Variation with soil depth, topographic position and host species in the capacity of soils from an Australian locale to nodulate Casuarina and Allocasuarina seedlings

• Published in: Plant and soil 1989-08, Vol.118 (1), p.1-11
• Main Authors: Dawson, J.O. (Illinois Univ., Urbana, IL (USA). Dept. of Forestry), Kowalsky, D.G, Dart, P.J
• Format: Article
• Language: English
• Subjects: Allocasuarina; Alluvial soils; AUSTRALIA; AUSTRALIE; Buried soils; CASUARINA; CONTENIDO DE AGUA EN EL SUELO; FIJACION DEL NITROGENO; FIXATION DE L'AZOTE; Forest soils; FORMATION DE NODOSITES; Frankia; HOSPEDEROS; HOSTS; HOTE; NITROGEN FIXATION; NODULACION; Nodulation; Nodules; PERMEABILIDAD; PERMEABILITE; PERMEABILITY; ROOT NODULATION; Seedlings; Soil depth; Soil samples; Soil water; SOIL WATER CONTENT; TENEUR EN EAU DU SOL
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/BF02232785

Sandy alluvial soils in a floodplain supporting a native stand of Casuarina cunninghamiana Miq. produced about three times as many nodulated seedlings and more than twice as many nodules per nodulated seedling on roots of baited Casuarina spp. than did clay loam red earth soils from the adjacent valley slope. Moist and well-aerated subsurficial alluvial sands had the greatest nodulation capacity of all the soils sampled. For all topographic positions, soil samples from depths greater than 20 cm promoted 76% more nodulated Casuarina seedlings than samples from the surficial 20 cm. Seedlings of three provenances of C. cunninghamiana, together with seedlings of C. glauca Sieb, ex Spreng., C. cristata F. Muell ex Miq. and C. obesa Miq. developed significantly more nodules per pot and nodules per nodulated seedling in soils from this locale than seedlings of two Casuarina equisetifolia Forst, provenances. Seedlings of two provenances of Allocasuarina torulosa (Ait.) L. Johnson had fewer than 1% nodulated seedlings, a significantly lower level by far than that of Casuarina seedlings. A. torulosa provenances also had significantly fewer nodulated seedlings per pot and nodules per nodulated seedling than all Casuarina hosts excepting one poorly-nodulated provenance of C. equisetifolia. Nodulated seedlings of all Casuarina species had the capacity to fix atmospheric N₂, as indicated by acetylene-reduction capability. The presence of yellow cladodes and low rates of acetylene reduction per plant for C. cristata Miq. suggest that this association was poorly effective.