Soil is the basic material on the earth where life begins, so it holds the whole bag of nutrients in it. Plants uptake directly or indirectly from soil, perhaps need to be checked properly. Soil test can determine wide variety of soil. It is used to diagnosis of plant problem.
Generally soil is tested for-
PH in soil:
PH scale contains 0-14 .
where, 0-6 indicates acid soil and 8-14 indicate basic soil. around 7 indicates neutral in nature.
according to soil test PH is determined and it is modify as per our convivence.
As we know nitrogen is the main component in plant structure, it is needed in the larger amounts.
Nitrogen is determined by khjeldhal method which is given by subbaiah .
This test is based mainly on titration. Due to change in the colour nitrogen percentage is known
by knowing nitrogen percentage, we apply fertilizers.
Potassium test is done in the flame photometer.
The movement of ions indicate the percentage of potassium.
So, as per need muriate of potash is applied to the soil.
Phosphorous is determined by spectrophotometer.
Here, we find due to intensity of different rays in spectrophotometer.
Accordingly, we supply chemical fertilizers DAP, SSP, MAP.
Likewise, soil can be tested differently for different nutrients.
IMPORTANCE OF SOILTESTING:
Identifies the deficiency of different nutrients.
Improves productivity in right way.
It mainly gives information about the percentage of nutrients to be applied.
To minimize fertility usage.
To avoid soil degradation