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CIR1168 Fertilization of Pepper in Florida1 George Hochmuth2 1. This document is CIR1168, one of a series of the Horticultural Sciences Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date May 1996. Reviewed May 2003. Visit the EDIS Web Site at http://edis.ifas.ufl.edu. 2. George Hochmuth, Professor, Horticultural Sciences Department, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville FL 32611. The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Larry Arrington, Dean Pepper is the second most valuable vegetable crop in Florida. Bell peppers were produced on 22,000 acres in the 1993-94 season and had a value of $235 million (Freie and Pugh, 1995). In addition to the bell peppers, there might be 2000 to 3000 acres of various hot peppers and other specialty peppers such as cubanelle. Counties with the largest pepper acreage are in southern Florida and include Collier, eastern Palm Beach, Hendry, Hillsborough, Lee, and Manatee. Production costs for pepper average $9,500 per acre with about $6,700 due to preharvest variables of which fertilizer accounts for about 5% (Smith and Taylor, 1995). Although fertilizer accounts for a relatively small portion of the total production costs, proper, judicious use of fertilizer is required for maximizing yield and quality of pepper fruits and for minimizing potential negative impacts to the environment caused by nutrient leaching or runoff. Fertilization requirements and practices for pepper have been exhaustively researched in Florida during the last 50 years. This publication presents the current pepper (bell and specialty) fertilization recommendations and pertinent research documentation behind the recommendations. FERTILIZATION RECOMMENDATIONS Soil pH.Peppers grow well under a wide range of soil pH from 5.5 to 7.5. Acidic soils should be limed to a pH of 6.0 to 6.5 using the recommendations of a calibrated lime requirement test, such as the Adams -Evans test used by the University of Florida. High-cal lime can be used to raise the pH, although dolomite might be preferred where Mg is also needed. Overliming can lead to reduced micronutrient availability. N, P, K.Pepper P and K fertilization recommendations are based on the calibrated Mehlich-1 soil test results and vary according to the soil-test level of P and K (Table 1). N requirements are 175 lb per acre for the season (Hochmuth and Hanlon, 1995). Research documenting the N, P, and K recommendations is cited in the literature list at the end of this publication, especially in Circ. S-357 by Hochmuth and Hanlon (1989).
Fertilization of Pepper in Florida 2 Magnesium, sulfur, and calcium.Magnesium (Mg) and sulfur (S) are mobile in Floridas sandy soil so do not build up to appreciable levels. The Mehlich-1 extractant is used by the University of Florida to test soils for Mg. The soil is low in Mg if the Mehlich-1 index is below 15 ppm, medium if between 15 and 30 ppm, and high if above 30 ppm. For soils low in Mg, growers should apply 40 lb Mg per acre from potassium-magnesium sulfate or magnesium sulfate. The Mg requirement will be satisfied if dolomite was used as the liming source to correct soil pH. Calibrated soil tests for sulfur do not exist for Floridas sandy soils. Usually 40 lb S per acre will satisfy the S requirement of any vegetable. The S can be supplied from several sources (Hochmuth, 1988) and is usually included in the blended fertilizer placed in the bed or could be supplied via fertigation through the season. Calcium (Ca) is needed by all vegetables for normal growth and fruit development. Pepper is particularly sensitive to Ca shortages which lead to blossom-end rot. If the soil contains 300 ppm of Mehlich-1 Ca, then there is ample soil Ca for normal pepper production. The challenge then becomes one of ensuring that enough of that Ca is present in the plant when fruits are developing. Ca moves preferentially with the water stream in the plant so fruits usually do not receive their fair share of Ca when plants are under water stress. Factors that reduce Ca movement to the fruits and thus encourage blossom-end rot are: Water stress (drought). Since Ca moves with the water stream in the plant, any water stress, even temporary (one day) stress can lead to blossom-end rot. Dry soils, high soil soluble salts, windy conditions, etc., can reduce Ca movement to the fruits. Under these conditions, Ca moves mostly to the leaves and young vegetative growing areas. Excessive N and K fertilizer. High N encourages excessive vegetative growth and most Ca then moves to the leaves and actively growing shoot tips. High K leads to high soluble salt concentrations in the soil restricting water movement, and thus Ca movement, into the root. Damage to root system. Ca is absorbed by roots near the root tips. Anything (flooding, root disease, nematodes, mechanical damage, etc.) that