Urea: A Low Cost Nitrogen Fertilizer with Special Management Requirements

Urea (46-0-0) usually has the lowest cost per pound of nitrogen compared to other single-element nitrogen fertilizers. However, urea undergoes unique chemical transformations when field applied and severe losses in efficiency may result if special management practices are not followed. The purpose of this fact sheet is to briefly describe urea transformations and to suggest how urea-N may be conserved with proper management in the field.

Urea Composition and Transformation  in the Field

In common with most commercial nitrogen fertilizers, urea is manufactured from anhydrous ammonia (NH3). The high analysis of urea&#;46% N&#;is the main reason for the low cost of this form of nitrogen fertilizer. Freight costs and storage and handling are all lower than with lower analysis fertilizers such as ammonium nitrate (34-0-0) or ammonium sulfate (21-0-0).

When field applied, urea changes to ammonium bicarbonate. This is a natural process resulting from the activity of the enzyme urease. Chemically the reaction is:

(NH2)CO + 2H2O ))) NH4HCO3 + OH-

This chemical reaction takes place after the urea is dissolved in water and will be complete within about 48 hours under field conditions. The water solution in which the reaction takes place has an alkaline pH, to as high as 8.5, and the ammonium (NH4+) tends to convert to ammonia gas (NH3). This gas will volatilize to the air if not protected. Urea placed on the soil surface or plant foliage may loose from 50% to 90% of its N as ammonia if not protected within a few hours of application.

Conserving Urea-N

If the urea-to-NH4 reaction takes place in the soil the nitrogen will be captured as exchangeable ammonium on the soil exchange complex and little if any loss of ammonia gas to the air will occur. Therefore, the key to conserving urea fertilizerurea fertilizer nitrogen is to put the urea into the soil and not merely on the soil.

Soil incorporation of urea can be done several ways. Since urea is completely water soluble, when applied to the soil surface it can be moved down with irrigation water or rainfall, if one or the other occurs immediately after fertilization. Also, urea can be broadcast and plowed down immediately. And urea can be injected or banded into the soil.

Soil banding or injection is usually not feasible with an established crop such as pasture. Under these conditions the nitrogen fertilizer of choice would be either ammonium nitrate, ammonium sulfate, or one of the ammoniated phosphates (for example 11-52-0).

Urea is applied alone or in combination with other fertilizers. It is available in solid prills and in water solution. The latter includes a 50-50 mix of urea and ammonium nitrate, which is sold under various trade names and is guaranteed at 32% nitrogen (32-0-0). The urea-to-NH4 transformation will take place regardless of whether another nitrogen form or other fertilizer element is present in the fertilizer.

Summary

Urea is a low cost nitrogen fertilizer form. This is because of its high nitrogen composition and consequent low transport and storage costs. Urea may be the fertilizer of choice when only nitrogen is needed in a soil fertility program.

Urea converts to ammonium bicarbonate within about 48 hours after field application. Nitrogen in this form will tend to volatilize to the air as ammonia gas. This lost fertilizer investment risk can be minimized or eliminated by assuring that the urea gets into the soil and does not merely remain on the surface of the soil or crop foliage. This can be accomplished by irrigating in the urea; by plowdown soon after surface broadcast application; or by banding or injecting the urea directly into the soil.

Authors

D. W. James, Extension Soils Specialist

There are so many choices that "analysis by paralysis" can take over. Let's make it easier.

I&#;ve been in the business of helping professionals manage natural grass surfaces for more than 40 years. These pros grow grass for a living &#; sports turf managers for high school, municipality, university and professional teams; golf course superintendents; and lawn care managers.

But when the U.S. Environmental Protection Agency says Americans buy 70 million pounds of fertilizers every year, that&#;s staggering, even for me.

In the past 25 years, technological advancements shaped fertilizer products and how we use them. Today, they&#;re much more efficient, safer for the environment and easier to use.

