Differences in phosphorus acquisition and critical phosphorus requirements among nine Desmanthus spp. genotypes

Mclachlan, Jonathan W; Guppy, Chris N; Flavel, Richard J

doi:10.1071/CP20313

Author(s)

Mclachlan, Jonathan W

Guppy, Chris N

Flavel, Richard J

Publication Date

2021-10

Abstract

The extensive grazing systems of northern Australia are dominated by C4 grasses and are established in N- and P-responsive soils that receive minimal nutrient input. Under these conditions, tropical pasture legumes are expected to improve the quality of grazing forage and fix atmospheric N2. However, legume persistence is relatively poor, which may be due to a presumed disparity in P requirements among tropical pasture species. This disparity suggests that P-efficient legumes may improve legume persistence, yet the P requirements of many tropical pasture legumes remain unquantified. Nine Desmanthus spp. genotypes were grown in pots to determine differences in shoot yield and root morphology in response to soil P supply (0-100 mg applied P kg-1 soil; 5-63 mg Colwell P kg-1 soil). The shoot yield of each genotype increased in response to increased P supply. When P supply was adequate for maximum plant growth, the shoot yield of the best genotype (3.5 g DM pot-1; JCU 9) was 1.7-fold larger than that of the next most productive genotype. There were also substantial differences in the critical external P requirements of the genotypes (29.4-64.0 mg P kg-1 soil), although these differences did not always reflect the efficiency of dry matter production per unit of applied P fertiliser. Differences in shoot yield and P acquisition were positively associated with differences in the development of root length. The results indicated that P-efficient genotypes of Desmanthus spp. can be identified for improved growth in the P-responsive pastures of northern Australia. These genotypes may compete more effectively with C4 grasses and form resilient pasture swards as climate patterns change.

Citation

Crop and Pasture Science, 72(9), p. 742-753

ISSN

1836-5795

1836-0947

Link

https://hdl.handle.net/1959.11/30783

Language

en

Publisher

CSIRO Publishing

Title

Differences in phosphorus acquisition and critical phosphorus requirements among nine Desmanthus spp. genotypes

Type of document

Journal Article

Entity Type

Publication

Author(s)	Mclachlan, Jonathan W Guppy, Chris N Flavel, Richard J
Publication Date	2021-10
Abstract	The extensive grazing systems of northern Australia are dominated by C<sub>4</sub> grasses and are established in N- and P-responsive soils that receive minimal nutrient input. Under these conditions, tropical pasture legumes are expected to improve the quality of grazing forage and fix atmospheric N<sub>2</sub>. However, legume persistence is relatively poor, which may be due to a presumed disparity in P requirements among tropical pasture species. This disparity suggests that P-efficient legumes may improve legume persistence, yet the P requirements of many tropical pasture legumes remain unquantified. Nine <i>Desmanthus</i> spp. genotypes were grown in pots to determine differences in shoot yield and root morphology in response to soil P supply (0-100 mg applied P kg<sup>-1</sup> soil; 5-63 mg Colwell P kg<sup>-1</sup> soil). The shoot yield of each genotype increased in response to increased P supply. When P supply was adequate for maximum plant growth, the shoot yield of the best genotype (3.5 g DM pot<sup>-1</sup>; JCU 9) was 1.7-fold larger than that of the next most productive genotype. There were also substantial differences in the critical external P requirements of the genotypes (29.4-64.0 mg P kg<sup>-1</sup> soil), although these differences did not always reflect the efficiency of dry matter production per unit of applied P fertiliser. Differences in shoot yield and P acquisition were positively associated with differences in the development of root length. The results indicated that P-efficient genotypes of <i>Desmanthus</i> spp. can be identified for improved growth in the P-responsive pastures of northern Australia. These genotypes may compete more effectively with C<sub>4</sub> grasses and form resilient pasture swards as climate patterns change.
Citation	Crop and Pasture Science, 72(9), p. 742-753
ISSN	1836-5795 1836-0947
Link	https://hdl.handle.net/1959.11/30783
Language	en
Publisher	CSIRO Publishing
Title	Differences in phosphorus acquisition and critical phosphorus requirements among nine Desmanthus spp. genotypes
Type of document	Journal Article
Entity Type	Publication

Differences in phosphorus acquisition and critical phosphorus requirements among nine Desmanthus spp. genotypes

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