NITRATE-NITROGEN MOVEMENT THROUGH THE SOIL-PROFILE BENEATH A CONTAINERIZED GREENHOUSE CROP IRRIGATED WITH 2 LEACHING FRACTIONS AND 2 WETTING AGENT LEVELS
Rj. Mcavoy, NITRATE-NITROGEN MOVEMENT THROUGH THE SOIL-PROFILE BENEATH A CONTAINERIZED GREENHOUSE CROP IRRIGATED WITH 2 LEACHING FRACTIONS AND 2 WETTING AGENT LEVELS, Journal of the American Society for Horticultural Science, 119(3), 1994, pp. 446-451
'Rose Grenadine' and 'Buckaroo' garden chrysanthemums [Dendranthema x
grandiflorum (Ramat.) Kitamura] were produced in 15-cm pots in the gre
enhouse and fertilized with either 550 or 1000 ml of a 15 mol-m-3 N so
lution at each irrigation. The nutrient solution applied to half the p
ots contained a wetting agent (WA), and the remaining pots received no
WA. Core samples were removed at 15-cm increments to a depth of 90 cm
from the soil beneath the pots. The average leaching fraction (LF) fr
om pots receiving a WA was 0.29 but was 0.26 from pots receiving no WA
. However, WA did not affect the leachate NO3-N concentration or the t
otal NO3-N deposited on the soil beneath; these were most influenced b
y LF. After week 2, NO3-N concentration in the upper 15 cm soil layer
was 3.4 times higher with a high LF than with a low LF (30 and 8.8 g.m
-3 respectively). At week 10, the NO3-N concentration in the 30 to 45
cm soil layer averaged 71.9 g.m-3 under the high LF and 35.5 g.m-3 und
er the low LF. Total N and NO3-N in the potting medium was higher in t
he low LF pots than the high LF pots, while NO3,-N was higher in the m
edium of pots irrigated without WA than with WA. Final plant shoot mas
s was higher in pots irrigated to a high LF or without WA than in pots
irrigated to a low LF or with WA.