Emergence and Seedling Growth of Seven Cool-Season Annual Clovers as Influenced by Soil pH

Abstract

ABSTRACT Legumes are generally more sensitive to soil pH than grasses which sometimes results in poor legume establishment and growth. The objective of this study was to determine the effect of soil pH on the emergence and seedling growth of seven cool-season annual clover species. A Lilbert loamy fine sand (Loamy, siliceous, thermic, Arenic Plithic Paleudult) was amended with sulfur or agricultural lime resulting in soil pHs of 4.3, 5.1, 5.5, 6.4, 7.4, and 8.0. Arrowleaf (Trifolium vesiculosum Savi.), berseem (T. alexandrinum L.), crimson (T. incarnatum L.), Persian (T. resupinatum L.), rose (T. hirtum All.), and subterranean (T. subterraneum L. and T. brachycalycinum Katzn.) clovers were seeded in pots containing the different pH soils in a greenhouse. Clover species response to soil pH was determined by measuring emergence rate index (ERI), shoot and root dry weight, root/shoot ratio, shoot and root crude protein (CP), and nodules per seedling. Species × pH interactions were significant (P ≤.001) for all seedling traits. Aluminum toxicity became a problem at pH ≤ 5.1. Arrowleaf and crimson clovers were the most pH tolerant but arrowleaf shoot and root growth were optimum at pH 6.5. Berseem and Persian clovers preferred a neutral to basic pH with most seedling traits decreasing as pH decreased. Both subterranean species and rose clovers grew best at pH of 6.0 to 7.0. Selecting the best clover species for a given soil pH or amending the soil pH for a given clover species will improve clover establishment and growth.