With 1 to 2 million acres planted annually, wheat is a major crop in Minnesota's agriculture. When diseases and other crop pests are not limiting, average yields continue to increase slowly with time. Adequate and efficient use of fertilizer has been a major contributor to this increase.
How N guidelines are calculated
The modern wheat grower receives more return for money spent on nitrogen (N) than any other nutrient. It is important to focus on using this nutrient as efficiently as possible.
When thinking about how much fertilizer N to apply, start with geography. For the western portion of the state where most of the wheat is grown, the soil NO_{3}^{}N test (soil samples collected to two feet) is the best and most accurate management tool for predicting the amount of fertilizer N to use. Use this soil test if wheat is grown in the shaded area of the state shown in Figure 1.
For the soil nitrate test, calculate the amount of fertilizer N required with the following equation:
N_{rec} = (2.5) (EY)  STN_{(024 in.)}  N_{Pc}
Where:
 EY = expected yield (bu./acre)
 STN = nitratenitrogen (NO_{3}^{}N) measured to a depth of 24 in. (lb./acre)
 N_{pc} = amount of N supplied by the previous legume crop (lb./acre).
Table 1 summarizes N credits.
Table 1 lists various crops that might precede wheat in a crop rotation. Use these credits when the soil nitrate test is used.
Table 1: Firstyear nitrogen credits from previous crops.
Previous crop  Firstyear nitrogen credit 

Soybean  20 lbs. of N per acre 
Edible beans, field peas  10 lbs. of N per acre 
Harvested alfalfa*: 4 to 5 plants per square foot  75 lbs. of N per acre 
Harvested alfalfa*: 2 to 3 plants per square foot  50 lbs. of N per acre 
Harvested alfalfa*: 1 to 2 plants per square foot  25 lbs. of N per acre 
Harvested alfalfa*: 1 or fewer plants per square foot  0 lbs. of N per acre 
Harvested red clover  35 lbs. of N per acre 
Sugarbeet: Yellow leaves  0 lbs. of N per acre 
Sugarbeet: Yellowgreen leaves  15 to 20 lbs. of N per acre 
Sugarbeet: Darkgreen leaves  60 to 70 lbs. of N per acre 
* Add 20 lbs. of N per acre to the listed credits if the third or fourth cutting wasn’t harvested.
Table 2 lists nitrogen credits for some forage legumes if wheat is planted two years after the legume.
Table 2: Secondyear nitrogen credits
Legume crop  Secondyear nitrogen credit 

Harvested alfalfa: 4 or more plants per square foot  35 lbs. of N per acre 
Harvested alfalfa (2 to 3 plants per square foot) and birdsfoot trefoil  25 lbs. of N per acre 
Red clover  20 lbs. of N per acre 
Fertilizer guidelines for eastern Minnesota
Table 3 summarizes nitrogen fertilizer guidelines for the eastern portion of the state. Use the fertilizer N guidelines for soils having a high organic matter content when wheat is grown is southeast Minnesota. This statement applies in Goodhue, Wabasha, Olmsted, Winona, Fillmore and Houston Counties.
The wheat crop can also use nitrogen supplied by legume crops if planted two years after the legume. Table 2 summarizes these nitrogen credits. Subtract these values from the N guidelines listed for crops in Group 2 in Table 3.
In a wheatsugarbeet rotation, the wheat plant can use nitrogen from the decomposing sugarbeet tops. Table 1 lists these N credits, which are based on the color of the sugarbeet tops at harvest 1. If using the soil NO_{3}^{}N test, use the value for the right color nitrogen credit from the previous crop (N_{pc}) in the N guideline equation. If using Table 3, subtract the value for the appropriate color from the appropriate N guideline listed in the table.
In table 3, use these recommendations for wheat in when the soil NO_{3}^{}N test isn’t used.
Table 3: Nitrogen guidelines
Crop grown last Year  Soil organic matter level*  Expected yield: 4049 bushels per acre  Expected yield: 5059 bushels per acre  Expected yield: 6069 bushels per acre  Expected yield: 7079 bushels per acre  Expected yield: 80+ bushels per acre 

