Straw Production and Grain Yield Relationships in Winter Wheat
- Edwin Donaldson,
- William F. Schillinger * and
- Stephen M. Dofing
Winter wheat (Triticum aestivum L.) –fallow is the predominant cropping system in low-precipitation regions (<250 mm annually) of the inland Pacific Northwest (PNW) in the USA. Wind erosion is a recurrent problem during and after fallow periods when inadequate crop residue amounts are retained on the soil surface. Management options that optimize both grain yield and straw production are needed. A 3-yr field study was conducted to determine sowing rate and sowing date effects on straw and grain yield, and grain yield components of winter wheat cultivars with semidwarf, standard height, or tall growth habit. Four winter wheat cultivars were evaluated at three sowing rates (65, 130, and 195 seeds m−2) and three sowing dates in August, September, and October. A split plot design was used, with sowing dates as main plots and sowing rate × cultivar combinations as subplots. The greatest effect of sowing date was on straw production. Straw biomass from mid-August sowing averaged 6.70 Mg ha−1 compared with 4.65 and 2.78 Mg ha−1 from mid-September and mid-October sowing, respectively. Grain yield was highest for mid-August sowing during two years and lowest for mid-October sowing all years. Averaged across years, the semidwarf cultivar produced the highest grain yield on all sowing dates and was equal to the standard height and tall cultivars for straw production. Path coefficient analysis showed that variation in grain yield was due primarily to differences in spikes per unit area (SPU) and kernels per spike (KPS). Late sowing resulted in a large reduction in SPU and, therefore, grain yield. For cropland susceptible to wind erosion in east-central Washington, early sowing results in increased wheat straw production and generally higher grain yield compared with mid-to-late sowing dates.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 2001.