Skip to main content Skip to navigation

Weed control in fallow with two glyphosate formulations and various surfactants

C. R. Thompson and D. C. Thill
Two nonionic surfactants tank mixed with varied rates of two different glyphosate formulations were evaluated for control of weeds and volunteer crops. Studies were established at two sites. The sites were located south of Lewiston in the Tammany area and east of Moscow, ID. Treatments were applied with a CO2 pressurized backpack sprayer calibrated to deliver 10 gal/a at 38 psi and 3 mph (Table 1). Treatments were applied to 6 to 10 in. downy and ripgut brome (Bromus sp.) and 2 to 5 in. bur chervil (ANRCA) at Lewiston on April 24, 1992. Treatments were applied to jointed winter wheat, 5 to 10 in. peas, 3 in. mayweed chamomile (ANTCO), and 6 to 15 in., flowering field pennycress (THLAR) at Moscow on May 1, 1992. Control was evaluated visually 7, 14, and complete block and wee replicated four times.

Table 1. Application and soil analysis data
 

Temperature (F)

Soil temperature at 2 in. (F)

relative humidity (%)

Wind speed (mph-direction)

Soil pH

OM (%)

CEC (meq/100 g soil)

Texture

Moscow5464

66

2-W

6.1

2.8

16.3

silt loam

Lewiston4846

72

2-N

5.6

4.1

26.0

silt loam