Rasprskivači i adjuvanti: mogućnosti za povećanje efikasnosti herbicida i smanjenje zanošenja

Abstract

Primena herbicida u sklopu integrisanog sistema suzbijanja korova mora biti urađena tako da se postigne najviša moguća efikasnost i smanji potencijalan negativan uticaj na životnu sredinu i susedne biljke. Na taj način je moguće produžiti životni vek herbicida, s obzirom na veoma mali broj novih herbicida na tržištu. Izborom odgovarajućeg ađuvanta menjaju se fizičko-hemijske osobine rastvora, čime se povećava usvajanje herbicida od strane biljke preko smanjenja površinskog napona ili interakcijom sa kutikulom. Pojedini ađuvanti ukrupnjavaju kapljice herbicida ujedno smanjujući drift. Rasprskivači, kao završni elementi u primeni herbicida, određuju pokrovnost i zanošenje herbicida. Ukoliko su proizvedene kapljice manje od 100 mikrometara, one su veoma podložne odnošenju sa primarnog mesta pod uticajem vetra i obrnuto. Brojni literaturni podaci ukazuju na značajno povećanje efikasnosti herbicida ukoliko primenu prati dodavanje adjuvanata. Ukoliko rasprskivači nemaju uticaja na efikasnost herbicida, moguće je da se koriste oni rasprskivači koji proizvode grube kapljice (veće od 600μm), čime se sprečava zanošenje herbicida na susedne useve. Rezultati naših istraživanja u kontrolisanim uslivima ukazuju da dodatak ađuvanata u herbicidni rastvor povećava efikasnost od 18,7 do 38,3 % u odnosu iste herbicidne tretmane bez adjuvanata. Isto tako, u dvogodišnjem poljskom ogledu povećana je efikasnost nikosulfurona kada je primenu pratio dodatak nejonskog surfaktanta kao adjuvanta za 6,8 %. Da zanošenje herbicida predstavlja potencijalnu opasnost po susedne biljke pokazao je ogled u kontrolisanim uslovima u kome je simuliran drift. Mikro doze dikambe, glifosata, mezotriona i nikosulfurona značajno su oštetile suncokret, soju, uljanu tikvu, uljanu repicu, paradajz, papriku i zelenu salatu. Izbor rasprskivača nije značajno uticao na efikasnost mezotriona i rimsulfruona sa tifensulfuron-metilom kod četiri od šest testiranih korova u kontrolisanim uslovima. Sa druge strane, u poljskom dvogodišnjem ogledu kada je nikosulfuron primenjen gotovo da nije postojala razlika u smanjenu biomase korova bilo XR (proizvodi fine kapljice) ili TTI diznom (veoma krupne kapljice). Dobijeni podaci ukazuju da postoji mogućnost primene herbicida i rasprskivačima koji proizvode krupne kapljice, s tim da je njih potrebno koristiti kada su pojačana vazdušna strujanja.

Herbicide application as a part of an Integrated Weed Management system must be done correctly in order to achieve the highest possible efficacy and decrease potentially negative effects on the environment and neighbour crops. This approach makes it possible to prolong herbicide usage, because of a limited portfolio for weed control on the market. The choice of the appropriate adjuvant may changes the physico-chemical properties of the solution, which increases the uptake of the herbicide by the plant through a reduction in surface tension or interaction with the cuticle. Some adjuvants enlarge the herbicide droplets while reducing drift. Nozzles, as the final elements in the applications, determine the coverage and drift. If the produced droplets are smaller than 100 μm, they are prone to an off-target movement from the primary site under the influence of wind and vice versa. Numerous literature data indicate a significant increase in the effectiveness of herbicides if the application is accompanied by the addition of adjuvants. If the nozzles do not affect the effectiveness of the herbicide, it is possible to use those nozzles that produce coarse droplets (larger than 600μm), which prevents the herbicide from spreading to neighbouring crops. The results of our research in controlled conditions indicate that the addition of adjuvants to the herbicidal solution increases the efficiency by 18.7 to 38.3% in relation to the same herbicide treatment without adjuvants. In a two-year field trial, the efficiency of nicosulfuron was increased when the application was accompanied by the addition of a non-ionic surfactant as an adjuvant by 6.8%. That herbicide drift represents a potential danger to neighbouring plants was shown by an experiment in controlled conditions in which drift was simulated. Micro doses of dicamba, glyphosate, mesotrione and nicosulfuron significantly damaged sunflower, soybean, pumpkin, canola, tomato, paprika and lettuce. The nozzle selection did not significantly affect the efficacy of mesotrione and rimsulfuron with thifensulfuron-methyl in four out of six weeds tested under controlled conditions. On the other hand, in a two-year field trial when nicosulfuron was applied, there was no difference in the weed biomass reduction with either XR (fine droplet products) or TTI nozzle (very coarse droplets). The obtained data indicate that there is a possibility of application of herbicides with nozzles that produce large droplets, when wind velocity is higher.