F. Wiesler et Wj. Horst, DIFFERENCES AMONG MAIZE CULTIVARS IN THE UTILIZATION OF SOIL NITRATE AND THE RELATED LOSSES OF NITRATE THROUGH LEACHING, Plant and soil, 151(2), 1993, pp. 193-203
In a 2-year field experiment conducted on a Gleyic Luvisol in Stuttgar
t-Hohenheim one experimental and nine commercial maize cultivars were
compared for their ability to utilize soil nitrate and to reduce relat
ed losses of nitrate through leaching. Soil nitrate was monitored peri
odically in CaCl2 extracts and in suction cup water. Nitrate concentra
tions in suction water were generally higher than in CaCl2 extracts. B
oth methods revealed that all cultivars examined were able to extract
nitrate down to a soil depth of at least 120 cm (1988 season) or 150 c
m (1987 season). Significant differences among the cultivars existed i
n nitrate depletion particularly in the subsoil. At harvest, residual
nitrate in the upper 150 cm of the profile ranged from 73-110 kg N ha-
1 in 1987 and from 59-119 kg N ha-1 in 1988. Residual nitrate was clos
ely correlated with nitrate losses by leaching because water infiltrat
ion at 120 cm soil depth started 4 weeks after harvest (1987) or immed
iately after harvest (1988) and continued until early summer of the fo
llowing year. The calculated amount of nitrate lost by leaching was st
rongly influenced by the method of calculation. During the winter of 1
987/88 nitrate leaching ranged from 57-84 kg N ha-1 (suction cups) and
40-55 kg N ha-1 (CaCl2 extracts), respectively. The corresponding val
ues for the winter of 1988 / 89 were 47-79 and 20-39 kg N ha-1, respec
tively.