Agriculture Reference
In-Depth Information
addition microbial action is constantly changing NH
4
into NO
3
. Nitrogen is a
component of all proteins and amino acids. When living things die, their protein
breaks down and ammoniacal NH
4
is released. Nitrate Nitrogen is associated with
rapid growth while ammonia Nitrogen is associated with flowering, fruiting, and
plant maturity.
Having an optimum level of
Sulfur
is important to conserve N in the soil. In the
absence of adequate Sulfur, much of the ammonia N generated from the
breakdown of organic matter in the soil or in compost will off-gas to the air and be
lost.At the same time much of the Carbon will be lost as it off-gasses as CO
2
.
When optimum levels of S are present, a greater portion of N and C will be
incorporated into stable humus and remain in the soil. The recommended Sulfur
amount for the Ideal Soil method is ½ of Ideal Potassium, with a minimum of 50
ppm S for any productive agricultural soil.
The only way to get an accurate N test that will tell what is available in the soil right
now is to express mail a sample to the lab, or to use a home testing system such
as the LaMotte soil test, which is designed to measure only those elements
immediately available in the soil, not the amount of reserves.
Nitrogen requirements vary greatly due to climate and crop, and should be
addressed by individual crop needs. Some crops such as corn (maize) and alliums
(onions, leeks, garlic) benefit greatly from an N boost or two during the growing
season; for other crops this would only cause rank growth and delay flowering and
maturity. Most crops do well with around 40 to 50 ppm available N, split evenly
between nitrate and ammonia forms. (See Carey Reams'Ideal Soil recipe in the
appendix.)
The only naturally occurring mineral source of Nitrogen is
Chilean nitrate of soda
,
which contains around 16% N. It is a great source of natural N, especially in cold
soils, but should not be used for more than 25% of Nitrogen needs due to its high
level of Sodium. Chilean nitrate may not be allowed under some organic
certification rules. If your farm is Certified Organic, check with your certifying
agency before using Chilean nitrate.
The Ethics of Nitrogen in Organic Agriculture
Here are the N fertility inputs allowed under the USDANOP organic rules:
Blood meal
Fish meal
Bone meal
Feather meal
Animal manures
Chilean nitrate of soda
and