Visiting your local garden center or big box store to purchase lawn fertilizer can be daunting, with seemingly endless choices. Most of the confusion stems from marketing efforts by manufacturers trying to find a niche that differentiates their product from others. So let&#;s try to simplify and look at the options in four easy-to-grasp categories.

Note: Lawn fertilizer packaging must show the contents of the product. It&#;s the law and this information appears on the front or back of the bag as the Guaranteed Analysis. Toward the bottom of this section, you&#;ll find a statement beginning with the phrase &#;Derived from.&#; This includes the nutrient sources.

Quick-Release Fertilizers

This group represents the lion&#;s share of residential lawn fertilizers. (They&#;re also the mainstream type used by professionals.) They consist mostly of urea-based nitrogen sources, including straight urea, sulfur-coated urea and stabilized urea. Other types of nitrogen in this type include ammonium sulfate and ammonium nitrate.

Pros:

• Inexpensive;
• Quick color response after application;
• Available in granular, water-soluble or liquid form;
• Work better in low temperatures.

Cons:

• Won&#;t last long so you must reapply more often;
• Leaches through the soil more easily;
• Damages your lawn if misapplied

Examples of this type are Jonathan Green Veri-Green Nitrogen Fertilizer and Scotts Turf Builder.

Under Derived from, look for urea, polymer-coated sulfur-coated urea, ammonium sulfate and ammonium nitrate. Also, look for added enhancers like dicyandiamide and NBPT.

Urea-based lawn fertilizers can be found anywhere you purchase lawn and garden products.

Who should buy this?

Homeowners looking for an economical alternative to fertilizing their lawns and immediate greening should buy this type. It can be used on all kinds of lawn grasses.

Extended-Release Fertilizers

These contain nitrogen sources that last longer than urea-based sources, though they may contain some urea. By coating urea with a resin or changing its chemical makeup, you can extend the time it feeds your lawn. Think of them as fertilizers on cruise control.

Pros:

• No need to fertilize as often;
• Less fertilizer leaches through the soil;
• Release more predictable with less growth surge;
• More environmentally friendly.

Cons:

• More expensive;
• Don&#;t work as well in cool temperatures;
• Won&#;t give quick spring green-up response

One of my all-time favorites is The Andersons Professional 16-0-8. It contains methylene-urea, a slow-release nitrogen source with the bonus of 12% humic acid. This feeds beneficial organisms in the soil, making it a healthier medium to grow anything, including lawn grasses.

Other lawn fertilizers containing polymer-coated urea can provide up to six months of nitrogen. These offer some of the best options but are difficult to find. Look for brand names like Polyon, Duration or EPEC.

Under Derived from, look for polymer-coated urea, methylene-urea and urea-formaldehyde.

Who should buy this?

Those who don&#;t like fertilizing their lawn any more than they have to should use this type. It lasts a long time. And if you&#;re a consumer looking for the best value rather than the cheapest price, this one&#;s for you.

Natural Organic Fertilizers

This type is generally derived from natural sources like composted manures, biosolids or &#; the best overall &#; meal-based nutrients containing blood meal, bone meal, meat meal and feather meal. They provide a slower, more gentle feeding. They&#;re also safe for people, pets and other two- and four-legged critters.

Pros:

• Most environmentally friendly choice;
• Can be used year-round;
• Won&#;t burn your grass;
• Improves soil health by feeding beneficial microbes.

Cons:

• More expensive;
• Low amounts of nutrients in the bag so you need to use more;
• Unique odor that some find offensive.

Natural organic fertilizers are fairly easy to find. Look for meal-based options like Scotts Natural Lawn Food or Safer Brand Lawn Restore Natural Lawn Fertilizer. Both contain quality ingredients.

Poultry manure-type organic fertilizers are also good, although they can be trickier to handle due to potential damage to turf if over-applied. They may also smell bad. Check out options like Espoma Organic Chicken Manure or Sustane Organic & Natural Plant Food.

