| Slow Release Nitrogen
Fertilizers
What is Nitroform®?
The Advantages of Nitroform
Nitroform is a 38-0-0 methylene urea nitrogen source
produced by reacting urea and formaldehyde under carefully controlled
conditions, creating intermediate and long-chain polymers of methylene
ureas, collectively called ureaform. About one-third of the nitrogen
in Nitroform is composed of the short-chain water-soluble methylene
urea polymers accompanied by a slight amount of urea.
The majority of Nitroform nitrogen—about
70 percent—is water-insoluble. This water-insoluble fraction
results in good residual plant response. Release of nitrogen from
Nitroform depends on soil microorganisms.
However, even in low organic soils, Nitroform encourages the buildup
of soil bacteria by providing sustained food (nitrogen) and energy
(carbon) to soil microorganisms. They, in turn, convert the water-insoluble
nitrogen fractions back to available nitrogen over the course of
the growing season. A small amount may carry over and be converted
in the subsequent growing season.
All of the carbon in any of the methylene urea
sources may serve as an energy source for soil microorganisms. Carbon
from urea-based, slow-release fertilizers such as IB and coated
ureas is converted immediately to carbon dioxide by hydrolysis.
As such, it is useless as an energy source for the vast majority
of soil microbes. Microbial activity and nitrogen release work hand-in-hand.
Factors affecting microbial activity, such as soil temperature,
moisture, pH, and aeration, also affect nitrogen release. If conditions
are unfavorable for microbial activity, nitrogen will be released
more slowly. But microbial activity usually occurs during times
when plants are actively growing, and slows down when plants stop
growing. So, in short, Nitroform releases nitrogen only when plants
can best utilize it.
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Applying Nitroform to a soil system inherently
low in microorganisms will provide the carbon and nitrogen necessary
to build up the numbers and sustain a good population over a long
period of time. More and more research indicates that maintaining
a healthy, active soil microorganism population helps turf withstand
stresses of all types—disease, insects, heat, traffic and
drought.
All plants have optimum temperatures for growth.
While these temperatures vary by species, in general plant functions
tend to decline at approximately 50 degrees F and 100 degrees F.
As plant function decreases so do nutritional requirements.
Reacted nitrogen sources (Nutralene, Nitroform)
are converted to plant usable nitrate nitrogen by soil microorganisms.
Their conversion is in synchronization, by design of nature, with
plant requirements. As plant demand increases with temperature to
its optimum, so does conversion as microorganisms become increasingly
active. This is the single most important benefit from reacted sources.
Because nitrate conversion is largely completed by microorganisms
versus plant demand, leaching potential is minimal. Why? The plant
is able to uptake nitrogen to meet its needs; excess nitrogen (nitrates)
are not converted and potentially lost.
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What is Nutralene®?
The Advantages of Nutralene
 Nutralene
is an advanced short-chain methylene urea, which offers the advantages
of both water-soluble and slow-release nitrogen. It provides a guaranteed
analysis of 40-0-0. As a controlled-release reacted methylene urea
polymer, Nutralene’s dual release mechanisms give the turf
and ornamental professional a three-fold advantage. First, water-soluble
nitrogen is released in the first four weeks, followed by six weeks
of slowly available water-soluble nitrogen, and further reinforced
with six weeks of water-insoluble nitrogen (WIN).
The unique dual action release of Nutralene gives
the professional a number of important advantages. Hydrolysis
releases nitrogen quickly so turf and other plants can get a boost
at the start of the growing season. Microbial
activity then releases nitrogen more slowly for more sustained
feeding. As a result, the plant professional is assured of twelve
(12) to sixteen (16) weeks of controlled release and sustained plant
growth under a broad range of environmental conditions. Furthermore,
Nutralene offers the professional the significant benefit of enriching
soil microbiology throughout its total release period.
Because of its release characteristics, Nutralene
also provides an excellent nitrogen source in cooler temperatures.
Its low salt index means it won’t burn turf and sensitive
ornamentals even during hot dry weather. You can count of Nutralene
for uniform sustained feeding even after heavy rains due in part
to slowly available water-soluble nitrogen (SAWSN) and water-insoluble
nitrogen (WIN). And unlike other controlled-release nitrogen sources,
Nutralene is not dependent on a coating or particle size for nitrogen
release. Its ability to resist leaching and volatilization results
in extremely low nitrogen loss from these causes. Application of
Nutralene is easy, as particles will not fracture when applied through
standard equipment.
Nutralene will not produce flushes of growth, which
lead to excessive amounts of clippings. As turf professionals know,
excessive clippings create excessive disposal problems and loss
of nitrogen in the leaf blade.
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What is SCU?
The Advantages of SCU
Sulfur Coated Urea, commonly known as SCU,
is recognized as an economical source of relatively short residual
nitrogen. Regardless of application, ranging from professional lawn
care, golf, specialty agriculture and consumer markets, SCU can
provide quick plant response.
Developed in the late 1950s and early 1960s by
the Tennessee Valley Authority, SCU quickly became the product of
choice for nitrogen. It offered improved performance versus the
most common nitrogen sources including urea. Better residual meant
fewer applications, thus saving money and reducing possible plant
injury. However, as new nitrogen sources were developed such as
ureaform and methylene urea, which offered still improved performance,
SCU usage changed.
SCU is manufactured by coating
a urea substrate first with sulfur, then with a sealant. This sealant
may be a resin or various types of polymer (plastic) (PSCU) coatings
such as polyurethane. The thickness and type of coating determines
the length of release.
The nitrogen release process starts as soil
microorganisms and soil moisture begin to erode the coating.
Soil temperature is also a major factor in releasing its nitrogen.
This fact may make coated products not a good choice for application
in certain climactic conditions.
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What is IB® Nitrogen?
The Advantages of IB® Nitrogen
Isobutylidenediurea, commonly known as IBDU or
IB nitrogen, is considered by many to be the industry standard for
hydrolysis released, reacted nitrogen sources. Developed in Japan
in the late 1960s for the fertilization of rice, IB nitrogen remains
a highly effective nutrient for fertilization applications ranging
from professional turf, to nursery & ornamentals and specialty
agriculture.
IB nitrogen is a controlled-release nitrogen source
made by reacting isobutylidene and urea to form a precipitate, with
the end product being granular IB suitable for blending or direct
applications.
Although IB is defined as controlled-release
and having 90% water-insoluble nitrogen, its release is totally
dependent upon hydrolysis. How
is this possible?
The release rate of .02 grams per 100-ml.water
is very specific; it involves the concentration of water on the
surface of the particle. You could envision a bar of soap in water.
Only so much of the soap dissolves—you must keep replacing
the water to further dissolve the soap.
Because IB nitrogen releases only by hydrolysis
it is ideal for fall/winter applications. Although topical growth
may cease as temperatures fall, root growth continues thus the need
for nutrients continue, as carbohydrates are produced and stored.
Mineralization, the process of forming plant usable nitrates or
ammonium, is similar for all nitrogen as they are urea based. Mineralization
is determined by first dissolution then chemical hydrolysis. Once
IB is solublized it is then gradually converted into urea.
Because IB is released by hydrolysis, and that
rate is dependent upon concentration on the surface, the size of
the particle does affect release rates. Simply stated, the larger
the particle the slower the release. It is a matter of surface area.
Similarly, soil moisture also affects release.
Again, IB is released by hydrolysis thus the higher the moisture
content, the faster the release.
Temperature also affects its release, which
is a desirable performance characteristic. Because mineralization
continues even at low soil temperatures, it is ideal for fall/winter
feeding mentioned above. Soil pH is not a significant factor in
release.
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