The optimal and critical concentration of the solution of humate
Theoretical substantiation and practical confirmation of the optimal concentration of humate solution is given. The analysis of possible ranges of humate concentration for various methods of its application is carried out.
Among the factors determining the level of effectiveness of humates, it is necessary to include the content and qualitative characteristics of biologically active substances, the concentration of working solutions and the dose, the soil state, temperature, humidity, etc. However, other things being equal, the effectiveness of humates is determined by two factors - concentration in solution and dose. The concentration of humate in the solution is measured in mg / l or in%, and the dose in kg / ha, g / m2 of surface or in kg / m3 of the volume of the active soil layer. Both these factors are directly dependent on the method of application: presowing soaking of seeds , foliar (foliar) fertilization of plants with aqueous solutions or the introduction of humate directly into the soil. Each of these methods requires different optimal concentrations and doses.
The interval of the optimal range of factors, in which the positive effect of the humates is most pronounced, may not be very broad. Therefore, sometimes it must be established experimentally, conducting a series of control experiments with a sufficiently small step. For a confident reproduction of the found optimum, it is necessary to use humic preparations with a higher stability of properties than those that existed before.
Employees of "AgroBio" by experience have come to the conclusion that the greatest biological activity with foliar application is an aqueous solution with a humate concentration of 0.005 -0.009% in the Far East. In further studies of many scientists and agronomists, solutions of this concentration were used.
The optimum of stimulating effect of humate in the concentration range 0.004 - 0.01% was obtained by the method of biotesting on maize coleoptiles with the use of distilled water.
These data completely coincide with the conclusions of SN Chukov, who established a concentration maximum in the range 0.005 - 0.012%.
In the work of E.I. Ermakova gives the value of the concentration optimum for monocots 0.001%, and for dicots (cucumber, sunflower) 0.01%.
The data of the field experiment on the cultivation of carrots are given, where a clearly pronounced maximum in the humate concentration range 0.006 - 0.009% is also observed (Fig. 8). It should be noted that these data were obtained in Irkutsk using very soft Angara water. In hard water, some of the molecules of humic compounds will immediately become bound by the cations of calcium, magnesium and iron that are present in it, and a different, higher concentration will be required.
Fig. 8 Dependence of the increase in the yield of carrots on the concentration of the solution of humate (Irkutsk, 1996)
Some shift in the maximum for various researchers is explained by methodological errors, the presence of chemically active impurities in ordinary water used for the preparation of highly diluted solutions of humate, or other factors, but the form of the dependence is the same.
The common for all these dependences is a surge in the activity of humate in the optimum and the presence of a concentration interval in the vicinity of the optimum in which the effect of humate manifests itself most strongly. The exact location of the maximum depends on the conditions and complexity of the experiment and, in particular, on the hardness of the water, but in all cases for the foliar treatment of plants we must use highly dilute solutions.
Comparison of the experimental data with the physical model of penetration of solutions into the plant leaf during surface treatment showed that the optimal concentration of the working solution 0.005 - 0.01% is somehow related to the penetrating ability of the humate solution in the leaves and partly to the optimal concentration of humate in the intercellular plasma and inside the cells, equal to 0.0002 - 0.005% (see below in section 1.5).
Consider a scheme of foliar treatment of plants, in which a film of a solution of potassium humate is sprayed onto the plant leaf by spraying. The solution, on the one hand, is absorbed by the sheet, and on the other, water evaporates from it. Since the evaporation of water from the film most often goes faster than the absorption, then at a high initial concentration of humate, there may come a time when, due to evaporation, it will reach such a level that aggregation of the molecules begins and they lose the ability to penetrate the sheet. Thus, the optimum concentration of the solution of potassium humate is related to the degree of penetration of the solution into the plant leaf and the rate of evaporation of water from the solution film and the optimum concentration of humate in the plant volume. However, the question of the local concentration of the humate solution on the plant surface remains open. The application of the spraying solution can lead to its localization in the radius of the drops that have fallen on the leaves and the aerial part. It is assumed that in the future, the molecules of humate from the microzone of droplets penetrate deeper into the leaves and stems and are evenly distributed throughout the green mass and root system. This mechanism, as well as technologies for improving the parameters of spraying, has yet to be studied more deeply. The mechanism of penetration of the humate molecule from the surface of the sheet into its interior also needs to be specified.
In the literature and reports at conferences and seminars, there are other recommendations on the optimal concentrations of sodium humate solutions for foliar treatment, established 0.001, 0.01, 0.02, 0.03, 0.05, 0.1%, and sometimes even higher, as determined experimentally . Unfortunately, we can not determine the causes of changes in solution concentrations to the indicated lower and upper boundaries, although we do not exclude the possibility that they can be justified by some additional factors, including the presence of several optima.
