fertilizer, achieving an improvement of the fertilizer distribution of 10.5%. In addition, this work highlights the difficulties of obtaining uniform distribution of fertilizer in a centralized irrigation system when there are users that do not want to make use of it.

Uniformidade de distribuição do potássio e do nitrogênio em sistema de irrigação por gotejamento

O uso da fertirrigação possibilita a obtenção de bons resultados, todavia é notada a necessidade de trabalhos que venham possibilitar a adoção correta da técnica. Dessa forma ,o presente trabalho buscou comparar a uniformidade de distribuição do potássio e do nitrogênio em sistema de irrigação por gotejamento. A solução de fertilizantes foi injetada durante 25 minutos, sendo recolhidas amostras de solução em diferentes momentos, durante e após ter sido finalizada a operação de injeção, tendo sido especificado o tempo de 35 minutos após o início da operação de injeção da solução de fertilizantes, como tempo-limite para a coleta da última amostra. As amostras coletadas tiveram os teores de potássio (K+) e nitrogênio (NO3- + NH4+) determinados. Com os resultados obtidos, concluiu-se que não houve variação significativa da uniformidade de distribuição de nitrogênio e de potássio no sistema de irrigação por gotejamento; maiores tempos de funcionamento de sistemas de irrigação, quando em operação de fertirrigação, possibilitam melhores uniformidades de distribuição do fertilizante, e deve-se calcular o tempo de lavagem do sistema de irrigação, pois é uma forma de melhorar a uniformidade de distribuição do fertilizante no campo.

Technical Note: Effect of Vane Shape on Fertilizer Distribution Uniformity in Single-Disc Rotary Fertilizer Spreaders

Vanes used in rotary fertilizer spreaders can be straight, curved, or composite-shaped. No information was found in the literature on the effect of different vane shapes on fertilizer distribution uniformity. In this study, the effect of different vane shapes on the fertilizer distribution uniformity in single-disc rotary fertilizer spreaders was investigated using triple superphosphate and calcium ammonium nitrate. The vane shapes used in the study were straight, composite, forward-curved-5, forward-curved-10, back-curved-5, and back-curved-10. The results of the study showed that the shape of vane had a significant effect on fertilizer distribution uniformity. The straight vane shape, the most commonly used, did not give the best fertilizer distribution uniformity. The best fertilizer distribution uniformity was obtained from the forward-curved-5 vane shape for both triple superphosphate and calcium ammonium nitrate.

Effect of Cone Angle and Revolution Speed of Disc on Fertilizer Distribution Uniformity in Single-Disc Rotary Fertilizer Spreaders

Effect of Cone Angle and Revolution Speed of Disc on Fertilizer Distribution Uniformity in Single-Disc Rotary Fertilizer Spreaders

EFFECT OF VANE NUMBER ON DISTRIBUTION UNIFORMITY IN SINGLE-DISC ROTARY FERTILIZER SPREADERS

Rotary fertilizer spreaders with single or twin discs are commonly used to distribute granular fertilizer ormaterials. These granular fertilizer and materials are distributed by the vanes on the disc. However, the effect of different vanenumber on the fertilizer distribution uniformity with different flow rates is unknown. In this study, therefore, the effect of vanenumber on the distribution uniformity in single-disc rotary fertilizer spreaders with different flow rates was studied usingtriple superphosphate and calcium ammonium nitrate. The number of vanes tested in the experiments was 2, 4, 6, 8, 10, and12. The orifices of 30-, 40-, and 50-mm diameters were used at the bottom of the hopper to obtain the different fertilizer flowrates. The data from this study showed that the best distribution for both fertilizers was obtained with the combination of twovanes and an orifice diameter of 30 mm and that distribution uniformity became worse as the number of vanes increased.

