Absorption of Herbicides by Soybean Seeds and Their Influence on Emergence and Seedling Growth

Abstract

The total quantity and concentration of six herbicides, isopropylm-chlorocarbanilate (chlorpropham), 2-chloro-4-(ethylamino)-6-(isopropylamino-s-triazine (atrazine), 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea (linuron), 2-chloro-2′,6′-diethyl-N-(methoxymethyl)acetanilide (alachlor), 3-amino-2,5-dichlorobenzoic acid (chloramben), and (2,4-dichlorophenoxy)acetic acid (2,4-D), in unaerated, aqueous solutions absorbed by seeds of 11 soybean(Glycine max(L.) Merr.) strains were measured. Mechanism of movement of the herbicides from the aqueous solutions to the seeds in the experimental procedure employed was diffusion. Total quantity and concentration of herbicide found in the seeds differed significantly for both herbicides and soybean strains. Total quantity of herbicide absorbed was determined by total oil and percent oil of the seeds. The capacity of the seeds to absorb a given herbicide was more closely related to percent oil of the seeds than to total oil of the seeds. The emergence and seedling shoot weight of ‘Cutler’ soybeans were not affected appreciably by concentrations of linuron, atrazine, and chloramben (potassium salt) but were reduced by high concentrations of chlorpropham and alachlor and relatively low concentrations of 2,4-D (potassium salt) in the seeds.