Herbicidal Effects on the Nodulation of Glycine Max (L.) Merrill¹

Abstract

Nodulation of legumes is one of the processes in the soil that is liable to be adversely affected by the application of herbicides. This investigation was conducted in a greenhouse and in the field to determine what effects selected pre‐ and post‐emergence herbicides had on total number, dry weight, fresh volume, and Fe content of nodules formed on soybeans [Glycine max (L.) Merrill]. Five soils were employed in greenhouse experiments. Several rates of seven herbicides were surface‐applied to the air‐dried, soils in pots at planting and each pot was watered immediately. After 5 to 7 weeks of growth the roots were carefully isolated from the soil, the nodules were removed, and the total number and dry weight of the nodules were determined. Analyses of the results indicated that different rates of several of the herbicides had detrimental effects on the nodulation process in four of the five soils used. Dry weight was more readily affected than was total number of nodules. With three of the soils, analyses were made to determine the effects of the herbicides on tap‐root and lateral‐root nodulation. Adverse effects were found at both sites with the greater sensitivity being noted on the tap‐root nodules. Field studies were conducted for 3 years on an Olivier silt loam soil using both pre‐ and post‐emergence herbicides. Plants were excavated from the soil after 8 to 12 weeks of growth and the nodules were removed from the roots. Analyses of the data obtained from determining both the dry weight and the Fe content of the nodules did not reveal any detrimental effects from any of the herbicides used.

Effect of soil interacting herbicides on soybean nodulation in Balcarce, Argentina

“…The characteristics of the soil in which the experiments were carried out (high organic matter and clay content), may have been responsible for the mild effect herbicides had on nodulation through adsorption phenomena mediated by the soil colloids. Besides that, this type of soil exhibited a developed microbial biomass whose metabolism could enzimatically degrade the herbicides, causing a dilution effect on the applied doses (Dunigan et al, 1972;Moyer, 1979;Bollich et al, 1985).…”

“…For this reason herbicides mixtures are recommended to achieve optimum weed control (Eyherabide, 1993(Eyherabide, , 1995. Although research has demonstrated that individual herbicides applied to the soil interfere with nodulation (Dunigan et al, 1972 ;Bollich et al, 1985;Han & Oh, 1989;Moraes et al, 1989;Akhtar et al, 1990;Dalton, 1992;Yueh & Hensley, 1993), studies about the influence of mixtures of herbicides on the association is scarce.…”

Effects of the herbicides Lindex and Simazine on chloroplast and nodule development, nodule activity, and grain yield inLupinus albus L.

“…The use of herbicides therefore seems appropriate, if it does not interfere with nitrogen fixation. Although the study of the effect of herbicides on nitrogen fixation has received some attention (Avrov, 1966;Bethlenfalvay et al, 1979;Bollish et al, 1985;Dunigan et al, 1972;Kumar et al, 1981;Rennie and Dubetz, 1984), their effects are still unclear. In lupin plants 99 a stimulatory effect was observed with Simazine on the nodule bacteria (Avrov, 1966).Studies carried out in the field with lupin plants, in soils rich in native rhizobia, have demonstrated that the macrosymbiont is more sensitive to the herbicide than the microsymbiont (Kecsk6s et al, 1977).…”

Further Evidence of Meiotic Instability Induced by Atrazine in Grain Sorghum

“…potential soil and air pollutants (Cottam 1965, Epstein and Legator 1970, Dunigan et al 1972) and their repeated use may induce resistance in pests they are intended to control (Kerr 1963). Routine application of herbicides to seed fields already has been cited as a possible cause of genetic and morphological changes contributing to instability in seed stocks (Unrau and Larter 1952, Suneson 1960, Wuu and Grant 1966, Liang, Feltner and Russ 1969.…”