Organic fertilizers containing biosolids are another option. These contain processed sewage sludge and can be used on lawns as well as in most gardens. Milorganite and EcoScraps Slow-Release Fertilizer are worth a look.

Under Derived from, look for biosolids, composted turkey or chicken litter and meals (bone, blood, meat, feather, soybean, alfalfa).

Who should buy this?

Environmentally conscious homeowners should use these fertilizers. If you have kids or pets, this one is potentially less harmful if ingested, or if it comes in contact with skin or fur.

Combination Fertilizers Plus Weed Control

If convenience is a priority, consider controlling weeds at the same time you fertilize your lawn. Generally, the fertilizers in these combo products are quick-release. Besides feeding your lawn, these products can also prevent crabgrass from attacking it. Many kill existing broadleaf weeds like dandelions and clover.

Pros:

• Convenience. You&#;re getting rid of weeds while feeding your lawn.
• They offer a safer way to apply lawn chemicals because they&#;re less concentrated, and there&#;s less human exposure during application. These also don&#;t drift on windy days, offering less chance of damaging nearby shrubs and flowers.

Cons:

• Herbicide combined with fertilizer doesn&#;t work as well as when you apply it separately as a spray.
• Requires careful timing to best fit weed growth, not turf growth.
• More expensive.

Fertilizers with crabgrass preventers like Scotts Turf Builder with Halts and Greenview Lawn Food Crabgrass Control use different types of pre-emergent herbicides. Both do a great job controlling crabgrass.

Other weed-and-feed type fertilizers will control broadleaf weeds like dandelions, clover and other nuisances. A good one is Scotts Turf Builder Weed and Feed. Other combination products include a crabgrass preventer and broadleaf weed killer. A great example is Greenview&#;s Spring Fertilizer Weed & Feed with Crabgrass Preventer.

Under Derived from, look for urea and polymer-coated sulfur-coated urea.

Who should buy this?

Homeowners looking for convenience should use these. They&#;re convenient because you&#;re eliminating weeds at the same time you&#;re feeding your lawn.

&#;

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Urea Composition and Transformation  in the Field

In common with most commercial nitrogen fertilizers, urea is manufactured from anhydrous ammonia (NH3). The high analysis of urea&#;46% N&#;is the main reason for the low cost of this form of nitrogen fertilizer. Freight costs and storage and handling are all lower than with lower analysis fertilizers such as ammonium nitrate (34-0-0) or ammonium sulfate (21-0-0).

When field applied, urea changes to ammonium bicarbonate. This is a natural process resulting from the activity of the enzyme urease. Chemically the reaction is:

(NH2)CO + 2H2O ))) NH4HCO3 + OH-

This chemical reaction takes place after the urea is dissolved in water and will be complete within about 48 hours under field conditions. The water solution in which the reaction takes place has an alkaline pH, to as high as 8.5, and the ammonium (NH4+) tends to convert to ammonia gas (NH3). This gas will volatilize to the air if not protected. Urea placed on the soil surface or plant foliage may loose from 50% to 90% of its N as ammonia if not protected within a few hours of application.

Conserving Urea-N

If the urea-to-NH4 reaction takes place in the soil the nitrogen will be captured as exchangeable ammonium on the soil exchange complex and little if any loss of ammonia gas to the air will occur. Therefore, the key to conserving urea fertilizer nitrogen is to put the urea into the soil and not merely on the soil.

Soil incorporation of urea can be done several ways. Since urea is completely water soluble, when applied to the soil surface it can be moved down with irrigation water or rainfall, if one or the other occurs immediately after fertilization. Also, urea can be broadcast and plowed down immediately. And urea can be injected or banded into the soil.

Soil banding or injection is usually not feasible with an established crop such as pasture. Under these conditions the nitrogen fertilizer of choice would be either ammonium nitrate, ammonium sulfate, or one of the ammoniated phosphates (for example 11-52-0).

