Fertilizers for drip irrigation: fertigation technology. Tomato Drip Irrigation

Fertigation is the application of soluble fertilizers with irrigation water.

In case of “top” irrigation by sprinkling, when water gets on the leaves and other above-ground parts of the plant, small doses of fertilizers dissolved in the water can play the role of foliar feeding, in addition to participating in the soil nutrition of the plants. However, water ingress in the aisle with continuous irrigation, sharply stimulating the growth of weeds, is a factor due to which fertigation is used quite rarely during top irrigation (which cannot be said of foliar dressings during spraying, which are becoming more common and recognized).

Watering the soil with various solutions and infusions of organic fertilizers practiced in small private farms can also be attributed to fertigation. However, in professional crop production only modern fully soluble chelate-based mineral fertilizers are used, with the addition of traditional well-soluble saltpeter, potassium, ammonium and sodium, if necessary. With the help of relatively inexpensive saltpeter, it is possible to satisfy the demands of plants for nitrogen and potassium, but more expensive fertilizers are needed to ensure phosphoric nutrition — monopotassium phosphate, pecicide, complex chelate fertilizers with an increased dose of phosphorus. Superphosphate, ammophoska and other traditional phosphorus-containing fertilizers are not suitable for fertigation, being not completely soluble.

Fertigation has received deserved recognition for drip irrigation, which allows fertilizing point-to-point. When watering, the concentration of fertilizers in the system is kept at a level no higher than 1 g / l. The fertilizer solution (mother liquor) is prepared in a separate tank, from where the metered flow into the main line occurs. The most common and cheap device for fertigation is the Venturi injector, which is connected in parallel to the main line and the suction solution of fertilizers due to the pressure difference created by the overlap of the main line between the injector inlet and outlet. Working with an injector requires a certain skill and has some features — for example, the intake is affected by the height difference between the mortar unit and the area to be watered, i.e. when water is supplied up the slope, absorption becomes difficult. In general, venturi injector  is a reliable device that has been tested for decades.

A more expensive, but easier to manage solution is to connect to the fertilizer pump line, which will pump the fertilizer solution under pressure that exceeds the line pressure.

In unison with the development of drip irrigation, the fertigation system masters more and more areas. Over the past 40 years, a breakthrough has been made in this area in the development of equipment, sensors and controllers, software for automating the irrigation process and fertilizing. The introduction of fertigation allows you to optimize the conditions of plant nutrition, reduce fertilizer rates and increase their utilization rates, reduce human labor costs and minimize the negative impact on the environment. These advantages attract both small farmers and large landowners. Improving yields and product quality makes it possible to more than recoup the costs of drip irrigation and fertigation.

Irrigation is quickly taking up agricultural land in many parts of the world. Due to climate change, even those regions that were considered wet half a century ago now require irrigation to get stable yields. Micro irrigation is a relatively new method of irrigation, but its development trends indicate high potential and efficiency. In the last ten years in Ukraine, drip irrigation has become the main intensive technology of growing vegetable crops. The key factor is that the technology of drip irrigation in vegetable production allows you to move to new levels of yield and minimize production costs.

Today in Ukraine, according to various sources, vegetables “on a drop” are grown on an area of ​​about 35 thousand hectares. At the same time, according to the calculations of the Institute of Water Problems and Land Reclamation of the National Academy of Agrarian Sciences of Ukraine, this is only 30–40% of the potential need, and by 2025 the area of ​​drip irrigation in vegetable production open ground  will be from 60 to 75 thousand hectares. The growth of areas is predicted in the forest-steppe zone and the northern part of the Steppe: Kharkiv, Sumy, Poltava, Kirovograd, Cherkasy, Vinnitsa, Kiev regions and a number of other regions.

Along with the development of micro-irrigation systems, more and more areas are being fertilized using the system fertigation (fertilization with irrigation water). This became necessary in view of the fact that with this method of irrigation the volume of irrigated soil decreased, and other methods of fertilization became ineffective. During fertigation, the batteries are supplied to a moist, rooting medium, where the roots absorb them most actively. For its part, the micro-irrigation system turns out to be most effective for the application of fertigation, since in this case the frequency of fertilizer application operations during irrigation can be easily controlled. When fertilizers are applied through the micro-irrigation system, it becomes possible to distribute the fertilizers more evenly, to bring them in the timeframe most relevant to the needs of the plants, while significantly reducing labor costs and application rates, which saves on fertilizers.

Fertigation makes it possible to use soils that are unproductive for traditional methods - saline, sandy soils, mountain slopes, etc. Using the fertigation system helps the farmer choose the most appropriate fertilizer for his particular soil, source of irrigation water, plant requirements and climatic conditions, which contributes to high yields with excellent quality indicators and, at the same time, the prevention of possible environmental pollution.

The main benefits of using fertigation  can be formulated as follows : (1) fertigation makes it possible to harmonize the supply of water and batteries; (2) fertilizer can be applied when it is needed, regardless of weather and organizational conditions; (3) more uniform application compared to other methods with equal other conditions; (4) reduced soil compaction and mechanical damage to plants, inevitable with the passage of technology through the field; (5) fertilizer rates per unit of production are reduced, as their utilization rate rises compared with other fertilizing methods; (6) the losses of fertilizers that occur when fertilizing the soil (immobilization, leaching, gaseous losses) are reduced, because fertilizers are applied in small doses; (7) fertilizer application costs are reduced; (8) batteries in solution are in ionic form, the only available for plants; (9) fertigation makes it possible to fully control not only the content, but also the ratio between all the necessary nutrients, taking into account the needs of a particular culture at each stage of development; (10) in case of a properly selected composition, an excess of batteries and their toxic effect on plants is very unlikely; (11) Fertigation is the most appropriate method of fertilizer application in greenhouses.

