Agriculture Reference
In-Depth Information
TABLE 1
(Continued)
Treatments
Macronutrients (mg kg
-1
soil)
2010
2011
Mean
N
P
K
N
P
K
N
P
K
FI
+4.29
a
+0.93
a
+4.65
a
+1.78
a
+0.51
a
+1.93
a
+3.03
a
+0.72
a
+3.29
a
2010
2011
Mean
Fe
Mn
Cu
Zn
Fe
Mn
Cu
Zn
Fe
Mn
Cu
Zn
RDI
0
-0.72
b
-0.53
b
-0.21
a
-0.12
b
-0.78
b
-0.60
b
-0.24
a
-0.14
b
-0.75
b
-0.56
b
-0.23
a
-0.13
b
2010
2011
Mean
Fe
Mn
Cu
Zn
Fe
Mn
Cu
Zn
Fe
Mn
Cu
Zn
RDI
50
-0.97
a
-0.89
a
-0.26
a
-0.18
a
-0.99
a
-0.92
a
-0.28
a
-0.21
a
-0.98
a
-0.90
a
-0.27
a
-0.20
a
FI
-1.19
a
-1.06
a
-0.27
a
-0.23
a
-1.24
a
-1.11
a
-0.31
a
-0.27
a
-1.22
a
-1.08
a
-0.29
a
-0.25
a
'+' sign indicates the increase and '-ve' sign indicates decrease in the magnitude of the variables.
Data in one column followed by different letter are significantly different at
P <
0.05
,
as per separation by Duncan's
multiple range test
The changes in available macronutrients (N, P and K) in root zone of the plants
under various irrigation treatments show that the nutritional status of the soil improved
in both the years of experiment (Table 1). This happened due to the application of
NPK-based fertilizers to the plants during irrigation seasons. The maximum increase
in the soil available N, P and K was observed with FI, followed by RDI
50
. However, the
effect of irrigation on available-P was statistically insignifi cant, due to low solubility
and slow movement of P in soil water continuum [1]. The increase in available nutrient
amount was higher in 2010 than 2011, indicating higher nutrients uptake by plants in
the latter year.
The magnitudes of available micronutrients (Fe, Cu, Zn, Mn and Cu) in the soil
decreased, irrespective of irrigation treatments (Table 1). The maximum decrease in
concentration of available micronutrients was observed under FI and the minimum
was with RDI
0
. The higher loss of micronutrients in soil under FI might be caused due
to higher plant uptake of these nutrients under increased soil water content in this treat-
ment. However, the effect of irrigation on available Cu was insignifi cant. The consis-
tent amount of Cu maintained in soil under different treatments was due to the applica-
tion of Cu-based fungicides, which is a common recommendation against
Phytopthora
disease in the crop. The consistent reduction of micronutrients (except Cu) in soil sug-
gests a need for application of appropriate quantity of micronutrients-based fertilizers
to mandarin plants to improve the effi ciency and longevity of the orchards.
19.3.3
CHANGES IN LEAF NUTRIENTS COMPOSITION
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