damages the roots can inhibit Ca uptake. Micronutrients.Micronutrients, boron (B), copper (Cu), manganese (Mn), and zinc (Zn) are needed by pepper in very small quantities and excessive amounts available to the crop can lead to toxicities. The interpretation of the Mehlich-1 micronutrient soil test is presented in Table 2. Micronutrients should be applied to the soil with the preplant fertilizer since there is the possibility of precipitation in drip irrigation tubing. Fungicides commonly used for control of pepper diseases can supply sizable quantities of some micronutrients such as Cu, Mn, and Zn. Boron can leach and, since there is no calibrated soil test for B in Florida, up to 2 lb B per acre could be applied with the preplant fertilizer where plant tissue test results have indicated potential B deficiencies. Foliar sprays of B will not be effective since B does not move out of the leaf on which it is sprayed to help cure a deficiency in the younger part of the plant. FERTILIZER APPLICATION Nearly all pepper in Florida is now produced on polyethylene mulched beds. Peppers are grown with two major types of irrigation systems, drip irrigation and subsurface irrigation, although there is a small acreage irrigated with sprinklers. Although fertilizer amounts are the same with the various irrigation
Fertilization of Pepper in Florida 3 methods, the management of the fertilizer, including placement and timing will be different. Subsurface irrigation.All P and micronutrients should be applied to the soil in the preplant fertilizer. About 15 to 20% of the total N and K amount also should be applied preplant. The preplant fertilizer can be incorporated in the bed soil. Remaining N and K should be banded in a 2to 3-inch deep groove in the center of the bed. Depending on the sources used for the N and K, the S requirement also would be present in the band. Bed placement of fertilizer risks all of the fertilizer before the crop is planted when high water tables from overirrigation or heavy rainfall could leach soluble N or K. An alternative practice would be to use a liquid fertilizer injection wheel to split-apply a portion of the N and K in the early part of the crop growth cycle. Drip irrigation.With drip irrigation, all P and micronutrients should be applied to the soil preplant along with 20% of the N and K. Mg and S can be applied with the preplant fertilizer although the S also could be applied through the drip system. Remaining N and K should be injected through the drip system (fertigated) as the crop develops. The fertilizer can be injected every day or less frequently such as every 3 or 4 days, or once per week. The choice depends on water management and the potential for leaching. For situations where potential for leaching is low, then weekly injection is acceptable. Scheduling injections with the crop growth rate would result in the most efficient use of N and K. However, injections can consist of equal portions of the total seasonal N and K needs. The schedule for injection of N and K in Table 3 follows the growth and development of the crop. IRRIGATION Irrigation management.Fertilizer efficiency is closely related to water management. N and K are highly soluble in sandy soils and can be leached with the water when the water-holding capacity of the soil is exceeded by excessive irrigation. For subsurface-irrigated crops, water tables should be closely monitored and maintained at 18 to 24 inches below the surface of the bed. Soil water tension measured by tensiometers 6 to 8 inches deep should be about -8 to -12 centibars. Tensiometers also should be used with drip-irrigated crops, keeping the tensiometer gauge at -8 to -12 centibars for the soil at the 6 to 8-inch depth. Water does not move laterally more than about 8 to 10 inches from the drip tube emitter. When water requirements are high, then irrigation should be operated in several cycles per day. Each cycle should not exceed 1.5 hours for a system with tubes applying 0.5 gal. per minute per 100 ft. TISSUE TESTING Whole-leaf testing.Fertilization programs can be monitored with plant tissue testing. Most testing procedures use the most-recently-matured leaves with petiole attached for mobile nutrients such as N, P, K, and Mg. Younger leaves should be used for nonmobile elements such as micronutrients. Sufficiency ranges for whole-leaf analyses for various crop growth stages are presented in Table 4 Petiole sap testing.Sometimes turn-around time may be too long and cost too high for whole-leaf analyses. A leaf petiole sap analytical procedure has been developed for Florida pepper. Petiole sap can be tested for nitrate-N and K and the results used in making decisions regarding adjustments in N and K fertilization programs. These analyses are particularly useful for fertigation programs. Sufficiency ranges for petiole sap analyses for nitrate-N and K are presented in Table 5.
