Root and Herbage Growth Response of Birdsfoot Trefoil Entries to Subsoil Acidity
- M. W. Alison and
- C. S. Hoveland
Stand productivity and longevity of legumes are often limited by subsoil acidity in the highly weathered soils of the eastern USA. This study was conducted to determine differences among four birdsfoot trefoil (Lotus corniculatus L.) entries for tolerance to acid subsoil. The entries were grown in the greenhouse in 13 ✕ 60 cm polyethylene tubes containing a representative profile of Appling sandy loam (clayey, kaolinitic, thermic Typic Hapludult) soil. The surface soil (0 to 15 cm) was limed to pH > 6.0. The subsurface soil (15 to 60 cm) was either limed (pH > 6.0) or not limed (pH < 4.9). All entries had similar root length in the surface and subsurface soil when subsurface soil was limed. Root length of GA 1, ‘Norcen’, and ‘Fergus’ in unlimed subsurface soil was 93, 52, and 35%, respectively, of the ‘AU Dewey’ root length. Root length of AU Dewey in the surface soil was nearly twice as much when the subsurface soil was not limed as when it was limed. Root length of the other entries was similar in the surface soil, regardless of the subsurface soil treatment. Herbage yield of AU Dewey was similar on limed and nonlimed soils, while herbage growth by the other entries was less when the subsurface soil was not limed. Relative herbage yields of AU Dewey, Norcen, GA 1, and Fergus with acid subsurface soil were 100, 68, 64, and 24%, respectively. These differences show that birdsfoot trefoil cultivar selection in acid soil environments is important and that breeding for acid soil tolerance may be possible.
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