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Differential growth response of R ytidosperma species (wallaby grass) to phosphorus application and its implications for grassland management
Author(s) -
Waddell H. A.,
Simpson R. J.,
Henderson B.,
Ryan M. H.,
Lambers H.,
Garden D. L.,
Richardson A. E.
Publication year - 2016
Publication title -
grass and forage science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.716
H-Index - 56
eISSN - 1365-2494
pISSN - 0142-5242
DOI - 10.1111/gfs.12170
Subject(s) - lolium perenne , biology , shoot , temperate climate , phosphorus , bromus , grassland , agronomy , human fertilization , botany , zoology , poaceae , chemistry , organic chemistry
Rytidosperma species (formerly A ustrodanthonia ) are native grasses common in temperate grasslands of southern Australia. Nine Rytidosperma species, Lolium perenne and Bromus hordeaceus were grown as microswards in pots in a glasshouse, and their growth response to six levels of applied P was measured. Shoot yield differed up to twofold between the highest‐ and lowest‐yielding Rytidosperma species. Some Rytidosperma species were slow growing with minimal ability to respond to increased soil P availability. However, three species, Rytidosperma duttonianum , Rytidosperma racemosum and Rytidosperma richardsonii , had a similar shoot yield to L. perenne . Species that grew well at high P also grew well at low P, except B. hordeaceus , which was the lowest‐yielding species at low P, but had among the highest yields at high P. No species showed evidence of P toxicity. The species exhibited a range in critical external P requirement (i.e. amount of P applied for 90% maximum yield). Among the fast‐growing Rytidosperma species, R. richardsonii was notable because it had a low critical external P (16·3 mg P pot −1 ) and high agronomic P‐use efficiency (94·1 g DW g −1 P applied). In contrast, R. duttonianum had a higher critical external P requirement (22·4 mg P pot −1 ) and lower agronomic P‐use efficiency (85 g DW g −1 P applied). It was concluded that it is important to know which Rytidosperma species are present in a grassland to understand how it may respond to P fertilization. The results help to explain the diverse opinions expressed about the productivity of pastures containing Rytidosperma species.