Agriculture Reference
In-Depth Information
with soil carbon pools, soil nitrogen pools or soil C:N ratio (Raich and
Potter, 1995).
11.5.1 SOIL MICROBIAL POPULATION
Variation in rhizosphere soil temperature under two different systems of
nutrient management showed that soil temperature irrespective of tim-
ing, was invariably lower under INM-treated compared to IF-treated trees
(
Table 11.1
).
During 4-month study, soil temperature within rhizosphere
of INM-treated trees was lower by 1-3°C over conventionally IF-treated
trees rhizosphere. Variation in bacterial count (BC) and fungal count (FC)
both, displayed large variation between two timings of observation and
between two nutrient management systems. From January to April, with
the rise in both morning and afternoon temperature, from 18.2 to 24.4°C
and from 22.4 to 37.6°C under IF, the BC reduced from 108 × 10
4
to 54
× 10
4
cfu g
-1
, and from 81 × 10
4
to 31 × 10
4
cfu g
-1
, respectively. While,
FC reduced from 69 × 10
3
to 18 × 10
3
cfu g
-1
and from 52 × 10
3
to as low
as 10 × 10
3
under IF with morning and afternoon temperature variation
of 18-24.4°C and 22.4-37.6°C, respectively. On the other hand, INM-
treated plants rhizosphere maintained a much high population of bacteria
in morning (168 × 10
4
-111 *10
4
cfu g
-1
) and afternoon (142 × 10
4
- 76 ×
10
4
cfu g
-1
), although, the count reduced during afternoon but distinctly
higher than IF-treated plants rhizosphere. The FC recorded likewise on the
higher side, which reduced from 81 × 10
3
× 48 × 10
3
with rise in morning
temperature from 18.2 to 24.4°C and from 72 × 10
3
to 28 × 10
3
cfu g
-1
with
rise in afternoon temperature from 21.4 to 34.3°C (Table 11.1).
11.5.2 RHIZOSPHERE MICRONUTRIENTS AVAILABILITY
Availability of micronutrients within the rhizosphere was observed to be
influenced by variation in soil temperature under both IF-and INM-treated
plants rhizosphere (Table 11.1). Interestingly, DTPA-Cu and DTPA-Zn
were not so much influenced by variation in soil temperature compared
to availability of DTPA-Fe and DTPA-Mn. Under IF-treated plants rhizo-
sphere, rise in morning temperature from 18.2 to 24.4°C was associated in
reduction in DTPA-Fe from 10.1 to 9.0 mg kg
-1
and DTPA-Mm from 8.2
to 7.0 mg kg
-1
, without any distinct change in DTPA-Cu and DTPA-Zn.
