|Shrefler, James - OKLAHOMA STATE UNIV.|
Submitted to: Proceedings of Southern Weed Science Society
Publication Type: Abstract Only
Publication Acceptance Date: February 5, 2003
Publication Date: June 6, 2003
Citation: Webber, C.L. III, Shrefler, J.W. Effect of cover crop, tillage, and weed competition on black bean yields. Proceedings for the Southern Weed Science Society Conference. 2003. Abstract v. 56. p. 257. Technical Abstract: The selection and use of a winter cover crop may have both long-term benefits, such as reduced soil erosion, and short-term consequences such as decreased weed competition and nutrient availability. In addition, the selection of a spring tillage/planting system following the winter cover crop may either be beneficial or injurious to dry bean production by affecting weed growth and soil moisture availability. The objective of this research was to determine the effect of winter cover crops, tillage/planting systems, and weed control on black bean yield components. The five winter cover crops, planted in the fall of 1999 and 2001, were "barley" (Hordeum vulgare L.) cv. 'Tambar,' oats (Avena sativa) cv. 'Nora,' "rye" (Secale cereale) cv. 'Maton,' "wheat" (Triticum aestivum L.) cv. 'Coker,' and "None" (no winter cover crop). Black beans (Phaseolus vulgaris L.) cv. 'Black Knight' were planted in the spring of 2000 and 2002 at Lane, OK on 91-cm row spacings at 222,400 seeds/ha. The four weed control treatments included a "weedy check," a "early season," a "late season," and a "full season" treatment. In the weedy check treatment the weeds were allowed to grow throughout the 90-day growing season. Weeds were removed by handweeding during the first 45 days for the early season weed control, during the last 45 days for the late season weed control, and during the entire growing season for the full season weed control treatment. Rainfall during both growing seasons was below the 30-yr average for the location, therefore, the soil moisture conservation in the no-tillage planting system and plant stress resulting from weed competition became significant factors in affecting the black bean yield components. When averaged across tillage/planting systems and weed control levels, the beans following oats produced significantly greater black bean yields (372 kg/ha) than either rye (214 kg/ha) or wheat (164 kg/ha). The oat cover crop also resulted in a greater number of black bean pods per plant (3.5 pods/plant) than the wheat cover crop (2.1 pods/plant). The black bean plant populations were significantly less following the rye and wheat cover crops than the barley. The conventional tilled/planted black beans had 17% lower plant populations (110,000 plants/ha) than the no-tillage beans (132,300 plants/ha). Early weed removal was more beneficial than weed removal during the second half of the season. The best production system included oats as a cover crop, the no-tillage planting system, and either an early or a full season weed control.