Fertigation approaches vary greatly from simple use of irrigation water to supply the plant with basic nutrients (NKP) in several installments throughout the season, making the main emphasis on the flow of all other elements from the soil, to providing the plants with all the elements in small doses throughout the growing season. often even daily.

Through the system of fertigation can be made all the necessary for plant nutrition. However, most often contribute macronutrients - nitrogen, phosphorus and potassium, less often - calcium and magnesium. Trace elements can also be successfully introduced through the system of fertigation, but they are often introduced in the form of foliar fertilizing, since the need for them is low.

Along with obvious advantages, fertigation is not without some deficiencies: (1) fertilizer components can be corrosive to irrigation equipment; (2) if improperly mixed, a precipitate may form that adversely affect the operation of the equipment; (3) the choice of fertilizers is organic compared to other methods of application, as well as their higher price; (4) excessive irrigation may result in movement of fertilizer elements over the surface or soil profile and release into soil and surface waters; (5) requires additional equipment costs required for the dissolution and the introduction of fertilizers in irrigation water; (6) requires a high level of management, continuous monitoring of the state of crops, as well as highly qualified personnel who are able to understand the needs of culture.

Four "whales" of successful fertigation

When choosing fertilizers for fertigation, the following should be considered four main factors  (Kafkafi, 2005): (1) the characteristics of a plant and its stage of growth and development, the need for nutrients, antagonism and synergy between ions; (2) soil properties (substrate); (3) water quality; (4) characteristics, availability and price of fertilizers, their compatibility with each other and with the water used.

(1) Characteristics of a plant, its developmental stage, the need for nutrients

The composition of the fertigative solution is selected taking into account the needs of the culture, the phase of development, the substrate. For each culture, the needs of a particular nutritional element at different stages of development have been developed. As a rule, the life cycle of a plant is divided into periods requiring special approaches to irrigation and fertilization. For flowering plants, this is most often three periods: (1) from germination (transplanting) to flowering; (2) from flowering to the formation of the first fruits; (3) from the formation of the first fruits to the end of fruiting. For plants in which vegetative organs (cabbage, onions) are productive, there are two periods: (1) from germination (transplanting) before the formation of productive organs begins; (2) from the beginning of the formation of productive organs to technological ripeness. It is important to take into account the relationship between the batteries at each stage (mainly between the main macroelements - NPK).

It should be remembered that during the absorption of plants, the batteries enter into interactions, manifesting as antagonistic or synergistic. For example, with an excess of magnesium plants absorb calcium less, and with an excess of chlorine - nitrate ions. Monovalent ions (for example, K +, NO 3 -) are absorbed faster by plants than divalent (Ca 2+, Mg 2+).

It is important to take into account the relation of plants to the presence of chlorine in the fertilizer, as well as to the ratio between ammonium and nitrate nitrogen.

(2) Soil conditions

For plants grown on soil, soil diagnostics is a prerequisite for monitoring both soil salinity and the ability of the soil to supply nutrients to plants. The difference between the needs of plants and the capabilities of the soil to provide them is covered by the use of fertilizers.

When growing plants on a substrate, the analysis of the nutritional status of all components of the system is important both for correcting fertigation programs and for diagnosing the conditions of plant nutrition and preventing possible deficiency.

Alkaline soils are characterized by a high content of calcium carbonates and an excess of Ca ions in the soil solution, a high level of nitrification, as well as some retrogradation (fixation) of phosphorus introduced. On these soils, all forms of nitrogen fertilizers are effective, and even urea, which has a significant increase in pH in the application zone, can be safely used in a drip irrigation system. Ammonium fertilizers are fixed exchange by clay particles, without exerting a toxic effect on the plant roots, which makes it possible to use any ammonium fertilizers. There are also no restrictions on the choice of potash fertilizers and all other macro- and micronutrients introduced in chelate form, except for Fe 2+: the iron complex with EDTA loses stability at a pH above 6.5, and Fe-DTPA is recommended for soils with pH up to 7 5, therefore, for alkaline soils, the choice should be made in favor of Fe-EDDHA, which is stable at pH up to 9.0.

Acid soils are characterized by a high content of Al ions, low Ca, a slower level of nitrification, and strong fixation of mobile phosphorus introduced with fertilizers. Nitrogen nitrate fertilizers contribute to a slight increase in pH in the zone of the rhizosphere due to the absorption of nitrate ion by plants, which reduces the toxic effect of aluminum ions and promotes root growth. It is not recommended to use physiologically acidic nitrogen fertilizers, such as ammonium sulfate and ammophos, as well as phosphoric acid.

An important parameter is the temperature of the soil. For example, under greenhouse conditions at high temperatures in the root zone of the soil, ammonium nitrogen can cause damage to the roots, since its binding will use the carbohydrates necessary for increased respiration of the roots, whereas at low temperatures this effect is not observed.

The soil size distribution affects the direction and speed of water movement, the absorption of nutrients and the possible risks of leaching.

