Abstract:
Fertilization of plants in greenhouse soilless cultivation is used in a closed system with
recirculating nutrient solution or in an open system w
here the excess of nutrient solution
is discharged into the soil or sewage. In Poland, most of basic greenhouse vegetables are
grown in the open soilless system. The excess of highly concentrated nutrient solution
leaking from growing slabs causes contamin
ation of soil and shallow groundwater.
The
aim of the study was to monitor component changes in nutrient solution and nitrate
nitrogen in the plant root zone, drainage water, as well as in shallow groundwater present
in arable lands in the immediate vicini
ty of the soilless tomato culture. The study was
conducted in 2013
-
2015 and compared tomato cultivated in Rockwool versus
biodegradable organic substrate. Changes of nutrient content including N
-
NO
3
in the root
zone and drainage water depended on the typ
e of the substrate in which tomato plant was
cultivated as well as on the plant growth stage. Higher content of nitrate nitrogen in the
root zone and drainage water was found in tomatoes grown in Rockwool compared to the
organic substrate. The peak content
of N
–
NO
3
(117 mg
dm
-
3
)
was detected in the
groundwater present directly under the soilless tomato culture and it decreased
proportionally to the distance from the greenhouse.
Keywords:
Drainage water, Nitrate nitrogen, Nutrient solution, Organic substrat
e.