The lower practical limit of concentration (0.005%) is determined both by economic considerations associated with excessive water consumption to ensure the optimal dose, and an allowable physical limit, depending on the hardness of the water. If the solution of humate, as shown above, has a sufficiently high concentration, the rigidity of water does not affect its aggregative stability, since the molecules of the humates of calcium, magnesium and other metals are surrounded by molecules of humate, which protect them from precipitation. In colloid chemistry, this very common phenomenon is called "colloidal protection." When diluting the solution with hard water, we, on the one hand, increase the content of calcium and other metals, and, on the other hand, reduce the concentration of the protective ions. As a result, at a certain concentration of the humate solution corresponding to a certain water hardness, precipitation of the humates of alkaline earth metals is observed. Therefore, the lower limit of the concentration of the working solution of humate should not be lower than the level determined by the hardness of the water. The study of Energena solutions in hard water (Sergiev Posad, Moscow Region) showed that at a solution concentration of 0.005%, the precipitate of calcium and magnesium humates precipitates almost instantaneously, at a concentration of 0.01%, the precipitate falls for several minutes, at a concentration of 0.05% - for half an hour , but a concentration of 0.08% makes it possible to obtain a stable solution. Therefore, the lower limit of the concentration of the working solution of humate should not be lower than the level determined by the hardness of the water. The study of Energena solutions in hard water (Sergiev Posad, Moscow Region) showed that at a solution concentration of 0.005%, the precipitate of calcium and magnesium humates precipitates almost instantaneously, at a concentration of 0.01%, the precipitate falls for several minutes, at a concentration of 0.05% - for half an hour , but a concentration of 0.08% makes it possible to obtain a stable solution. Therefore, the lower limit of the concentration of the working solution of humate should not be lower than the level determined by the hardness of the water. The study of Energena solutions in hard water (Sergiev Posad, Moscow Region) showed that at a solution concentration of 0.005%, the precipitate of calcium and magnesium humates precipitates almost instantaneously, at a concentration of 0.01%, the precipitate falls for several minutes, at a concentration of 0.05% - for half an hour , but a concentration of 0.08% makes it possible to obtain a stable solution.
If we talk about the upper limit of the working solution for foliar treatment, its value is determined by the solubility of the humate, taking into account the water hardness, and the ability of humate to penetrate through the leaf surface, which decreases with increasing concentration, and the dose received in the volume of the sheet that determines biological efficiency . As already mentioned, with an excessive dose, instead of stimulation, suppression of plant development can be obtained. This boundary largely depends on the processing conditions of plants and its value is in the range 0.01-0.08%.
Experienced our employees also established the optimal concentration and consumption of the humate solution, not only for foliar treatment, but also for soaking seeds.
For example, to soak corn seeds, she recommended an increased solution concentration of 0.1% to compensate for the low duration (48 hours) of contact of the seeds with the humate. American agronomist, well-known expert in the field of humic preparations, Robert Faust also recommends the use of 0.1% solution, but only for large seeds: corn, cucumbers, beans. For smaller seeds, such as tomatoes, he recommends a 0.5% solution with a soaking time of 72 hours, or a 2% solution with a soaking time of 30 minutes. The theoretical justification for the fact that the optimal concentration of a solution of humate for soaking seeds should be an order of magnitude higher than the concentration of the solution for foliar treatment of plants, is the need to intensify the short-term process of penetration of sodium humate through the surface layer of the seed. To establish a detailed mechanism for activating seeds, additional research is needed. In this case, a factor such as a dose is taken into account indirectly by ensuring that the seeds are completely wetted with a solution of a certain concentration for a certain time.
In some cases, the technology of spraying seeds and tubers is preferable to soaking technology. The optimal concentration of the solution will be higher while the dose is lower. This is explained by the different mechanism of penetration of humate into the depth of the planting material. When soaking, the process is more intense, but it stops almost immediately after removing the planting material from the solution. Spraying technology is designed for the fact that the humate from the human shell will continue to penetrate into the planting material under the action of soil moisture and after planting in the ground.
It is known that the molecules of humic acid are bound by forces of intermolecular interaction to aggregates with an average molecular weight of up to 100,000 D and a coil size of about 150 Angstrom. It can be assumed that as the concentration of the solution decreases, the aggregates gradually break down into smaller formations up to individual molecules, and then, as a result of hydration, at a concentration of 0.005-0.009%, a new structure forms, which greatly facilitates their penetration into the leaves, stems and roots of the plant. It is possible that in the soil under natural conditions there is also a consumption of hydrated molecules of humic substances by the plants at optimal concentrations of the solution.
Read the continuation of the article
List of articles for the category of blog MicronutrientsRead more... List of articles for the category of blog Micronutrients
Ukraine has an agrarian orientation of the economy and in modern conditions one of the most perspective areas for agriculture is the use of organic preparations and is based on the application of exclusively natural components that offers production AGRO.BIO - liquid concentrate GUMAT KALIYA , which helps to rationally and effectively restore the natural components of the main asset - the soil.
In a soil environment, there is not always enough nutrition for plant growth and development, but this disadvantage can be improved by additional fertilization, namely: GUMAT KALIYA UNLIMITED WITH LEONARDITA produced by AGRO.BIO - ecologically safe complex fertilizer and growth stimulator for organic plants that promote soil fertility.
In order to make it easier for you to read our products below, there are articles about potassium humate and multicompules.