Skip to Main navigation Skip to Left navigation Skip to Main content Skip to Footer

University of Minnesota Extension
www.extension.umn.edu
612-624-1222

Extension > Agriculture > Nutrient Management > Nutrient/Lime Guidelines > Fertilizer Recommendations for Agronomic Crops in Minnesota > Sunflower

Print Icon Email Icon Share Icon

Fertilizer Recommendations for Agronomic Crops in Minnesota

Sunflower

Daniel E. Kaiser, Extension Soil Scientist; John A. Lamb, Extension Soil Scientist; and Roger Eliason, Director, University of Minnesota Soil Testing Laboratory

Revised 2011

Sunflower will respond to fertilization. Nitrogen, phosphate, and potash are important. The appropriate recommendations are listed in the tables that follow.

subsoil map

Figure 1. Reference Map for lime
guidelines.

Nitrogen

Nitrogen (N) fertilizer guidelines can be based on the results of a soil NO3--N test or the consideration of expected yield, previous crop, and soil organic matter content. The soil NO3--N test is appropriate for western Minnesota (see Figure 1). When the soil nitrate test is used, the fertilizer N guidelines are calculated as follows:

Nrec = (0.05) (EY) - STN(0-24 in.) - NPc

Where:

EY = expected yield (lb./acre)
STN = nitrate-nitrogen (NO3--N) measured to a depth of 24 in. (lb./acre)
Npc = amount of N supplied by the previous legume crop (lb./acre).
These N credits are summarized in Table 1.

The N fertilizer guidelines for situations where the soil NO3--N test is not used are summarized in Table 2.

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, sorghum-sudan, sugar beet, sunflower, sweet corn, triticale, and wheat.

Phosphate and Potash

Current phosphate recommendations are summarized in Table 3. Recommendations for potash use are in Table 4.

CAUTION! Do not apply more than 10 lb N + K2O per acre in contact with the seed. Do not place ammonium thiosulfate (12-0-0-26) in direct contact with the seed. Do not place fertilizers containing boron in direct contact with the seed.

Table 1. Nitrogen credits for various legume crops that might precede barley in a crop rotation. Use these credits for the "Npc" factor in situations where the soil nitrate test is used.

Previous Crop 1st Year Nitrogen Credit
  lb. N/acre
  Soybean 20
  Edible  beans, field peas 10
  Harvest sweetclover 10
  Harvested alfalfa*  
    4 to 5 plants/ft2 75
    2 to 3 plants/ft2 50
    1 or fewer plants/ft2 0
  Harvested red clover 35

* Add 20 lb. N/acre to the credits listed if the 3rd or 4th cutting was not harvested.

Table 2. Nitrogen fertilizer guidelines for sunflower production for situations where the soil NO3--N test is not used.

    Expected Yield (lb./acre)
Crop grown last year Organic matter level* 1400-1900 1901-2400 2401-2900 2901-3300 3300 +
  Alfalfa (4+ plants/ft2) Low
Med and high
0
0
0
0
0
0
0
0
0
0
  Alfalfa (2 to 3 plants/ft2) Low
Med and high
0
0
20
0
40
10
60
30
80
50
  Soybeans
  Alfalfa (1 or less plants/ft2)
Low
Med and high

30
0

50
20
70
40
90
60
110
80
  Group 1 Crops Low
Med and high
0
0
15
0
25
0
45
25
65
45
  Group 2 Crops Low
Med and high
70
40
90
60
110
80
130
100
150
120

* low = less than 3.0%; medium and high = 3.0% or more.

Table 3. Phosphate fertilizer suggestions for sunflower production in Minnesota.

    Phosphorus (P) Soil Test, ppm *
Expected
Yield
Bray: 0-5 6-10 11-15 16-20 21 +
Olsen: 0-3 4-7 8-11 12-15 16 +
lb./acre   — P2O5 to apply (lb./acre) —
1400-1900   55 35 15 0 0
1901-2400   65 45 20 0 0
2401-2900   75 55 25 0 0
2901-3300   85 65 25 10 0
3300 +   90 70 30 10 0

* Use one of the following equations if a phosphate guideline for a specific soil test and a specific expected yield is desired.

P2O5 rec = [0.0225 - (0.0011) (Bray P, ppm)] (Expected Yield)
P2O5 rec = [0.0225 - (0.0014) (Olsen P, ppm)] (Expected Yield)

Table 4. Potash fertilizer suggestions for sunflower production in Minnesota.

Expected
Yield
Potassium (K) Soil Test, ppm *
0-40 41-80 81-120 121-160 161 +
lb./acre K2O to apply (lb./acre)
1400-1900 55 40 20 15 0
1901-2400 75 50 30 15 0
2401-2900 90 65 35 20 0
2901-3300 110 75 40 25 0
3300 + 115 80 45 25 0

* Use the following equation if a potash guideline for a specific soil test and a specific expected yield is desired.

K2O rec = [0.0410 - (0.00027) (Soil Test K, ppm)] (Expected Yield)

Other Nutrients

Research trials conducted in Minnesota have shown that other nutrients are not needed in a fertilizer program for sunflower production.

  • © Regents of the University of Minnesota. All rights reserved.
  • The University of Minnesota is an equal opportunity educator and employer. Privacy