The influence of the soil size distribution on the direction and speed of water movement (Source:Haifa)

The substrates used for growing crops can be classified according to their origin (Abad Berjon et al., 2005):

(1) mineral substrates: (a) natural (obtained from minerals or rocks without treatment or with simple physical treatment, for example, screening — sand, gravel, volcanic slags, etc.); (b) past physical or chemical treatment - expanded clay, perlite, vermiculite, mineral felt; (c) wastes or by-products of industry: fragments of bricks, blast-furnace coal.

(2) organic substrates: (a) natural - peat, peat moss (sphagnum), green moss, pine litter, leaf litter, woody plants; (b) synthetic - organic polymers, non-biodegradable, obtained by chemical synthesis; (c) domestic, industrial or agricultural waste and by-products, most of which must be composted before use, - rice husks, tree bark, manure, sawdust, coconut fiber, cork waste, municipal solid waste, prepared sewage sludge, etc. .

For normal plant development, the substrate must satisfy the following characteristics: (1) physical characteristics: high water retention, good aeration, low density, high porosity, high water permeability for effective drainage; (2) chemical characteristics: high cation-exchange ability, normal content of batteries and the ability to supply them to plants, buffering ability to maintain pH at the same level, low content of soluble salts, for organic substrates - low C / N ratio.

Not all of these characteristics can satisfy all substrates, but there is always the opportunity to improve them with the help of a rationally selected system of irrigation and fertilization. Often, two or more substrates are mixed to complement the properties of each of them, and as a result, the mixed substrate satisfies the required characteristics.

The properties of the substrate must be considered when developing the system of fertigation. Chemical properties are especially important because they are very different for inert, inorganic and active organic substrates.

Inert substrates are characterized by almost zero cation-exchange ability, do not have buffering properties, and are unable to supply the nutrients themselves to the plants. Fertigation in this case is similar to hydroponic solutions, supplying all the necessary elements to plants. Along with the ability to fully control the nutritional conditions of plants, under such conditions it is very important to follow all the recommendations, since any error in the system can lead to irreparable consequences. When choosing a fertilizer, it is necessary to carefully analyze the irrigation water for the presence of batteries and other ions (in particular bicarbonates). Also, due to the lack of buffering properties of the substrate, it is necessary to carefully monitor the pH of the solution (it is recommended daily analysis of the filtrate to make timely adjustments to the composition of the supplied nutrient solution).

Organic substrates have opposite properties to inert substrates: high cation-exchange ability, high buffering, usually much more stable in performance. The interaction between irrigation water and the substrate determines the composition of the solution.

(3) Water quality

Water quality has a great influence on the operation of drip irrigation systems and their lifespan. Poor quality water, such as high salt content, can adversely affect soil properties and plant growth, as well as worsen the nutritional conditions of plants during fertigation.

Among the properties of water, the ion composition, the salt content in water, the pH level, the concentration of bicarbonates and the redox potential affect most fertigation.

the pH of the water needs to be known in order to calculate the amount of acid needed to achieve the optimum pH of the nutrient solution (from 5.5 to 7.0). For this purpose, orthophosphoric acid is most often used, since it is relatively safe to handle it (unlike sulfuric and nitric acids). However, at a high pH level of water, the amount of phosphorus introduced in the form of phosphoric acid to achieve the optimum pH may exceed the plants' need for an element. In this case, nitric acid is added.

Since the pH of the water is a fairly dynamic indicator, changing seasonally, regular monitoring is recommended. Also, the pH of the solution changes after the introduction of fertilizers, so this must also be taken into account.

When analyzing water for the fertigation system, it is important to clarify four aspects:

1.1. Influence of water quality on plant nutrition.

Often water is not considered as a source of batteries. However, for plants, water may provide for the need for minor macro- and microelements: for example, irrigation water may contain enough calcium, magnesium, and sulfur for plant development. Water from surface waters usually contains a lower content of soluble salts than water sources. Therefore, the analysis requires not just a general analysis (hardness, electrical conductivity, pH), as well as an analysis of the content of batteries.

Water with high salt content is typical for areas with arid and semi-arid climates. It is known that plants and their varieties differ in sensitivity to the salt content, and the values ​​of water electrical conductivity (EC), at which plants significantly reduce growth processes, can also vary within fairly wide limits. For example, the sugar beet after the seedling stage can transfer EC values ​​up to 7 dS / m, while tomatoes reduce the yield already at EC 2.5 dS / m.

Chlorine is also often present in saline water and can be absorbed by plants in large quantities. Components of some fertilizers can reduce the absorption of Cl - plants: for example, KNO 3 and Ca (NO 3) 2, introduced into the solution. For its part, nitrates in irrigation water can reach significant concentrations, which must be taken into account when using it for fertigation.

1.2. Effect of water on soil properties.

The use of irrigation water with a high content of sodium on soils of heavy particle size distribution may cause focal alkalinization. Sodium in irrigation water can cause dispersion of the soil, disruption of its structure, problems with water infiltration and accumulation of sodium in plants.

The increased content of heavy metals in irrigation water can lead to their accumulation in the soil in elevated concentrations.

