General Information
- UF/IFAS fertilization and liming recommendations are advisory in nature and emphasize efficient fertilizer use and environmentally sound nutrient management without losses of yield or crop quality.
- It is assumed the nutrients will be supplied from purchased commercial fertilizer and the expected crop yields and quality will be typical of economically viable production.
- Growers should consider UF/IFAS recommendations in the context of their entire management strategy, such as return on investment in fertilizer and the benefits of applying organic soil amendments.
Fertilizer Rates
For potatoes using a soil test with a target pH* of 6.0:
N | P2O5 Low | P2O5 Med | P2O5 High | K2O Low | K2O Med | K2O High |
---|---|---|---|---|---|---|
See table below | Up to 120** | Up to 120** | Up to 120** | 150 | 150 | 150 |
*Where scab-resistant cultivars are grown, a pH between 6.0 and 6.5 is optimum. Where scab-susceptible cultivars are grown, the pH should be below 5.2 or above 7.2.
**See Interim P recommendation below.
Total tuber yield goal (cwt/acre) | Recommended N rate (lbs/acre) |
---|---|
100 | 67 |
150 | 100 |
200 | 132 |
250 | 166 |
300 | 197 |
350 | 224 |
400 | 250 |
- Indicated fertilizer rates plus the nutrients already in the soil will satisfy the crop nutrient requirement for this cropping season. Excessive fertilization has been shown to reduce vegetable quality.
- On soils that have not been in vegetable production within the past 2 years, or where micronutrients are known to be deficient, apply 5 lb Mn, 3 lb Zn, 4 lb Fe, 3 lb Cu, and 1.5 lb B/A. Use soil testing to monitor micronutrient status every 2 years to avoid micronutrient toxicity, because some micronutrients can build up in the soil. When deciding about micronutrient applications, consider micronutrients added to the crop via fungicides.
- Up to 40 lb/acre Mg might be needed when soil test is medium or lower in Mg. Mg can be supplied in fertilizer or from dolomitic limestone, when liming is recommended. Calcium concentrations are typically sufficient in most soils used continuously for vegetable production or where the Mehlich-3 Ca index is >300 ppm. Calcium is added during liming activities and from calcium carbonate present in irrigation water drawn from aquifers in Florida. These sources should be considered in the determination of Ca fertilizer needs.
Fertilizer Timing and Placement
- Band all phosphorus.
- Apply 50% to 70% of N and 50% of K2O at emergence and the remaining N and K at 35 to 40 days after planting.
- Potatoes planted in cool soils might respond to up to 25 lb/ac P2O5applied as starter fertilizer in the furrow with the seed pieces.
Fertilizer Sources
- Supply 25% to 50% of the N in the nitrate form if soils were treated with multipurpose fumigants or if the soil temperature will stay below 60°F for up to one week following transplanting or germination.
Water Management
- Fertilizer and water management are linked. Maximum fertilizer efficiency is achieved only with close attention to water management. Supply only enough irrigation water to satisfy crop requirements. Excess irrigation may result in leaching of N and K, creating possible plant deficiencies.
- For subsurface irrigation, maintain a constant water table between 18 (at planting) and 24 inches (near harvest) below the top of the bed. Monitor water table depth and do not fluctuate to avoid fertilizer loss below the root zone.
References
CIR 1152 UF/IFAS Standardized Nutrient Recommendations for Vegetable Crop Production in Florida
HS 1429 Nitrogen Fertilization Guidelines for Potato Production in Florida
HS 945 Potato Physiological Disorders -- Brown Center and Hollow Heart
HS 711 Soil and Fertilizer Management for Vegetable Production in Florida
CV 296 Vegetable Production Handbook Ch. 2: Fertilizer Management of Vegetable Production in Florida
Other Resources
HS 941 Controlled-Release Fertilizers for Commercial Potato Production in Florida
SL 401 How to Calculate a Partial Nitrogen Mass Budget for Potato
HS 1361 How to Fertigate Plant Vines via Center Pivots for Commercial Potato Production in Florida
SL 346 A Summary of N, P, and K Research with Potato in Florida