Alfalfa (4+ plants per square foot)  Low  0 lbs. of N per acre  30 lbs. of N per acre  55 lbs. of N per acre  80 lbs. of N per acre  95 lbs. of N per acre 
Alfalfa (4+ plants per square foot)  Medium and high  0 lbs. of N per acre  0 lbs. of N per acre  35 lbs. of N per acre  60 lbs. of N per acre  75 lbs. of N per acre 
Alfalfa (2 to 3 plants per square foot)  Low  10 lbs. of N per acre  35 lbs. of N per acre  60 lbs. of N per acre  85 lbs. of N per acre  100 lbs. of N per acre 
Alfalfa (2 to 3 plants per square foot)  Medium and high  0 lbs. of N per acre  15 lbs. of N per acre  40 lbs. of N per acre  65 lbs. of N per acre  80 lbs. of N per acre 
Soybeans Alfalfa (1 or fewer plants per square foot)  Low  60 lbs. of N per acre  85 lbs. of N per acre  110 lbs. of N per acre  135 lbs. of N per acre  150 lbs. of N per acre 
Soybeans Alfalfa (1 or fewer plants per square foot)  Medium and high  40 lbs. of N per acre  65 lbs. of N per acre  90 lbs. of N per acre  115 lbs. of N per acre  130 lbs. of N per acre 
Edible beans, field peas  Low  70 lbs. of N per acre  95 lbs. of N per acre  120 lbs. of N per acre  145 lbs. of N per acre  160 lbs. of N per acre 
Edible beans, field peas  Medium and high  50 lbs. of N per acre  75 lbs. of N per acre  100 lbs. of N per acre  125 lbs. of N per acre  140 lbs. of N per acre 
Group 1 crops (see below)  Low  30 lbs. of N per acre  55 lbs. of N per acre  80 lbs. of N per acre  105 lbs. of N per acre  110 lbs. of N per acre 
Group 1 crops (see below)  Medium and high  0 lbs. of N per acre  35 lbs. of N per acre  60 lbs. of N per acre  85 lbs. of N per acre  100 lbs. of N per acre 
Group 2 crops (see below)  Low  80 lbs. of N per acre  105 lbs. of N per acre  130 lbs. of N per acre  155 lbs. of N per acre  170 lbs. of N per acre 
Group 2 crops (see below)  Medium and high  60 lbs. of N per acre  85 lbs. of N per acre  110 lbs. of N per acre  135 lbs. of N per acre  150 lbs. of N per acre 
Organic soils    0 lbs. of N per acre  0 lbs. of N per acre  0 lbs. of N per acre  30 lbs. of N per acre  35 lbs. of N per acre 
*Low = less than 3.0 percent; medium and high = 3.0 percent or more.
Crops in Group 1:
Alsike clover, birdsfoot trefoil, grass/legume hay, grass legume pasture, fallow,and red clover.
Crops in Group 2:
Barley, buckwheat, canola, corn, grass hay, grass pasture, oat, potato, rye, sorghumsudan, sugar beet, sunflower, sweet corn, triticale and wheat.
Application method
Inseason applications of liquid urea ammonium nitrate solutions (28 or 32%) from 2 to 5 days after anthesis have been shown to increase grain protein. In years where expected yields are greater than the grain yield used, you can use a foliar application of N to increase protein. Research has shown that protein can be raised by 0.5 to 1.0% by an application of 30 lbs N per acre. Some leaf burning can be expected but generally will not result in lower yields.
CAUTION — DO NOT TANK MIX 28 OR 32% UAN SOLUTIONS WITH FUNGICIDES
Nitrogen guidelines, whether calculated from the equation or obtained from Table 3, should also be used for winter wheat production. For this crop, 15 to 30 lb. N per acre should be applied in the fall either before or at the time of seeding. The remainder of the amount of fertilizer N needed should be topdressed early in the following spring.
Suggestions for phosphate use are summarized in Table 4. The phosphorus (P) status of Minnesota soils is determined by using either the Bray or the Olsen analytical procedure. In general, the Olsen test provides more accurate recommendations if the soil pH is 7.4 or higher.
Table 4 summarizes phosphate recommendations for wheat production in Minnesota. Use one of the following equations if you want a phosphate guideline for a specific expected yield and a specific P soil test.

Recommended P_{2}O_{5} = [1.071  (0.054) (Bray P in ppm)] (Expected yield)

Recommended P_{2}O_{5} = [1.071  (0.067) (Olsen P in ppm)] (Expected yield)
Table 4: Phosphate fertilizer guidelines
Expected yield  P soil test: 05 parts per million (ppm) Bray and 03 ppm Olsen  P soil test: 05 parts per million (ppm) Bray and 03 ppm Olsen  P soil test: 610 ppm Bray and 47 ppm Olsen  P soil test: 610 ppm Bray and 47 ppm Olsen  P soil test: 1115 ppm Bray and 811 ppm Olsen  P soil test: 1115 ppm Bray and 811 ppm Olsen  P soil test: 1620 ppm Bray and 1215 ppm Olsen  P soil test: 1620 ppm Bray and 1215 ppm Olsen  P soil test: 21+ ppm Bray and 16+ ppm Olsen 