1.3. Impact on irrigation equipment.

Iron in water is a frequent problem for areas where aquifers have formed on sandy or organic soils. Iron is present in water in the form of a Fe 2+ cation, prone to form silt. Iron bacteria, such as Gallionella sp. leptolhris, Sphaerotihus, Pseudomonas and Enterobacter, which are present in water, oxidize ferrous iron to the trivalent Fe 3+ cation, which forms insoluble compounds that can clog droppers and irrigation equipment. For drip irrigation systems, an iron concentration of 0.15-0.22 g / m 3 is already potentially dangerous. In practice, water with an iron content above 0.5 g / m 3 should not be used in a drip irrigation system without prior chemical preparation.

Chlorination or acid treatment is usually carried out for water treatment. Chlorination contributes to the elimination of contamination of organic origin, preventing clogging with bacterial mucus, and acid treatment to prevent precipitation of various chemicals (Ca, Fe, Mn).

1.4. The interaction of fertilizers and water in the irrigation system.

The use of phosphate fertilizers in the fertigation system is very sensitive to the quality of water and its pH. The content of Ca in irrigation water is especially important; therefore, to prevent the formation of Ca-P precipitation, the pH of the water must be kept in the acidic range.

Sulfides with high content in irrigation water can cause precipitation of iron and manganese, which are practically insoluble, even in acidic water. In this case, constant acidification or the use of settling basins for the precipitation of iron and manganese is recommended. When the sulfide content is more than 0.1 mg / l in the drip irrigation system, the growth of sulfur bacteria can begin, which will require regular chlorination.

When using hard water, the addition of urea can cause calcium carbonate to precipitate, as the fertilizer raises the pH of the solution.

(4) Properties of fertilizers

Three groups of products can be used in fertigation:

1) Traditional fertilizers.

Fertilizers used in traditional agricultural practice are generally poorly suited for fertigation in the system due to the high amount of impurities that may be insoluble or form insoluble compounds, which leads to clogging of droppers.

Among traditional solid fertilizers, ammonium sulphate, urea, potassium chloride and potassium nitrate, as well as liquid phosphoric acid, are most often used in the preparation of the mother liquor for fertigation. These fertilizers are inexpensive, and the solution can be easily prepared in the field.

An obstacle to using them in fertigation can often be the presence of air conditioners. Most dry fertilizers are covered with anti-caking agents and other conditioners, allowing them to preserve their mechanical properties. To avoid the problem of blocking irrigation equipment, when using these fertilizers, it is necessary to first prepare a small amount of the solution and analyze for the presence of sediment at the bottom of the container, foam on the surface or suspension. Most often, anti-caking agents are added to ammonium nitrate, as well as to potassium and calcium nitrate, since these fertilizers are characterized by high hygroscopicity.

2) Chemical reagents of the technical grade "tech." (And for microelements - also pure "ch.").

Chemical reagents are a good choice for fertigation, as they contain less impurities and, accordingly, have a higher content of batteries. Chemicals have different levels of purity, and for fertigation, the most applicable are technical or pure grade substances due to their purity and price.

The IC “Infoindustry” analyzed the origin of the main salts available on the market for fertigation. Calcium Nitrate Ca (NO 3) 2 - China (Jiaocheng Knlan Chemicals, Changsha Green Mountain Chemical, Xuzhou Tianchang Chemical), Ukraine (Donetsk-Reagent, Himdivision), KNO 3 potassium nitrate has mainly Polish (Zaklady Azotowe Chorzow) and domestic ( Donetsk-reagent) origin, magnesium nitrate Mg (NO 3) 2 - Ukraine (Donetsk-reagent), China (Crown Champion International Group, Jiaocheng Knlan Chemicals), mono-potassium phosphate KH 2 PO 4 - China (Shifang Chuanteng Chemical Industry, Sichuan Xinchuangxin Chemical , Xiamen topusing AXA Chemical, Shenzhen Nonglinfeng Ind. And Traid. Co. and others), potassium sulfate K 2 SO 4 - Ukraine (Donetsk-reagent, Konstantinovsky Chemical Plant), Germany (K + S Kali GmbH), Belgium ( Tessenderlo Chemie), Lithuania (Livitas).

The “pitfalls” of using chemical reagents may be the presence of undesirable impurities, undeclared by the manufacturer or distributor.

3) Specialized fertilizers.

Depending on the physicochemical properties of the fertilizer solution, a large number of both solid and liquid specialized fertilizers can be used in the fertigation system. For large areas, solid fertilizers are generally cheaper than liquid formulations. The solubility of these fertilizers is very high. Among them are simple and complex specialized fertilizers. The following are the main brands and manufacturers of fertilizers present on the Ukrainian market.

A) Simple: Ca (NO 3) 2: Ducanit (Duslo, Slovakia), YaraLiva Calcinit (Yara, Norway); KNO 3: Yara Krista K (Yara, Chile), Multicrop 14-0-44 (DoctorTarsa Tarim, Turkey), Multi-K Products (Haifa Chemicals, Israel); Mg (NO 3) 2: Magnesium nitrate (Alwernia, Poland); MCR: Krista MCR (Rotem Amfert Negev, Israel), Haifa MKP (Haifa Chemicals, Israel), Hydroponica MKP (Rotem Amfert Negev, Israel), MKP (Prayon, Belgium), Pekacid (Rotem Amfert Negev, Israel); MAP: MAP (Prayon, Belgium), Haifa MAP (Haifa Chemicals, Israel), Nova MAP (Rotem Amfert Negev, Israel), NovaTec Solub 14-48 (Compo, Germany); potassium sulfate: Yara Krista SOP (SQM Salar, Chile), Multicrop 0-0-44 (DoctorTarsa Tarim, Turkey), SoluPotasse (Tessenderlo chemie, Belgium); MgSO 4: Magnesium Sulphate (Doktor Tarsa Tarim, Turkey), Microcomplex (Intermag, Poland), etc.

