Blog | S.S.S | Bizi Takip Edin |

Fertilization and Irrigation Automation

esular-gubreleme

Fertilization and Irrigation Automation

Fertilization and irrigation automation represents a significant step towards the future of modern agriculture. In this article, we will examine the benefits of fertilization and irrigation automation for the agricultural sector, how it works, and the most commonly used fertilizers.

Timely fertilization and irrigation are crucial for plant development in agricultural areas. Agricultural fields are often located far from residential areas, making it difficult to carry out irrigation and fertilization. To alleviate the human burden in agriculture, increase productivity, and address challenges, a IoT system consisting of mobile applications and hardware has been developed. With the mobile application, irrigation and fertilization instructions can be entered according to the days. As a result, agricultural fields can be managed regularly and efficiently.

esular-gubre-dozajlama

What is Fertigation?

Fertigation is the simultaneous application of irrigation and fertilization. Due to the continuous flow in irrigation systems, fertilizer can be applied to the root zone of plants at the desired time and in sufficient quantities. This way, nutrients for plants can be maintained at optimal levels throughout the growth period, saving time, fertilizer, and labor. On the other hand, the accumulation of harmful substances in the soil is prevented.

The efficiency of water and fertilizer use by plants is important both economically and environmentally. Excessive irrigation and fertilizer applications lead to groundwater contamination through leaching. In this context, it has been demonstrated that effective fertilization in plants irrigated by drip irrigation is achieved through fertigation, which is an important practical way to protect the environment. The key in practice is to apply plant nutrients close to the plant roots to achieve the highest efficiency from the fertilizer and unit irrigation water that plants can easily absorb. This method can be used with almost all irrigation techniques, but when fertigation is mentioned, drip irrigation method comes to mind first. The reason for this is the challenges encountered in other irrigation methods. In surface irrigation method, successful fertilization cannot be achieved when land leveling is not done properly. In sprinkler irrigation, excessive fertilizer concentration can lead to some diseases and pests on plant leaves. Considering these conditions, drip irrigation method comes to mind first when fertigation is mentioned.

Advantages of Fertigation Method

The advantages of the fertigation method can be listed as follows:

  • Since fertilizers are applied to the root zone of the plant along with water, extra fertilizer is not applied to areas where root development is not present.
  • Fertigation reduces both production costs and groundwater pollution by applying less fertilizer and water.
  • Ensures the full and uniform delivery of nutrients to the root zone. Thus, control of water and nutrient elements in the soil prevents nutrient loss through leaching and surface runoff.
  • Provides energy and labor savings.
  • Increases yield and quality of the product.
  • Reduces the exposure of applicators to applied chemicals.
  • Allows fertilization without the need for machinery to enter the field.
  • Increases the efficiency of saline nutrients, thereby increasing fertilizer efficiency.
  • Reduces the negative impact of wastewater.
  • Minimizes fertilizer losses due to leaching.
  • Facilitates disease control as the upper part of the plants is not wetted.
  • If desired, appropriate agricultural control agents and other chemical substances can be applied simultaneously.
  • Suitable for automation.
esular-gubreleme-besin

Injectors Used in Fertilization with Fertigation

The injectors used for fertilization with fertigation are:

  • Fertilizer tank
  • Piston pump
  • Venturi injector system

Fertigation with a simple fertilizer tank: This tank is a cylindrical, epoxy-coated, irrigation system’s pressure-resistant metal tank connected to the pressure control pipe as a bypass. The fertilizer tank operates by creating a pressure difference with the valve partially closed between the tank’s inlet and outlet pipes. A portion of the water flow is diverted from the main line to enter the tank from below. This water flow mixes with the fertilizer solution, and the diluted solution is supplied to the irrigation system. The fertilizer concentration is initially high and becomes very low by the end of operation.

Piston pump: This type of injector derives its power from the system’s water pressure. Bypass can be installed directly on the source line, not on the line. The irrigation system’s water flow activates the pistons, maintaining a constant injection rate by delivering fertilizer solution from a tank to the system. The injection rate varies between 9-2500 liters/hour depending on the irrigation system pressure. These injectors, made of durable plastic material, come in different models and sizes. Piston pumps are much more expensive than Venturi-type injectors.

Venturi injector system: This injector is based on the Venturi tube principle, requiring a pressure difference between the injector inlet and outlet. Therefore, it is connected to a bypass arrangement installed on an open tank containing the fertilizer solution. The injection rate of the Venturi-type injector is highly sensitive to pressure changes, sometimes requiring small pressure regulators for consistent injection. Friction losses are approximately 1.0 bar. Venturi injectors are manufactured from plastic material in sizes ranging from 1/2 to 2 inches, with injection rates between 40-2000 liters/hour. Compared to other injectors, Venturi injectors are relatively cheaper.

