![](media/image1.png){width="6.5in" height="0.6in"}Natural Resources
Conservation Service

6200 Jefferson NE

Albuquerque, New Mexico 87109

**Phone**: (505) 761-4400 **Fax**: (505) 761-4462

**Web site**: [www.nm.nrcs.usda.gov]{.underline}

[\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_]{.underline}

October 7, 2004

**New Mexico AGRONOMY TECHNICAL NOTE NO.71**

**SUBJECT: ECS -- fertilizer "jar test"**

**[Purpose]{.underline}**: To distribute an Agronomy Technical Note No.
71.

**[Effective Date]{.underline}**: Maintained on web page.

**[Filing Instructions]{.underline}:** Discard when noted.

Attached is Agronomy Technical Note 71. Refer to this technical note
when injecting new fertilizer solution into a drip system.

KENNETH B. LEITING

State Resource Conservationist

Attachment

Dist:

AC (4)

DC (37)

Ecological Sciences Division, Washington, DC (2)

Adjoining States --- UT, CO, TX, OK, AZ (1 each)

Technical Services (1 file)

![](media/image2.png)

TECHNICAL NOTES

U.S. DEPARTMENT OF AGRICULTURE NATURAL RESOURCES CONSERVATION SERVICE

NEW MEXICO October, 2004

**AGRONOMY TECHNICAL NOTE NO. 71**

**FERTILIZER "JAR TEST"**

Before you inject a new fertilizer solution into your drip system,
always perform a \"jar test\". This will help you avoid annoying and
unnecessary line or emitter clogging due to fertilizer incompatibility.

Whether you begin with water-soluble or liquid fertilizers, dissolved
chemicals such as phosphates, calcium, and magnesium can react together
or with the irrigation water. This can lead to insoluble chemical
combinations precipitating in the water. These precipitates can clog the
emitters. There are also fertilizer compatibility charts available, such
as the one below. But they may not list the fertilizers you are
considering to use.

The \"jar test\" is easy. If you can prepare a half-decent
shaken-not-stirred-Bond martini, you are well on your way. The key is to
approximate the dilution rate that you expect to be injecting through
the drip system. This jar test method comes from the Irrigation Training
and Research Centre fertigation manual

To get started you will need:

1\. the injection rate (gal per hr)

2\. the drip system delivery rate (gal per hr)

3\. the stock fertilizer or fertilizer combinations that you will be
using (stock solution to water applied ratio)

4\. a jar with a sealing lid

5\. the water that you use for irrigating (use the buffer (6.5pH)
irrigation water)

For example, a fertilizer stock solution is injected at a rate of 30
gallons per hour and delivered at a rate of 1200 gallons per minute.

**Step one:**

Convert system delivery rate from gallons per minute to gallons per
hour.

> *1200 gallons per minute X 60 minutes = 72,000 gallons per hour.*

**Step two:**

Calculate the dilution ratio. This is ratio of the injection rate to the
delivery rate.

*30 gallons per hour: 72,000 gallons per hour = 1:2,400 (72,000 divided
by 30 = 2,400)*

**Step three:**

> Add fertilizer stock solution and irrigation water into the jar at the
> same dilution ratio, 1:2400. Do this by adding 1 mL of fertilizer
> stock solution to 2400 mL or 2.41- of the irrigation water. Hopefully
> your jar wasn\'t too small. Always wear protective clothing and safety
> glasses when performing any jar test.

**Step four:**

Tighten the lid and shake it up!

**Step five:**

> Watch what happens. Does any precipitate form on the bottom of the
> jar? Does the water become milky or cloudy? If this happens within one
> or two hours after mixing, there is a chance that the fertilizer
> solution or combination of fertilizers could cause line or emitter
> plugging.
>
> Whether you begin with liquid or dissolved water-soluble fertilizers,
> you need to be aware of fertilizer compatibility. So before you mix it
> up, give it a shake.