B) Complex: AgritechDrip, NutriFlex, Novalon (DoctorTarsa Tarim, Turkey), Intermag Micro Plus, Intermag-Nitro, Intermag-Phospho, Intermag-Kali, Intermag-Opti, Hydropon (Intermag, Poland), Hakaphos (Compo, Germany), NovaTec Solub (Compo, Germany), Poly -Feed® Drip (Haifa Chemicals, Israel), Yara Ferticare (Yara, Norway), Nutrivant Drip (ICL Fertilizers, Israel), Drip Fert (Laris, Turkey), Fertimix (Seto, Turkey), etc.

Complex specialized NPK fertilizers are popular when applied to vegetables, fruits, vineyards. These formulations are often balanced for cultures and different periods  plant development, contain essential trace elements. They are completely water-soluble, therefore, as a rule, they have a high price. Therefore, their use is justified for highly profitable crops and in breeding grounds.

Specialized fertilizers for fertigation generally do not contain calcium and sulphur, which often form sediment with other components of the fertilizer. If these elements are not sufficient in irrigation water, then it is recommended to use a separate tank with a mother solution of calcium chloride or magnesium sulfate.

Fertilizer used for fertigation should meet the following requirements: high quality of the product, high solubility and purity that meets the requirements of pH, fertilizer must be well adapted to the program of fertilization of crops in the economy, not to cause corrosion of the metal parts of the equipment.

One of the main requirements for fertilizers for use in the fertigation system - solubility. Fertilizers in a liquid preparative form can be directly introduced into the irrigation system, while dry granular or crystalline must be dissolved in water beforehand. The solubility of fertilizers depends both on the properties of the fertilizers themselves and on the temperature and pH of the irrigation water. Thus, during storage of the fertilizer solution throughout the season, precipitation is possible with a decrease in temperature in the autumn as a result of a decrease in salt solubility. Also, some fertilizers (mostly nitrogenous) dissolve with energy absorption, reducing the temperature of the total solution, which should also be taken into account.

The solubility of different fertilizers depends on the type of fertilizer and the manufacturer. So, potassium nitrate has a low solubility - 1: 8 (1 kg of dry fertilizer dissolves in 8 liters of water); the solubility of potassium chloride 1: 3, ammonium nitrate and calcium nitrate 1: 1. Dry phosphate fertilizers have a solubility of about 1: 2.5.

Acidity- the second important characteristic of fertilizer for fertigation. Nitrogen fertilizers have the greatest effect on soil acidity, but their influence depends on the form of fertilizer (nitrate forms alkalize the soil, while ammonium fertilizers are acidified), soil type (high-buffering soils are able to withstand pH changes) and irrigation water quality. At least two times per season, the soil pH should be determined: at the beginning of the season and at the end.

Also the choice of fertilizer for fertigation should be based on their compatibility with each other. To do this, you must first carry out a compatibility test or use compatibility tables.

When preparing a stock solution, calcium often becomes a problem, since it forms insoluble compounds with phosphorus and sulfur. In this case, it is recommended to use two separate tanks: for commercial fertilizers and for acid and calcium and sulfur fertilizers. With the introduction of solutions from these tanks in the fertigation line, the concentration of elements is significantly reduced, which reduces the risk of precipitation.

Fertilizer application system with drip irrigation

The calculation of the need of plants for fertilizers is carried out by traditional methods with adjustment for the availability of the soil. It only needs to be remembered that when determining the availability of nutrients to the soil, it is necessary to take into account the fact that with drip irrigation the roots occupy a smaller amount of soil, therefore, the plant’s nutrients will be consumed from a smaller volume.

After the need for fertilizers has been established, it is necessary to plan how much will be added to the main application, and how much - by means of fertigation. It is considered rational when 20-30% of nitrogen from the calculated norm, 50-70% of phosphorus and 30-50% of potassium are introduced into the main soil application. The rest of the batteries are in the form of supplements in the fertigation system. The general rate of fertilizer applied to fertigation is divided by the number of irrigations, and then the amount of fertilizer needed for one irrigation is calculated taking into account the irrigation rate. For the main application, any fertilizer can be used, whereas for fertigation - only specialized, completely soluble.

However, growing tomatoes in sandy soil without daily phosphorus intake with fertigation leads to the fact that within a radius of 10 cm from the roots, the entire supply of phosphorus is quickly used, and by the time high plant demand for P may not be sufficient for fruit development. Therefore, the introduction of NPK in fertigation is preferable to the introduction of phosphorus before sowing.

The international practice of fertigation shows that on sandy and sandy soils all fertilizers are better applied by this method. On medium-sized (light- and medium-loamy) soils, with a low level of battery content, the main fertilizer application is combined with fertigation, and with an average and high level of supply with batteries, only fertigation is used. On soils that are heavy in their mechanical composition — various types of chernozem and heavy loamy podzolized soils — with a low and medium level of supply with batteries, the main application of fertilizers is combined with fertigation, and with high indicators of the number of macronutrients only fertigation is used.

The need for fertigation and application rates are adjusted based on diagnostic data (chemical and express diagnostics of plants). Monitoring of plant nutrition under drip irrigation, when only a part of the soil profile is moistened and the roots occupy a relatively small fraction of the total soil volume, is a necessary condition for crop cultivation technology.