Broadcast  Band  Broadcast  Band  Broadcast  Band  Broadcast  Band    
4049 bushels per acre  40 lbs. of P2O5 per acre  20 lbs. of P2O5 per acre  30 lbs. of P2O5 per acre  15 lbs. of P2O5 per acre  15 lbs. of P2O5 per acre  10 lbs. of P2O5 per acre  0 lbs. of P2O5 per acre  1015 lbs. of P2O5 per acre  0 lbs. of P2O5 per acre 
5059 bushels per acre  50 lbs. of P2O5 per acre  25 lbs. of P2O5 per acre  35 lbs. of P2O5 per acre  20 lbs. of P2O5 per acre  20 lbs. of P2O5 per acre  15 lbs. of P2O5 per acre  0 lbs. of P2O5 per acre  1015 lbs. of P2O5 per acre  0 lbs. of P2O5 per acre 
6069 bushels per acre  60 lbs. of P2O5 per acre  30 lbs. of P2O5 per acre  45 lbs. of P2O5 per acre  25 lbs. of P2O5 per acre  20 lbs. of P2O5 per acre  15 lbs. of P2O5 per acre  0 lbs. of P2O5 per acre  1015 lbs. of P2O5 per acre  0 lbs. of P2O5 per acre 
7079 bushels per acre  70 lbs. of P2O5 per acre  35 lbs. of P2O5 per acre  50 lbs. of P2O5 per acre  25 lbs. of P2O5 per acre  25 lbs. of P2O5 per acre  20 lbs. of P2O5 per acre  0 lbs. of P2O5 per acre  1015 lbs. of P2O5 per acre  0 lbs. of P2O5 per acre 
80 or more bushels per acre  80 lbs. of P2O5 per acre  40 lbs. of P2O5 per acre  55 lbs. of P2O5 per acre  30 lbs. of P2O5 per acre  25 lbs. of P2O5 per acre  20 lbs. of P2O5 per acre  0 lbs. of P2O5 per acre  1015 lbs. of P2O5 per acre  0 lbs. of P2O5 per acre 
Suggestions for potash use are summarized in Table 5. As with phosphate, application rates vary with placement and soil test level for K. No broadcast potash will be needed when the soil test for K is 121 ppm or higher. No potash fertilizer (either drilled or broadcast) is suggested when the soil test for K is 161 ppm or higher.
It may not be practical to broadcast some of the low rates of suggested phosphate and potash. When low rates are suggested for a broadcast application, it may be more practical to double the suggested broadcast rate and apply in alternate years if the grain drill is not equipped to apply fertilizer with the seed.
Table 5 summarizes potash recommendations for wheat production in Minnesota. Use the following equation if you want a potash guideline for a specific expected yield and a specific P soil test.
Recommended K_{2}O = [2.710  (0.017) (K soil test)] (Expected yield)
Table 5: Potash fertilizer guidelines
Expected Yield  K soil test: 040 ppm  K soil test: 040 ppm  K soil test: 4080 ppm  K soil test: 4180 ppm  K soil test: 80120 ppm  K soil test: 80120 ppm  K soil test: 120160 ppm  K soil test: 120160 ppm  K soil test: 160+ ppm 