Fertilizer "Jar Test" Page 2 of 3

Fertilizer compatibility chart (B.C. Trickle Irrigation Manual, 1999)

+----------+---+---------+---------+------+-------+-------+--------+
| urea     | u | A       | A       | Cal  | Pota  | Pota  | Pot    |
|          | r | mmonium | mmonium | cium | ssium | ssium | assium |
|          | e |         |         |      |       |       |        |
|          | a | nitrate | s       | nit  | ni    | chl   | su     |
|          |   |         | ulphate | rate | trate | oride | lphate |
+----------+---+---------+---------+------+-------+-------+--------+
|          |   |         |         |      |       |       |        |
+----------+---+---------+---------+------+-------+-------+--------+
| Ammonium |   |         |         |      |       |       |        |
|          |   |         |         |      |       |       |        |
| nitrate  |   |         |         |      |       |       |        |
+----------+---+---------+---------+------+-------+-------+--------+
| Ammonium |   |         |         |      |       |       |        |
|          |   |         |         |      |       |       |        |
| sulphate |   |         |         |      |       |       |        |
+----------+---+---------+---------+------+-------+-------+--------+
| Calcium  |   |         | **xx**  |      |       |       |        |
|          |   |         |         |      |       |       |        |
| nitrate  |   |         |         |      |       |       |        |
+----------+---+---------+---------+------+-------+-------+--------+
| Po       |   |         |         |      |       |       |        |
| tassium, |   |         |         |      |       |       |        |
|          |   |         |         |      |       |       |        |
| nitrate  |   |         |         |      |       |       |        |
+----------+---+---------+---------+------+-------+-------+--------+
| P        |   |         |         |      |       |       |        |
| otassium |   |         |         |      |       |       |        |
|          |   |         |         |      |       |       |        |
| chloride |   |         |         |      |       |       |        |
+----------+---+---------+---------+------+-------+-------+--------+
| P        |   |         | **x**   | **   |       | **x** |        |
| otassium |   |         |         | xx** |       |       |        |
| sulphate |   |         |         |      |       |       |        |
+----------+---+---------+---------+------+-------+-------+--------+
| Ammonium |   |         |         | **   |       |       |        |
|          |   |         |         | xx** |       |       |        |
| p        |   |         |         |      |       |       |        |
| hosphate |   |         |         |      |       |       |        |
+----------+---+---------+---------+------+-------+-------+--------+
| Iron,    |   |         |         | **   |       |       | **x**  |
| zinc,    |   |         |         | xx** |       |       |        |
| copper,  |   |         |         |      |       |       |        |
| m        |   |         |         |      |       |       |        |
| anganese |   |         |         |      |       |       |        |
|          |   |         |         |      |       |       |        |
| sulphate |   |         |         |      |       |       |        |
+----------+---+---------+---------+------+-------+-------+--------+
| Iron,    |   |         |         | *    |       |       |        |
| zinc,    |   |         |         | *x** |       |       |        |
| copper,  |   |         |         |      |       |       |        |
| ma       |   |         |         |      |       |       |        |
| nganese, |   |         |         |      |       |       |        |
| chelate  |   |         |         |      |       |       |        |
+----------+---+---------+---------+------+-------+-------+--------+
| M        |   |         |         | **   |       |       | **x**  |
| agnesium |   |         |         | xx** |       |       |        |
| sulphate |   |         |         |      |       |       |        |
+----------+---+---------+---------+------+-------+-------+--------+
| Ph       |   |         |         | **   |       |       |        |
| osphoric |   |         |         | xx** |       |       |        |
| acid     |   |         |         |      |       |       |        |
+----------+---+---------+---------+------+-------+-------+--------+
| S        |   |         |         | **   |       |       | **x**  |
| ulphuric |   |         |         | xx** |       |       |        |
| acid     |   |         |         |      |       |       |        |
+----------+---+---------+---------+------+-------+-------+--------+
| Nitric   |   |         |         |      |       |       |        |
| acid     |   |         |         |      |       |       |        |
+----------+---+---------+---------+------+-------+-------+--------+

Fully compatible - y

Reduced solubility - X

Incompatible - XX

Fertilizer "Jar Test" Page 3 of 3

Fertilizer compatibility chart (B.C. Trickle Irrigation Manual, 1999)

