The southwest U.S. continues to endure the conditions of “megadrought,” a term used to describe drought conditions lasting at least two decades. As a result, the public questions “why” we grow certain crops in the desert, specifically alfalfa. 

The share of water going toward alfalfa hay production supports the dairy and livestock industry, ultimately our local food supply chain. Still, some believe the amount of water used to irrigate alfalfa is a major contributing factor to the region’s shortage, and fail to recognize alfalfa’s economic efficiencies, environmental impacts, and agronomic benefits to our ecosystem. 

Alfalfa in the southwest ecosystem provides many environmental benefits: 

  • Besides its economic importance, alfalfa also may help reduce the impacts of climate change. Because it covers the soil for a longer time than any other crop, alfalfa is envisioned as a leading option for soil carbon sequestration, also known as “regenerative agriculture,” especially with the need to decrease carbon emissions and introduce the carbon credits initiative. 
  • Incorporating a perennial legume such as alfalfa can help to stabilize soils nutritionally depleted by row crop or specialty crop production, as has occurred in many agricultural areas in the western US. Alfalfa was introduced into crop rotation in Europe, and encouraged globally, as a measure of the Agri-Environmental Scheme (AES) to reduce the impacts of agriculture intensification on the environment. 
  • Switching from annual forage crop production for dairy animals and livestock feed to perennial alfalfa can minimize soil disturbance and erosion. This practice can help restore depleted soils, minimize inputs, and decrease the footprint of agricultural production. 
  • While suspected of higher total applied irrigation water than many other crops, alfalfa has greater water use efficiency. Additionally, the entire above-ground portion of the plant is harvested as many as twelve times per year in the Southwestern region. When compared to other crops harvested less frequently, alfalfa’s ratio of harvestable biomass/water applied shows it is far more water efficient. Furthermore, the majority of the irrigation water used in alfalfa is recycled back into the environment.  
  • Alfalfa is a rich habitat for wildlife allowing for a diversity of local niches and preserving many endangered species from different animal families.
  • Alfalfa fields are important contributors to the biodiversity of agricultural systems by functioning as insectaries for beneficial insects, many of which are pollinators or natural enemies that play important roles in the low desert agroecosystem. Beneficial insects move from alfalfa fields into other crops, where they play crucial roles in pollination and biological control. These roles reduce our reliance on synthetic insecticides, which if used incorrectly could have negative impacts on human, animal, and environmental health.  
  • Western alfalfa production is quite different from production in other areas where non-dormant, irrigated varieties provide year-round habitat for insects. This fact allows alfalfa to play an important role in insecticide resistance. management by acting as a refuge, especially for aphids and whiteflies. 
  • Alfalfa improves soil characteristics with its deep roots; as a legume, it fixes atmospheric nitrogen through bacteria in the root nodules.
  • Because of its nature as a perennial plant that stays in the field for 3 to 5 years, alfalfa helps trap sediments and takes up nitrate pollutants; mitigates water and air pollution.
  • Incorporating a perennial legume such as alfalfa can help to stabilize soils nutritionally depleted by row crop or specialty crop production, as has occurred in many agricultural areas in the western US. Alfalfa was introduced into crop rotation in Europe, and encouraged globally, as a measure of the Agri-Environmental Scheme (AES) to reduce the impacts of agriculture intensification on the environment. 

In summary, if alfalfa fields are eliminated or significantly reduced, it is highly likely most of the original acreage will be converted to residential and commercial uses. This situation will likely decrease farmland and increase the population in those areas. As a result, the region may experience shortages of certain food products thereby relying on food from non-local sources, including those imported from abroad. This will likely increase food prices and extend the supply chain. With the increase in population comes all known environmental impacts, alteration of ecosystems, and pollution of air, water and soil all of which impact our carbon footprint.  

 

Further reading:

Del Portillo, D.G, B. Arroyo & M.B. Morales (2022) The adequacy of alfalfa crops as an agri-environmental scheme: A review of agronomic benefits and effects on biodiversity.  Journal for Nature Conservation 69(2):126253. file:///C:/Users/ayman/Downloads/1-s2.0-S1617138122001261-main.pdf.

 

Mostafa, A.M. (2015) The Benefits of Alfalfa to the Southwest Ecosystem. Arizona Agriculture. https://arizonaag.com/2015/05/18/the-benefits-of-alfalfa-to-the-southwest-ecosystem/. 


 Putnam, D. (2015) Why alfalfa is the best crop to have in a drought. University of California- Davis. Alfalfa and Forage News. https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=17721. 

 

Yost, M., N. Allen, E. Creech, D. Putnam, J. Gale & G. Shewmaker (2020) Ten Reasons Why Alfalfa is Highly Suitable for the West. Utah State University Extension. https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=3100&context=extension_curall.