Reference No.: 214
Title: Nutrient Management for Commercial Fruit & Vegetable Crops in Minnesota
Author: Carl J. Rosen, Roger Eliason
Primary Topic: Farming
Year: 2005
URL: https://emswcd.org/wp-content/uploads/2016/04/MN-Nutrient-Mgt-Guide-short.pdf
My notes on this reference #
Introduction
- 17 essential nutrients are required for plant growth, including macronutrients (N, P, K, Ca, Mg, S) and micronutrients (B, Zn, Fe, etc.).
- Carbon (C), hydrogen (H), and oxygen (O) are obtained from the air and water, while all others come from the soil.
- When soil nutrient levels are insufficient, fertilizers are needed to ensure optimal plant growth.
- Fertilization recommendations for fruit and vegetable crops in Minnesota are based on soil test results.
- Soil testing removes guesswork and improves efficiency in nutrient management.
Soil Sampling & Testing
- Proper soil sampling ensures accurate representation of nutrient levels.
- Samples should be taken at a consistent time each year, ideally in spring or fall.
- Each field should be divided into uniform areas with the same soil texture, cropping history, and past fertilizer applications.
- Sampling depth:
- Annual crops: 6-8 inches.
- Perennial crops: 10-12 inches.
- Soil samples should be mixed thoroughly and submitted to a testing laboratory.
- Nitrate tests (0-2 ft depth) can help determine nitrogen needs for certain crops in western Minnesota.
Fertilizer Analysis & Application
- Fertilizer nutrients are expressed in percentages:
- Nitrogen (N)
- Phosphate (P₂O₅)
- Potash (K₂O)
- Fertilizer grades indicate nutrient content, e.g., 10-10-10 contains 10% N, 10% P₂O₅, and 10% K₂O.
- To determine the amount of fertilizer needed, divide the required nutrient amount by the percentage in the fertilizer.
- Nitrogen fertilizers should be applied in split applications to minimize leaching and runoff.
- Phosphorus and potassium fertilizers should be incorporated into the soil to maximize availability.
Soil pH Management
- Ideal pH range:
- Most crops: 5.8 - 7.0 for mineral soils, 5.4 - 6.2 for organic soils.
- Blueberries: 4.5 - 5.2 (prefer acidic soil).
- Potatoes: Can tolerate a wide range but scab disease increases at pH > 5.3.
- Liming (Raising pH)
- Used to reduce soil acidity in areas with high rainfall or intensive cropping.
- Liming materials include calcitic limestone (CaCO₃) and dolomitic limestone (CaMg(CO₃)₂).
- The amount of lime required depends on soil texture and organic matter content.
- Acidification (Lowering pH)
- Elemental sulfur or iron sulfate can be used to lower soil pH.
- Best applied one year before planting.
- Requires monitoring of soil pH over time to maintain the desired level.
Nutrient Management for Crops
- Primary Macronutrients:
- Nitrogen (N): Essential for leafy growth; deficiency causes yellowing of leaves.
- Phosphorus (P): Important for root development, flowering, and fruit production.
- Potassium (K): Aids in water regulation and disease resistance.
- Secondary Macronutrients:
- Calcium (Ca): Prevents disorders like blossom-end rot in tomatoes.
- Magnesium (Mg): Required for chlorophyll production.
- Sulfur (S): Needed for protein synthesis.
- Micronutrients (B, Zn, Fe, Mn, Cu, Mo, Cl, Ni):
- Deficiencies can cause stunted growth, poor fruit set, and leaf discoloration.
Organic & Inorganic Fertilizers
- Inorganic fertilizers:
- Provide immediately available nutrients.
- Can be over-applied, leading to environmental concerns.
- Organic fertilizers:
- Include compost, manure, and plant-based fertilizers.
- Slow-release and improve soil structure over time.
- Need to be broken down by soil microbes before plants can absorb nutrients.
Animal Manure & Biosolids
- Animal manure:
- Nutrient content varies by livestock type, storage, and application method.
- Provides nitrogen, phosphorus, and potassium but requires composting to reduce pathogens.
- Sewage sludge (biosolids):
- Contains nutrients but may have heavy metals and contaminants.
- Not recommended for edible crops.
Green Manures & Cover Crops
- Green manures are crops grown and tilled into the soil to improve fertility.
- Cover crops prevent erosion and increase soil organic matter.
- Legumes (e.g., clover, alfalfa):
- Can fix 100-200 lbs of nitrogen per acre.
- Non-legumes (e.g., rye, oats):
- Improve soil tilth but do not fix nitrogen.
- Some plants (e.g., buckwheat, oilseed radish) help make phosphorus more available.
Fertigation & Irrigation
- Fertigation: Applying fertilizer through irrigation systems.
- Requires proper backflow prevention to avoid contamination.
- Overhead irrigation:
- Used for large-acreage crops (e.g., sweet corn, potatoes).
- Can apply 20-40 lbs N per acre per application.
- Drip irrigation:
- More efficient, reduces disease risk.
- Best for high-value crops like tomatoes, peppers, strawberries.
- Nitrogen and potassium are commonly applied through drip systems.
Foliar Fertilization
- Quick fix for nutrient deficiencies (e.g., calcium in apples, magnesium in leafy greens).
- Not a substitute for proper soil fertility management.
- Most effective for micronutrients like zinc and boron.
- Should be applied based on tissue analysis results.
Crop-Specific Nutrient Guidelines
- Different crops have unique nutrient needs.
- Lima Beans:
- Nitrogen needs depend on the previous crop.
- Requires 25-125 lbs K₂O/acre depending on soil test.
- Peas:
- Require 0-40 lbs N/acre, depending on soil organic matter.
- Need up to 100 lbs P₂O₅/acre on low-phosphorus soils.
- Potatoes:
- Highly responsive to nitrogen; requires up to 200 lbs N/acre.
- High potassium demand (up to 500 lbs K₂O/acre on low-potassium soils).
- Snap Beans:
- Require 0-50 lbs N/acre.
- Potassium requirements depend on soil test results.