Target Soil pH

For all wheat crops—including wheat grain, wheat grain and straw, and wheat straw—the target soil pH is 6.0 for mineral soils and 5.6 for organic soils.

Nitrogen

Suggested nitrogen (N) application rates for wheat at different nitrogen-to-wheat price ratios are as follows.

If crops follow a legume crop, reduce N applications according to legume N credits. Take appropriate credits if manure has been applied.

For wheat following corn on loamy soils, the MRTN has been further refined based on the preplant nitrate test (PPNT) results. Substantial residual N may remain from the corn crop, particularly if excess N was applied to corn or drought conditions prevented the use of all the N that was applied. Accounting for this N will improve the N use efficiency of wheat, increase profitability, and reduce potential for nitrate losses to groundwater. Soils with a PPNT less than or equal to 50 lb N/a have higher N rate guidelines than soils with a PPNT of 51-100 lb N/A, reflecting a lesser amount of nitrogen in the soil profile. On soils where the PPNT is more than 100 lb N/a, wheat will not respond profitably to N additions and the MRTN rate is 0 lb N/a. If the previous crop is corn, and the PPNT was not taken, then the N rate guidelines for a PPNT of less than 50 lb N/a should be followed.

As with corn, the N response of wheat on loamy soils is similar for previous crops of soybean or small grains. Based on Wisconsin’s current N response database, a clear distinction in N need is not apparent between soils with varying PPNT values. Thus there is no differentiation in MRTN guidelines based on PPNT when wheat follows soybean or small grain. However, if a PPNT is taken in this situation and it is less than or equal to 50 lb N/a, then the top end of the profitable range should be used. If, on the other hand, the PPNT is 51 to 100 lb N/a, consider using the bottom end of the profitable range (link to soil nitrate tests to adjust nitrogen application rates). Soybean rotation N credits should not be used with the MRTN approach to selecting a N rate for wheat.

Wheat’s N response does not vary with previous crop when grown on sandy (sand and loamy sand) soils. The PPNT is not suggested for use on sandy soils. At this time, the MRTN guidelines for wheat on sandy soils are the same regardless of whether or not the field is irrigated.

Additional Considerations for Wheat Nitrogen Rate Selection

• When wheat follows a forage legume or leguminous vegetable, use the MRTN rate for wheat following corn, with a PPNT less than or equal to 50 lbs. N per acre and take the legume credit.
• Manure N credits must be subtracted from the recommended N rates
• If 100% of the N will come from organic sources, use the top end of the range.
• Reduce N rates by 10 lbs. N per acre for spring wheat
• On loamy soils with less than 2% organic matter, reduce rates by 30 lbs. N per acre.
• No N is required on organic soils

Phosphorus

Moisture content at which yield is reported and phosphorus (P) removal values for wheat are below.

Phosphorus application recommendations for wheat grain and wheat grain and straw are as follows.

Potassium

Moisture content at which yield is reported and potassium (K) removal values for wheat are below.

Potassium application recommendations for wheat grain and wheat grain and straw are as follows.

Secondary and Micronutrient Recommendations