When selecting fertilizer for fertigation, four main factors should be considered:

  • Plant variety and growth period
  • Soil conditions
  • Water quality
  • Availability / effectiveness and price of the fertilizer

Plant Nutrients Absolutely Necessary in Fertigation

Plants require certain substances to develop healthily. These essential nutrients, which plants need, are called essential nutrients. The absence of one or more of these substances in the growing environment prevents plants from completing their normal development, leading to yield and quality loss in the crop. These nutrients are:

 

Absolutely Essential Nutrients
Karbon (C)
Potasyum (K)
Bakır (Cu)
Hidrojen (H)
Kükürt (S)
Mangan (Mn)
Oksijen (O)
Kalsiyum (Ca)
Molibden (Mo)
Azot (N)
Magnezyum (Mg)
Bor (B)
Fosfor (P)
Demir (Fe)
Klor (Cl)
Sodyum (Na)

When all these factors are evaluated together, it becomes apparent that our agricultural soils are not as productive as commonly believed. For agriculture to be conducted scientifically, it is necessary to have a good understanding of the properties of the soil and to develop fertilization programs accordingly.

Common nitrogenous fertilizers include:

Nitrate fertilizers: There are also fertilizers containing nitrogen in the nitrate form, such as calcium nitrate, potassium nitrate, and magnesium nitrate. Concentrated nitric acid (HNO3), which contains 17% nitrogen (N) by volume, is used in greenhouse production to reduce the pH value of irrigation water and to clear clogs in drip irrigation systems.

Ammonium and nitrate fertilizers (15% – 34.5% N): These fertilizers contain nitrogen in both ammonium (NH4) and nitrate (NO3) forms. In our country, Turkey, fertilizers containing 26% N and 33% N ammonium nitrate are produced. Types of ammonium nitrate fertilizer containing 26% N and 33% N are mainly used in agriculture for top dressing (in-between rows, irrigation, on the soil surface during wheat cultivation). Types containing 33% N or 34.2% N can be applied to plants more with drip irrigation and sprinkler systems. Although ammonium nitrate fertilizer is neutral in reaction, it can show a slightly acidic character due to the conversion of ammonium ions to nitrate and NH4 uptake.

 Common Phosphorus Fertilizers:

Monoammonium Phosphate (MAP): It is a composite fertilizer containing phosphorus and nitrogen together. This fertilizer, also known as MAP, contains 11-25% nitrogen (N) and 48-51% phosphorus (P2O5). Due to its very high total effective material content (approximately 70-75%), it is the most widely used fertilizer as a phosphorus source in drip irrigation in greenhouse cultivation. MAP is a slightly acidic, high-phosphorus-containing fertilizer, and almost all of its phosphorus content becomes suitable for plants.

Diammonium Phosphate (DAP): It is a composite fertilizer similar to MAP, containing phosphorus and nitrogen together. DAP fertilizer contains 16-18% nitrogen (N) and 48-51% phosphorus (P2O5). It is in granular form, dark gray or dirty white in color. It contains 3 kilograms of phosphorus for every 1 kilogram of nitrogen, making it primarily used as a phosphorus fertilizer. Approximately 90% of its phosphorus content is water-soluble. Physiologically, it has a slightly alkaline character. Upon contact with soil and decomposition, its reaction becomes acidic.

Mono Potassium Phosphate (MKP): MKP is a composite fertilizer containing 52% P2O5 and 34% K2O. It has a high solubility in water, does not contain any filler additives, has a white crystal structure, and a physiological acidic character. Similar to MAP fertilizer, it can be used for fertigation and foliar feeding. When dissolved in water, the phosphorus it contains can be easily absorbed by plant roots under slightly acidic greenhouse conditions. In terms of plant nutrients, it has the highest effective substance among all fertilizers (% 52 P2O5 + % 34 K2O = % 86).

Common Potassium Fertilizers:

Potassium Nitrate (KNO3): Potassium nitrate is a white, crystalline fertilizer that contains potassium and nitrogen elements together. It has a high solubility in water, a physiological alkaline character, and contains approximately 13% nitrogen in the form of nitrate (NO3) and 46% potassium equivalent to K2O. Widely used in drip irrigation and foliar applications, this fertilizer has been produced in recent years with a physiological acidic character called “low pH KNO3” fertilizer, ensuring safer use for plant fertigation. Potassium nitrate fertilizer should be applied especially in irrigated and rainy areas either at sowing or after sowing.

