Influence of No-Tillage Planters on Tolerance of Soybeans to Linuron

Abstract

Soybeans [Glycine max(L.) Merr.] planted conventionally or no-tillage tolerated approximately four times the recommended preemergence rates of linuron [3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea] depending on the type planter used. Least injury to high rates of linuron was with a planter that placed seed slightly below the level of the surface of the field with a slightly rounded ridge of soil over the row. A planter leaving the seed under a slight furrow resulted in intermediate crop injury and a planter which deposited seed under a furrow 5 to 10 cm deep resulted in greatest crop injury. There was no consistent trend in the tolerance to linuron of soybeans planted conventionally or planted without tillage in small grain stubble with the straw removed. Row profile and its relation to seed placement was important in the tolerance of soybeans to linuron.