Spring Wheat Plant Parameters as Affected by Fallow Methods in the Northern Great Plains
- D. L. Tanaka
Conservation tillage and no-tillage practices for wheat (Triticum aestivum L.) production reduce soil erosion, conserve soil water, and alter crop environments. A study was conducted on a Williams loam (Typic Argiboroll) to determine the influences of stubble mulch, reduced tillage, and chemical fallow on grain yield and yield components, N and P concentrations in grain, water-use efficiency, and straw production in a spring wheat-fallow rotation. Average quantity of surface resldue prior to seeding spring wheat on chemical fallow plots (1371 kg/ha) was about three times the quantity on stubble-mulch plots (399 kg/ha) and two times the quantity on reduced tillage (703 kg/ha) averaged over the 4-yr study. The greater quantity of surface residue on chemical fallow plots in 1985 and 1986 resulted in significantly greater stored soil water to 1.70-m depth when compared to stubble-mulch plots. However, greater stored soil water did not result in significantly higher grain yield, although straw production for chemical fallow plots (2831 kg/ha) was significantly higher than for stubble-mulch plots (2036 kg/ha) in 1985. Results of this study suggest that during years of crop stress resulting from limited soil water and above normal early spring temperatures, chemical fallow may produce more spring wheat than stubble-mulch fallow. However, with limited water or temperature stress, stubble-mulch fallow may produce more spring wheat than chemical fallow. Grain N concentrations were similar for all years except 1983 when N concentrations were greater for stubble-mulch plots than chemical fallow plots. Fallow method did not influence grain P concentration. Grain water-use efficiency was greater for wheat grown on stubble-mulch plots than on chemical fallow plots.
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