Segmental Liming of Soil and Its Effect on the Growth of Wheat1

Abstract

AbstractThe use of fertilizers and the leaching of basic cations from the soil by winter rain and irrigation have resulted in the acidification of soils and the need for lime applications to most crops grown in western Oregon. As the cost of spreading lime often exceeds $20.00 per ton, there is a need to examine the feasibility of reducing liming rates through partial mixing of lime with the soil. The effects of mixing 2.2, 6.7, and 11.2 ton/ha of lime with 10, 30, 60, and 100% of the soil volume on the growth of Nugaines wheat (Triticum aestivum L.) were studied using an acid Dayton silt loam soil in a growth chamber. The soil was placed in boxes measuring 30 on wide × 30 cm deep × 1 cm thick with the limed soil being located in equispaced vertical columns. Maximum wheat growth resulted when 6.7 ton/ha of lime was mixed with 30% of the soil. Root growth characteristics in limed and unlimed soil illustrated the chemotropic characteristics of the wheat roots with aluminum toxicity symptoms occurring in unlimed soil and where 2.2 ton/ha of lime was mixed with more than 30% of the soil. The water potential of wheat plants was increased when the root growth was reduced by soil acidity.