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Fertilizer Recommendation Tables - 2008 Revision

Author: Keith Reid - Soil Fertility Specialist/OMAFRA
Creation Date: October 2007
Last Reviewed: November 2008
2008 Revision

Potassium Requirement Table - Field Crops

Potash (K2O) required - kg/ha
  Soil Potassium (1M ammonium acetate extract) mg K L-1 of soil (ppm K)      Spring barley, mixed grain, spring wheat      Corn, sweet corn, sorghum, sunflower     Soybeans, peas, field beans, snap beans, lima beans,
0‑15 90 HR

170 HR

120 HR
16‑30 80 HR

160 HR

110 HR
31‑45 70 HR

140 HR

90 HR
46‑60 50 HR

110 HR

80 HR
61‑80 40 HR

80 MR

60 MR
81‑100 30 MR

50 MR

40 MR
101‑120 20 MR

30 MR

30 MR
121‑150 20 MR

0 LR

0 LR
151‑180 0 LR

0 RR

0 RR
181‑210 0 RR

0 RR

0 RR
211‑250 0 RR

0 RR

0 RR
250+ 0 NR*

0 NR*

0 NR*

* adding nutrients to soils with these levels of nutrients may reduce crop yields or quality by interfering with the uptake of other nutrients.



Potash (K2O) required - kg/ha
  Soil potassium (1M ammonium acetate extract) mg K L-1 of soil
(ppm K)		  Oats, spring rye, mustard, canola, fodder rape, kale, buckwheat, flax, millet, unimproved pasture  Winter wheat, winter barley, winter rye, or winter triticale with or without seeding down (at seeding) Spring cereals, seeded down, (oats, mixed grain barley, rye) direct seeding (at seeding). (See next column for fall application)    Established hay-pasture, fall application. New seedings (after harvest)
0‑15

70 HR

50 HR

90 HR

480 HR
16‑30

50 HR

40 HR

80 HR

400 HR
31‑45

40 HR

30 HR

70 HR

320 HR
46‑60

30 HR

20 HR

50 HR

270 HR
61‑80

20 MR

20 MR

40 HR

200 HR
81‑100

20 MR

20 MR

30 MR

130 HR
101‑120

0 LR

20 LR

20 MR

70 MR
121‑150

0 RR

0 RR

20 MR

20 MR
151‑180

0 RR

0 RR

0 LR

0 LR
181‑210

0 RR

0 RR

0 RR

0 LR
211‑250

0 RR

0 RR

0 RR

0 RR
250+

0 NR*

0 NR*

0 NR*

0 NR*

* adding nutrients to soils with these levels of nutrients may reduce crop yields or quality by interfering with the uptake of other nutrients.

 

The fertilizer rates in this table are designed to produce highest economic yields when accompanied by good or above average management. Research data show that higher rates will occasionally produce higher yields but that these increases in yield are likely to be small and uneconomic.

HR, MR, LR, RR, and NR denote, respectively, high, medium, low, rare and no probabilities of profitable crop response to applied nutrient.

 

Approved: Ontario Soil Management Research and Services Committee (June 2008).

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