Sweet Corn - Fertility

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Sweet Corn - Fertility

Author:	OMAFRA Staff
Creation Date:	01 February 2006
Last Reviewed:	01 February 2006

Excerpt from Publication 363 - Vegetable Production Recommendations
Note: Page references refer to pages in the 2006-2007 version of Publication 363.

Nitrogen

If manure is applied or legume sod is plowed down, reduce the nitrogen (N) application. (See Table 1-8, Adjustment of Nitrogen Requirement Where Sod Containing Legumes Is Plowed Down, on page 9, and Table 1-7, Average Amounts of Available Nutrients for Different Types of Manure, on page 9.)
On all soils, 90 kg N/ha (80 lb/ac) is recommended.

A portion of the nitrogen should be applied preplant or at the time of planting. Apply the planter-fertilizer in a band 5 cm (2 in.) to the side and 5 cm (2 in.) below the seed. To avoid fertilizer injury, do not exceed the maximum banded application rates listed below. Side-dress the remainder of the nitrogen before the corn is 30 cm (12 in.) high.

Maximum Banded Application Rates¹
Fertilizer	kg/ha	lb/ac
Nitrogen	75	67
Nitrogen plus potash	75 + 45	67 + 40
Urea	40	36
Urea plus potash	40 + 40	36 + 36

¹Based on 75-cm (30-in.) rows.

Alternatively, pop-up fertilizer may be applied in the furrow directly with the seed:

Do not use more than 9 kg nitrogen-plus-potash/ha (8 lb/ac).
Do not place urea with the seed.

Avoid "pop-up" starter fertilizers that use urea as the nitrogen source. If the N component is more than half as much as the P component, the starter may contain urea.

Table 9-86. Sweet Corn Nutrient Sufficiency Ranges

Adapted from Maynard, D.N., and G.J. Hochmuth. 1997. Knott's Handbook for Vegetable Growers, 4^th Edition. John Wiley & Sons, Inc. New York.

Plant Part: Whole seedlings

Time of Sampling	N	P	K	Ca	Mg	S
3-leaf stage	3-4%	0.35-0.5%	2.5-4%	0.6-0.8%	0.25-0.5%	0.4-0.6%
6-leaf stage	3-4%	0.25-0.5%	2.5-4%	0.5-0.8%	0.25-0.5%	0.4-0.6%

Time of Sampling	Fe	Mn	Zn	B	Cu
3-leaf stage	50-100 ppm	40-100 ppm	30-40 ppm	10-30 ppm	5-10 ppm
6-leaf stage	50-100 ppm	40-100 ppm	30-40 ppm	10-30 ppm	5-10 ppm

ppm = parts per million

Plant Part: Most recently mature leaf

Time of Sampling	N	P	K	Ca	Mg	S
30 inches tall	2.5-4%	0.2-0.4%	2.5-4%	0.5-0.8%	0.20-0.4%	0.2-0.4%
Just prior to tassle	2.5-4%	0.2-0.4%	2-3.5%	0.3-0.6%	0.15-0.4%	0.2-0.4%

Time of Sampling	Fe	Mn	Zn	B	Cu
30 inches tall	40-100 ppm	40-100 ppm	25-40 ppm	10-30 ppm	4-10 ppm
Just prior to tassle	30-100 ppm	30-100 ppm	20-40 ppm	10-20 ppm	4-10 ppm

ppm = parts per million

Plant Part: Ear leaf

Time of Sampling	N	P	K	Ca	Mg	S
Tasselling	1.5-2.5%	0.2-0.4%	1.2-2%	0.3-0.6%	0.15-0.4%	0.2-0.4%

Time of Sampling	Fe	Mn	Zn	B	Cu
Tasselling	30-100 ppm	20-100 ppm	20-40 ppm	10-20 ppm	4-10 ppm

ppm = parts per million

Phosphorus

Test the soil to determine phosphorus requirements. Where the soil test values are 31 mg P per L soil (ppm) or higher, sweet corn fields are unlikely to respond to additional phosphate applications. For soils testing lower than 31 mg P per L soil (ppm), see Table 1-10, Phosphorus Requirements: Vegetables on Mineral Soils, on page 12.

Phosphate is best banded at the time of planting. Depending on the soil test rating, additional broadcast P applications may not be necessary.

Potassium

Test the soil to determine potassium requirements. Where the soil test values are 121 mg K per L soil (ppm) or higher, sweet corn fields are unlikely to respond to additional potash applications. For soils testing lower than 121 mg K per L soil (ppm), see Table 1-12, Potassium Requirements: Vegetables on Mineral Soils, on page 14.

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