Radishes - Fertility

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, and Table 1-7, Average Amounts of Available Nutrients for Different Types of Manure, on page 9.)

On mineral soils, apply up to 60 kg N/ha (53 lb/ac). On muck soils, apply 40 kg N/ha (36 lb/ac).

Phosphorus

Test the soil to determine phosphorus requirements. On mineral soils where the soil test values are 51 mg P per L soil (ppm) or higher, radishes are unlikely to respond to additional phosphate applications. For soils testing lower than 51 mg P per L soil (ppm), see Table 1-10, Phosphorus Requirements: Vegetables on Mineral Soils, on page 12.

On muck soils, radishes are unlikely to respond to additional phosphate fertilizers if the soil test values are 61 mg P per L (ppm) soil or higher. For soils testing lower than 61 mg P per L soil (ppm), see Table 1-11, Phosphorus and Potassium Requirements: Vegetables on Muck Soils, on page 13.

Potassium

Test the soil to determine potassium requirements. Where the soil test values are 181 mg K per L soil (ppm) or higher, radishes grown on both mineral and muck soils are unlikely to respond to additional potash applications. For soils testing lower than 181 mg K per L soil (ppm), see Table 1-12, Potassium Requirements: Vegetables on Mineral Soils, on page 14, or Table 1-11, Phosphorus and Potassium Requirements: Vegetables on Muck Soils, on page 13.

Micronutrients

Crops vary greatly in their response to micronutrient fertilizers. For complete information, see the section Micronutrients, on page 16.

Boron deficiencies on radish result in the splitting and cracking of the skin. Calcium deficiencies cause a backward cupping of leaves and discolouration of the leaf margins. Magnesium and manganese deficiencies appear as bronzing or yellowing of the leaf tissue between the veins.

Also see Table 1-13, Application Rates for Magnesium, Calcium and Micronutrients, on page 16. Use caution when applying boron. This nutrient can built to toxic levels quite quickly, harming rotational crops.

Plant Analysis

When used in conjunction with a soil analysis, plant analysis is a useful tool for diagnosing crop problems or for evaluating a fertilizer program. The objective of a good fertilizer program is to maintain tissue nutrient concentrations on the lower side of the sufficiency range. Attempting to bring the nutrient analysis up to the higher end of the range could possibly result in over-fertilization and may not be economical. For more information, see the section Plant Analysis, on page 3.

Only use sufficiency ranges as a reference and a guideline. Plant analysis does not replace soil testing or a sound soil fertility program. See Table 9-72, Radish Nutrient Sufficiency Ranges.

Table 9-72. Radish 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: Most recently mature leaf

Related Links

• Publication 363 - Vegetable Production Recommendations

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