Potassium Sulfate (K2SO4): This fertilizer, which has a crystal-like appearance with a dirty white salt structure, contains both potassium (50-53% K2O) and sulfate (18% S). Due to its absence of chlorine and its combination of potassium and sulfur, it is widely used in horticulture, gardening, and greenhouse farming through soil application and drip irrigation. Potassium sulfate has a physiological acidic character and can lower the soil pH when continuously applied to the same soil. It should be applied to the soil at planting, and it is successfully used in crops such as potatoes, tobacco, citrus, and sugar beets, which are sensitive to chlorine.

Fertilizer Fertigation: Things to Consider

For the effective and accurate application of fertilizers and other chemicals in fertigation, it is crucial to follow the guidelines provided below:

  • Fertilizers that do not completely dissolve in water (such as urea and ammonium sulfate) are not suitable for drip irrigation systems. If these fertilizers need to be used, they should be dissolved in another container beforehand and the solid particles should be filtered out before being added to the fertilizer tank.
  • Only water should be supplied until the operating pressure is reached before applying fertilizer solution to the irrigation system.
  • Besides nitrogen, phosphorus, and potassium, it is possible to apply other macro and micro nutrients in appropriate proportions and quantities through fertigation.
  • Despite some plant nutrients being completely soluble in water in the fertigation method, they may react with other nutrients or ions present in the irrigation water, such as calcium or magnesium, to form precipitates. Therefore, knowing the quality of the irrigation water and the compatibility properties of the fertilizers is crucial for success in practice.
  • If the irrigation water is calcareous, phosphorus fertilizer should be applied to the soil as the basic fertilizer.
  • The annual fertilizer requirement of plants can be calculated for fertigation by dividing it by the number of irrigations. However, the fertilizer amount in the irrigation system should not exceed 5 g/L.
  • In fertigation, fertilizers should be of high quality, high solubility, and purity, with a low salt index and suitable pH.
  • Fertilizers containing phosphate should not be used together with those containing calcium.
  • After fertilization is completed, the drip irrigation system should continue to run with water only for 10-15 minutes.
  • The pH level of the irrigation water used in fertigation should be between 5.5 and 6.5. To maintain this range, acids such as phosphoric acid, nitric acid, sulfuric acid, or hydrochloric acid can be used. Otherwise, clogging may occur in laterals and emitters.
  • When using acid, it should be added to water, not the other way around.
  • Never mix an acid or acidic fertilizer with chlorine. Acid and chlorine should not be stored in the same room.
  • Concentrated fertilizer solutions should not be mixed with another concentrated fertilizer solution.
  • Compounds containing calcium should not be mixed with compounds containing sulfate. This will result in the formation of insoluble gypsum.
  • At the end of the irrigation season, the irrigation system should be cleaned by running it with 0.3% Nitric Acid.
  • High concentrations of some fertilizer combinations can lead to crystallization and pipe clogging.

Concentrations causing crystallization:

  • Calcium nitrate + ammonium sulfate = calcium sulfate
  • Calcium nitrate + potassium sulfate = calcium sulfate
  • MKP + calcium phosphate = calcium phosphate
  • MAP + calcium nitrate = calcium phosphate
  • Phosphoric acid + calcium nitrate = calcium phosphate

Automatic Fertilization and Fertigation Systems

Automatic fertilization systems ensure the mixing of fertilizer and water to deliver the required amount of fertilizer to the plant. With the increasing use of liquid fertilizers and the development of soilless farming practices, the demand for such systems has grown. The aim here is to automate the process of injecting fertilizer into the system.

Automatic Fertilization Working Principle:

The various fertilizers and acids in the mixing tank are injected into the main irrigation line in the form of a homogeneous solution in dosages. The absorption of fertilizer and acid in the dosage channels is based on the venturi principle, which relies on the differentiation of pressure in the main line. It can be designed in 3+1, 4+1, 5+1 formats according to the need.

