BEHAVIOR OF INORGANIC NITROGEN IN TEA FIE LD SOILS HEAVILY APPLIED WITH NITROGEN AND CHANGES IN AMINO-ACID CONTENT OF THE FIRST CROP ACCOMPANYING THE REDUCTION OF NITROGEN
N. Tachibana et al., BEHAVIOR OF INORGANIC NITROGEN IN TEA FIE LD SOILS HEAVILY APPLIED WITH NITROGEN AND CHANGES IN AMINO-ACID CONTENT OF THE FIRST CROP ACCOMPANYING THE REDUCTION OF NITROGEN, Nippon Sakumotsu Gakkai Kiji, 64(3), 1995, pp. 523-528
We investigated the behavior of nitrogen heavily applied to inter-row
spaces of the fields and the deterioration in amino acid contents caus
ed by the reduction in nitrogen. The concentrations of inorganic nitro
gen in soil solution collected from inter-row soil layers at different
depths showed the maximum level in August. A high correlation was fou
nd between the amount of nitrogen applied and the concentration of ino
rganic nitrogen in soil solution. The average concentration of inorgan
ic nitrogen in soil solution collected from inter-row soil layers and
under canopy edge was significantly high at 495 ppm, white that in the
soil solution collected under the canopy ranged from 30 to 100 ppm. A
reduction in the amount of nitrogen supplied resulted in a decrease i
n the amino acid content in green tea leaves in the first year, regard
less of the amount of nitrogen applied. However, the total content of
amino acids in lower application plots recovered to almost the same le
vel as that in the heavy application plot in the second year. This det
erioration in the amino acid content in the first year after reduction
in nitrogen application seems to mainly attributable to a growth diso
rder of roots caused by the preceding heavy application of nitrogen.