Thus, fertigation is not a “panacea”, but the toolkit that allows you to make growing plants more efficient. Additional costs are often more than paid off by increased yields. However, we see the main limiting factor for the spread of the fertigation system in Ukraine in the technological difficulties and the lack of qualified personnel capable of ensuring proper management.

In order for plants to fully develop, it is necessary not only to water them, but also to maintain an optimal nutrient regime in the soil. Fertigation is the fertilization of plants, the process of supplying them with nutrients during irrigation. During fertigation, special water-soluble substances are used, which come to the plants along with the water.

Fertigation technology is used in drip irrigation systems. Their advantage is that they provide the optimum amount of moisture and feed it to the root system of plants.

Watering through such systems is uniform and fully controlled. Nutrients through special droppers in the same quantity go to the roots of plants.

What is the feature of drip irrigation systems?

The drip irrigation apparatus is represented by a system of tubes with holes through which water flows to the plants. The system is connected to the pipeline, and the hoses are distributed over the entire area of ​​the bed.

The tubes may differ from each other, but their main purpose is the same - to supply water by the drop method with low pressure and a small stream with strong. Some systems have special droppers that supply the same amount of water, regardless of pressure.

In certain cases, not tapes but tapes are attached to the irrigation system. This option is more affordable, but the water supply in this situation will be less accurate. This method is suitable for beds where plants are at the same distance from each other.

Drip irrigation system has many advantages:

How to fertilize the drip irrigation system?

To add fertilizer to the water, you can use a special tank, an injector, as well as a dosing pump. These devices must be connected to a hose through which water enters the system.

You can also use a fertilizer tank. This is a tank with taps, which is hermetically closed. If you open the tap, a pressure drop occurs, and water enters the tank. Fertilizer preparations are poured inside the tank before it. After the liquid enters the container, the preparations dissolve in it and exit.

Popular fertilizer products

Fertigation technology involves the use of only water-soluble drugs. These include fertilizers with the maximum amount of nutrients: Rexolin, Multikrop, Mortar, etc. These are complex drugs that can be combined with traditional and more affordable means: magnesium sulfate, potassium, potassium nitrate, etc.

It is important: in order to protect the irrigation system from clogging, it is not necessary to use products that are characterized by poor solubility.

In the List of fertilizers and agrochemicals permitted in the territory of the Russian Federation more than 700 pages, not all fertilizers are suitable for you for a number of reasons, for this reason we made a selection for you for drip and macro-irrigation (Fertigation), where the ideal price-quality ratio, ease of use-macro content items:

Calcinit ™

Calcium nitrate special nitrate is produced using YARA special technology, which has no analogues in the world. It is recommended to use in systems of drip irrigation (fertigation), which allows to extend the service life of drip irrigation systems, also applies to foliar foliar dressing plants. Fertilizer granulated, has 90% of granules with a size of 2-4 mm.

Agrochemical features of Kaltsinit ™ chemically pure fertilizer that meets all environmental regulations of EU countries; fully water soluble fertilizer (table 5); stimulates the development of the root system, improves the formation of cell membranes and plant walls; improves photosynthesis, transportation of hydrocarbons and the assimilation of nitrogen by plants; increases plant resistance to stress, fungal, bacterial and physiological diseases resulting from calcium deficiency, for example, apical rot of tomatoes; Global-katalog.ru is physiologically alkaline fertilizer, it must be dissolved in a separate tank, before using it in drip irrigation systems.

The use of Calcinite ™ promotes the absorption of ions of calcium, magnesium, potassium, ammonium and other cations from the soil due to nitrate nitrogen compounds that are part of the fertilizer. Kaltsinit ™ is also used for foliar foliar plant dressing. in 0,5-2,0%  concentration (in physical mass), shows high efficiency under adverse weather conditions, which do not contribute to the normal absorption of calcium cations and lead to the appearance of calcium deficiency in plants.

Monopotassium phosphate

phosphorus-potassium concentrated water-soluble fertilizer, it is recommended to apply in systems of drop irrigation, in systems of hydroponics and for non-root leaf dressings of vegetable, fruit, decorative crops, vineyards on all types of soil or substrates.

Many forms of fertilizer, in addition to the nutrient needed by our plants, contain much more that prevents plants from developing and leads to problems, the harm from which may be greater than the intended benefits of feeding. Take, for example, potassium chloride (a popular fertilizer with a potassium content of 50 to 60%). After making high doses of such a fertilizer, the plants actively assimilate the potassium contained in it, releasing the chlorine ions that are toxic to the roots, and which accumulate in the soil pose a threat to crop formation, the higher the application dose was.

Sometimes farmers naively choose potash salt (since chlorine does not sound in its name), but this is still a big mistake, because potash salt is a mixture of potassium chloride and sodium chloride (kitchen salt, if you speak the usual language) and in this case the accumulation of toxic ions and the development of salinization processes will go even faster. A similar problem is typical for many fertilizers from the group of so-called “simple salts”, including the popular nitrophosphate and potassium magnesia and superphosphate.

This can often be tolerated when growing field crops — with low yields and the tradition of applying such fertilizers for plowing (mixing them with three thousand tons of arable soil per hectare), but this practice often becomes destructive in intensive vegetable farming. For irrigated vegetables there are ballast-free water-soluble fertilizers. This group, for example, includes fertilizer brand.

