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IRRIGATION WATER (LOW RANGE)
In agricultural areas it is quite common to find altered values in the chemical composition of irrigation waters.
The problem concerns mostly the high nitrate concentration, usually determined by excessive fertilization or
irrational liquid manure spreading. The analysis of irrigation waters allows us to find out which are the
substances present in major or minor quantity and to organize an advantageous fertilization plan.
For example, if the quantity of water utilized for crop cultivation is 250 mm/ha (= 2500000 L/ha) and
the nitrate (NO
3
¯) concentration is 150 mg/L (34 mg/L as nitrate-nitrogen NO
3
-N), soil receives 85 kg/ha
of nitrogen. In choosing type and quantity of fertilizer to be used, it is important to consider this
information, in order not to waste fertilizer nor to induce soil pollution.
NUTRIENTS SOLUTIONS (MEDIUM AND HIGH RANGE)
The nutrients requirements of the plants are determined by the type of plant, its age and the
environmental conditions. The control of chemical composition of nutrients solutions given to the plants is an
operation that allows a correct preparation of the fertilizer. In analyzing the solution, it is possible to choose
between medium range and high range values, depending on the concentration of substances.
Medium range usually covers the analysis of residual solutions in recycling systems. The nutritive elements
are differently absorbed by the plants, hence the nutrient solution loses substances, becomes impoverished
and must be enriched.
High range normally corresponds to the typical values of nutrients solutions. It is therefore possible to verify
that the solution given to the plants contains the correct quantities of nutritive substances.