Sunflower is a highly profitable, strategic crop for Ukraine. If the agrotechnics of cultivation is executed properly and the scientifically grounded time for returning it to a crop rotation is provided, a yield of 3-4 tonnes / ha is possible. There is an opinion that sunflower “sucks all the juices” from the ground. We believe that returning it to its original place after 6-8 years has a beneficial effect on the subsequent crops in the crop rotation. Let’s consider, is this true? Sunflower plants do have a powerful root system capable of absorbing water from deep soil horizons of 1.5-2 m, and the subsequent crop, for example, winter wheat, consumes water mainly from 0-100 cm of layer, which is 70% replenished over the winter. Therefore, for winter cereals the lack of moisture reserves in deep horizons is not the most important. In the course of its vital activity, the root system of sunflower transfers inaccessible food elements to more accessible ones, and also draws them from deeper horizons of 30-40 cm in soil, which positively influences the development of the subsequent crop.
The ashes of sunflower contain 40% of potassium. The lack of potassium nutrition is particularly noticeable from the budding period to the ripening of the seeds. In most of Ukraine, the availability of potassium is sufficient. The introduction of potassium fertilizers is justified on soils with a low content – leached black soil, gray forest. If you take into account the peculiarities of sunflower nutrition in the crop rotation system and give proper attention to the nutrition of the subsequent crop, it turns out that it is a good predecessor, for example, for winter wheat, much better than barley, wheat and even more so corn.
With a yield of 3 t / ha of oilseeds, sunflower extracts 180 kg of nitrogen, 80 kg of phosphorus and 560 kg of potassium from the soil. Growing of short and medium-sized (120-170 cm) varieties and hybrids reduces the total consumption of nitrogen in comparison with cereals.
Nitrogen promotes active growth of plants. However, its excess leads to a significant increase in the vegetative mass and irrational use of moisture. Phosphorus has a beneficial effect on the development of the root system, stimulating its development, as a result of which the plant can provide itself with the necessary elements. It plays an exceptionally important role in the processes of energy exchange in plant organisms. The energy of sunlight in the process of photosynthesis and the energy released during oxidation of previously synthesized organic compounds in the process of respiration accumulates in plants as energy of phosphate bonds in so-called macroergic compounds, the most important of which is adenosine triphosphate (ATP). Accumulated in ATP energy is used for all life processes of plant growth and development, absorption of nutrients from the soil, synthesis of organic compounds, their transport. Phosphorus, perhaps, is the most underestimated nutrient, due to the lack of which there is a shortage of active organic matter (humic and fulvic acids) in the soil. Especially sharply the phosphorus deficiency affects all plants with the formation of reproductive organs. Its deficiency inhibits development and delays maturation, causes a decline in yield and a deterioration in the quality of products. Plants with a lack of phosphorus dramatically slow growth, and their leaves are first obtained from the edges, and then over the entire surface of a gray-green, purple or red-violet color. Symptoms of phosphorus fasting are usually manifested even at the initial stages of plant development, when they have an underdeveloped root system and are unable to absorb hardly soluble soil phosphates.
Potassium participates in the processes of synthesis and outflow of carbohydrates in plants, causes water-retaining capacity of cells and tissues, affects the resistance of plants to unfavorable environmental conditions and diseases.
It is known that phosphorus and potassium very poorly penetrate plants through the leaves in comparison with other elements. The fastest penetrates N (nitrogen), Mg (magnesium), Na (sodium), slower – S (sulfur), even slower – Ca (calcium), K (potassium), P (phosphorus) and other microelements. Nevertheless, even potassium and phosphorus are absorbed through the leaf surface several times faster than from the soil, especially with a poorly developed root system.
From micronutrients most sharply on sunflower is expressed the lack of Boron, the use of which in a small amount also justifiably affects positively on the subsequent culture. Auxiliary elements of antistress agents are Magnesium, which is responsible for the transport function and, in particular, the same phosphorus, as well as Sulfur, which is a part of amino acids and actively participates in protein and carbohydrate metabolism, i.e. promotes the qualitative assimilation of nitrogen.
Stress is a general nonspecific adaptive reaction of the body to the action of any unfavorable factors. There are three main groups of factors that cause stress in plants:
physical – insufficient or excessive humidity, illumination, temperature, radioactive radiation, mechanical effects;
chemical – salts, gases, xenobiotics (herbicides, insecticides, fungicides, industrial wastes, etc.);
biological – defeat by pathogens of diseases or pests, competition with other plants, influence of animals, flowering, ripening of fruits.
