Michigan State University Extension
Soils & Soil Management - Fertilizer - 06039707
07/10/97
Tri-state Fertilizer Recommendations for Corn, Soybeans, Wheat and Alfalfa Extension Bulletin E-2567 (New), July 1995
M.L. Vitosh, Michigan State University; J.W. Johnson, The Ohio State University; D.B. Mengel, Purdue University; Co-editors
Different crops require different soil pH levels for optimum performance; when pH falls below these levels, performance may suffer (Vis. 1). The pH of organic soils (more than 20 percent organic matter) is generally maintained at much lower levels than the pH in mineral soils (less than 20 percent organic matter) to minimize chances of micronutrient deficiencies. The topsoil in fields with acid subsoils (most common in eastern Ohio) should be maintained at higher pHs than those fields with neutral or alkaline subsoils to minimize chances for nutrient deficiencies associated with acid soil conditions.
Soil pH should be corrected by liming when the pH in the zone of sampling falls 0.2 to 0.3 pH units below the recommended level. The rates of application given in (Vis. 2) are based on the lime test index obtained using the SMP-buffer lime requirement test and are applicable to an 8-inch depth. For no-till and established forages, lime recommendations are based on a 0- to 4-inch depth, so the rates of application should be one-half the values given in (Vis. 2). These rates are for agricultural ground limestone with a neutralizing value of 90 percent. They should be adjusted if other types of liming material are used. To adjust for a liming material with a different neutralizing value (nv), multiply the lime recommendation given in the table by 0.90 and divide by the new neutralizing value.
Example: Lime recommendation = ((tons per acre x 0.90) / 0.80) if nv is 80 percent.
The relative availability of the liming material is also affected by the lime particle size. For information on adjusting lime recommendations because of differences in lime particle size, see in-state publications.
Lime rates also should be adjusted for other depths of incorporation. To adjust for other depths, divide by 8 and multiply by the new incorporation depth.
Example: Lime recommendation = ((tons per acre / 8) x 10) if incorporation depth is 10 inches.
Lime recommendations (LR) are calculated from the lime test index (LTI) for mineral soils and the soil pH for organic soils using the following formulas and rounding to the nearest tenth of a ton:
Mineral soils
to pH 6.8: LR = 714 - 1.03 x LTI to pH 6.5: LR = 60.4 - 0.87 x LTI to pH 6.0: LR = 49.3 - 0.71 x LTI
Organic soils
to pH 5.3: LR = 32.9 - 6.31 x soil pH
These rates should raise soil pH to the desired pH level, but the exact pH is not always achieved. Applications of less than 1 ton/acre often may not be practical and will not appear in computer-generated recommendations. When the recommendation is for 2 tons/acre or less, the application can be made any time in a cropping sequence. When the lime recommendation exceeds 4 tons per acre, apply the lime in a split application -i.e., half before plowing and half after plowing. Do not apply more than 8 tons of lime in one season. Large applications of lime without thorough mixing may cause localized zones of high alkalinity, reducing the availability of some essential nutrients. If the soil test indicates more than 8 tons per acre are required, retest two years after the application to see if more lime is needed.
Surface applications of urea forms of N fertilizer are not recommended on fields where lime has been surface applied recently. The potential N loss by ammonia volatilization is high when urea reacts with unincorporated lime. Urea forms of N should not be surface applied within one year of the lime application. Surface applications of ammonium nitrate, ammonium sulfate, or injected 28 percent N or anhydrous ammonia are preferred when lime is not incorporated.
| Visual title - Visual size | Visual title - Visual size |
|---|---|
| Soil pH recommended for various crops on various soils - 13K | Tons of ag limestone needed to raise soil pH based on SMP lime - 32K |