Fertilization of Pepper in Florida 4 RELATED LITERATURE Everett, P.H., and R. Subramanya. 1983. Pepper production as influenced by plant spacing and nitrogen-potassium rates. Proc. Fla. State Hort. Soc. 96:79-82. Freie, R.L., and N.L. Pugh. 1995. Florida Agricultural Statistics, Vegetable Summary. Fla. Agric. Statistics Serv., Orlando, FL. Hanlon, E.A., J.G. Gonzalez, and J.M. Bartos. 1994. IFAS Extension soil testing laboratory chemical procedures and training manual. Fla. Coop Ext. Serv. Circ. 812. Hanlon, E.A., and G.J. Hochmuth. 1989. Calculating fertilizer rates for vegetable crops grown in raised-bed cultural systems in Florida. Fla. Coop. Ext. Serv. Special Series SS-SOS-901. Hochmuth, G. (ed.). 1988. Pepper production guide for Florida. Fla. Coop. Ext. Circ. 102. Hochmuth, G. 1994. Plant petiole sap-testing guide for vegetable crops. Fla. Coop. Ext. Circ. 1144. Hochmuth, G.J., and E.A. Hanlon. 1989. Fertilizer management for bell pepper production in Florida. Fla. Agr. Exp. Sta. Circ. S-357. Hochmuth, G. J. and E. A. Hanlon. 1995. IFAS standardized fertilization recommendations for vegetable crops. Fla. Coop. Ext. Circ. 1152. Hochmuth, G., and E. Hanlon. 1995. Commercial vegetable crop nutrient requirements for Florida. Fla. Coop. Ext. Circ. SP-177. Hochmuth, G.J., E.A. Hanlon, and R.C. Hochmuth. 1994. Responses of pepper, muskmelon, watermelon, and sweet corn to P and K fertilization at Live Oak, FL. Suwannee Valley Agr. Res. Educ. Center Res. Report 92-28. Hochmuth, G., and R. Hochmuth. 1994. Jalapeno pepper response to N and K fertilization. Suwannee Valley Agric. Res. Educ. Center Res. Report. 94-05. Hochmuth, G., D. Maynard, C. Vavrina, and E. Hanlon. 1991. Plant tissue analysis and interpretation for vegetable crops in Florida. Fla. Coop. Ext. Special Series SS-VEC-42. Hochmuth, G.J., K.D. Shuler, and P.R. Gilreath. 1990. Fertility management for peppers grown with drip and seepage irrigation. Proc. Fla. Pepper Inst. Fla. Coop. Ext. Serv. Special Series SSVEC-002. Hochmuth, G.J., K.D. Shuler, P.R. Gilreath, and R.L. Mitchell. 1988. Field-testing of revised Mehlich-1-predicted potassium fertilizer recommendations for mulched pepper. Soil and Crop Sci. Soc. Fla. Proc. 47:30-35. Hochmuth, G., K. Shuler, E. Hanlon, and N. Roe. 1994. Pepper response to fertilization with soluble and controlled-release potassium fertilizers. Proc. Fla. State Hort. Soc. 107:132-139. Hochmuth, G.J., K.D. Shuler, R.L. Mitchell, and P.R. Gilreath. 1987. Nitrogen crop nutrient requirement demonstrations for mulched pepper in Florida. Proc. Fla. State Hort. Soc. 100:205-209. Locascio, S.J., and M.R. Alligood. 1992. Nitrogen and potassium source and N rate for drip-irrigated pepper. Proc. Fla. State Hort. Soc. 105:323-325. Locascio, S.J., and J.G.A. Fiskell. 1977. Pepper production as influenced by mulch, fertilizer placement, and nitrogen rate. Soil and Crop Sci. Soc. Fla. Proc. 36:113-117. Locascio, S. J., and J. G. A. Fiskell. 1979. Pepper response to sulfur-coated urea, mulch, and nitrogen rate. Proc. Fla. State Hort. Soc. 92:112-115. Locascio, S. J., J. G. A. Fiskell, and F. G. Martin. 1981. Responses of bell pepper to nitrogen sources. J. Amer. Soc. Hort. Sci. 106:628-632. Locascio, S.J., and W.M. Stall. 1994. Bell pepper yield as influenced by plant spacing and row arrangement. J. Amer. Soc. Hort. Sci. 119:899-902.
Fertilization of Pepper in Florida 5 Smith, S.A., and T.G. Taylor. 1995. Production cost for selected vegetables in Florida, 1994-95. Fla. Agr. Exp. Sta. Economic Information Report EI 95-1. Stanley, C.D., and G.A. Clark. 1993. Water use and nitrogen balance for subirrigated fresh-market bell pepper production. Proc. Fla. State Hort. Soc. 106:202-204.
