Agriculture Reference
In-Depth Information
We need to add
69 ppm
of Sulfur S.
Chlorine Cl and Potassium Chloride KCl Fertilizer
Chlorine is an essential nutrient for plants, animals, and people, but it is not
measured on a standard soil test. Under natural conditions Chlorine in supplied
from the breakdown of chloride minerals in the soil such as Sodium or Potassium
chloride. Cl is also naturally found in rainwater, especially near seacoasts.Areas
far from the ocean such as mid-continent areas may have little natural Cl in the
atmosphere or rain but may still have significant amounts derived from burning
fossil fuels.
Chlorine deficiency is rare in most agricultural soils today; chlorine excess is much
more common, due to using chlorinated water for irrigation or even more
commonly, Potassium chloride fertilizers. Most commercial fertilizers that contain
Potassium are formulated with Potassium chloride, KCl, because it is cheap and
readily available. It is also effective in the short term, giving a strong growth
response. However, in large amounts it is toxic to soil organisms, from bacteria to
earthworms. Use of KCl will also prematurely age the clay in the soil, reducing the
exchange capacity.
Another major drawback is that KCl fertilizer can rapidly deplete the upper soil
layers of Calcium. In the soil the K+ can exchange for Ca++ on a negative - site
(or KCl can react with free Ca or with lime present in the soil), releasing a Calcium
ion, but that Ca++ ion may immediately bond with the Chlorine ion from the KCl,
forming Calcium chloride CaCl
2
. Calcium chloride is highly water soluble and will
easily leach to a lower soil horizon.
It is impossible to have a healthy, living soil if Potassium chloride is being used in
large quantities, e.g. more than 20% of K supply. Potassium sulfate, while more
expensive, does not harm the soil life. Potassium sulfate is allowed for Certified
Organic use by the USDANational Organic Program. Potassium chloride is not
allowed.
From the Ideal Soil Chart
Chlorine (Cl)- min 25ppm 1x to 2x Sodium Essential, but ages clays rapidly when used in large
amounts
The simplest way to ensure adequate Chlorine in the soil is to add regular salt,
Sodium chloride NaCl. Sea salt, mineral salts like Redmond's, or even table salt.
NaCl is 40% Sodium and 60% Chlorine.
If there is reason to believe the soil needs more Chlorine, but the soil already
contains adequate or high levels of Na, or if amendments like Sodium nitrate are to
