Alfalfa, also known as lucerne, is a perennial legume highly valued as a forage crop for livestock feed due to its protein content and nitrogen-fixing capabilities. It is characterized by a strong, deep taproot system, which allows it to draw water and nutrients from lower soil profiles. The plant’s ability to regrow after cutting allows for multiple harvests in a single season, making it a highly productive agricultural commodity.
Global Cultivation Landscape
Alfalfa is cultivated worldwide, thriving in temperate climates. The United States is a leading global producer, followed by Argentina, Canada, and Russia. US production is concentrated in the Western and Upper Midwest regions.
Key production states include California, Idaho, and Montana, with significant output also coming from Wisconsin, South Dakota, and Nebraska. California often leads in total production due to its high yields per acre in irrigated areas like the Central Valley. Production is less common in the Southeastern US due to poor soils and prevalent leaf and root diseases.
Climate Requirements for Optimal Growth
Alfalfa is a cool-season perennial that requires a long growing season with abundant sunshine to maximize biomass production. It needs six to eight hours of direct sunlight daily to maintain high photosynthesis rates. High solar radiation promotes the production of sugars and proteins, enhancing the forage’s overall quality.
Optimal temperatures for active growth range between 65 and 77 degrees Fahrenheit (18 to 25 degrees Celsius). Temperatures exceeding 86 degrees Fahrenheit (30 degrees Celsius) can accelerate metabolism, potentially reducing forage quality. For germination, the soil temperature needs to be at least 37 degrees Fahrenheit (3 degrees Celsius).
The plant exhibits cold tolerance, especially varieties adapted to northern climates that enter winter dormancy. Alfalfa has a high water requirement, typically needing between 20 to 46 inches (500 to 1170 millimeters) of water per growing season. This substantial need often necessitates advanced irrigation systems in arid or semi-arid regions.
Soil Requirements and Management
Successful alfalfa production depends on the physical structure and chemical composition of the soil. The most critical physical requirement is excellent soil drainage, as the plant cannot tolerate waterlogged conditions. Poor drainage restricts oxygen movement to the roots and can lead to root diseases and plant death.
The deep taproot system requires a soil profile that is deep and permeable, ideally exceeding 25 inches in depth. This long taproot enables the plant to access moisture and nutrients far below the surface. Shallow soils or those with hardpans near the surface will severely limit the plant’s potential yield.
Chemically, alfalfa performs best in neutral to slightly alkaline soils, with an optimal pH range for growth and nutrient uptake between 6.5 and 7.0. This environment is necessary for the Rhizobia bacteria to efficiently fix atmospheric nitrogen. In areas with naturally acidic soils, agricultural lime must be applied to raise the pH, which should be incorporated six to twelve months before seeding.