Summary

This project evaluated pasture legumes in the Murray Plains during the 2021 season. Studenica vetch, Volga vetch, PM 250 strand medic, and Bartolo bladder clover excelled in spring biomass production. Cefalu arrowleaf clover produced the highest level of summer ground cover. Dry weight biomass high performers included Studenica vetch, Volga vetch, Nitro Plus persian clover, and Cefalu arrowleaf clover. Higher seeding rates increased biomass for strand medic and bladder clover. The results of the trial have supported growers in optimising legume selection for Murray Plains conditions.

Background

The Murray Plains region poses challenges for pasture establishment due to its variable rainfall and there has been a perception by local growers that the region is too low in rainfall to reliably grow good pastures. Newer pasture varieties present an opportunity for more reliable establishment and better performance in Murray Plains conditions.

Research Aims

The core objectives of the project were to:

• Identify appropriate pasture species for the Murray Plains’ low rainfall zone environment, accounting for variable soil types while delivering nitrogen fixation and a suitable break in the cropping rotation.
• Build capacity to manage the agronomic requirements of pastures, from successful establishment and in-season growth to maximising seed-set.
• Improve awareness of the economics of including an improved pasture in a cropping rotation, and the subsequent benefits to livestock for mixed farmers.

In The Field

The trial was conducted at one site the Murray Plains in 2021, focusing on the evaluation of pasture legume varieties under specific seasonal conditions, comprising of 11 cultivars tested with four replicates. A second pasture demonstration assessed the effect of sowing rates on three of the cultivars.

Various legume species were assessed for fresh weight biomass, dry weight biomass density (in either September or February), spring ground cover, and summer pasture cover.

All trial plots were then sown with Vixen wheat in 2022 to investigate an effect of legume choice on subsequent wheat performance.

Late spring rainfall in late September and October caused late season growth, which was assessed as part of the trial.

The project was co-funded by the Murraylands and Riverland Landscape Board, who funded an economic analysis of the results by Pinion Advisory, along with additional soil testing and extension activities.

Results

The trial identified key findings to support growers in pasture selection, offering a detailed evaluation of pasture legume performance across various metrics:

Highest spring fresh weight biomass: Studenica vetch, Volga vetch, PM 250 strand medic, and Bartolo bladder clover. These varieties demonstrated robust spring growth, responding well to the late-season rainfall patterns experienced in 2021.

Highest dry weight biomass availability: Studenica vetch (assessed in September), Volga vetch (September), Nitro Plus Persian Clover (February), and Cefalu Arrowleaf Clover (February).

Highest spring percentate ground cover: Studenica vetch (54.9 per cent ground cover), PM 250 Strand Medic (50.3 per cent), Volga vetch (49.7 per cent), and Bartolo Bladder Clover (46.7 per cent).

Highest summer pasture cover: Cefalu arrowleaf clover (65 per cent ground cover), Bartolo Bladder Clover (64 per cent), and Nitro Plus Persian Clover (64 per cent).

Economic analysis: Volga and Studenica vetch produced the highest economic return in the one-year trial. It should be noted however that vetches are soft seeded and are unlikely to regenerate reliably in future years compared to the other species in the trial. The next-best performers were Cefalu arrowleaf clover and Nitro Plus persian clovers, which benefited from the late-spring rains, demonstrating the variability of outcomes in differing seasonal conditions.

Seeding rates: Higher seeding rates were found to significantly improve biomass production for strand medic and bladder clover.

Following season wheat yield: There were no differences in grain yield in 2022 between the different pasture legumes, though there were differences in crop biomass. There was an effect on grain protein levels, with wheat sown after Studenica and Volga vetch the only ones able to meet H1 quality, with all other varieties resulting in H2.

An economic analysis and agronomic recommendation based on the trial were presented by Tony Craddock of Pinion Advisory at the 2022 Murray Plains Farmers (MPF) post-harvest meeting, and the results from the project were presented at MPF events in 2022 and 2023, with a total attendance of 120 people across all events.