Growing Peanuts – Crop Nutrition 101

What soil type, pH and climate do peanuts prefer?

• Soil Type: Peanuts thrive in deep, fine, sandy loam soils with good drainage. The soil should be light-colored, loose, and friable to allow for easy root penetration and air movement.
• Soil pH: Peanuts grow best in a pH range of 5.8 to 7, an ideal range for fertilizer efficiency. Soil testing should be conducted in the fall to determine if liming or pH amendment is necessary to raise the pH. Over-liming should be avoided as a pH higher than 7.5 can reduce the availability of essential micronutrients.
• Climate: Peanuts require a warm climate with consistent rainfall throughout the growing season. Adequate soil moisture is essential, particularly during the pegging and pod development stages. Soil moisture can also inhibit Ca uptake

Key Nutrients & Fertilization Practices: 

• Balanced Fertility Program: Utilize a fertility program that maintains adequate levels of phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and micronutrients. Soil testing should guide the application rates and timing. Soil test recommendations show 3:1 ratio of Ca to K
• Calcium (Ca): Calcium is the most critical nutrient for achieving high yields and grades. A lack of calcium can result in unfilled pods (pops), darkened plumules, poor germination, and increased risk of aflatoxin contamination.
  • Application Type: Surface application of gypsum or Polysulphate is recommended at early bloom to ensure adequate calcium in the pegging zone. Polysulphate demonstrates comparable performance to gypsum, offering a dependable and economically viable approach to maximizing peanut yield. Surface application of Ca at early bloom is recommender since Ca below the 3” pegging zone can cause Ca deficiencies
  • Timing: Soil calcium (Ca) is needed in high levels for viable seed development. Polysulphate applied at 200 lbs./A alone can sufficiently provide Ca, K, and Mg for peanut crop. Monitoring calcium levels in the pegging zone 10-14 days after planting is crucial to avoid deficiencies.
• Potassium (K): High levels of Potassium (K) can inhibit Ca uptake. Excessive potassium can lead to an increased incidence of “pops” and pod rot, negatively impacting peanut quality and yield.
  • Application Type: Apply potassium based on soil test recommendations, but avoid excessive potassium in the upper four inches of soil to prevent interference with calcium uptake.
  • Timing: Apply potassium during pre-planting or early growth stages, ensuring it is adequately incorporated into the soil.
  • Note: Excessive potassium can lead to an increased incidence of “pops” and pod rot, negatively impacting peanut quality and yield.

• Nitrogen: Peanuts, like other legumes do not require a lot of Nitrogen (N) fertilizer and can fulfill their own N needs with adequate (yearly) inoculation
• Micronutrients:  Micronutrients, including zinc, iron, manganese, copper, boron, and molybdenum, are crucial for plant health, but their availability decreases as soil pH increases. High-pH soils are particularly prone to micronutrient deficiencies, particularly boron and manganese, even if soil tests indicate adequate levels.
  • Application Type: Based on soil test results and visual deficiency symptoms, foliar manganese or boron applications may be necessary.\
  • Timing: Apply manganese at the first sign of interveinal chlorosis, usually during the early growth stages. Apply boron as a foliar spray in early July to prevent kernel defects like “hollow hearts,” characterized by depressed and darkened inner surfaces of the cotyledons.

Nutrient Removal:  

Nutrient balance is key to quality yields.  

Nutrient removal by Peanut  

(Alabama Extension: ANR-0449) 

Nuts (4000 lb) 

Vines (5000 lbs)  

Role of Nutrients in Peanut Production: 

Key quality and yield parameters can be affected by different nutrients. See how they can influence your harvest. 

+ = improving 

– = decreasing 

+/- = different results, depending on the rate of nutrient applied 

Yield: N++, P+, K+/-, Mg+, Ca++, S+ Quality: N+, P+, K+/-, Mg+, Ca++, S+

• Calcium (Ca): Crucial for pod and seed development. Adequate calcium must be available in the pegging zone during seed and pod development to prevent issues like unfilled pods and poor germination.
• Nitrogen (N): Peanuts are efficient nitrogen fixers, synthesizing their own nitrogen through symbiosis with rhizobium bacteria. Inoculation at planting is recommended, especially in fields with no recent history of peanut cultivation.
• Potassium (K): Supports overall plant health and is involved in various physiological processes. However, it must be balanced with calcium to avoid competition that can impair pod development.
• Micronutrients: Elements like manganese, boron, and zinc play vital roles in preventing disorders such as interveinal chlorosis, kernel defects, and overall plant health. Regular soil testing and targeted foliar applications can address deficiencies.

Key Fertility Challenges for US Peanut Growers

• Soil pH Management:
  • Challenge: Over-liming can lead to high soil pH, reducing the availability of essential micronutrients like manganese and boron.
  • Solution: Maintain soil pH in the optimal range of 5.8 to 6.5. Regular soil testing is essential to determine lime needs and prevent over-application.
• Calcium Deficiency:
  • Challenge: Insufficient calcium during the pegging and pod development stages can result in unfilled pods, poor germination, and increased susceptibility to aflatoxin.
  • Solution: Apply gypsum or Polysulphate at early bloom and monitor calcium levels in the pegging zone. Consider the calcium content in irrigation water as a supplemental source. Polysulphate provides peanuts with gradual release of sulfur-based, plant-available S, K, Mg and Ca and trials show Polysulphate produced similar yields to a high amount of gypsum on peanuts with greater economic returns based on the application rates.
• Potassium Interference:
  • Challenge: Excessive potassium in the soil can inhibit calcium uptake, leading to quality issues like pod rot and unfilled pods.
  • Solution: Follow soil test recommendations and avoid high potassium levels in the pegging zone. A balanced 3:1 ratio of calcium to potassium is ideal.
• Micronutrient Deficiency:
  • Challenge: High pH soils are more prone to micronutrient deficiencies, even if soil tests show adequate levels.
  • Solution: Monitor crops for deficiency symptoms and apply micronutrients through foliar sprays when necessary. Be particularly vigilant for manganese and boron deficiencies.