Sustainable lucerne

Date posted: 21 July 2016

Lucerne is grown for seed, as a pasture for animals to munch and for hay, chaff (dry, scaly plant material) and silage (compacted and stored lucerne that can be used later). It can also be processed into pellets for animals to eat.

With South Australian farmers producing 83 per cent of the nation’s lucerne seed across 16,000 hectares of land at Keith, Naracoorte, Tintinara and Bordertown, sustainable production is a must.

Lucerne has a number of nifty traits on the sustainability front, making it a valuable crop for a farmer to include in their production system:

It’s drought tolerant

Lucerne’s deep tap root means it can access water and nutrients deep in the soil profile. This means lucerne is better adapted to drought conditions than other shallow rooted cereal plants — handy if you have hungry dairy cows to feed.

It’s an ongoing food source

Lucerne can be grazed by dairy cattle for up to 20 years. Unlike many annual crops, which are sown and harvested within the year, lucerne stands can be grazed by dairy cattle time and time again. Using rotational grazing, where the stands are grazed then rested and allowed to regenerate before being grazed again, they will keep reshooting and provide a continual food source.

It fixes soil nitrogen

Because lucerne is a legume, it has the ability to "fix" atmospheric nitrogen. This process takes nitrogen from the air and releases it into the soil via nodules and hairs on the plant’s roots. Nitrogen, an essential nutrient for healthy plant growth, helps increase the yield and quality of subsequent cereal crops. It also helps farmers save money by reducing the need of nitrogen fertilisers.

It improves soil structure

Lucerne’s deep roots act as a valuable soil anchor, improving soil structure and reducing erosion.

It helps manage dryland salinity

Lucerne uses more water than many annuals because of its longer growing season and deeper root systems. Root depth (which can reach 1.5–6 metres), water use and length of plant activity throughout the year influence annual evapotranspiration (water being transferred from the land to the atmosphere by evaporation from the soil, plants, etc.) and water use. Drying out the soil profile over summer and autumn creates a system similar to native vegetation. Managing soil moisture recharge (when precipitation increases and soil moisture stores fill, with high infiltration and little surface run-off) can prevent or even reverse salinity by keeping the water table at bay.

With benefits to boot, lucerne is a valuable crop to have if you're a farmer — no wonder it’s referred to as the king of fodder!