Cultural Practices for Irrigated Winter Wheat Production1
- Paul W. Unger,
- Ronald R. Allen and
- Jessie J. Parker2
Rototilling, moldboard plowing, disking, burn-listing, and listing were satisfactory tillage methods for managing the residues produced by continuous irrigated winter wheat (Triticum aestivum L.). Grain yields averaged highest for moldboard plowing and lowest for lister plowing. Nitrogen fertilizer at 90 or 135 kg N/ha resulted in significant grain and residue yield differences in a few years, but no consistent trends were apparent. Irrigation water infiltration was highest for moldboard plowing and lowest for lister plowing. The list and burn-list treatments resulted in similar infiltration. Water-use efficiencies were similar for all treatments.
At the end of the 5-year study, soil organic matter content was lowest (1.66%) for burn-lister tillage and highest (1.72%) for lister and disk tillage. Water-stable aggregation was highest (84.5%) for rototilling and lowest (79.3%) for burn-lister tillage. Bulk density increased in all plots, but it increased the least in plots that were moldboard plowed. Moldboard plowing resulted in the lowest (21.9) and burn-lister tillage in the highest (28.6) percentage of fine aggregates (<0.42 mm). All treatments resulted in a relatively high percentage of wind-erodible aggregates (<0.84 mm).
Applying 135 kg N/ha maintained soil organic matter and total nitrogen at higher levels than did 90 kg N/ha. Applying N soon after harvest of the previous crop generally was as beneficial as applying N at seeding. Soil bulk density, water-stable aggregation, and dry aggregate distribution were not significantly affected by fertilizer treatments.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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