In the main chemical stress we undergo sunflower, using the technology of SUMO and CLEARFIELD
In our time, selection achievements have made significant progress in creating the technology of the “Clean Field”. There are two directions: hybrids resistant to herbicide type Express in a dose of 25 and 50 g / ha and resistant to Euro-lightning and its analogues. This is a powerful breakthrough in growing sunflower with the possibility of complete control of weeds. But, as you know, everything has the reverse side of the coin, and we are increasingly confronted with it. Let’s take a step-by-step look at the basic elements of these technologies to objectively understand the process in a complex. We use SUMO technology mainly to control weeds. But, as is known, the correct combined use of soil herbicides of acetochlorous (and better metal-chlorine-containing, for example, Avangard) and prometrin-containing are able to control up to 90% of weeds in the early stages of sunflower development. The role of soil herbicides with this technology is also significant, as in the cultivation of classic hybrids. First, they protect the plant, so to say, in the “cradle”, at the earliest stages, and the herbicide Express works in a phase of 2 to 6 true leaves in the crop. Secondly, the herbicide Express does not control cereal weeds. If you still decided to sow sunflower using this technology, then do not rely only on the Express and do not wait until the weed grows. It is better to make a soil prometrin-containing herbicide in the minimum dose, and then work as an Express.
Let’s return to stresses. Whichever hybrid you sow, the use of Express causes stress! The strength of stress depends on you: this is the dose, and the frequency of application, as well as many factors that need to be considered. I would just like to remind you that a dose of 20 g / ha is enough for wheat. Why did we decide that sunflower needs at least 25 grams? Whatever it was, but the next day you will see a pale sunflower plant, subject to stress with immunity at zero. This condition usually lasts 10 days and “grief-chemists” say: do not touch, let it come out of the “herbicide pit,” then do the nutrition. 10-12 days of depression and, as a consequence, a sharp jump in disease. Well, it was traced in 2016, when there was an outbreak of diseases, and then there was a weakened plant. So how to relieve stress? You will not remove stress, but we will try to soften it. We can weaken its effect by 30% and, if lucky, by 70% and not 10-12 days, but 3-4 days. What is needed for this? It’s simple! We need phosphorus, magnesium and sulfur in the most accessible form. Such a preparation can be, for example, “Complex for nutrition of oil-bearing crops” in a dose of 2 l / ha, as well as various types of humates. And do not forget to add a little nitrogen 3-5 kg of carbamide, not more. Processing is made necessarily in the evening for the next day or a day after the introduction of the Express. This method is needed after every pesticide application or other stress and, most importantly, this does not apply as nutrition. This is not a top dressing, but an attempt to soften the stress caused by us.
CLEARFIELD technology is designed to combat not only weed vegetation, but also with such parasitic plant as broomrape, which has become a scourge of our fields. If you do not have problems with broomrape, then it is advisable to avoid using this technology: it is expensive and has some consequences on the subsequent crop in the arid regions of Ukraine. There is an opinion that when using this technology it is possible to sow early without a soil herbicide. weed can be controlled all. But this is not so. Euro-lightning, when properly applied, controls the weed for 4-8 weeks, and broomrape for 3-4 weeks. In practice, the preparation is introduced from 2 to 8 leaves in sunflower, the optimal period of application is the phase of 4 true leaves. If the soil herbicide in the early sowing we did not make, then by this time there is already a carpet of weed. Processing Euro-lightning, sunflower and weed vegetation turn yellow, then the last die, and it seems that everything should be perfect. But by the time of harvesting we have ragweed, chenopodium, cocklebur and other weeds with a height of sunflower. And that’s why. Sunflower seedlings in cold soil appear only on day 16-18, and weed seeds are closer to the soil surface than in sunflower, where they warm up and germinate faster. And by the time of treatment we have completely closed soil with leaves of overgrown weeds, which are already beginning to “suck out” sunflower plants. As a result of spraying, all Euro-lightning (or analog) falls only on the leaves. And the correctness of using such a drug is that it not only falls on young weeds, but also on the soil. Then the herbicide also acts as a soil, restraining the germination of the following weeds. And this is possible in early crops only with the use of soil herbicides. And for the removal of stress for the next day, treatment with preparations containing phosphorus, sulfur and magnesium with the addition of humate is suggested.
