Abstract:
Soil fertility and productivity depend on soil chemical, physical
and biological properties. Sri Lanka is an agricultural country and extensive
use of inorganic fertilizers by the farmers has harmful impact on human and
the environment. Therefore, promoting application of organic fertilizer is a
need. Legumes are not only grown as human food but also improve soil
fertility through biological nitrogen fixation. Rhizobium, a soil borne
bacteria living in nodules of legume plants, fixes aerial nitrogen on a
symbiotic association. Thus it reduces nitrogen requirement of legume and
make the legume based cropping system sustainable. The response of
cowpea variety Waruni to seed inoculated Rhizobium, cattle manure, and
inorganic nitrogen fertilizer was investigated conducting field experiments.
The results indicate that the seed inoculated rhizobia increased number of
nodules and nodules dry weight per plant, 100 seed weight, number of pods
per plant, yield, hydration coefficient and cookability. Control treatment
significantly increased total defects and non-soakers. Moisture content was
not showed statistically significant different among the treatments. When
perform the correlation analyses the moisture content showed non
significant effect with other seed physical properties. Cookability showed
significant positive correlation with non-soaker seeds and non-soaker seeds
showed highly significant (p<0.0001) positive correlation with total defects.
Seed inoculated Rhizobium had the highest performances in nodule formation,
yield and seed physical properties. Present study concludes that the seed
inoculated rhizobium is successfully applied in legume fertilization as a
supplement to the inorganic fertilizer as well as to reduce the amount of
organic fertilizer.
