How to prevent herbicides leaching in the soil?
Soil herbicides used in modern agrotechnologies have become one of the main ways of weed control in critical for plants period. Becoming a competitor to the crop for water, light, and nutrient elements in the first stages of growth and development due to faster germination and more active growth of plant biomass, these highly damaging plants cause a loss of 20-50%, and in case of high level of presence - even 100% of the crop.
Scientific research and field practice have shown that the effectiveness of soil herbicides is closely related to the soil moisture level. So, in case of soil drying, the preparation applied on its surface can lose its properties due to evaporation, weathering or might decompose under ultraviolet light. In addition, insufficient moisture in soil often inactivates the active factor of the herbicide and does not provide the desired phytotoxic effect. Excessive moisture caused by heavy rains or uncontrolled watering also has negative effects, because it causes destruction of the herbicide “screen” and undesirable washing out of the preparation in the area of the seed bed. This can cause negative effects for the seedlings of most crops, despite selectivity of the plants to the active factors of the recommended herbicides. A significant environmental threat, especially for reservoirs, is caused by washing off of the herbicides when applied on soil on the slopes, which are exposed to water erosion.
One of the most effective solutions to these problems is Liposam®, a natural adhesive based on biopolymers. Good lipogenic properties and presence of various functional groups of polysaccharides in the composition of Liposam® provide a soft retention of the working solution on the soil surface and prevent washing out of the herbicide when added to the mixture with a soil herbicide. In addition, the effectiveness of the pesticide enhances under conditions, optimal for weed germination, when their seedlings appear within 3-5 days after the last soil treatment or sowing.
Unlike most surfactants, which reduce the surface tension of the working solution, the physical properties of Liposam® enable keeping the micro-moisture content in the area of the protective screen, providing active contact of moisture and the active factor of the herbicide, thereby preventing blocking its effect on weed seedlings. This is especially crucial in conditions of long period of their germination, for example, due to cold weather.
When there is a high probability of heavy rains, which in recent years have occurred in almost all soil and climate zones, application of the adhesive Liposam® is appropriate in tank mixtures with herbicides, especially those that are highly soluble in water, because they are prone to washing out and getting into the area where the seeds of the crop are located.
The results of experiments held in Kyiv region on typical chernozem prove that use of the bioadhesive Liposam® (0.5-0.8 l/ha) in the mixture with the herbicide Primextra TZ Gold (4.0 l/ha) increased the effectiveness of the latter at the stage of formation of 4-6 leaves by 21-27 %. At the same time, the biological yield increased by 0.15 t/ha in the case of Liposam® application with rate of 0.5 l/ha, and when the application rate was increased to 0.8 l/ha, the yield increased by 0.18 t/ha in contradistinction to the level of 3.46 t/ha on the control plot without the adhesive. In another experiment, in one of the farms in Vinnytsia region, the use of Liposam® at the rate of 0.8 l/ha with the reduced rate of the herbicide Primextra TZ Gold (3.5 l/ha) provided control of not only annual but also perennial species of dicotyledonous weeds. Efficiency from the application of such a mixture expressed in the form of the crop yield increase was 0.4 t/ha.
Therefore, application of Liposam® is agronomically and environmentally justified measure to increase the effectiveness of the soil herbicides, and its economic attractiveness is provided by an affordable price.