Controlled Release of TBH Herbicide Encapsulated on Ca-ALG Microparticles: Leaching and Phytointoxication Plants

Abstract

The aim of this work was to demonstrate a detailed study of the controlled release of the herbicide Tebuthiuron (TBH) encapsulated in microparticles of calcium alginate (Ca-ALG), to evaluate the phytotoxicity in different concentrations of herbicide (4, 6 and 8 g L-1), and their correlation with the depth of leaching using bioindicator plants. The Ca-ALG microparticles were prepared from the crosslinking of sodium alginate by Ca++ containing varied amounts of TBH supplied in calcium chloride (CaCl2) aqueous solution. The results showed that TBH herbicide, when encapsulated, leached to shallow depths relative to the conventional, non-encapsulated herbicide (which moved to a depth of 40-50 cm). The concentration of 4 g L-1 was the one that leached most in the PVC columns, but its mobility did not exceed 30 cm of depth. The results of the dry mass corroborated with the phytotoxicity results of the bioindicator plants, evidencing the mobility of the conventional herbicide in the soil at depths around 40 and 50 cm, while the herbicide encapsulated in the Ca-ALG microparticles did not show leaching beyond 20 -30 cm deep. The encapsulation of TBH in Ca-ALG microparticles can thus be considered as a more eco-friendly technology, reducing the leaching process and consequently soil contamination.

Assessment of Antifungal Efficacy and Release Behavior of Fungicide-Loaded Chitosan-Carrageenan Nanoparticles against Phytopathogenic Fungi

“…Release studies in diverse soil and media improved the controlled release compared to commercial acetamipirid and acidic soils gave the best results. A detailed study of the controlled release of the herbicide Tebuthiuron encapsulated in microparticles of calcium alginate and its correlation with leaching depth using bioindicator plants was demonstrated [ 61 ]. Rychter [ 62 ] found a herbicidal effect exhibited by the herbicide glyphosate with chitosan nanoformulations and established the slow and sustained release of the active ingredient from the polymer matrix.…”

Effect of encapsulated herbicides on weed control, productivity and nutrient uptake of rice (Oryza sativa)

“…Bommayasamy et al (2018) reported that weeds can be effectively controlled by slow release herbicide formulations with reduced doses selectively non-toxic to crops, which remain in the soil for a long period to take care of frequently germinating weeds without leaving any residue at the end of crop season. Leaching of tebuthiuron herbicide encapsulated with calcium alginate microparticle was only to a shallow depth which resulted in minimal contamination of soil (Macedo et al, 2019;Xie et al, 2019). oxadiargyl loaded with biochar.…”

Toxicity Assessment and Control of Early Blight and Stem Rot of Solanum tuberosum L. by Mancozeb-Loaded Chitosan–Gum Acacia Nanocomposites

“…An earlier study showed that the application of herbicide-loaded nanoparticles could be used to reduce the use of herbicides with improved efficacy and environmental safety [ 29 ]. While working with sodium alginate nanoparticles on cucumber plants, leaching of commercial herbicide tebuthiuron in soil was found to be higher (40–50 cm deep), while for nanoformulations, it was lower (20–30 cm), suggesting enhanced uptake by plants and less toxicity to non-target organisms such as fish and other aquatic organisms [ 66 ]. Thus, it can be said that encapsulation reduced the cytotoxicity of commercial mancozeb in the present study.…”