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. Select fully expanded
recently matured leaves. The general rule of thumb is to sample the most
recently matured leaves. The recommended time to sample many plants usually
occurs just prior to the beginning of the reproductive stage. 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 liter
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 us at analab@rediffmail.com
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