Urea is applied alone or in combination with other fertilizers. It is available in solid prills and in water solution. The latter includes a 50-50 mix of urea and ammonium nitrate, which is sold under various trade names and is guaranteed at 32% nitrogen (32-0-0). The urea-to-NH4 transformation will take place regardless of whether another nitrogen form or other fertilizer element is present in the fertilizer.

Summary

Urea is a low cost nitrogen fertilizer form. This is because of its high nitrogen composition and consequent low transport and storage costs. Urea may be the fertilizer of choice when only nitrogen is needed in a soil fertility program.

Urea converts to ammonium bicarbonate within about 48 hours after field application. Nitrogen in this form will tend to volatilize to the air as ammonia gas. This lost fertilizer investment risk can be minimized or eliminated by assuring that the urea gets into the soil and does not merely remain on the surface of the soil or crop foliage. This can be accomplished by irrigating in the urea; by plowdown soon after surface broadcast application; or by banding or injecting the urea directly into the soil.

Authors

D. W. James, Extension Soils Specialist

There are so many choices that "analysis by paralysis" can take over. Let's make it easier.

I&#;ve been in the business of helping professionals manage natural grass surfaces for more than 40 years. These pros grow grass for a living &#; sports turf managers for high school, municipality, university and professional teams; golf course superintendents; and lawn care managers.

But when the U.S. Environmental Protection Agency says Americans buy 70 million pounds of fertilizers every year, that&#;s staggering, even for me.

In the past 25 years, technological advancements shaped fertilizer products and how we use them. Today, they&#;re much more efficient, safer for the environment and easier to use.

Visiting your local garden center or big box store to purchase lawn fertilizer can be daunting, with seemingly endless choices. Most of the confusion stems from marketing efforts by manufacturers trying to find a niche that differentiates their product from others. So let&#;s try to simplify and look at the options in four easy-to-grasp categories.

Note: Lawn fertilizer packaging must show the contents of the product. It&#;s the law and this information appears on the front or back of the bag as the Guaranteed Analysis. Toward the bottom of this section, you&#;ll find a statement beginning with the phrase &#;Derived from.&#; This includes the nutrient sources.

Quick-Release Fertilizers

This group represents the lion&#;s share of residential lawn fertilizers. (They&#;re also the mainstream type used by professionals.) They consist mostly of urea-based nitrogen sources, including straight urea, sulfur-coated urea and stabilized urea. Other types of nitrogen in this type include ammonium sulfate and ammonium nitrate.

Pros:

• Inexpensive;
• Quick color response after application;
• Available in granular, water-soluble or liquid form;
• Work better in low temperatures.

Cons:

• Won&#;t last long so you must reapply more often;
• Leaches through the soil more easily;
• Damages your lawn if misapplied

Examples of this type are Jonathan Green Veri-Green Nitrogen Fertilizer and Scotts Turf Builder.

Under Derived from, look for urea, polymer-coated sulfur-coated urea, ammonium sulfate and ammonium nitrate. Also, look for added enhancers like dicyandiamide and NBPT.

Urea-based lawn fertilizers can be found anywhere you purchase lawn and garden products.

Who should buy this?

Homeowners looking for an economical alternative to fertilizing their lawns and immediate greening should buy this type. It can be used on all kinds of lawn grasses.

Extended-Release Fertilizers

These contain nitrogen sources that last longer than urea-based sources, though they may contain some urea. By coating urea with a resin or changing its chemical makeup, you can extend the time it feeds your lawn. Think of them as fertilizers on cruise control.

The company is the world’s best npk 20 20 20 te fertilizer supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.

Pros:

• No need to fertilize as often;
• Less fertilizer leaches through the soil;
• Release more predictable with less growth surge;
• More environmentally friendly.

