I am new to Oklahoma and to alfalfa production. What should I look for in a good alfalfa soil? 

EXPLANATION: Productive alfalfa stands require deep soils with good infiltration, yet with sufficient clay and organic matter to hold large quantities of water. Planting in soil with high water-holding capacity is important because high alfalfa yields require large quantities of water (approx. 6" of available water for each ton of hay). 

Soil Depth: Generally, deep soils hold more water than shallow ones simply because of greater volume. Alfalfa's long tap root is one of its strong points that sets it apart from many other crop species. Alfalfa roots can penetrate 25 ft. in deep soils. Growing alfalfa in a shallow soil tends to limit this strength. 

Good Drainage: Despite its large water requirement, alfalfa needs good soil drainage -- both internal and surface drainage. When water stands on the soil surface during warm seasons, alfalfa grows poorly and may even die within a few hours from a condition known as "scald." This condition results because oxygen is not available to roots and the water holds in heat. Scald is most severe on bright sunny days and usually occurs in thin stands or just after harvest when foliage does not shade the soil. 

Waterlogged soils have poor aeration, inhibit nitrogen fixation, and promote growth of certain root-rotting diseases. Several adapted varieties are available with root rot resistance. They perform better in "wet soils" than susceptible varieties but still cannot tolerate extended periods of standing water. 

Fertile Soils: High yielding alfalfa requires highly fertile soil. Fertilizer can be added, but cost of production is decreased if soil is already fertile. 

Loamy Soils: Alfalfa tends to be more productive in loamy soils than sands or clay soils. Also, these soils are easier to work than clay soils, facilitating stand establishment. Not only do loamy soils have better internal drainage than clay soils, they normally hold more nutrients and hold more water than sandy soils, allowing alfalfa to be productive longer into dry periods.

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I want to produce more alfalfa hay, but I don't have any additional good alfalfa soil. What should I expect on the shallow soils that usually produce pretty good wheat yields? 

Neutral pH: A neutral pH is best for both the alfalfa plants and the nitrogen fixing rhizobium bacteria. Optimum pH primarily works by improving availability of nutrients necessary for plant and bacterial growth. 

EXPLANATION: Alfalfa will grow on infertile shallow soils, but yield is usually reduced by rapid depletion of water and nutrients in shallow root zones. Stand longevity may also be shorter in shallow soils if drought persists for extended periods. 

Some soils are not considered to be "alfalfa soils" because of low pH, and alfalfa should not be planted without applications of lime. Alfalfa production on soils with pH of 5.2 or below is rarely satisfactory and should be avoided. Establishing a stand in low pH soils is difficult because of unavailability of nutrients and once established, nitrogen fixation is usually reduced. 

In shallow and/or infertile soils, there may be insufficient alfalfa growth for profitable harvests. Harvesting alfalfa when hay yield is less than ½ ton/A is a questionable practice because harvest costs may exceed the value of the hay. Grazing low-yielding alfalfa instead of cutting hay may be a profitable alternative. 

When shallow soils need lime to adjust the pH and fertilizer (phosphorus and/or potassium), correcting these deficiencies before establishing alfalfa will maximize efficient water use by the crop. This will assist in making shallow, infertile soils more productive for alfalfa.

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How does profitability of alfalfa compare to wheat, soybeans, grain sorghum, and corn on shallow soils? 

EXPLANATION: Since profitability is affected by so many different factors, it would be impossible to consider everything in a short discussion. For brevity, the general assumptions listed below must be accepted to compare profitability of these crops. Producers must then adjust the scenario to fit their production practices. 

-- Soil pH is 6 or above. 

-- The level of phosphorus and potassium are at least 80% sufficient and no lime, phosphorus, or potassium will be applied. (NOTE: It is not recommended to plant any crop with less than 100% sufficiency of major fertilizer nutrients.) 

-- Annual land preparation costs are approximately equal. Land preparation costs are higher for alfalfa than for the others crops in the establishment year; however, when prorated on an annual basis alfalfa costs may be somewhat lower than for annual crops. 

-- Herbicide and insecticide costs are approximately the same for all crops. These costs are highly variable but, on average, equivalent. 

-- Rooting depth is at least 3 feet. 

To compare profitability among crops, the remaining variables are potential yield, value of the product, and harvest costs for each crop. In Table 1 values of products are estimated on conservative historical values, and harvest costs are estimated from published custom charges (OSU Current Report 216). Yield estimations are primarily dependent on rainfall, and for the sake of simplicity, we used average annual rainfall totals of 25, 30, and 35 inches. 

Realistically, a range of plus or minus 25% should be considered for each of the values in Table 1. Data can be modified to better fit any given circumstance. We modified the price of alfalfa hay for this purpose to $70/ton, rather than the normal $80/ton because quality is expected to be somewhat lower. Readers are cautioned to keep in mind the assumptions discussed above and remember that there is no clear, objective method for comparing yields that fully reflect an individual producer's ability to manage any of these crops. 

In each case, it is assumed that 75% of the rainfall will be stored in the root zone. Each situation will differ greatly from producer to producer. Producers are encouraged to calculate their own potential profits for various crops. 

Alfalfa appears to be the most profitable crop for western Oklahoma where annual rainfall averages 25 to 30 inches, without considering income from grazing or seed production. Cattle are available in most areas to graze the late season production that may not be good enough to pay for baling. 

This scenario excludes deep or sub-irrigated soils and illustrates that it is not essential to harvest 5 to 6 tons/A of alfalfa to make money. A problem with this illustration is the fact that alfalfa requires much work and "art." Inexperienced producers may not be able to bale their hay correctly; however, the fact remains that good producers can probably make more profit by increasing their use of shallow soils for alfalfa production. Most producers can make 2 to 3 tons/A of hay from the first two cuttings each year. 

* "Profit" = income (yield X price) - harvest costs. Real profit depends on individual producer's practices regarding costs of fertilization, pesticides, establishment, etc. 
** Rain-fed corn and soybean are not reliable with less than 30" average annual precipitation.

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