We have been successfully working with this product for three years now and in practice we have repeatedly seen the responsiveness of vegetable crops to the correct strategy in mineral nutrition.

Solubility problem. Plants absorb nutrients from the soil in the form of ions. That is, only dissolved in the soil solution. And because the solubility of fertilizer is directly related to its digestibility for plants. This is important in mineral nutrition in general, but it is especially important when grown in drip irrigation, where we use fertigation (fertilization with irrigation water).

From the practice of application - when preparing the stock solution directly in the field (without heating the water) it is easy to achieve a concentration of 0.1 kg / liter. Moreover, this is a true solution, not a suspension, as in the case of attempts to make solutions from superphosphate and ammophos. Suspensions clog droppers that cause huge crop losses, and the solution not only does not clog them, but due to its acidity it even clears the droppers from the deposited salts.

Fertigation - fertilization with drip irrigation

For the productive cultivation of plants of course they must be timely and properly watered. And with this task drip irrigation works best of course. But over time, even the most fertile land is depleted. What to do in this situation? Of course use artificial fertilizer. This fertilization is called fertigation, i.e. fertilizers are fed to the plant along with watering. This method was invented back in the 70s of the last century.

How to carry out fertigation

Fertilizers can be applied periodically or continuously. But the most advantageous is the regular application of fertilizers with a low concentration of about 3-15 kg / ha. For the dosing of fertilizers in irrigation water, there are several methods and types of equipment.

Fertigation equipment:

• fertilizer capacity;
• venturi type injector (Venturi dispenser);
• metering pump (metering).

The fertilizer tank is a hermetically closed tank with a fertilizer solution that has taps at the inlet and outlet. This tank is designed for simplified application of mineral fertilizers and other chemicals through the drip irrigation system. With the help of the crane of the fertilizer head, a small pressure drop and a parallel flow through the tank are created, in which water is mixed with fertilizers and fed into the drip irrigation system.

For simplicity, fertilizer capacity is the most reliable and least capricious device in operation. But it has disadvantages: uneven concentration of the fertilizer solution. The solution first has a high concentration, then the concentration gradually decreases.

The Venturi Injector is a tube with special conical tapers at the ends. The Venturi injector operates on the principle of pressure drop. The flow of water passing through the venturi injector creates a vacuum that sucks the fertilizer solution into the main channel, where it mixes with irrigation water and goes further along the drip irrigation system.

Venturi injector and the simplest scheme of its connection

The venturi injector is usually made from special polymer materials that are resistant to fertilizer. In professional systems, the venturi injector is installed in the drip irrigation system on the so-called fertilizer head, which allows to separate the irrigation and fertigation processes. The venturi injector has a strictly defined flow direction; this is usually indicated by an arrow. The Venturi injector gives a good homogeneity of mixing the fertilizer solution with the main flow of water and maintains a given concentration throughout the entire time the solution is applied.

A metering pump (metering unit) is a hydraulic metering unit that is used for proportional fertilizer and other chemicals through a drip irrigation system. It guarantees high precision dosing of fertilizers.

Dosing pump and its wiring diagram

The batcher can be mounted directly to the irrigation system or through a fertilizer head. The working turbine inside the metering unit is driven only by the pressure of water in the system, as a result of which the device sucks a well-defined amount of solution from the fertilizer tank, then a homogeneous mixture forms in the mixing chamber with water, which is fed into the irrigation system. Dosatron adjusted once. In the future, he does not require control.

What fertilizer to use for fertigation

For fertigation, only water-soluble mineral fertilizers can be used, for example: Terraflex, Novalon, Kemira kombi, Crystalon, Fegtisage, Universol, MadMih, potassium monophosphate, ammonium and potassium nitrate, urea, and others. It is impossible to use rare complex fertilizers - this is full of clogging up the irrigation system. Also, do not use poorly water-soluble fertilizers, like nitroammofoski.

Before using an unfamiliar fertilizer, make a solution from it and check it on samples of the drip irrigation line, as even an unpredictable reaction is possible when mixing the fertilizer with water.

How and how much to apply fertilizer

Fertigation is recommended to start 20 minutes after the start of irrigation, when the water flow and pressure in the drip irrigation line is stabilized. The duration of fertigation is usually at least 30 minutes, followed by mandatory washing with clean irrigation water for at least 30 minutes.

As experts advise, the total amount of fertilizers should not exceed 1-1.2 kg of fertilizers per 1000 liters of water. The rates of fertilizer application and their ratio to water are most often an individual value. It depends on the soil and climatic conditions at the place of cultivation, the phase of plant development, the type of plants, the technology of their cultivation and the scale of agriculture is developed by experts for each site individually.

On the scale of individual farming, of course, most often there is no possibility of attracting a specialist in fertigation, therefore, it will be necessary to select concentrations and types of fertilizers either independently or use the experience of other gardeners. But it is, of course, better to start in your own research from general recommendations for agriculture and common sense. And of course, when working with fertilizer concentrates, extreme care must be taken.

Pekatsid is a chlorine-free concentrated acid in dry form with the function of phosphorus-potassium fertilizer for drip irrigation with hard water and on alkaline soils.

