USE OF FORESTRY WASTES FROM PINUS-RADIATA D DON - CONTROLLED-RELEASE FORMULATIONS OF HERBICIDES

Herbicide formulations were prepared by physical and chemical methods using 2,4-dichlorophenoxyacetic acid (2,4-D), 2-methyl-4-chlorophenoxy acetic acid (MCPA) and trichloroacetic acid (TCA) herbicides in polyme ric supports. Lignin, Pinus radiata bark and their components were use d as supports, Physical formulations were obtained by adsorption over the supports, obtaining an incorporation of 2-7%. The active ingredien ts (a.i) were also incorporated to a matrix formed by crosslinking the polyphenolic material by using formaldehyde, the incorporation values ranged between 3-7%. Chemical formulations were prepared through the formation of esters, previous formation of the acid chloride of the re spective herbicides, incorporating about 11-30% a.i. TCA and 2,4-D del ivery in water showed a matrix effect compared with the monomeric bark unit, catechin. These formulations are being tested in weed control i n a greenhouse conditions, obtaining an important percentage of contro l and persistence of availability in soil greater than those of conven tional formulations.