The Journal of Research ANGRAU

INFLUENCE OF INM ON PHYSICAL PROPERTIES
sources FYM, had a consistent response to improve
the infiltration of water significantly atleast during the
part of rice growing period. Kumar et al., (1992) also
recorded significant improvement in infiltration rate
of water due to integrated nutrient management of
nutrients in rice-wheat cropping system.
Hydraulic conductivity
The hydraulic conductivity of the soil supplied
with different levels of fertilizers ranged from 0.25 to
0.27 cm h -1 at transplanting in kharif season during
2005-06 and from 0.23 to 0.25 cm h -1 in the
subsequent rabi (Table 6). A significant improvement
in this physical property of the soil was recorded both
in kharif and rabi due to the substitution of FYM @
25 % N fertilizer equivalent in kharif. But the
substitution of 25 or 50 % recommended level of N
through glyricidia significantly improved the hydraulic
conductivity both in kharif and rabi seasons during
the second year. The hydraulic conductivity was
significantly low in the kharif season in the fertilizer
treatments than in integrated nutrient management
treatments by substituting 25 or 50 % recommended
level of NPK through FYM or glyricidia only in the
second year. Such improvement was not recorded
in the rabi season during both the years. No significant
variation in the hydraulic conductivity in the surface
soil upto 15 cm depth was recorded either in kharif or
rabi season at harvest stage of the crop during 2005-
06 or 2006-07.
The hydraulic conductivity was invariably low
in the lower (15 – 30 cm) depth than upper layer of
the soil in all the treatments at different stages of
crop growth (Table 7). It ranged from 0.20 to 0.22 cm
h -1 at the time of transplanting in kharif 2005 and from
0.19 to 0.21 cm h -1 during 2006 due to different levels
of fertilizer application. During the subsequent growth
phases of panicle initiation and harvesting, hydraulic
conductivity was similar in unfertilized, fertilized and
integrated nutrient management treatments during
both the years.
Water holding capacity
The maximum water holding capacity of the
soil was reduced consistently with advance in age of
the crop from transplanting to panicle initiation and
at harvest in all the treatments (Table 8). The soil
supplied with different levels of nutrients through the
fertilizers held 42.04 - 42.14 % water at transplanting
in kharif and 41.26 – 41.41 % in rabi during 2005-06.
The water retention of the soil improved significantly
by substituting 25 or 50 % recommended level of N
with FYM. This effect was long lasting until harvest
both during kharif and rabi in the first year. Paddy
straw and glyricidia were also effective sources to
retain more moisture at different stages of crop growth
during the two years. The water holding capacity was
relatively low at 15-30 than 0-15 cm soil depth
irrespective of the treatment during both the years
(Table 9). Unlike in the top layer, the substitution of
organics at 25 or 50 % fertilizer N equivalent was
distinct with significantly higher moisture content than
in the fertilized or unfertilized plots from transplanting
to panicle initiation stage in the kharif season.
The water holding capacity was also best
improved by the substitution of 50 or 25 per cent N
fertilizer with FYM in the Kharif season. The
improvement in this soil physical property was long
sustained until harvest due to the cumulative
influence of reduced bulk density, increased porosity
vis –a- vis an increase in the infiltration and hydraulic
conductivity of the soil during the early periods of
crop growth. The substitution of 50 or 25 per cent N
fertilizer with rice straw or glyricidia also in general
had a long lasting effect in better water retention for
good crop management. The lower 15-30 cm soil layer
was not influenced by organic matter additions. An
improvement in water holding capacity of the soil by
the combined application of organic and inorganic
source of nutrients was also recorded by Vennila and
Muthuvel (1998).
Grain yield
The unfertilized crop produced low grain yield
of 2475 and 2199 kg ha -1 in kharif and 2025 and 1545
kg ha -1 in rabi during 2005-06 and 2006-07,
respectively (Table 10). The fertilizer application
benefited the crop to produce more yield. The
production increased to 3739 and 3920 kg ha -1 in two
seasons during 2005-06, while it increased to 2911
and 2801 kg ha -1 in kharif and rabi in 2006-07. The
strategy to apply 50 % recommended dose of
fertilizers in kharif and recommended dose of
fertilizers in rabi maintained the proportion of
production in consonance with the increase in level
of nutrients added. The production raised enormously
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