Abstract:
Nitrogen losses by leaching only occur when the
capacity of the ecosystem to accumulate nitrogen has been
saturated (which may take considerable time if the rate of
nitrogen input is low). The research study was conducted at
Nkango Irrigation Scheme in Kasungu district to determine
the impact of nitrogen application regime on N leaching.
Maize (SC 407) was a test crop. The planting and harvest
were done on Julian day of 2012152 and 2012250
respectively. Water regime was kept constant at 100% of
maize full water requirement regime (FWRR) while N
application varied from 92 kg N/ha which represents Typical
Nitrogen Placement Rate in the area (TNPRA), 125% of
TNPRA (115 N kg/ha); 75% of TNPRA (69 N kg/ha); to 50%
of TNPRA (46 N kg/ha). The EU-Rotate_N model was used
to run the field data. The paper concluded that treatments
that received high amount of inorganic N fertilizer lost more
nitrogen through N leaching. Plant roots will only absorb
nitrogen it requires leaving excess to be leached by water
below the active rooting zone. The study also concluded that
EU-Rotate_N model to perfectly predict N leaching from
irrigated maize production. The study also found out that
applying N fertilizers at once increase its susceptibility to
leaching and therefore the study recommended that to apply
N fertilizer in several small applications during the cropping
season.