+----------+-------+---------+---------+-------+--------+------+----+
| urea     | Amm   | Iron,   | Iron,   | Magn  | Phos   | S    | >  |
|          | onium | zinc,   | zinc,   | esium | phoric | ulph | Ni |
|          |       |         |         |       |        | uric | tr |
|          | phos  | copper, | copper, | sul   | acid   |      | ic |
|          | phate |         |         | phate |        | acid | >  |
|          |       | ma      | ma      |       |        |      | >  |
|          |       | nganese | nganese |       |        |      | ac |
|          |       |         |         |       |        |      | id |
|          |       | [       | chelate |       |        |      |    |
|          |       | sulphat |         |       |        |      |    |
|          |       | e]{.und |         |       |        |      |    |
|          |       | erline} |         |       |        |      |    |
+----------+-------+---------+---------+-------+--------+------+----+
|          |       |         |         |       |        |      |    |
+----------+-------+---------+---------+-------+--------+------+----+
| Ammonium |       |         |         |       |        |      |    |
|          |       |         |         |       |        |      |    |
| nitrate  |       |         |         |       |        |      |    |
+----------+-------+---------+---------+-------+--------+------+----+
| Ammonium |       |         |         |       |        |      |    |
|          |       |         |         |       |        |      |    |
| sulphate |       |         |         |       |        |      |    |
+----------+-------+---------+---------+-------+--------+------+----+
| Calcium  |       |         |         |       |        |      |    |
|          |       |         |         |       |        |      |    |
| nitrate  |       |         |         |       |        |      |    |
+----------+-------+---------+---------+-------+--------+------+----+
| P        |       |         |         |       |        |      |    |
| otassium |       |         |         |       |        |      |    |
|          |       |         |         |       |        |      |    |
| nitrate  |       |         |         |       |        |      |    |
+----------+-------+---------+---------+-------+--------+------+----+
| P        |       |         |         |       |        |      |    |
| otassium |       |         |         |       |        |      |    |
|          |       |         |         |       |        |      |    |
| chloride |       |         |         |       |        |      |    |
+----------+-------+---------+---------+-------+--------+------+----+
| > P      |       |         |         |       |        |      |    |
| otassium |       |         |         |       |        |      |    |
|          |       |         |         |       |        |      |    |
| sulphate |       |         |         |       |        |      |    |
+----------+-------+---------+---------+-------+--------+------+----+
| Ammonium |       |         |         |       |        |      |    |
|          |       |         |         |       |        |      |    |
| p        |       |         |         |       |        |      |    |
| hosphate |       |         |         |       |        |      |    |
+----------+-------+---------+---------+-------+--------+------+----+
| Iron,    | *     |         |         |       |        |      |    |
| zinc,    | *xx** |         |         |       |        |      |    |
|          |       |         |         |       |        |      |    |
| copper,  |       |         |         |       |        |      |    |
|          |       |         |         |       |        |      |    |
| m        |       |         |         |       |        |      |    |
| anganese |       |         |         |       |        |      |    |
|          |       |         |         |       |        |      |    |
| sulphate |       |         |         |       |        |      |    |
+----------+-------+---------+---------+-------+--------+------+----+
| Iron,    | **x** |         |         |       |        |      |    |
| zinc,    |       |         |         |       |        |      |    |
|          |       |         |         |       |        |      |    |
| copper,  |       |         |         |       |        |      |    |
|          |       |         |         |       |        |      |    |
| m        |       |         |         |       |        |      |    |
| anganese |       |         |         |       |        |      |    |
|          |       |         |         |       |        |      |    |
| chelate  |       |         |         |       |        |      |    |
+----------+-------+---------+---------+-------+--------+------+----+
| M        | *     |         |         |       |        |      |    |
| agnesium | *xx** |         |         |       |        |      |    |
| sulphate |       |         |         |       |        |      |    |
+----------+-------+---------+---------+-------+--------+------+----+
| Ph       |       |         | **x**   |       |        |      |    |
| osphoric |       |         |         |       |        |      |    |
|          |       |         |         |       |        |      |    |
| acid     |       |         |         |       |        |      |    |
+----------+-------+---------+---------+-------+--------+------+----+
| S        |       |         |         |       |        |      |    |
| ulphuric |       |         |         |       |        |      |    |
| acid     |       |         |         |       |        |      |    |
+----------+-------+---------+---------+-------+--------+------+----+
| Nitric   |       |         | **xx**  |       |        |      |    |
| acid     |       |         |         |       |        |      |    |
+----------+-------+---------+---------+-------+--------+------+----+

Fully compatible - y

Reduced solubility - X

Incompatible - XX