Weed Control in Corn Planted into Untilled Winter Wheat Stubble1
- Orvin C. Burnside and
- Gail A. Wicks2
As reduced tillage production systems expand in the Great Plains, critical need will be non-tillage methods for controlling established weeds prior to planting the crop. This research dealt with finding selective weed control methods for corn (Zea mays L.) in an ecofarming system consisting of a winter wheat (Triticum aestivum L.)-corn-fallow rotation on a Sharpsburg silty clay loam (Typic Argiudolls) at Lincoln and a Holdrege silt loam (Typic Argiustolls) at North Platte, Nebraska. Both established and subsequently emerging weed species must be selectively controlled without tillage in order to better conserve the soil, water, energy, and labor requirements in this marginal corn production area. This research has as an objective the moving of dryland corn production further west in the Great Plains region. Adequate control of annual grass weeds as a group was more difficult than control of broadleaf weeds. The more difficult to control weed species were velvetleaf (Abutilon theophrasti Medic.), fall panicum (Panicum dichotomiflorum Michx.), large crabgrass [Digitaria sanguinalis (L.) Scop.], and clammy groundcherry (Physalis heterophylla Nees). Weed yields were the lowest and corn yields were the highest on plots receiving atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazinel at 2.2 kg/ha, cyanazine (2-[[4-chloro-6-(ethylamino)-s-triazin-2-yl]amino]-2-methyl-propionitrile) at 2.8 kg/ha, or a combination of the two at 0.9 + 1.9 kg/ha. Four foliar-active herbicide treatments—2,4-1) [(2,4-dichlorophenoxy)acetic acid] at 1.1 kg/ha, 2,4-D at 1.1 kg/ha + 9.4 liters/ha Sunspray HE oil, paraquat (1,1'-dimethyl-4,4'-bipyridinium ion) at 0.3 kg/ha, and glyphosate[N'-(phosphonomethyl)glycine| at 0.6 kg/ha—were equally effective for controlling established weeds and maintaining high corn yields when combined with the s-triazine herbicides. The no-till farmer has a number of herbicides available which will selectively destroy established and subsequently germinating weed species in corn without tillagePlease view the pdf by using the Full Text (PDF) link under 'View' to the left.
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