Growth Response of Cultivars to Conservation Tillage in a Continuous Wheat Cropping System
- Thanh. H. Dao and
- H. T. Nguyen
Changes in tillage methods to cope with the continual erosion of our soil resource prompted the need to reassess current management practices for annual cropping systems of wheat (Triticum aestivum L.). A field study was conducted on Bethany silt loam (fine, mixed, thermic Pachic Paleustoll) from 1983 through 1987 near El Reno, OK to determine whether 10 hard red winter wheat cultivars respond differently to tillage systems. The cultivars were planted in moldboard-plowed seedbeds, stubble-mulch-tilled seedbeds, or directly in standing stubble (no-tillage). The effects of tillage method on plant stand, phenology, grain yield, and yield components were determined. Tillage method ✕ cultivar interactions varied with agronomic traits and years. In general, reducing tillage intensity delayed plant maturation beginning in the spring. Anthesis and leaf-area duration periods occurred about 1 to 8 d later in mulch-tilled and no-tilled plots, compared with plowed plots. The prolonged vegetative phase indicated a potential benefit of no-tillage in a wheat-production system that includes a livestock grazing component during the winter months. Grain-fill periods of no-tillage wheat increased between 1 to 4 d in early-maturity cultivars while those of later-maturity cultivars were variable. The lack of tillage method ✕ cultivar interaction for grain yield indicated that development of wheat cultivars for emerging conservation technology may not be necessary. Notillage wheat yields were similar to conventional-tillage yields, or slightly better in years with cold autumns that had erosive rains or dry springs. Early maturity cultivars consistently had stable yields during 1983 to 1987 with good resilience against environmental variations, but late-maturity ones may not be suitable for no-tillage winter wheat production. High temperature tolerance may be a potential breeding objective for plant types adapted to conservation tillage in the Southern Plains.
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