And what is the situation with broomrape? After all, fighting with it is the main reason for choosing technology. The seeds of the parasitic plant begin to germinate at a stable +15 ° C in the soil, which corresponds to the middle of May and attack the root system until soil temperature is above + 40 ° C or moisture is absent (end of June). Those, when sowing in mid-April, the infection begins to occur by falling to the processing time of Euro-lightning. It protects the sunflower for 3-4 weeks and the action of the drug is over. At the end of June – a new wave of infection! If, however, the treatment with herbicide is moved to the later phases of sunflower 6-8 leaves, the preparation will kill the already infected broomrape and protect the plants from a new infection.
Therefore, in the early sowing of sunflower using CLEARFIELD technology, the use of soil herbicides is also advisable. And now the protection of sunflower crops is 99%!
The best option is if the fields are clogged with a broomrape parasite plant, to sow classic sunflower hybrids that have genetic resistance to the latest races of broomrape. They are able to control it throughout the whole vegetation period. You can not spend a lot of money on the herbicides of SUMO and CLEARFIELD technologies, and apply only soil herbicides. And that will be enough! In addition, sunflower plants treated with Euro-lightning and Express herbicides experience a severe stress in the form of yellowing of leaves (which is the death of chlorophyll and the week of absence of photosynthesis), due to which hybrids lose their yield potential from 10 to 25%. Growing broom-resistant hybrids and applying micronutrients, you no longer struggle with the elimination of stress (or in simple terms, spend extra money to eliminate the negative consequences and return the hybrids to their normal life so that they give the level of harvest that was before treatment), but really invest money in an additional yield increase. After all, if you apply the entire complex of foliar dressings with classical technology, you will get a yield 20-25% more than from technology with the application of insurance herbicides. In addition, the cost of seeds of broom-resistant domestic hybrids, for example, Lyman OR, Donbass OR and Commandor 777, is 2-3 times cheaper than foreign seeds for the above technologies. These infectious hybrids belong to the selection of the company LIST, in the portfolio of which besides these hybrids there are a number of highly productive classical hybrids, characterized by stability and flexibility.
Two more words about foliar dressing. As we know, this is the fastest and most effective way of delivering elements to plant cells. It is also known that in the plant cells are updated in 21 days. Those. after 21 days the effect of fertilizing does not affect 100%. Therefore, it would be ideal for a plant to receive them every 10 days. What would like to “see” a plant? It needs to receive small, but balanced doses of fertilizing. And the wider the range of elements, the more effectively those elements that are available in the soil are used. Everyone already knows that sunflower needs a boron. This is so, but with the amendment, it is needed in the second half of the vegetation period for flowering, and not in the period of growth, and certainly not for the development of the root system. This element is zinc. So the use of zinc is justified not only on cereals and corn, but also on sunflower. Boron should be given in the second treatment and it is better not before the phase 10-12 of the real leaves. And to remove stresses from herbicides and active plant start in the technology of fertilizing, it is recommended to include complexes for plant nutrition containing NPKS.
In total, you need to make 2 top-dressing on the vegetation with the latter, if possible, into the budding stage. And the processing of the seed material is carried out by a complex of macro- and microelements with growth stimulators. Important in the technology is the use of an adhesive, this protects against the washing off of sediment preparations and makes it possible to work at minimal doses, increasing efficiency. Carbamide, shampoo and microfertilizers do not possess these properties. Many firms do not quite accurately comment on the effect of drugs. Yes, urea and chelates help to quickly assimilate the drug, but do not provide resistance to rinsing or wind blowing after drying. Also, I note that chelators are digested for 6 or even 12 hours. Therefore, if the rain has gone after 2 hours, do not flatter yourself, part of the money you spent on the drug, it was washed off the leaves. Adhesive Agrolip at a dose of 0.1-0.2 l / ha completely copes with the task.
What do we get for our labor with fertilizing? One-time processing is able to provide an average increase of 10%, and in the complex – 2 treatments + seed treatment can be calculated stably for an increase of 15-25% with classical technology, and 20-30% using SUMO and CLEARFIELD technologies, mainly from partial removal of pesticide stress.