Agriculture Reference
In-Depth Information
While afternoon temperature rise from 22.4 to 37.6°C induced reduction
in DTPA-Fe from 8.1 to 6.9 mg kg
-1
, DTPA-Mn from 7.2 to 5.8 mg kg
-1
with marginal rise in DTPA-Cu from 1.10 to 1.18 mg kg
-1
, without much
change in DTPA-Zn (0.81 to 0.80 mg kg
-1
). Under INM-treated plants rhi-
zosphere, these changes were of comparatively lower order. There was a
reduction in DTPA-Fe form 14.2 to 13.0 mg kg
-1
, DTPA-Mn from 11.4 to
10.8 mg kg
-1
without much change in either DTPA-Cu or DTPA-Zn with
rise in morning temperature from 17.2 to 22.3°C. While under same INM-
treated trees rhizosphere, afternoon rise in soil temperature from 21.4 to
34.3°C, brought reduction in DTPA-Fe from 13.2 to 12.5 mg kg
-1
, DTPA-
Mn from 10.9 to 9.6 mg kg
-1
with just marginal increase in DTPA-Cu
(1.76-1.79 mg kg
-1
) and just marginal reduction in DTPA-Zn (1.06 to 1.04
mg kg
-1
). These preliminary observations provide some database support
to the fact that differential index of microbial and nutrient availability is
maintained within the plants rhizosphere.
Soil bacteria count and fungal count exhibited direct relation with air
11.2
). The highest bacterial count and fungal count (46−60 ´ 10
4
cfu g
-1
soil and 18-24 ´ 10
4
) was observed in the air temperature (maximum)
range of 32.3-38.4°C and soil temperature range of (29.2-29.5°C) dur-
ing September-October which bacterial and fungal count further reduced
drastically (26-27 ´ 10
4
cfu g
-1
bacterial count and 13-15 ´ 10
4
cfu g
-1
soil
fungal count) with rise in soil temperature up to 34.5°C in March at Site
1 (Pipla Kinkhede, Nagpur). While at Site 2 (Jarud, Warud, Amravati),
almost similar pattern was observed, although maximum air temperature
was on the comparatively lower side (26.8-28.2°C) but relative humid-
ity was almost the same during September-October. The highest bacterial
count and fungal count (28-47 × 10
4
cfu g
-1
soil and 16-23 × 10
4
cfu g
-1
soil) was observed during September-October. Again, during February-
March, their no change in either maximum air temperature (27.8-33.8°C)
or soil temperature (30.1-30.7°C), the bacterial count and fungal count
(27-30 × 10
4
cfu g
-1
soil and 13-14 × 10
4
cfu g
-1
soil) showed no further
substantial decline during February to March.
Efforts were further made to study the dynamics of six major microbial
species (
Bacillus mycoides, Pseudomonas fluorescens, Bacillus polymyxa,
Azotobacter chroococcum, Trichoderma harzianum
and
Bacillus licheni-
formis)
in
relation to different soil and climatic factors with a purpose
to identify optimal conditions for different species and dominant species