NPK gubre

Main Components of Automatic Fertilization​

Venturi: This equipment operates according to the well-known Venturi principle. The speed of the fluid moving in a venturi increases as it passes through the narrowing region of the venturi, and due to this increase, reverse pressure occurs in this region. This reverse pressure creates a vacuuming effect within the contraction zone and causes the transfer of fluid without consuming any extra energy. There are numerous types of Venturis available, but the simplest and easiest to use are those, like the ones used in our system, which do not require additional equipment apart from the constriction in the flow path. During the use of the Venturi, a check valve should be present on the line from the solution tank to the Venturi to prevent backflow.

esular-gubreleme-

EC Sensor: EC stands for electrical conductivity. Since the conductivity of water depends on the ions dissolved in it, EC also expresses the rate of salt dissolved in water. In other words, it is a measure of the salinity of water. The relevance to plants is as follows: If the plant’s sap is denser than the water around its roots, the water around its roots is absorbed by the plant. However, if this water is saltier than the plant’s sap, absorption will not occur. If this problem intensifies, it can lead to the death of the plant. If the nutrient solution prepared for the plant contains a salinity level higher than the maximum tolerance of the plant, the plant will be unable to absorb water and will dry out.

In this system, the fertilization dosing allows for the controlled delivery of fertilizer into the system at the desired and adjusted EC and pH levels. The control unit also provides EC control in a proportional fertilization program combined with water volume. Electrical conductivity measurement enables the adjustment of the density of fertilizers added to the irrigation water. Similarly, each crop has specific EC requirements based on its characteristics and growth stages. Adjusting, measuring, and applying all these factors together is necessary. This ensures that the highest yield and quality of fruits or vegetables can be achieved. The EC sensor measures the conductivity value of the solution in the fertilization control device’s output line. If the desired measurement value cannot be reached, the system is stopped with a warning.

 

  • Avoid using chloride-based fertilizers in soils with high EC values.
  • EC/TDS
  • EC Range: 0.0 to 10.0 mS/cm
  • EC Resolution: 0.1 mS/cm
  • EC Accuracy: ±0.078 mS/cm

 

pH sensor: pH is a measure unit defining the acidity or alkalinity of a solution. The pH value of pure water is 7. As the pH value of a solution approaches 0, its acidity increases, and as it approaches 14, its alkalinity increases. For plants to absorb necessary nutrients from the soil, pH levels need to be within certain ranges. In soils with low pH, the absorption of heavy metals such as copper, manganese, iron, zinc, aluminum, and boron, along with the conversion of nitric cations (urea to ammonium), increases, while the absorption of magnesium, calcium, nitrate, phosphorus, and potassium decreases. This directly affects productivity. In soils with high pH, the absorption of micronutrients such as iron, manganese, boron, and zinc, as well as phosphorus, becomes more difficult for plants.

If the fertilization process is done with ideal values, the plant can receive all the necessary nutrient values without any deficiencies. In our country, irrigation waters generally experience high pH issues. High pH values lead to yield losses and a decrease in soil quality in the cultivated plants. With the sensor we have developed, these values are continuously measured, and fertilization is carried out at appropriate intervals for the development of the plant by adjusting the fertilizer concentration according to the obtained values. If there is a high pH issue, nitric acid is added to the system. In other words, by adding nitric acid to the system, our high pH value is lowered to the desired level. In this way, the quality of irrigation water is improved, and a more efficient fertilization can be achieved. Sample pH and EC requirements according to plant types are shown in the table below.

esular-gubreleme

Float flowmeter: These types of flow meters are used to detect the instantaneous flow of liquid and corrosive fluids. Installed vertically, the float moves freely without friction as the flow passes from bottom to top, being pushed by the fluid. This change in position is dependent on the flow rate, the weight of the float, and the density and viscosity of the fluid. Thanks to its PVC body, it can be used for long periods in corrosive environments.

esular-gubreleme-

Stainless Steel Centrifugal Pump: The preferred pump in this system is made of AISI 304 stainless steel, which is highly resistant to high pressure and high temperatures. It has been selected for long-term use in environments containing acid and fertilizer. Using a single pump in the system significantly reduces costs and minimizes maintenance and repair expenses in the future.

esular-gubreleme

Advantages Provided by Fertilization System

Advantages provided by the system:

  • All components used in this system are selected from acid and fertilizer resistant PVC and stainless materials.
  • Easy installation and transportation can be achieved.
  • Requires less time and labor in application.
  • Thanks to the ability to disassemble and reassemble parts, repairs and maintenance can be easily performed in case of any malfunction.
  • It can operate without the need for large equipment that could occupy extra space in the fertilizer mixing tank and in the field.
  • Different formulations can be developed in production according to the need to design the most suitable device.
  • Proportional valves or on/off valves can be added to the system as desired.
  • User input management provides protection against unauthorized use in application.
  • Sequential or programmed irrigation can be defined through the application.
Fertilization and Irrigation Automation

Leave a Reply

Your email address will not be published. Required fields are marked *

Scroll to top