The Benefits of Alfalfa to the Southwest Ecosystem

By Ayman Mostafa, assistant area agent, ANR/Field Crops IPM for University of Arizona College of Agriculture & Life Sciences Maricopa County Cooperative Extension: The possibility of “mega drought” in the southwest U.S. is a subject of great concern in the region, which involve many topics like historical record, probable causes and possible solutions for the shortage in water in the region, how to harmonize environmental goals, urban expansion and agriculture needs and the share of water going toward crops in the region, including alfalfa hay production that supports the dairy and livestock industry. This is a good opportunity to emphasize some facts. 

Alfalfa in the southwest ecosystem provides many environmental benefits:

  1. It is a rich habitat for wildlife;
  2. Provides an insectary for diverse beneficial insects;
  3. Improves soil characteristics;
  4. Fixes atmospheric nitrogen;
  5. Traps sediments and takes up nitrate pollutants;
  6. Mitigates water and air pollution; and
  7. Provides aesthetically pleasing open spaces.

To give more specificity to the environmental benefits of this perennial legume crop, you might consider the following information.

  • Areas depleted of row crop or specialty crop production, like many agricultural areas in the western U.S. would benefit environmentally by stabilizing soils when incorporating a perennial legume such as alfalfa.
  • 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.
  • Alfalfa also plays an important role in insecticide resistance management by acting as a refuge, especially for aphids and whiteflies. Low desert alfalfa production is quite different from production in other areas where non-dormant, irrigated varieties provide a year-round habitat for insects.
  • As Perennial crop with deep roots, high water use efficiency, use of residual moisture and high flexibility with summer deficits, alfalfa is a lower risk crop that, unlike any other commercial crop in the region, can reinitiate itself after water deficiency or even summer cutoff.
  • Non-dormant alfalfa hay varieties are uniquely adapted to the low desert climates of central and southern Arizona and the adjacent region of California along the Colorado River. Unlike many other production regions in the nation, low desert alfalfa is irrigated and produces an average of eight cuttings every year. Alfalfa acreage in the region is likely to increase given the importance of the dairy industry and other livestock enterprises and a reduction in cotton acreage due to low cotton prices.

Editor’s Note: Last week, we covered Arizona Agriculture’s Amazing Alfalfa and highlight the value it brings to our state. Mostafa’s article gives us environmental insights into this amazing forage crop. Additionally, this article first appeared in a recent issue of the Maricopa County Cooperative Extension newsletter

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