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Fertilizer Recommendation Tables - 2007 Revision

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

Phosphorus and Potassium Requirements - Vegetables on Organic Soils

Phosphate (P205) required - kg/ha
Soil Phosphorus (0.5 M sodium bicarbonate extract) mg P L-1 of soil (ppm P)

Cabbage**,
cauliflower, broccoli,
brussels sprout, potato,
carrot, parsnips, onion***, garlic, lettuce, spinach, radish, beet.

 Celery
0‑3

100 HR

120 HR
4‑5

100 HR

120 HR
6‑7

100 HR

120 HR
8‑9

100 HR

120 HR
10‑12

90 MR

120 HR
13‑15

90 MR

110 MR
16‑20

80 MR

100 MR
21‑25

70 MR

90 MR
26‑30

60 MR

80 MR
31‑40

50 LR

70 LR
41‑50

30 LR

50 LR
51‑60

20 LR

40 LR
61‑80

0 RR

0 RR
80+

0 NR*

0 NR*

 

Potash (K2O) required - kg/ha
Soil Potassium (1 M ammonium acetate extract) mg K L-1 of soil (ppm K) Cabbage**, cauliflower, broccoli, brussels sprouts, celery Potato, carrot, parsnip, onion, garlic,  Lettuce, spinach, radish, beet
0‑15

200 HR

230 HR

100 HR
16‑30

190 HR

220 HR

100 HR
31‑45

170 HR

210 HR

90 HR
46‑60

150 HR

200 HR

80 HR
61‑80

120 MR

170 MR

60 MR
1‑100

90 MR

150 MR

40 MR
101‑120

70 MR

120 MR

30 MR
121‑150

50 MR

80 MR

20 MR
151‑180

40 MR

40 MR

20 MR
181‑210

0 LR

0 LR

0 LR
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.

** If no insecticide is used in the planting water, use a starter solution high in nitrogen such as 20‑20‑20 at 1 kg/200 L. Under high temperatures use 1/2 the fertilizer concentration.

*** If maturity of onions is a problem on organic soils less than 40 cm deep, additional phosphate may be required. The fertilizer rates in this table are designed to produce highest economic yields when accompanied by good or above average management.

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 2007)

 

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