Hanna Instruments HI 38050 - Manual (Page 4)

4
Nitrogen (N) is an indispensable element for plant life. It is present in proteins,
vitamins, chlorophyll, etc. Nitrogen allows the development of the vegetative activity
of the plant, in particular, causes a lengthening of trunks and sprouts and increases
the production of foliage and fruit. It directly increases the crop yield, though the crop
quality depends on other elements.
Nitrogen, mostly absorbed by plants as nitrate (NO
3
- ), derives from the mineralization
of organic matter and the application of fertilizers. Nitrate-nitrogen is not durable in
soil. The large amount required for crop production, makes it necessary to administer
this element in moderate quantities during the crop growth season.
An excess of Nitrogen weakens plants' structure creating an unbalanced relationship
between the green and wooden parts. In addition, the plant becomes less resistant to
diseases. Furthermore excessive nitrogen fertilization can contaminate groundwater
and cause environmental problems.
The Hanna Nitrate Test Kit for Soil and Irrigation Water makes it possible to
determine the need for nitrogen fertilization. It also obtains the best crop response
and avoids over-fertilization.
Nitrogen is the most abundant element present on our planet and can be found in
many different forms. Only a very small part of the total nitrogen is available for
plant growth. The exchanges between available and unavailable nitrogen combine to
form a complex system which is called the nitrogen cycle.
INTRODUCTION
THE NITROGEN CYCLE
9
READ THE ENTIRE INSTRUCTIONS BEFORE USING THE KIT
1- Using the plastic pipette, fill each glass vial with 5 mL of
water sample (up to the mark).
2- Insert one of them into the left hand opening of the
checker disc. This is the blank.
3- Add to the other glass vial
1 packet of HI 38050-0
reagent. Replace the cap,
shake vigorously for 1
minute and wait for 5 min-
utes. This is the reacted
sample.
4- Remove the cap and insert the reacted sample into
the right hand opening of the checker disc.
5- Hold the checker disc so that a light source illumi-
nates the samples from the back of the windows.
6- Keep the checker disc at a dis-
tance of 30-40 cm (12-16") from
the eyes to match the color. Ro-
tate the disc while looking at the
color test windows and stop when
you find the color match. Read
the value in the result window
directly in mg/L (ppm) of nitrate-
nitrogen (N-NO
3
- ). Multiply the reading by 4.43 to obtain mg/L of nitrate (NO
3
- ).
Note: Perform the reading three times and take the average value (divide by 3 the
sum of the three numbers).
TEST PROCEDURE
FOR DETERMINING
NITRATE IN
IRRIGATION WATER
5 mL