Nutrient Management Research Database
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This presentation covers the basics of managing soil fertility for pepper production.
Many details are included within the presentation, which deserves to be looked at in it's entirety. A summary of the highlights is presented below.
Nutrient Uptake
A bell pepper crop producing 50,000 lbs of fruit/ac can take up 200-260 lbs N per acre, 40-60 lbs P2O5 per acre, and 240-320 lbs K2O per acre. Of this, 80-110 lbs N, 20-30 lbs P2O5, and 120-180 lbs K2O is in the pepper fruit.
Phosphorus (P) Management
For California soils, Olsen-P (also known as bicarbonate P) is a useful measurement of plant available P.
Every 10o F increase in soil temperature increase P availability by about 20%.
Olsen-P values less than 20 ppm will always show a yield response to P fertilization. Values between 20-40 ppm are likely to show a yield response, especially under colder conditions. Yield responses are unlikely when Olsen-P values are greater than 40 ppm.
Rates greater than 120-150 lbs P2O5 per acre are questionable regardless of soil test levels.
Nitrogen (N) Management
Crop N uptake varies by growth stage, from <1 lbs N per acre during early growth, 4-5 lbs N per acre during middle growth stages, and back to less than 3 lbs N per acre during fruit set.
Both residual soil N (remaining from previous years) and soil N mineralization should be considered when determining N application rates. N from mineralization can provide as much as 1 lb N per acre per day.
One inch of irrigation water can leaching as much as 20-30 lbs nitrate-N per acre out of the root zone.
Potassium (K) Management
Crop K uptake varies by growth stage, from <1 lbs K per acre during early growth, 4-7 lbs K per acre during middle growth stages, and back to less than 4 lbs K per acre during fruit set.
Pepper has moderately high K requirements, at 240-320 lbs K2O per acre. Most of that K ends up in the fruit, and is transferred there from plant leaves.
Fields greater than 200 ppm exchangeable K do not require K fertilization, while levels less than 150 ppm should be fertilized.
K fertilization is most effective during fruit set and early fruit development.
Crop Nutrient Monitoring
In season soil nitrate testing can aid in mid-season nutrient management. Nitrate-N concentrations greater than 20 ppm indicate that additional N application can be postponed.
Petiole testing values show current nutrient sufficiency, but cannot predict far into the future.
Deficiency Symptoms
Calcium deficiency symptoms are covered in-depth, and the picture guides are useful to help identify calcium deficiency.