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AGRICULTURAE
CONSPECTUS SCIENTIFICUS
Volume 63, Supplement No 4, 1998 (331-338)
ORIGINAL
SCIENTIFIC PAPER
Nitrogen
Leaching in Different Pipe Drainage Distances
Ž. KLAČIĆ 1
D. PETOŠIĆ 1
L. ČOGA 2
SUMMARY
The investigation
object was to determine the effect of different pipe drainage distances
upon the concentration and quantity of nitrogen leached in crop production
on hydromorphic soils of the central Sava River Valley. The obtained results
indicate that abundant precipitation in the studied period had a decisive
effect on the dynamics of nitrogen leaching in all trials variants. The
overall drainage discharge in the investigated drainage variants ranged
from 197 mm to 351 mm.
Average NO 3 -N concentrations in drainage water of all variants were
below 10 mg/l, whereas maximum concentrations went up to 30 mg/l. NO 3
-N concentrations higher than 10 mg/l were recorded during rainy periods,
after fertilizers was applied. Average NH 4 -N concentrations in drainage
water of all variants were higher than 1,00 mg/l, while maximum concentrations
went up to 8,65 mg/l. From the hygienic point of view, drainage water
from all variants may be regarded as polluted and hence a potential factor
of surface water pollution.
Significantly highest quantities of leached nitrogen were recorded in
variants involving pipe-drainage distance of 10 m and 15 m. In these variants,
leached nitrogen ranged from 20.553 kg N/ha to 21,688 kg N/ha. Between
11,031 kg N/ ha and 14,688 kg N/ha was leached in the variants with medium
drain spacing (20 m and 30 m). About 56 % of total leached nitrogen originated
from fertilizers added in basic and pre-seeding soil preparation.
Wheat yields obtained in variants were between 26,11 dt/ha and 40,85 dt/ha.
The significantly highest yield was achieved in the variant involving
pipe drainage spacing of 20 m with gravel backfill (40,85 dt/ha), which
was also the variant with the lowest quantity of leached nitrogen.
KEY WORDS
Soil, nitrogen
leaching, pipe drainage, distance, water pollution, drainage discharge
1
Department of Soil Amelioration
2 Department of Plant Nutrition
Faculty of Agriculture University of Zagreb
Svetošimunska cesta 25, 10000 Zagreb, Croatia
Received: November 12, 1998
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