Lucerne and SDI Global thoughts and the local context

Lucerne and SDI Global thoughts and the local context

Supplied by Netafim South Africa

In South Africa, an estimated 2000 – 3000 hectares of lucerne are cultivated with subsurface drip irrigation (SDI). This method of irrigation brings a host of benefits and is very well suited to lucerne cultivation. Charl van Reenen, agronomy manager at Netafim South Africa, says that although SDI on lucerne is less well-known relative to other practices, it has been successfully practiced locally for more than 20 years. “The greatest hurdle is however that it is a capital-intensive system, especially regarding initial cost of infrastructure and equipment. This is even more true in cases where power supply is problematic and additional costs must be incurred to set up infrastructure for power supply. Yet, this large capital input is very often outweighed by the long list of benefits, including increased yield and water-savings.”

Van Reenen adds that Netafim South Africa is busy investigating alternative product applications from within its range of products for the purpose of subsurface drip irrigation. “The purpose is to make the system more cost-efficient for farmers and finally open up the benefits of SDI on lucerne for more and more farmers.”

Locally, Team Netafim loves to tap into the global network of Netafim knowledge for the purpose of sharing ideas, learning from other countries, introspection and bringing global knowledge to local farmers. Recently one of our colleagues from Netafim USA, Mike Bloomfield, commercial lead for forage crops, penned an interesting piece on SDI and lucerne (Alfalfa) and the possibilities of not only maximising water-efficiency but also agricultural and environmental benefits. He writes this article in a context of increasing water shortage in the Colorado River system that is forcing everyone to look at how water is used in the arid Southwest of the USA and evaluate which water uses benefit the society most.

Let’s read an excerpt from Bloomfields’s article for a perspective from the USA.

Transforming Agriculture:
Maximizing Water Efficiency, Agricultural, and Environmental Benefits with Drip Irrigation and Alfalfa

By Mike Bloomfield, Netafim USA

Subsurface drip irrigation (SDI) is a time-tested and proven way to implement climate-smart agriculture at scale. By switching to subsurface drip irrigation, farmers and the environment stand to gain a variety of benefits that extend far beyond merely saving water; it also plays a vital role in mitigating greenhouse gas emissions in agriculture.

The business of growing lucerne and the plant itself is widely misunderstood. Unlike maize and wheat, which are recognisable and appear in our grocery stores or on our plates, lucerne’s role in our diets is not as apparent. However, it plays a critical role in our food system, especially in its role in the dairy and beef industries. It is packed with protein and fibre, has highly accessible nutrients, and provides an ideal cost-per-calorie ratio perfect for feeding livestock.

In the context of water shortages in the Colorado River system, when we analyse all the uses of the water from the river, we find that most of it is used in agriculture, and most of the water used in agriculture is used to irrigate lucerne. This simple connection makes it understandable that people are sceptical about farmers continuing to grow water-intensive crops such as lucerne. But this line of reasoning overlooks the vital importance of lucerne in our ecosystem. It omits alternative irrigation and fertigation solutions that can improve water efficiency and crop yields while reducing agricultural water demands. Conversations about this crop must never omit the immense importance of lucerne to our food supply, the economic and environmental benefits provided in the regions where it’s grown, and the innovative solutions that create thriving lucerne growing conditions while improving water and nutrient efficiency.

Water Efficiency

A major concern with growing lucerne is ensuring farmers maximise the output per water unit. SDI can improve water efficiency by up to 50%. At Netafim USA, we work with more lucerne growers than any other company in the United States. They turn to us for our expertise, and we’re happily converting farmers from flood irrigation to drip irrigation, helping them reduce water usage by an average of 25-40% and increasing yields by 25 – 40% as well. Installing a drip irrigation system allows farmers to continue growing lucerne without violating water restrictions. Efficiency improvements mean we can maintain productive agricultural land using fewer resources. Instead of fallowing land to reduce water use, drip irrigation offers growers a way to continue farming in a way that increases their productivity while simultaneously decreasing their natural resource consumption. This is a win-win for everyone. We can reduce the use of water and other natural resources while maintaining agricultural output to ensure that we sustainably provide sufficient food for a growing population.

Soil Fertility and Stability

Netafim USA has converted countless farmers over the years because SDI systems keep their overhead costs down. Additionally, SDI gives a farmer the control needed to maintain ideal soil moisture levels and naturally promote soil fertility.

When land is flood-irrigated, soil and crops constantly cycle between being too wet and too dry. This volatility destroys soil fertility and harms crop production. On the other hand, drip irrigation maintains soil moisture levels throughout the growing cycle, allowing bio-organisms and roots to flourish.

Lucerne significantly improves soil fertility by improving biodiversity, creating insecticide resistance, and improving water retention. The plant’s root structure helps soil retain moisture, preventing erosion and resulting in more stable soils that are resilient to extreme weather like extended drought or heavy rains. Lucerne’s deep roots also extract water from further down in the soil than other crops, conserving water while growing. Its deep root system allows the plant to absorb nutrients in the soil that could otherwise contaminate nearby bodies of water. With their massive underground biomass, these deep roots also capture more carbon and store it in deeper soil layers than most other crops. Additionally, when irrigated correctly, lucerne naturally stores nitrogen in the soil, improving soil fertility for the next crop rotation.

Sequesters carbon and more

Lucerne not only naturally improves soil nitrogen levels, but also sequesters carbon in the soil. It is a perennial crop with roots growing up to 15 feet deep. The deep roots pull carbon from the air, storing it deeper in the soil than other plants. Thriving and correctly irrigated lucerne has been shown to improve the plant’s naturally occurring ability to fix nitrogen and store carbon in the soil. Nitrogen makes up the building blocks of a plant’s DNA and is critical for crop production. Crop rotations following lucerne offer unique advantages by reducing the need for synthetic nitrogen application for one to two years. This is attributed to the nitrogen fixed by lucerne, which, in a more accessible form, benefits the subsequent crop without leaching into surrounding bodies of water as readily. The incorporation of carbon and nitrogen into the soil through lucerne’s root system occurs without the necessity for tilling, preserving the natural microbiome in the soil. Soil is the most biodiverse habitat and is home to 59% of all life on Earth. Human health depends on the health of our soils.

In addition to its soil-enriching properties, lucerne hosts numerous pollinator species, fostering a habitat for up to 1,000 insect species, including beneficial predators like beetles that aid in controlling aphids. It is also an excellent habitat for biodiversity in wildlife, mammals, and soil-dwelling organisms.

In the USA, the transition from traditional flood irrigation to drip irrigation transforms the cultivation of lucerne from a questionable use of resources into a strategic and environmentally beneficial practice that aligns with sustainable agriculture and regenerative practices. Our world has limited resources, and water availability will only decrease as climate change challenges continue. The agricultural community must work together to prioritise growing more crops with less available water, more efficiently using all resources, and regenerating our soils to withstand the damage expected from more extreme weather.

What do you think?

Having read Bloomfield’s thoughts and facts from the American context, what are your thoughts?
What are your main considerations in growing lucerne and selecting the methods of irrigation?
Share your thoughts with us at