Cons:

• More expensive;
• Don&#;t work as well in cool temperatures;
• Won&#;t give quick spring green-up response

One of my all-time favorites is The Andersons Professional 16-0-8. It contains methylene-urea, a slow-release nitrogen source with the bonus of 12% humic acid. This feeds beneficial organisms in the soil, making it a healthier medium to grow anything, including lawn grasses.

Other lawn fertilizers containing polymer-coated urea can provide up to six months of nitrogen. These offer some of the best options but are difficult to find. Look for brand names like Polyon, Duration or EPEC.

Under Derived from, look for polymer-coated urea, methylene-urea and urea-formaldehyde.

Who should buy this?

Those who don&#;t like fertilizing their lawn any more than they have to should use this type. It lasts a long time. And if you&#;re a consumer looking for the best value rather than the cheapest price, this one&#;s for you.

Natural Organic Fertilizers

This type is generally derived from natural sources like composted manures, biosolids or &#; the best overall &#; meal-based nutrients containing blood meal, bone meal, meat meal and feather meal. They provide a slower, more gentle feeding. They&#;re also safe for people, pets and other two- and four-legged critters.

Pros:

• Most environmentally friendly choice;
• Can be used year-round;
• Won&#;t burn your grass;
• Improves soil health by feeding beneficial microbes.

Cons:

• More expensive;
• Low amounts of nutrients in the bag so you need to use more;
• Unique odor that some find offensive.

Natural organic fertilizers are fairly easy to find. Look for meal-based options like Scotts Natural Lawn Food or Safer Brand Lawn Restore Natural Lawn Fertilizer. Both contain quality ingredients.

Poultry manure-type organic fertilizers are also good, although they can be trickier to handle due to potential damage to turf if over-applied. They may also smell bad. Check out options like Espoma Organic Chicken Manure or Sustane Organic & Natural Plant Food.

Organic fertilizers containing biosolids are another option. These contain processed sewage sludge and can be used on lawns as well as in most gardens. Milorganite and EcoScraps Slow-Release Fertilizer are worth a look.

Under Derived from, look for biosolids, composted turkey or chicken litter and meals (bone, blood, meat, feather, soybean, alfalfa).

Who should buy this?

Environmentally conscious homeowners should use these fertilizers. If you have kids or pets, this one is potentially less harmful if ingested, or if it comes in contact with skin or fur.

Combination Fertilizers Plus Weed Control

If convenience is a priority, consider controlling weeds at the same time you fertilize your lawn. Generally, the fertilizers in these combo products are quick-release. Besides feeding your lawn, these products can also prevent crabgrass from attacking it. Many kill existing broadleaf weeds like dandelions and clover.

Pros:

• Convenience. You&#;re getting rid of weeds while feeding your lawn.
• They offer a safer way to apply lawn chemicals because they&#;re less concentrated, and there&#;s less human exposure during application. These also don&#;t drift on windy days, offering less chance of damaging nearby shrubs and flowers.

Cons:

• Herbicide combined with fertilizer doesn&#;t work as well as when you apply it separately as a spray.
• Requires careful timing to best fit weed growth, not turf growth.
• More expensive.

Fertilizers with crabgrass preventers like Scotts Turf Builder with Halts and Greenview Lawn Food Crabgrass Control use different types of pre-emergent herbicides. Both do a great job controlling crabgrass.

Other weed-and-feed type fertilizers will control broadleaf weeds like dandelions, clover and other nuisances. A good one is Scotts Turf Builder Weed and Feed. Other combination products include a crabgrass preventer and broadleaf weed killer. A great example is Greenview&#;s Spring Fertilizer Weed & Feed with Crabgrass Preventer.

Under Derived from, look for urea and polymer-coated sulfur-coated urea.

Who should buy this?

Homeowners looking for convenience should use these. They&#;re convenient because you&#;re eliminating weeds at the same time you&#;re feeding your lawn.

&#;

If you are looking for more details, kindly visit water based fertilizer.