Broadcast  Band  Broadcast  Band  Broadcast  Band  Broadcast  Band    
4049 bushels per acre  105 lbs. of K2O per acre  55 lbs. of K2O per acre  75 lbs. of K2O per acre  40 lbs. of K2O per acre  45 lbs. of K2O per acre  25 lbs. of K2O per acre  0 lbs. of K2O per acre  1520 lbs. of K2O per acre  0 lbs. of K2O per acre 
5059 bushels per acre  130 lbs. of K2O per acre  65 lbs. of K2O per acre  95 lbs. of K2O per acre  50 lbs. of K2O per acre  55 lbs. of K2O per acre  30 lbs. of K2O per acre  0 lbs. of K2O per acre  1520 lbs. of K2O per acre  0 lbs. of K2O per acre 
6069 bushels per acre  155 lbs. of K2O per acre  80 lbs. of K2O per acre  110 lbs. of K2O per acre  55 lbs. of K2O per acre  65 lbs. of K2O per acre  35 lbs. of K2O per acre  0 lbs. of K2O per acre  1520 lbs. of K2O per acre  0 lbs. of K2O per acre 
7079 bushels per acre  180 lbs. of K2O per acre  90 lbs. of K2O per acre  125 lbs. of K2O per acre  65 lbs. of K2O per acre  75 lbs. of K2O per acre  40 lbs. of K2O per acre  0 lbs. of K2O per acre  1520 lbs. of K2O per acre  0 lbs. of K2O per acre 
80 or more bushels per acre  190 lbs. of K2O per acre  95 lbs. of K2O per acre  135 lbs. of K2O per acre  70 lbs. of K2O per acre  80 lbs. of K2O per acre  40 lbs. of K2O per acre  0 lbs. of K2O per acre  1520 lbs. of K2O per acre  0 lbs. of K2O per acre 
Applying fertilizer
Since most of the wheat acreage in Minnesota is usually planted in early spring when soil conditions are cold and wet, the application of some fertilizer with the drill should be a routine management practice.
CAUTION! — Do not place ammonium thiosulfate (120026) in direct contact with the seed. Do not place boron fertilizers in direct contact with the seed.
Damage from urea (4600) placed in contact with the seed is dependent on the moisture content of the soil at planting. Damage can be substantial if soils are dry at planting. If soils are dry at the time of planting, keep the amount of N as urea in contact with the seed to 10 lb. per acre or less. Higher rates can be used if the soil is wet at planting. The suggested rates for this use, however, are not well defined. High rates of potash in contact with the seed can cause problems if soils are dry at planting. Under typical moisture conditions, rates of K_{2}O up to 60 lb. per acre in contact with the seed should not cause problems with emergence.
Phosphate has no negative effect on seed germination and seedling growth. Therefore, ample amounts of phosphate can be applied in contact with the seed.
The use of air seeders has increased in popularity in recent years. Many seeders are equipped to apply a mixture of seed and dry fertilizer at the time of planting. There are, however, no firm guidelines for the amount of fertilizer that can be applied with the seed with this planting equipment.
The amount of urea that can be used with the air seeder is related to soil moisture content at planting. Recent trials showed that N rates in excess of 25 lb. per acre as urea can reduce germination if applied with the wheat using an air seeder when soils are dry. By contrast, 75 lb. N per acre as urea caused no emergence problems when soils were moist. Further research is being conducted to determine the amount of N as urea that can safely be mixed with wheat using an air seeder.
Recent trials have shown that rates of phosphate of 92 lb. P_{2}O_{5} per acre or less have not hindered germination if mixed with wheat seed planted with an air seeder. The amount of K_{2}O that can be applied in contact with the seed using an air seeder is not known at this time.
Other needed nutrients
Sulfur fertilization can increase wheat yields when the crop is grown on sandy soils. Research trials have shown that there is no need to add S to a fertilizer program when wheat is grown on finetextured soils in Minnesota.
The broadcast application of 25 lb. S per acre in the sulfate form will be adequate for growing wheat on sandy soils. For more efficient applications, use 10 to 15 lb. S per acre with the drill at planting.
When wheat is grown on organic soils, the plant may need a Copper (Cu) fertilizer program.
Table 6 summarizes suggestions for Cu. The suggestions in Table 6 are for organic (peat) soils only. The use of Cu in a fertilizer program is not currently suggested when wheat is grown on mineral soils. Use these recommendations for wheat.
Table 6: Copper fertilizer guidelines
Copper soil test  Broadcast: Copper  Broadcast: Copper sulfate  Foliar spray: Copper  Foliar spray: Copper sulfate 

02.5 (Low)  612 lbs. of Cu per acre  2428 lbs. of Cu per acre  0.3 lbs. of Cu per acre  1.2 lbs. of Cu per acre 
2.65.0 (Marginal)  6 lbs. of Cu per acre  24 lbs. of Cu per acre  0.3 lbs. of Cu per acre  1.2 lbs. of Cu per acre 
5.0+ (Adequate)  0 lbs. of Cu per acre  0 lbs. of Cu per acre  0 lbs. of Cu per acre  0 lbs. of Cu per acre 
Research in South Dakota has shown that spring wheat and winter wheat can respond to chloride fertilization. Collect soil samples from a depth of 0 to 24 inches and refer to establish levels listed below.
Table 7: Chloride levels
Chloride soil test  Relative level 

030  Low 
3160  Medium 
61+  High 
To use the chloride guideline, subtract the amount of chloride at 0 to 24 inches from 60. Any chloride should be broadcast and incorporated before seeding. Seed placement of chloride is not superior to broadcast application. Chloride is most economically applied by using muriate of potash (0060).
Research from throughout Minnesota has shown that magnesium, calcium, iron, boron, zinc, and manganese are not needed in fertilizer programs. Most soils are able to supply ample amounts of these nutrients to a highyielding wheat crop.
Reviewed in 2018