Increasing Resilience to summer drought - trialling Lucerne

 Roderick, Newton Farm, Brecon

The project will aim to monitor the establishment and management of a crop of lucerne which is drought resistant, potentially making Welsh farms resilient to recurring drier summers.  Lambs will graze the crop and their performance will be compared to a traditional ryegrass and clover ley. Data will be collected on crop yields, lamb performance and health, and economic analysis of both crops. This TOF will contribute to the Sustainable Land Management outcomes including:

• Resilient and productive farms     
• Reduce, reuse and recycle inputs, nutrients and waste     
• Reduce on farm emissions and maximise carbon sequestration    
• Protect and enhance the farm ecosystem    

Choice of fields

Lucerne needs deep free draining soils with pH above 6.0 at depth. Two adjacent fields with soils suited to Lucerne growing have been selected at Newton Farm alongside other grass blocks. This allows for run back to grass fields for transition when introducing stock and adjustment to stocking rates in the trial - if required.   

Soil analysis

Weed Control pre-sowing of lucerne

Field Inspection pre-sowing identified established docks. Sowing was delayed to allow enough leaf area on the docks to be effectively killed with herbicide.

Undersown with Barley Cover Crop

To optimise Dry Matter yield in the sowing season (2024) the Rodericks decided to undersow the Lucerne with a cover of 100 kg/ha (40kg/ac) Spring Barley (Home saved). This was then cut as green 50% Lucerne, 50% Barley silage on 11 August 2024. At the time of bailing an inoculation was applied to optimise fermentation. 

Sowing

The Barley seed was drilled at 25-30 mm depth prior to sowing the Lucerne. 

Lucerne seeds need to be shallow drilled or broadcast at 10-15 mm, then Cambridge rolled to consolidate.  

Field 1- sowing date: 6 June 2024 (delayed sowing due to a curlew nest in field)

Field 2- sowing date: 10 May 2024                   

Lime was applied at a rate of 5t/ha before sowing.           

Lucerne and grass variety choice

Two varieties are being evaluated. A very persistent and high yielding cutting variety, Artemis and a specialist grazing variety, Luzelle.

Lucerne is a very open crop. In high rainfall areas there is significant poaching risk. This can lead to ingress of weeds, particularly weed grasses and premature decline in yield. 

To reduce this risk, a companion crop of grass and White Clover was sown. It’s important the grasses do not outcompete the Lucerne. Only certain species are suitable. The trial fields were sown with a Lucerne dominant mixture of the selected variety (at full rate) combined with 4 kg/ha of a very dense, new Timothy, Baronaise and 2 kg/ha S184 very small leaved white Clover. 

Seed Rate

Recommended seed rate for Lucerne in northern Europe is 20kg/ha (c8.0 kg/acre) and normally 25kg/ha (c10kg/acre) for coated seed. Sowing rate for this trial found in the table below (Seed Rate/Hectare).

Cost Analysis: Availability of some of the varieties used in the trial was challenging in 2024. The Luzelle was unusually expensive, plus £12.00/ha was added for the extra inoculation. A budgeting figure of £250/ha for a similar mix would be appropriate. £219/ha (£90.87/ha for straight Lucerne).

Rhizobium Bacteria

Unlike Red and White Clover, the rhizobium species associated with Lucerne are not naturally occurring in most UK soils, Lucerne seed needs to be inoculated with bacteria. Most seeds in the UK are pre-inoculated, but the inoculant does not stay alive for many months. Both of the lucerne varieties sown were pre-inoculated. 

Grazing management 

On 3 October, 53 days after cutting the crop for bales, 400 Lambs averaging 37kg were introduced to the crop to start the grazing rotation.  Fields have been split with electric fencing to avoid overgrazing and poaching. 

The fields will be grazed once, before shutting for winter ready for spring grazing with ewes and lambs.