- What soil pHs range is recommended for this sward?
- 4.5-5.0
- 5.1-5.5
- 5.6-6.0
- 6.1-6.5
- 6.6-7.0
- 7.1-7.5
Most legumes need a higher soil pHs than most grasses. Recommended soil pHs levels for forages in Missouri range from 5.6 to 6.5, but certain crops require a higher soil pHs within this range than others. The University of Missouri also recommends different pHs ranges in different parts of the state for the same crop or forage. Specific pHs ranges for forages grown in Missouri can be found in the table below which is from University Extension Guidesheet no. 9112, "Interpreting Missouri Soil Test Reports."
Soil pHs is a measure of the acidity or alkalinity of the soil. The subscripted "s" in the pHs term simply denotes the type of laboratory test used to measure the acidity of the soil sample- in this case a salt testing solution. Values for pH (no subscript), however, is determined in the lab by a water-based test instead of a salt solution. The University of Missouri soil testing laboratory uses the salt testing solution and reports soil acidity levels as pHs . A value given for pHs is about 0.5 units more acidic than the same value given simply as pH. For example, a pHs value of 5.5 would be similar to a pH value of 6.0.
Most Missouri soils are acidic, however heavy applications of limestone can increase the soil pHs to basic or alkaline levels. A pH of 7.0 is neutral - meaning it is neither acidic or basic. Low soil pHs can have a dramatic impact on forage growth and persistence. The acidity of a soil increases by a factor of 10 for each integer below a pH of 7.0. For example, a pH of 6.0 is 10 times more acidic than 7.0, a pH of 5.0 is 100 times more acidic than 7.0, and a pH of 4.0 is 1000 times more acidic than 7.0.
Desired soil salt pH (pHº) ranges for Missouri crops.
| Crop | Ozark and borders | Other |
| Alfalfa and alfalfa - grass establishment | 6.6 - 7.0 | 6.1 - 6.5 |
| Birdsfoot trefoil and birdsfoot trefoil - grass establishment | 6.1 - 6.5 | 5.6 - 6.0 |
| Clover and clover - grass establishment and production | 6.1 - 6.5 | 5.6 - 6.0 |
| Cool-Season grass establishment and production | 5.6 - 6.0 | 5.6 - 6.0 |
| Lespedeza and lespedeza - grass establishmen | 6.1 - 6.5 | 5.6 - 6.0 |
| Overseeding legumes | 6.1 - 6.5 | 5.6 - 6.0 |
| Warm-season grass establishment and production | 5.6 - 6.0 | 5.6 - 6.0 |
| Sudan grass and sudan/sorghum crosses | 5.6 - 6.0 | 5.6 - 6.0 |
| All row crops | 6.1 - 6.5 | 6.1 - 6.5 |
