EFFECTS OF NITROGEN AND PHOSPHORUS FERTILIZERS AND SEED RATE ON GROWTH AND YIELD OF TWO UPLAND RICE (ORYZA SATIVA L) CULTIVARS.
EFFECTS OF NITROGEN AND PHOSPHORUS FERTILIZERS AND SEED RATE ON GROWTH AND YIELD OF TWO UPLAND RICE (ORYZA SATIVA L) CULTIVARS.
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Date
1994-04
Authors
MAGAJI, MUHAMMED DANYARO
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Abstract
Field experiments were conducted at the Fadama Farm of Usmanu Danfodiyo
University, Sokoto for three consecutive years during 1990-92 rainy seasons. The
objective of the investigation was to study the effects of nitrogen, phosphorus and
seed rates on two upland rice cultivars with a view to arriving at an optimum
combination rates of these factors for optimum paddy yield.
The analyzed data revealed that the cultivar Ex-China was significantly
superior to ITA 257 in both total and ear-bearing tiller number/unit area, but almost
at par with each other in panicle length. ITA 257 was, however, found to be
significantly taller and therefore more susceptible to lodging than Ex-China,
especially at high nitrogen rates. The latter was found to be of longer duration than
the former. In terms of grain number/ear and seed weight, ITA 257 was superior.
Also, in view of ITA's tall stature, it tended to produce more straw than its
counterpart, in spite of Ex-China's higher tillering ability. Ex-China turned out to be
higher paddy yielding than ITA 257.
The results also indicated that nitrogen significantly affected most of the
growth parameters and paddy yield components, notably tillering, panicle length and
plant height. But, in general, the nutrient had no significant effect on time to flowering
and maturity. The nutrient aggravated lodging, especially in the relatively taller
cultivar, ITA 257. Nitrogen also promoted grain number/ear significantly in most
years, but, on the whole, it showed no significant effect on seed weight. It also
affected both the straw and paddy yields significantly, but increasing the rates had
v i i
an adverse effect on grain:straw ratio. Seed rate, either alone, or in interaction with
nitrogen or phosphorus also increased most of the parameters examined, but mainly
up to 75 kg seed/ha beyond which competition set in. However, lodging and 1000-
seed weight were not significantly affected by increasing seed rates. Grain:straw
ratio was also little affected by this factor. Phosphorus showed no significant effects
on tillering, time to flowering and maturity, straw weight, and grain:straw ratio.
However, increasing levels of this nutrient significantly increased panicle length in
two out of the three seasons, and in respect of lodging, there was a lower incidence
of it with increasing phosphorus rate in only one season. An increase in the
phosphorus levels also increased paddy yield in only one season.
Polynomial responses to nitrogen and seed rates were, in general, linear,
indicating that paddy yield would continue to increase beyond the ranges of the
factors tried in this experiment. With regards to phosphorus, however, the response
was either inconclusive, or quadratic.
Correlation studies revealed that number of ear-bearing tillers/unit area was
the single most important paddy yield contributing component, in view of its
significant positive correlation with the yield throughout the conduct of the trials.
Thus, the other two paddy yield components, i.e., number of grains/ear and seed
weight were adjunct to it.
Description
A THESIS SUBMITTED TO THE POSTGRADUATE SCHOOL, AHMADU BELLO
UNIVERSITY, ZARIA, IN PARTIAL FULFILMENT OF THE REQUIREMENTS
FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN AGRONOMY.
DEPARTMENT OF AGRONOMY
FACULTY OF AGRICULTURE AND INSTITUTE FOR AGRICULTURAL
RESEARCH,
AHMADU BELLO UNIVERSITY, ZARIA.
Keywords
EFFECTS,, NITROGEN,, PHOSPHORUS FERTILIZERS,, SEED RATE,, GROWTH,, YIELD,, UPLAND RICE,, (ORYZA SATIVA L),, CULTIVARS,