7.3 Broadcast
7.4 Band Application
7.5 Fertigation
7.6 Foliar Application
7.7 Sidedress
7.8 Topdress
7.9 Seed Placement
7_Fertilizer-Application
Exercise 4a Soil Texture and Water Percolation
Exercise 4b Soil Separation
Fertilizer Application
Overview
Title Image "Foliar Application to Soybeans" by Mike Staton, MSU Extension is used with permission.
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Introduction
Learning Objectives
Describe different fertilizer application techniques.
Describe advantages and limitations of various fertilizer application methods.
Key Terms
broadcast - a method by which fertilizer is applied on the surface across an entire field
complete fertilizer - fertilizer that contains the three primary nutrients (nitrogen, phosphorus, and potassium)
fertigation - the practice of adding fertilizer to irrigation water
foliar - application of a small amount of fertilizer or mineral through direct spraying onto the leaves
injection - the practice of putting liquid or gaseous fertilizer below the soil near plant roots
sidedress - applying fertilizer between rows of young plants to provide a boost during periods of rapid growth and nutrient uptake
topdress - spreading fertilizer or manure on established fields
Introduction
Learning about essential elements reveals the issues that might arise if there are not enough nutrients in soil. Fertilizers are added to soil to improve plant growth and productiveness. Most fertilizers that are commonly used in agriculture are known as complete fertilizer because they contain the three basic plant nutrients: nitrogen, phosphorus, and potassium. Some fertilizers also contain certain micronutrients, such as zinc and other metals, that are necessary for plant growth. There are many methods used for fertilizer application.
Injection
Injection is used to place liquid or gaseous fertilizer below the soil near plant roots. All of the ammonia in manure, which can comprise 30% or more of the total nitrogen, can be lost through volatilization following land application. Research has shown that depositing manure below the soil surface can reduce ammonia losses by as much as 100% compared to surface-applied manures. Preventing ammonia volatilization increases the amount of nitrogen available for crop growth, thereby potentially benefiting producers through a reduced need for nitrogen fertilizer. In addition, decreasing the loss of ammonia from land-applied manures reduces their potential impact on air quality. Other benefits include the reduction in odor that occurs following subsurface application of manure and a reduction in the run off of nutrients to surface waters.
- Advantages: reduce losses through precise application of nutrients
- Disadvantages: slow, expensive, requires specialized equipment
Broadcast
Surface broadcast is a method by which fertilizer is applied on the surface across an entire field. High-capacity fertilizer spreaders are often used; these spin dry fertilizer or spray liquid fertilizer on the soil surface or on a growing crop.
- Advantages: fast, economical
- Disadvantages: high nutrient losses, low uniformity, P efficiency is only 1/3 to 1/4 that of banding
Broadcast incorporated improves on the efficiency of surface application by incorporating fertilizer through plowing or disking. Plowing is considered better in terms of nutrient availability, as it creates a nutrient-rich zone a few inches below soil surface (where developing plant roots can absorb it).
- Advantages: reduces losses compared to broadcast, improves plant uptake
- Disadvantages: slow, non-uniform application, erosion risk
Band Application
Band application is also known as starter application. Fertilizer is applied in bands near where developing roots will easily reach it; either to the side and below the seed rows, slightly below the seeds, or in between rows. A common practice is to band fertilizer two inches to the side and two inches deeper than the seeds or plants. This provides the plants with a concentrated zone of nutrients and can improve nutrient use efficiency. This process can be done before or simultaneous with planting or seed drilling, and liquid or dry fertilizers can be used. Many fields are deficient in phosphorous, due to soil binding and cold temperatures. Banding phosphorous makes it easier for plants to grow. It also slows NH4+ conversion to NO3- (nitrification), reducing the risk of leaching.
- Advantages: high nutrient use efficiency, jump-starts early growth.
- Disadvantages: costly, slow; risk of salt burn to plants
Fertigation
Fertigation is distribution with water-soluble fertilizers and chemicals through an irrigation system.
- Advantages: high nutrient use efficiency
- Disadvantages: irrigation equipment needed (injection pump, etc), risk of uneven application in windy situations
Foliar Application
Foliar application is application of a small amount of fertilizer or mineral through direct spraying onto the leaves.
- Advantages: rapid uptake
- Disadvantages: phytotoxicity, high expense, limited to small and/or repeated application
Sidedress
Sidedressing is when fertilizer is applied between rows of young plants to provide a boost during periods of rapid growth and nutrient uptake. The most common use is sidedressing nitrogen on corn plants. Application amount is dependent on the results of a Pre-Sidedress Nitrate Test (PSNT) done when corn plants are 12-24 inches tall.
There are three methods of sidedressing:
- Urea-ammonium nitrate applied with a pesticide sprayer fitted with drip nozzles
- Urea-ammonium nitrate injected between corn rows with disc openers
- Anhydrous ammonia injected into soil
- Advantages: high nutrient use efficiency
- Disadvantages: timing often falls during the wet and busy season, slow process
Topdress
Topdressing is when fertilizer or manure is spread on stablished fields (grasses, legumes).
- Advantages: high nutrient use efficiency
- Disadvantages: losses likely
Seed Placement
Seed placement is also known as pop-up application. A small amount of fertilizer is placed with corn seeds during planting, sometimes in conjunction with banding. Both liquid and dry can be used. Urea and DAP cannot be used, and to prevent salt burn the total rate must be kept below 10 lbs of N + K2
- Advantages: lower equipment costs, starter effect greater than just meeting nutrient requirements
- Disadvantages: can be phytotoxic if too much fertilizer is applied, retro-fitting planters can be expensive.
Dig Deeper
"Fertigation - Injecting Soluble Fertilizers into the Irrigation System" by Thomas D. Landis, Jeremy R. Pinto, and
Anthony S. Davis, United States Forestry Service, is in the Public Domain.
"Fertilizer" by the Florida Department of Transportation is in the Public Domain.
Unit 4 Lab Exercises
Exercise 4a: Soil Texture and Water Percolation
Students examine the different soil textures and understanding how they affect water movement through the soil. This exercise involves practical activities to measure and compare the percolation rates of various soil types.
Exercise 4b: Soil Separation
Students analyze soil composition by separating its components to understand the different textures and their properties. This exercise helps in identifying the proportions of sand, silt, and clay in a soil sample.
Attributions
"Nutrient Sources, Analyses, Application Methods" by Dr. Quirine Ketterings Ph.D., Cornell University. Copyright © Cornell University. Used with permission.