Pekatsid: nourishes plants, cleans droppers

Pekatsid eliminates the typical problems of drip irrigation. Among them:
1.   Clogging droppers, which leads to uneven watering and, consequently, to the non-uniform development of plants. This reduces the yield and increases the percentage of non-standard products.
2.   Alkalization of the soil. Prolonged watering with hard water leads to alkalization of the soil, with many trace elements (boron, iron, manganese, zinc, copper) becoming unavailable to plants. Lack of these nutrients leads to lower yields and product quality, and also provokes the occurrence of diseases.
3. Unavailability of phosphorus. On alkaline soils, phosphorus is in a form that is not accessible to plants, which negatively affects the development of the root system and the further growth of plants.

The agronomic advantages of Pekatsid primarily include its ability to significantly increase the yield and quality of crops by increasing the availability of macro-and micronutrients by maintaining optimal soil and water pH. As a result of the use of the drug, the mobility of nutrients in the root system increases, nitrogen losses decrease, its volatility decreases, and water filtration in the soil increases.
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   Pekatsid is especially needed for those who use irrigation water with a pH of more than 7.2 and grow vegetables, flowers or fruits on neutral or alkaline soils. The use of drip irrigation systems allows to increase the yield, eliminate the problem of dropper clogging and increase the availability of nutrients from the soil.
   Regular use of this product helps prevent the formation of limescale in tubes and droppers, prolongs the service life of drip irrigation systems.

Pekatsid is used to grow all crops: tomato, potato, cucumber, pepper, cabbage, roses, fruit trees  etc. For the season 50 - 100 kg of Pekatsid are applied per hectare.

Two options are possible:
   1 - 2 times a month at 0.5 - 1 kg / 1000 m2;

Acidifying properties:
   Bicarbonate (HCO3) neutralizing power = 0.240.
Pekatsid  - very effective acidifying agent: a dose of 240 g of Pekacid neutralizes 1 eq of bicarbonate (HCO3) per 1 m3 of water.
Technological advantages: provides a system of drip irrigation with acid in full to neutralize and destroy bicarbonates; when using the concentrated form (0.35 - 0.5%), Pekatsid destroys the existing carbonate sediment and cleans the drip irrigation system, increases the service life. Reduces labor costs, replacing the separate introduction of acid and phosphorus-potassium fertilizers.

Pekatsid - special fertilizer for drip irrigation

Pekacid 0-60-20 is a new, specially designed phosphorus-potassium fertilizer designed for use in drip irrigation systems. Specialists of the Israeli company Rotem Amfert Negev Ltd, part of ICL Fertilisers, have developed a new fertilizer - Pekatsid, which strongly acidifies water (pH 2.2) and is a highly concentrated source of phosphorus (60% P2O5) and potassium (20% K2O ). Thanks to these properties, in addition to nutrition, Pekacid perfectly cleans drip irrigation systems and drip lines of any type.

Clogging droppers leads to uneven watering and, accordingly, to the heterogeneous development of plants. This reduces the yield and increases the percentage of non-standard products.
   Prolonged watering with hard water leads to alkalization of the soil, with many trace elements (boron, iron, manganese, zinc, copper) becoming unavailable to plants. Lack of these nutrients leads to lower yields and product quality, and also provokes the occurrence of diseases.
   On alkaline soils, phosphorus is in a form that is not accessible to plants, which negatively affects the development of the root system and the further growth of plants.

Agronomic advantages:
   Maintains optimum soil and water pH.
   Increases the availability of nutrients, especially trace elements, as well as phosphorus and magnesium.
   Strengthens absorption and mobility of batteries in the root system.
   Reduces nitrogen loss through evaporation.
   Increases water filtration in the soil.

Cleansing system:
   Provides acid to neutralize and destroy bicarbonates.
   Prevents blocking droppers in the irrigation system.

When used in concentrated form, Pekacid destroys the existing carbonate sediment and purifies drip irrigation systems.

Acidifying properties:
   Bicarbonate (HCO3-), neutralizing power = 0.240.
Pekatsid  - very effective acidifying agent: Pekacid dose of 240 g neutralizes 1 eq of bicarbonate (H

СО3-) in 1000 l of water.
Nitric acid and phosphoric acid are traditionally used to acidify water and clean droppers. However, acids are hazardous substances, which complicates their transportation, storage and use.
   The solution to the problem of hard water was recently found in the homeland of drip irrigation - in Israel, where farmers get high yields of vegetables and fruits, even on stony desert soils and when watering with high salt concentrations.
   Pekatsid quickly dissolves in water (solubility at 20 ° C reaches 670 g / l) and is intended for use in drip irrigation systems and for watering through hoses. Regular use of this product prevents limescale from forming in pipes and droppers and extends the life of drip irrigation systems.

Two options are possible:
   1 - 2 times a month at 0.5 - 1 kg / 1000 m2.
   2 - 3 times per season at 2 - 3 kg / 1000 m2.
   The first watering is carried out 7 to 10 days after emergence or immediately after transplanting into the ground.
   Regular watering with solutions containing Pekatsid allows acidifying the soil and thus increasing the availability of phosphorus and trace elements to plants. The first tests of this fertilizer showed surprising results: the number of clogged droppers decreased, and the level of available phosphorus on alkaline soils increased significantly after the start of Pekacid use.
   Pekatsid is simply indispensable for those who use irrigation water with a pH of more than 7.2 and grow vegetables, flowers or fruits on alkaline soils. Its use in drip irrigation systems allows to increase the yield, eliminate the problem of dropper clogging and increase the availability of nutrient