Hay is forage cut and dried, typically below 18% moisture, for safe storage and preservation of nutritional value for livestock feed. Hay yield is measured in tons of dry matter per acre. Determining the yield of a specific field is highly variable, depending on environmental and management decisions. For producers managing a multi-harvest crop, the key metric is the tonnage achieved “per cutting.” Since hay production is a biological process influenced by local conditions, there is no single, fixed answer to how much any acre will produce in one harvest.
Key Factors Determining Hay Yield
The foundation for high hay yield begins beneath the soil surface, where nutrient availability sets the biological limit for plant growth. Soils require a near-neutral pH, ideally between 6.5 and 7.5, especially for legumes like alfalfa, to ensure nutrients are accessible. Adequate levels of phosphorus and potassium are important, supporting root health and stem strength. Organic matter improves water retention and provides a steady release of nitrogen, supporting the biomass accumulation necessary for maximum tonnage.
Climate controls hay production potential through water availability and the length of the growing season. Producing one ton of cured hay requires approximately four to six inches of water. In regions with limited natural rainfall, irrigation is necessary to meet this requirement and achieve higher yields. Temperature and the duration of the frost-free period also dictate the number of cuttings possible, with warmer climates allowing for more frequent harvests.
Management decisions regarding fertility directly influence the final yield per acre. For grasses, nitrogen fertilizer is a primary driver of biomass production and protein content. All forage crops remove large amounts of mineral nutrients with each cutting, necessitating a balanced fertilization program. Farmers rely on regular soil testing to determine the precise amounts of lime, phosphorus, potassium, and micronutrients needed to support the next cutting. Meeting these demands allows the forage to maximize its growth potential, translating into higher tonnage.
Average Yields by Forage Type
The typical tonnage harvested per cutting varies significantly based on the forage species and management intensity. Alfalfa, known for its high protein content, generally produces high annual yields, especially under irrigation. In temperate regions, an established alfalfa stand might yield 4 to 6 tons per acre annually over three or four cuttings. The first cutting in the spring is often the heaviest, contributing 35% to 45% of the total annual yield, resulting in a first cut of 1.5 to 2.5 tons per acre.
Under intensive management with irrigation in arid regions, annual alfalfa yields can exceed 8 to 10 tons per acre, harvested over five or six cuttings. The yield per cutting averages 1.5 to 2.0 tons, with a more consistent distribution across the season than rain-fed production. Alfalfa’s high-yielding nature requires strict management, including deep, well-drained soil and precise nutrient application.
Cool-season grasses, such as Timothy, Orchardgrass, and Fescue, typically have a lower total annual yield than alfalfa but provide a substantial first cutting. A productive stand may yield 3 to 5 tons per acre annually over two or three cuttings. The first cutting commonly falls in the range of 1.0 to 2.0 tons per acre, with subsequent cuts being lighter. These grasses are resilient in cooler climates and are a common choice for hay production.
Warm-season grasses, like Bermudagrass, are capable of high yields due to rapid growth during hot summer months. Irrigated Bermudagrass can produce over 6 tons per acre annually across three to five cuttings. Native Warm-Season Grasses, such as Eastern Gamagrass, are known for a very large initial harvest, sometimes approaching 4 to 5 tons per acre on the first cut alone, followed by a much smaller second cut. Summer annuals like Sorghum-Sudangrass hybrids are also high-tonnage crops, capable of producing 2 or more tons per acre in each of their two to three seasonal cuttings.
Maximizing Tonnage Through Cutting Timing
The decision of when to cut hay is a fundamental trade-off between maximizing harvest weight and optimizing nutritional quality. Cutting later in the plant’s life cycle allows for greater biomass accumulation, resulting in higher tonnage per acre. However, as forage plants mature, indigestible fiber increases, while protein and energy content decrease significantly. A heavier cut often results in lower-quality feed.
For grasses, the optimal balance is typically found just as the plant reaches the boot stage, where the seed head is enclosed within the leaf sheath. Harvesting at this stage maximizes nutrient density before the stem begins to lignify, which rapidly lowers digestibility. Delaying the cut past the boot stage and into the heading stage can increase the yield per cutting, but the resulting hay is less digestible for livestock.
Legumes like alfalfa are generally harvested at the bud stage or when approximately one-tenth of the plants are in bloom. This timing ensures significant tonnage while maintaining a high concentration of protein in the leaves. Harvesting more frequently at the bud stage maximizes the total annual yield of high-quality hay through a greater number of cuttings. Allowing alfalfa to reach full bloom adds tonnage to that single harvest, but it depletes the plant’s root energy reserves and can reduce the total number of cuts possible.
Cutting timing also dictates the recovery period and potential for subsequent harvests. A timely first cutting promotes vigorous regrowth, setting the stage for a strong second harvest. Frequent cutting, such as five or six times a year, is possible for intensively managed forages but requires careful monitoring to ensure plants replenish carbohydrate reserves in their roots. Ultimately, maximizing the yield per individual cutting often requires a compromise in quality, based on the intended livestock and market demands.