C. Medlin et al., SYSTEMS FOR RETURNING CONSERVATION RESERVE PROGRAM LAND TO WHEAT (TRITICUM-AESTIVUM) PRODUCTION, Weed technology, 12(2), 1998, pp. 286-292
Experiments were conducted near Duke and Forgan, OK, on land enrolled
in the Conservation Reserve program (CRP) that had been seeded to Old
World bluestem (OWB) to evaluate tillage systems for returning CRP gra
ssland to winter wheat production. Glyphosate controlled OWE 72% or le
ss in no-till (NT) wheal. Disk tillage (DT) and moldboard plow tillage
(MPT) for wheat seedbed preparation controlled OWB 87 and 99%, respec
tively, at Forgan and 96 and 100%, respectively, at Duke. At Forgan, O
WE control in NT was higher when glyphosate was applied in July than w
hen applied in May. Soil water content to a depth of 120 cm at plantin
g was as high in DT and MPT without herbicide as in NT with 1,680 g ae
/ha glyphosate. Within NT and MPT, glyphosate did not consistently inc
rease soil water content compared to the respective nontreated checks.
in DT, soil water content to a depth of 120 cm was greater following
glyphosate at 1,680 g/ha than without glyphosate. Wheat density was gr
eater in DT and MPT than in NT. Compared to the NT no herbicide treatm
ent, tillage tripled wheat yields. Wheat yields were often greater whe
re glyphosate was applied before tillage. No-till wheat production imm
ediately after CPR in Oklahoma without prior destruction of accumulate
d OWE residue does not appear feasible.