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Collecting sample for agricultural
analysis is extremely important since the sample must correctly represent the
area about which information is desired. Different cultivars (varieties) should be sampled and
tested separately. The
plantation of same
cultivar but with different age
also should be sampled
separately.
Soil sample
Plow depth or the plow zone is the layer
most commonly sampled for soil fertility evaluation. The plow zone is the layer
of greatest activity in the soil, and correctly evaluating the properties of
this layer go far in predicting fertilizer requirements. Lower horizons in the
soil are important too, but they do not change much from one year to another.
If basic information is available relative to characteristics of the soil from
the plow depths usually will suffice for soil fertility purposes. To obtain a
representative sample of a given area of soil, a large number of cores or sub
samples must be taken. For most cultivated fields, each composite sample should
consist of a minimum of 8-10 cores About 500grams of soil is needed for a
routine analysis.
A time for sampling must be selected
when leaf nutrient levels are relatively stable and best reflects the nutrient
needs of the tree. In case of grape, general practice is to collect petiole
samples, 45 days after pruning. We, over a period of 17 years evaluated samples
at various stages after pruning and data so generated were successfully
integrated in computer program. Samples
can be sent at any given point of time stating the date of pruning, our program
will take care of the rest. Select fully expanded recently matured, mid cane
leaves. Collect 1-2 leaves with petiole from one tree and make about 100 leaves
per sample plot. In order to prevent spoilage of the plant material, it is
important that the sample be thoroughly air-dried prior to mailing to a
laboratory for analysis. Place samples in a clean paper or cloth container
Avoid damaged leaves (insect, disease,
mechanical). Abnormal-appearing trees should be avoided. Young or senescent
leaves should be avoided. When sampling plants with suspected nutrient
deficiencies, take two samples, one from the normal plants and one from the
abnormal plants.
Water Sample
Run the water for at least 5 minutes
before collecting the sample. Collect 1 litre of sample in a clean bottle.
Complete the Sample submission form as accurately as possible.
The more complete the questionnaire is filled out the better the interpretation
and recommendation will be.
If
you have any questions about sampling procedures, contact: