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Growth responses of sugarcane to mycorrhizal spore density and phosphorus rate

Kelly, R.M. and Edwards, D.G. and Thompson, J.P. and Magarey, R.C. (2005) Growth responses of sugarcane to mycorrhizal spore density and phosphorus rate. Australian Journal of Agricultural Research, 56 (12). pp. 1405-1413.

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Publisher URL: http://www.publish.csiro.au/

Abstract

Arbuscular mycorrhizal (AM) fungi, commonly found in long-term cane-growing fields in northern Queensland, are linked with both negative and positive growth responses by sugarcane (Saccharum spp.), depending on P supply. A glasshouse trial was established to examine whether AM density might also have an important influence on these growth responses. Mycorrhizal spores (Glomus clarum), isolated from a long-term cane block in northern Queensland, were introduced into a pasteurised low-P cane soil at 5 densities (0, 0.06, 0.25, 1, 4 spores/g soil) and with 4 P treatments (0, 8.2, 25, and 47 mg/kg). At 83 days after planting, sugarcane tops responded positively to P fertilizer, although responses attributable to spore density were rarely observed. In one case, addition of 4 spores/g led to a 53% yield response over those without AM at 8 mgP/kg, or a relative benefit of 17 mg P/kg. Root colonisation was reduced for plants with nil or 74 mg P/kg. For those without AM, P concentration in the topmost visible dewlap (TVD) leaf increased significantly with fertiliser P (0.07 v. 0.15%). However, P concentration increased further with the presence of AM spores. Irrespective of AM, the critical P concentration in the TVD leaf was 0.18%. This study confirms earlier reports that sugarcane is poorly responsive to AM. Spore density, up to 4 spores/g soil, appears unable to influence this responsiveness, either positively or negatively. Attempts to gain P benefits by increasing AM density through rotation seem unlikely to lead to yield increases by sugarcane. Conversely, sugarcane grown in fields with high spore densities and high plant-available P, such as long-term cane-growing soils, is unlikely to suffer a yield reduction from mycorrhizal fungi.

Item Type:Article
Business groups:Agri-Science, Crop and Food Science
Additional Information:Reproduced with permission from © CSIRO Publishing. Access to published version may be available via Publisher’s website.
Keywords:AM colonisation; Arbuscular mycorrhiza; Australasia; Australia; bacteria (microorganisms); critical P concentration; fungi; fungus; Glomus clarum; growth response; mycorrhizal dependency; P nutrition; phosphorus; Queensland; Saccharum; Saccharum hybrid cultivar; sugar cane; yield.
Subjects:Science > Botany > Cryptogams
Plant pests and diseases > Individual or types of plants or trees > Sugarcane
Agriculture > Agriculture (General) > Fertilisers
Deposited On:02 Mar 2009 00:34
Last Modified:25 Oct 2011 04:42

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