scholarly journals Prospects for improving perennial legume persistence in mixed grazed pastures of south-eastern Australia, with particular reference to white clover

2019 ◽  
Vol 70 (12) ◽  
pp. 1141 ◽  
Author(s):  
R. C. Hayes ◽  
I. Ara ◽  
W. B. Badgery ◽  
R. A. Culvenor ◽  
R. E. Haling ◽  
...  

This review examines the prospect of improving perennial legume adaptation to grazed mixed pasture swards across the higher-altitude regions of south-eastern Australia through improved management, particularly as it relates to soil fertility. The range of adapted perennial species available to farmers often remains limited to only one perennial forage legume species, white clover (Trifolium repens L.). Despite recent advances in cultivars for increased persistence in dryland environments, white clover remains sensitive to drought with its inherently shallow root system and limited capacity to restrict water loss from herbage. With few alternative species likely to become widely available in the foreseeable future, prospects for extending the boundaries of perennial legume adaptation likely rely on a dual approach of improving soil fertility and further genetic improvement in white clover. Improved soil fertility would focus on overcoming soil acidity and addressing nutrient deficiencies, particularly of phosphorus, potassium, boron and molybdenum, which tend to be more widespread in the target region. Addressing these soil constraints would alleviate periodic moisture stress by: (1) increased water availability through improved infiltration and soil hydraulic properties; (2) increased root growth to maximise exploration of the soil volume; and (3) better maintenance of plant cell structures to foster improved osmotic regulation. However, the extent to which white clover adaption may be extended remains an issue of further research. This review highlights an opportunity for further genetic improvement of white clover by focusing on improving the capacity to recover from periodic droughts through seedling regeneration. Further breeding efforts in white clover should examine the feasibility of selecting for hard seed characteristics more similar to the best-adapted subterranean clover (Trifolium subterraneum L.) cultivars across this region to promote ongoing seedling regeneration.

1994 ◽  
Vol 34 (7) ◽  
pp. 959 ◽  
Author(s):  
MAE Lattimore

Legume-based pastures have long been an integral part of rice growing in the southern New South Wales irrigation areas and still offer potential to improve the productivity, profitability, and sustainability of the temperate rice-cropping system.This paper reviews both historical and current aspects of pastures in temperate rice rotations in southern New South Wales and highlights the importance of pastures in sustaining this cropping system as environmental pressures increase. Topics discussed include pasture species and rotations, their role in improving soil fertility and sustainability, the value of pastures in weed control, and their management for maximum profitability.


2010 ◽  
Vol 61 (8) ◽  
pp. 645 ◽  
Author(s):  
G. D. Li ◽  
Z. N. Nie ◽  
S. P. Boschma ◽  
B. S. Dear ◽  
G. M. Lodge ◽  
...  

The persistence and productivity of a diverse range of Medicago sativa germplasm including representatives of subspecies sativa, caerulea, falcata and varia were examined at 3 field sites in south-eastern Australia over 4 years. Sites were located at Tamworth, Barmedman and Hamilton, forming a 1200 km north–south transect with rainfall distribution varying from predominantly summer dominant in the north to winter dominant at the most southerly site. Several entries of subspecies varia and caerulea had herbage yields and persistence equivalent to that of M. sativa subspecies sativa cultivar Sceptre, a highly winter-active type that was used as a standard. The cultivar Cancreep, a cross of M. falcata and M. sativa, had a total yield over 3 years equivalent to 84–91% of Sceptre at the 2 sites where it was sown. Individual lines of subspecies varia demonstrated good persistence under grazing and were ranked 2nd and 6th out of 35 accessions for frequency in year 4 at Barmedman, the driest site, and 5th, 7th and 9th out of 33 accessions at Tamworth, the more summer-dominant rainfall site. Entries of subspecies falcata were among the least productive and persistent. The study indicated that germplasm from subspecies caerulea and varia offered hitherto unexploited potential for selection as persistent and drought-tolerant perennial legume alternatives to M. sativa for extensive low management grazing systems of south-eastern Australia.


2007 ◽  
Vol 47 (11) ◽  
pp. 1245 ◽  
Author(s):  
D. Adcock ◽  
A. M. McNeill ◽  
G. K. McDonald ◽  
R. D. Armstrong

Crop yield variability and productivity below potential yield on neutral and alkaline soils in the semiarid Mediterranean-type environments of south-eastern Australia have been attributed, in part, to variable rooting depth and incomplete soil water extraction caused by physical and chemical characteristics of soil horizons below the surface. In this review these characteristics are referred to as subsoil constraints. This document reviews current information concerning subsoil constraints typical of neutral and alkaline soils in south-eastern Australia, principally salinity, sodicity, dense soils with high penetration resistance, waterlogging, nutrient deficiencies and ion toxicities. The review focuses on information from Australia (published and unpublished), using overseas data only where no suitable Australian data is available. An assessment of the effectiveness of current management options to address subsoil constraints is provided. These options are broadly grouped into three categories: (i) amelioration strategies, such as deep ripping, gypsum application or the use of polyacrylamides to reduce sodicity and/or bulk density, deep placement of nutrients or organic matter to overcome subsoil nutrient deficiencies or the growing of ‘primer’ crops to naturally ameliorate the soil; (ii) breeding initiatives for increased crop tolerance to toxicities such as salt and boron; and (iii) avoidance through appropriate agronomic or agro-engineering solutions. The review highlights difficulties associated with identifying the impact of any single subsoil constraint to crop production on neutral and alkaline soils in south-eastern Australia, given that multiple constraints may be present. Difficulty in clearly ranking the relative effect of particular subsoil constraints on crop production (either between constraints or in relation to other edaphic and biological factors) limits current ability to develop targeted solutions designed to overcome these constraints. Furthermore, it is recognised that the task is complicated by spatial and temporal variability of soil physicochemical properties and nutrient availability, as well as other factors such as disease and drought stress. Nevertheless, knowledge of the relative importance of particular subsoil constraints to crop production, and an assessment of impact on crop productivity, are deemed critical to the development of potential management solutions for these neutral to alkaline soils.


1985 ◽  
Vol 33 (6) ◽  
pp. 677 ◽  
Author(s):  
H Wood ◽  
R Degabriele

Natural populations of Echium plantagineum on an east-west line across south-eastern Australia were sampled on three occasions during the growing season, and seeds collected from individual plants in each population were grown in a common glasshouse. In another experiment seedlings of E. plantagineum were divided and clones from each plant were grown under two soil moisture regimes. Field populations differed significantly in all seven characters measured at all sampling dates but, with one exception, between-population differences were unrelated to five climatic indices. Glasshouse populations differed significantly in 15 of 27 characters; variations in some of these characters were related by regression analysis to one or more of the climatic indices. Clones grown under moisture stress flowered later, had proportionally wider leaves and were smaller than well watered clones. The data suggest that an ecocline has developed, or is developing, in E. plantagineum in south- eastern Australia in response to large-scale and long-term aspects of climate, although extensive genetic variation between individuals in each population was also observed. This species exhibits a great deal of phenotypic plasticity in response to localized environmental factors.


Sign in / Sign up

Export Citation Format

Share Document