Effect of Subsoiling and Irrigation Regime on Dry Bean Production in the Pacific Northwest1
- D. E. Miller2
Zones of high strength are common in irrigated soils. Root penetration may be reduced if soil strength exceeds 1 to 3 MPa, resulting in a decreased supply of water and nutrients to the plant. On sandy soil this may allow plant water stress to develop between irrigations. Bean plants (Phaseolus vulgaris L.) are particularly sensitive to high soil strengths. A study was conducted on two soils to determine the effect of subsoiling on soil strength, bean root development, and plant reaction to different irrigation regimes. On a rigid uncemented matrix sandy soil, subsoiling reduced soil strength from >3 to <1 MPa, promoted deep rooting, and increased foliage. Without subsoiling, plants frequently suffered water stress between irrigations applied at 4-d intervals. This resulted in blossom drop and delayed maturity by about 2 weeks. The deeper rooting associated with subsoiling reduced water stress and bean plants grew and matured normally. On a loam soil subsoiling also reduced strength to about 1 MPa or less and increased rooting depth and foliage density compared to normal tillage. With the dense foliage, 65 to 80% of the bean plants were infected with Sclerotinia white mold and dry bean yields were low. Because of the Sclerotinia injury, results were inconclusive.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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