Fertilization of Pepper in Florida 6 Table 1. Table 1. Interpretation of Mehlich-1 soil test and nutrient recommendations for pepper. Element Parts per million in soil Very low Low Medium High Very high P <10 10-15 16-30 31-60 >60 K <20 20-35 36-60 61-125 >125 Fertilizer lb per acre (6-ft bed centers) P2O5 160 130 100 0 0 K2O 160 130 100 0 0 Adapted from G. Hochmuth and E. Hanlon, IFAS standardized fertilization recommendations for vegetable crops, Fla. Coop. Ext. Circ. 1152, (1995).
Fertilization of Pepper in Florida 7 Table 2. Table 2. Interpretations of Mehlich-1 soil tests for micronutrients. Soil pH (mineral soils only) 5.5 5.9 6.0 6.4 6.5 7.0 ppm Test level below which there may be a crop response to applied copper. 0.1 0.3 0.3 0.5 0.5 Test level above which copper toxicity may occur. 2.0 3.0 3.0 5.0 5.0 Test level below which there may be a crop response to applied manganese. 3.0 5.0 5.0 7.0 7.0 9.0 Test level below which there may be a crop response to applied zinc. 0.5 0.5 1.0 1.0 3.0 Adapted from G. Hochmuth and E. Hanlon, IFAS standardized fertilization recommendations for vegetable crops, Fla. Coop. Ext. Circ. 1152, (1995). Table 3. Table 3. Injection schedule for N and K for drip-irrigated pepper. Crop development Injection rate (lb/acre/day)z Stage Weeksy N K2O 1 2 1.0 1.0 2 2 1.5 1.0 3 7 2.5 2.5 4 1 1.5 1.0 5 1 1.0 1.0 zTotal seasonal amounts of nutrients are 175 N and 160 K2O (lb/acre), including any in-bed starter fertilizer. Extended-season applications can proceed at 1.0 to 1.5 lb N and K2O per acre per day. First week or two of injection can be omitted where 20% N and K was applied preplant. yNumber of weeks length of a particular crop stage.
Fertilization of Pepper in Florida 8 Table 4. Table 4. Sufficiency ranges for whole-leaf tissue testing of pepper at various stages in the season. Plant part Time of sampling Status N P K Ca Mg S Fe Mn Zn B Cu Mo % ppm MRMz leaf Prior to blossoming Deficient <4.0 0.3 5.0 0.9 0.35 0.3 30 30 25 20 5 Adequate range 4.05.0 0.30.5 5.06.0 0.91.5 0.350.6 0.30.6 30150 30100 2580 2050 510 High >5.0 0.5 6.0 1.5 0.6 0.6 150 100 80 50 10 Toxic (>) 350 MRM leaf First blossoms open Deficient <3.0 0.30 2.5 0.9 0.30 0.3 30 30 25 20 5 Adequate range 3.05.0 0.300.50 2.55.0 0.91.5 0.300.50 0.30.6 30150 30100 2580 2050 5-10 High >5.0 0.50 5.0 1.5 0.50 0.6 150 100 80 50 10 Toxic (>) 1000 350 MRM leaf Early fruit set Deficient <2.9 0.25 2.5 1.0 0.3 0.3 30 30 25 20 5 Adequate range 2.9-4.0 0.250.40 2.5-4.0 1.01.5 0.3-0.4 0.30.4 30-150 30100 2580 2050 5-10 High >4.0 0.40 4.0 1.5 0.4 0.4 150 100 80 50 10 Toxic (>) 350 MRM leaf Early harvest Deficient <2.5 0.20 2.0 1.0 0.3 0.3 30 30 25 20 5 0.1
Fertilization of Pepper in Florida 9 Table 4. Table 4. Sufficiency ranges for whole-leaf tissue testing of pepper at various stages in the season. Plant part Time of sampling Status N P K Ca Mg S Fe Mn Zn B Cu Mo Adequate range 2.53.0 0.200.40 2.03.0 1.01.5 0.30.4 0.30.4 30150 30100 2580 2050 510 0.10.2 High >3.0 0.40 3.0 1.5 0.4 0.4 150 100 80 50 10 Toxic (>) 350 zMRM, most-recentlymatured leaf.
Fertilization of Pepper in Florida 10 Table 5. Table 5. Sufficiency ranges for leaf petiole sap N and K concentrations for pepper. Crop development stage Fresh petiole sap concentration (ppm) Nitrate N K First flower buds 1400 1600 3200 3500 First open flowers 1400 1600 3000 3200 Fruits half-grown 1200 1400 3000 3200 First harvest 800 1000 2400 3000 Second harvest 500 800 2000 2400 Adapted from G. Hochmuth, Plant petiole sap-testing guide for vegetable crops. Fla. Coop. Ext. Serv. Circ. 1144, (1994).