Distribuição de fertilizantes em um sistema de fertirrigação por gotejamento

Objetivou-se, com este trabalho, avaliar a uniformidade de distribuição temporal e espacial de fertilizantes em um sistema de fertirrigação por gotejamento, instalado numa área cultivada com maracujazeiro amarelo, em Piracicaba, SP. O sistema de irrigação utilizado foi por gotejamento, com emissores de vazão de 2,4 L h-1. A fertirrigação foi realizada com uma bomba injetora de fertilizante de acionamento hidráulico e o tempo de injeção da solução no sistema foi de 1,0 h. Para se avaliar a uniformidade de distribuição de nutrientes nas linhas de irrigação, coletaram-se amostras da solução nas linhas laterais aos 2, 12, 22, 32, 42 e 52 min após o início da aplicação dos fertilizantes, nos gotejadores da primeira planta (2 m), e nos das plantas localizadas a 1/3 (10 m), 2/3 (22 m) e da última planta (34 m). A concentração de fertilizantes nas amostras foi determinada através da condutividade elétrica e a uniformidade de distribuição de fertilizantes avaliada pela relação entre os seus menores valores de condutividade elétrica e a média das amostras. Nas linhas lavadas antes da fertirrigação, os índices de uniformidade apresentaram-se maiores e se observou que a uniformidade de distribuição de fertilizantes aumentou com o tempo até os 42 min e se manteve constante a partir desse instante.

Overland Water Flow and Solute Transport: Model Development and Field-Data Analysis

The application of plant nutrients with irrigation water is an efficient and cost-effective method for fertilizer application to enhance crop production and reduce or eliminate potential environmental problems related to conventional application methods. In this study, a combined overland water flow and solute transport model for analysis and management of surface fertigation/chemigation is presented. Water flow is predicted with the well-known Saint-Venant's equations using a control volume of moving cells, while solute transport is modeled with the advection-dispersion equation. The 1D transport equation was solved using a Crank-Nicholson finite- difference scheme. Four, large-scale, field experiments were conducted on blocked-end and free draining furrows to calibrate and verify the proposed model. The results showed that application of solute during the entire irrigation event, or during the second half of the irrigation for blocked end conditions with appropriate inflow rates, produced higher solute uniformity than application of solute during the first half of the irrigation event. Measured fertilizer distribution uniformity of the low quarter ranged from 21 to 76% while fertilizer distribution uniformity of the low half values varied between 62 to 87%. The model was subsequently applied to the experimental data; results showed good agreement with all field data. Water balance errors for the different experiments varied from 0.004 to 1.8%, whereas fertilizer mass balance errors ranged from 1.2 to 3.6%. A sensitivity analysis was also performed to assess the effects of longitudinal dispersivity parameter on overland solute concentrations. A value of 10 cm for dispersivity provided a reasonable fit to the experimental data.

Fertigation Uniformity Affected by Injector Type

Application uniformity of fertilizers and pesticides is critical for crop uniformity, but can be difficult to determine when a fertilizer or chemical (fertigation/chemigation) is applied via drip irrigation or deep irrigation tape. Three injectors (venturi, pump, and proportional) were compared in a greenhouse experiment with a continuous-injecting experimental plot injector for fertilizer distribution uniformity in a drip irrigation system. Injection rate and solution volume were evaluated in a field experiment. Injection rate had a significant effect on fertilizer distribution uniformity. Better fertilizer distribution in the greenhouse experiment was obtained with venturi and proportional injectors. In the field, better distribution was obtained with the 1 gal/min (0.06 L·s-1) positive-displacement pump than with the 3 gal/min (0.19 L·s-1) pump. Injection times were longer with these injectors than with the other treatments, with the exception of the continuous injector. Injectors tested in this experiment will give uniform fertilizer distribution if the injector is properly sized with the water flow rate of the system.

Border fertigation: field experiments and a simple model

Fertilizers are commonly dissolved in border irrigation water. However, there are no available procedures for the proper design and management of surface fertigation. A series of experiments was conducted to determine the uniformity of fertilizer application under varying inflow discharges and fertilizer application times in blocked-end borders. Results from the fertigation evaluations showed that the fertilizer distribution uniformity of the low half (DULH) ranged from 2.9 to 51.6%, while water DULH ranged from 63.5 to 96.9%. A simplified border fertigation model based on one-dimensional convection was formulated and applied to the simulation of the experiments. The model was able to explain 43.8% of the variability in the fertilizer DULH. Application of the model to selected case studies revealed that short-duration applications, such as those resulting from instantaneous release of fertilizer into the irrigation stream, often produce low uniformities. This is particularly true for early applications in blocked-end borders and for early and late applications in level basins. In both irrigation systems, application of fertilizer at a constant rate during the entire irrigation event is frequently the best solution. In the presence of runoff, the model can be used to find a compromise between fertilizer application uniformity and runoff losses. Finally, if large deep percolation losses are expected, the model can identify uniform fertigation options based on late applications of fertilizer.