Hanna Instruments hi 38050 User Manual
6
6) From this mixture, take the quantity of soil that you need for the analyses.
7) Crumble the large chunks and distribute the soil sample on plastic to air dry it. The
7) Crumble the large chunks and distribute the soil sample on plastic to air dry it. The
sample dries faster if a fan is used to move air across the sample.
8) Use a small bar to crush the air dried sample and pass it through the 2-mm soil sieve.
Do not store the samples longer than 24 hours in a closed plastic bag. Store the
sample in a cold place and out of direct sunlight, if it can not be dried immediately.
Do not expose the soil to direct sunlight or any heat font.
Do not store the samples longer than 24 hours in a closed plastic bag. Store the
sample in a cold place and out of direct sunlight, if it can not be dried immediately.
Do not expose the soil to direct sunlight or any heat font.
Before sowing or transferring plants, use a slow-acting fertilizer to enrich the soil for
the long term. Adding organic substances (such as manure and compost) helps to
increase the soil fertility. In case of lack of nitrogen during the crop growth season, use
fertilizers containing nitrate. If necessary add the fertilizer before sprouting or wheat
raising, or as a side dressing while crop is growing. Do not give nitrate at the end of
the plant cycle to crops such as lettuce (where the product is the vegetable part), in
order to avoid its accumulation in the leaves (nitrate is carcinogenic).
The quantity of fertilizer to be added to the soil depends not only on the chemical
state of the soil but also on factors such as present cultivation, local climate, the
physical structure and microbiological activities. If the soil is irrigated, also nitrate
dissolved in the water contributes to the nitrogen fertility (each ppm of a nutrient
dissolved corresponds to 5.0 kg/ha if 50 cm of irrigation water is applied), so does
natural precipitation (about 5-15 kg/ha a year average, up to 50-60 kg/ha in
industrialized areas).
the long term. Adding organic substances (such as manure and compost) helps to
increase the soil fertility. In case of lack of nitrogen during the crop growth season, use
fertilizers containing nitrate. If necessary add the fertilizer before sprouting or wheat
raising, or as a side dressing while crop is growing. Do not give nitrate at the end of
the plant cycle to crops such as lettuce (where the product is the vegetable part), in
order to avoid its accumulation in the leaves (nitrate is carcinogenic).
The quantity of fertilizer to be added to the soil depends not only on the chemical
state of the soil but also on factors such as present cultivation, local climate, the
physical structure and microbiological activities. If the soil is irrigated, also nitrate
dissolved in the water contributes to the nitrogen fertility (each ppm of a nutrient
dissolved corresponds to 5.0 kg/ha if 50 cm of irrigation water is applied), so does
natural precipitation (about 5-15 kg/ha a year average, up to 50-60 kg/ha in
industrialized areas).
Test results indicate the actual nitrate concentration and allow a fast intervention if the
concentration is insufficient for crop. If the test results are lower than 10 ppm N-NO
concentration is insufficient for crop. If the test results are lower than 10 ppm N-NO
3
(as mg/kg soil) early in the growing season, the nitrate-nitrogen should be considered
deficient and a yield reduction can be expected. A first intervention with a direct
available nitrate fertilizer (about 100 kg N/ha) is recommended.
The exact amount of fertilizer required depends on the type of crop. A nitrogen
concentration between 20 and 25 ppm, for example, is considered as optimal for corn.
Above 26 ppm, addition of more N-fertilizer is not likely to increase yield.
To adjust the nitrogen concentration above 10 ppm of N-NO
deficient and a yield reduction can be expected. A first intervention with a direct
available nitrate fertilizer (about 100 kg N/ha) is recommended.
The exact amount of fertilizer required depends on the type of crop. A nitrogen
concentration between 20 and 25 ppm, for example, is considered as optimal for corn.
Above 26 ppm, addition of more N-fertilizer is not likely to increase yield.
To adjust the nitrogen concentration above 10 ppm of N-NO
3
in soil, add 11 kg N/ha
of side-dressing, for each incremental ppm of nitrate-nitrogen concentration. See the
FERTILIZATION
RECOMMENDATIONS
RECOMMENDATIONS
7
Table below for the fertilizer recommendations for Corn.
soil N-NO
soil N-NO
3
(ppm) fertilizer
soil N-NO
3
(ppm) fertilizer
recommendation
recommendation
(kg N/ha)
(kg N/ha)
<10
100-150
18
32-92
10
120-180
19
21-81
11
109-169
20
10-70
12
98-158
21
9-59
13
87-147
22
0-48
14
76-136
23
0-37
15
65-125
24
0-26
16
54-114
25
0-15
17
43-108
26
0
If soil has been previously fertilized (>140 kg N/ha) with slow decomposing
fertilizers
fertilizers
(e.g. manure or anhydrous ammonium), then use the lower value of
recommended fertilizer. Take more samples to assure your mixed sample is a
representative one for your field.
representative one for your field.
When this test is used for the first time, it is better to perform it during a complete
growth cycle without changing the normal fertilization program. This helps to
familiarize oneself with this test and provides a good reference point in order to
improve the fertilization program. In the subsequent growth cycle, preplant fertiliza-
tion rate should be reduced by approximately 30%. It is suggested to periodically
check possible nitrogen requirements and to add extra nitrogen if necessary.
Attention should be paid in case of temporarily changes to normal climatic conditions
such as lower temperatures (with a consequent reduction of the turnover of organic
matter) or heavy rainfalls, when nitrate-nitrogen concentrations are expected to be
very low or even absent. After the weather returns to normal, it should be checked that
the nitrate levels are also reinstated.
Whenever possible it is recommended to carry out some fertilization experiments on
small ‘strips’ of the field.
When this test kit is used over several years, it becomes a powerful tool to optimize
the nitrogen fertilization program and allows a fast intervention if the nitrogen
concentration becomes insufficient.
growth cycle without changing the normal fertilization program. This helps to
familiarize oneself with this test and provides a good reference point in order to
improve the fertilization program. In the subsequent growth cycle, preplant fertiliza-
tion rate should be reduced by approximately 30%. It is suggested to periodically
check possible nitrogen requirements and to add extra nitrogen if necessary.
Attention should be paid in case of temporarily changes to normal climatic conditions
such as lower temperatures (with a consequent reduction of the turnover of organic
matter) or heavy rainfalls, when nitrate-nitrogen concentrations are expected to be
very low or even absent. After the weather returns to normal, it should be checked that
the nitrate levels are also reinstated.
Whenever possible it is recommended to carry out some fertilization experiments on
small ‘strips’ of the field.
When this test kit is used over several years, it becomes a powerful tool to optimize
the nitrogen fertilization program and allows a fast intervention if the nitrogen
concentration becomes insufficient.
HOW TO PROGRAM
NITROGEN
FERTILIZATION
NITROGEN
FERTILIZATION