Lime

New Stand Establishment
Follow the guidelines below for lime application where incorporation into the soil is possible.

Less than 2 tons per acre recommended
A single application after plowing usually will give good results. Lime applied before plowing should be disked into the soil and then plowed in. Lime applied after plowing should be disked into the soil as thoroughly as possible.

More than 2 tons per acre recommended
For best results, apply one-half of the lime, disk it into the soil, plow it under, and then apply the second half and disk it into the soil. This method offers the best incorporation of lime into the soil and is important when the soil pH is very low and large amounts of lime are needed.

Establishment of new stands using no-till
Research with no-till forage establishment shows that surface-applied lime is effective in reducing soil acidity in the surface two to four inches of soil, especially in fields that have been limed to tillage depth in previous years. For no-till establishment where the lime will not be incorporated into the soil, follow the guidelines for pasture and hayfield maintenance.

Pasture and Hayfield Maintenance
Normally, a surface application of up to 2 to 3 tons of lime per acre will effectively reduce acidity in the upper two to four inches of soil.

When more than 3 tons of lime per acre is required, additional lime above the 3-ton rate applied to the surface will have little beneficial effect on crop growth. So, if the field is level enough to till without danger of excessive erosion, then consider plowing up the old sod and reseeding, at which time you can incorporate the lime. Otherwise, surface apply half the lime now and the remainder in six to 12 months.

Nitrogen, Phosphate, Potash

Nitrogen (N) fertilizer promotes grass growth and can produce significant yield increases when used on pastures or hayfields that are predominantly grass. Nitrogen is used most efficiently when it is applied in small frequent applications while plants are actively growing. Nitrogen also leaches easily from the soil, which is another reason split-applications are better.

Legumes fix nitrogen from the air into a plant-available form that is shared with grasses in mixed pastures. You do not need nitrogen where more than 25 percent of your pasture stands or 35 percent of your hay stands consist of tall-growing legumes (red clover, ladino clover, alfalfa).

In contrast to nitrogen, phosphate (phosphorus), and potash (potassium) move rather slowly in the soil and can be applied at any time of the year. In most cases it is economically advantageous to apply phosphorus (P) and potassium (K) at the same time nitrogen is being applied. Where possible, plowing or disking in these two nutrients (e.g., at seeding) will give the best results.

P stimulates root growth, especially on young plant seedlings. Therefore, use higher rates of P when establishing forages for hay or pasture as compared to maintenance P applications for established stands. Applying the extra P at establishment is a very important step in getting healthy seedlings for a vigorous stand of forage.

How you manage a field will affect its long-term needs for N, P, and K. If you cut the field for hay, you will remove greater amounts of plant nutrients. If you use the field for a pasture system, a considerable amount of nutrient cycling takes place. Research has shown that a 500-pound steer contains approximately 12.5 pounds N, 7.8 pounds P2O5, and 0.9 pounds K2O, whereas a ton of tall-grass hay may contain 50 pounds N, 16 pounds P2O5, and 52 pounds K2O. Thus greater amounts of nutrients, especially P and K, will be needed over time in a hay system to replace the nutrients removed in the harvested hay and maintain soil fertility. In pastures, N is cycled primarily through the microbial decomposition of plant residues from legumes and other plants, as well as from manure and urine, while in hay fields, N is cycled through dying plant roots or plant material left following harvest.

Trace Element Needs

Trace-element deficiencies have been found on the following forage crops in Virginia: boron - alfalfa and molybdenum - alfalfa. Soil testing is conducted to determine the need for B by alfalfa. However, soil tests are not a reliable predictor of crop response to molybdenum. For molybdenum, a general recommendation is made in situations where deficiencies would normally be found.

Reviewed by Steve Heckendorn, Laboratory Manager, Crop and Soil Environmental Sciences

Other resources in:

• Soils
• Pasture & Forage - Animal Agriculture
• Pasture & Forage - Crops & Soils

Other resources by:

• Steven Heckendorn
• Greg Mullins

Other resources from:

• Crop and Soil Environmental Sciences