This research compared seven field bindweed control treatments to a check in a 3-yr winter wheat-sorghum-fallow rotation. Treatments included 3 wk intervals of sweep tillage combined with one or two annual applications of 2,4-D (tillage and 2,4-D). Two other treatments were the same as tillage and 2,4-D, except dicamba or a mixture of picloram and 2,4-D were applied once in October after wheat harvest. A fourth treatment was identical to tillage and 2,4-D, except imazapyr was sprayed immediately after harvest of wheat. Also, three no-tillage systems using glyphosate and 2,4-D at monthly intervals were supplemented with either dicamba, picloram and 2,4-D, or imazapyr the same as in treatments involving tillage and 2,4-D. The check was sweep tilled every 6 wk. All treatments controlled field bindweed in one rotation of two fallow periods and two crops. After control was accomplished, wheat and sorghum yields were about twice the check. Using 1995 costs and returns, profit for an owner-operator for the two fallow periods and two crops was $123 ha−1for tillage and 2,4-D, compared to $19 ha−1for the check. Tillage and 2,4-D supplemented with picloram or imazapyr were almost as profitable as tillage and 2,4-D. Because of high herbicide cost and low yields, no-tillage treatments lost money. Profits with a 33:67 owner-tenant rental agreement were $105 and $21 ha−1, respectively, for owner and tenant using tillage and 2,4-D. With no field bindweed control practice, the tenant lost $33 ha−1and the owner made $51 ha−1.
AMOUNT, DISTRIBUTION, AND SEASONAL TREND OF CERTAIN ORGANIC RESERVES IN THE ROOT SYSTEM OF FIELD BINDWEED, CONVOLVULUS ARVENSIS L
