Abstract:
To guard against soil
phosphorus (P) toxicity in tuber
production and have optimum tuber yield
at lesser cost of P-fertilization, better
understanding of the dynamics of
phosphorus release in sandy loamy soil is
inevitable. Therefore, this work was carried
out to investigate the trend of P-release
from time of application to its optimum
release and its effect on sweet potato
growth and tuber production. To achieve
this, a 5-week incubation study under
laboratory conditions was carried out to
study P-release dynamics using different
P sources. Similar experiment was
conducted on the field using the same
P sources and application rate to monitor
the influence P-release rate on sweet
potato production. Data on number of
leaves, vine length, tuber yield, soil
extractable phosphorus and phosphorus
uptake of the plants were taken.
Relationships between P-uptake and tuber
yield, number of leaves, vine length were
also established. It was found that the
trend of phosphorus release was a sigmoid
shape. Leaf production and vine length
were improved by P-application, while
yield was suppressed. It is recommended
that P-fertilizer should not be applied to
the soil at short intervals to avoid nutrient
toxicity.
