SOIL QUALITY ASSESSMENT UNDER LONG TERM FERTILIZER EXPERIMENT IN RED AND LATERITIC SOILS OF RANCHI
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Date
2022
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Birsa Agricultural University, Ranchi
Abstract
An investigation was undertaken during 2018-19 on the soils of the ongoing
long term fertilizer experiment (LTFE) in progress since 1972 at the experimental
farm of Department of Soil Science and Agricultural Chemistry, Birsa Agricultural
University, Kanke, Ranchi in Jharkhand state. The experiment consisted of ten
treatments replicated thrice in a randomized block design i.e. T1:50% NPK, T2:100%
NPK, T3: 150% NPK, T4: 100% NPK+ Hand weeding, T5: 100% NPK+Lime, T6:
100% NP, T7: 100% N, T8: 100% NPK+FYM, T9: 100% N(S)PK and T10: Control.
Surface soil samples (0-15 cm) were collected during the soybean and wheat
growth stages for analysis of moisture content, soil pH, soil organic carbon, available
P and K. Surface (0-15 cm) and subsurface (15-30 cm) soil samples were collected
after the harvest of wheat (2018-19) for analysis of various physical, chemical and
biological properties for development of soil quality index (SQI). Sustainable yield
index of the soybean wheat cropping system over the years of experimentation was
calculated. System productivity was expressed in terms of mean wheat equivalent
yield (WEY).
Highest sustainable yield index (SYI) of the system (0.57) was recorded in
100% NPK+FYM treatment followed by 100% NPK + lime (0.50). The least value of
SYI values was recorded 100% N treatment (0.04). System productivity in terms of
mean WEY (q ha-1) over the years (1972-2019) followed the following order: 100%
NPK+FYM (70.3) >100% NPK+Lime (67.0) > 150% NPK (58.5) > 100% NPK
(57.8) =100% NPK +HW (57.8) > 50% NPK (44.5) > 100% NP (41.70) > 100%
N(S)PK ( 35.3) >Control ( 16.5) > N (10.3).
Amongst the soil properties analyzed at different crop growth stages, soil
organic carbon, available P and K exhibited significant correlation with system
productivity throughout the growing period of crops. Low variability (i.e. CV < 15%)
was exhibited by all the soil measurements that were assessed during the crop growth
stages (moisture content, soil pH, available P, available K and soil organic carbon).
Among the various soil quality parameters (physical, chemical and biological),
soil texture and DTPA-Pb showed no significant difference in both the soil depths and
therefore dropped from principal component (PCA) analysis. The rest of the soil
properties which showed significant difference among the treatments were subjected
to principal component analysis (PCA) using the SPSS software to identify the
minimum dataset (MDS) in order to compute soil quality index (SQI). The variables
identified as the minimum dataset (MDS) indicators for development of soil quality
index for surface soil (0-15cm) were: DHA, LOC, hot water soluble boron, soil pH
and exchangeable Ca. The MDS indicators identified in case of subsurface soil layer
(15-30 cm) were labile organic carbon, DHA, Hot water soluble boron, soil pH,
exchangeable Ca and bulk density. 100% NPK+FYM recorded the maximum value of
SQI followed by 100% NPK+Lime in both surface as well as subsurface soil layer.
The SQI ranged from 0.00 to 2.21 and 0.00 to 2.10 in surface and subsurface soil
layer, respectively. 100% N treatment recorded the lowest value of SQI (0.00) in both
the soil depths. Percentage contribution of key soil quality indicators or MDS
indicators for influencing SQI in the surface soil layer (0-15 cm) were: LOC (29.8%),
DHA (28.4%), boron (21.9%), soil pH (14.8%) and Ca (5.0%). Percentage
contribution of key soil quality indicators or MDS for influencing SQI in the
subsurface soil layer (15-30 cm) were LOC (29.1%), DHA (27.25%), hot water
soluble boron (20.41%), soil pH (16.02%), exchangeable Ca (5.13%) and bulk density
(2.15%).
The higher values of both sustainable yield index (SYI) and soil quality index
(SQI) in 100% NPK+FYM and 100% NPK +Lime suggests that conjoint use of lime
or FYM along with balanced NPK fertilizers are viable options for enhancing the
productivity and sustainability of the soybean-wheat cropping system together with
maintenance of soil quality in red and lateritic soils. Application of NPK fertilizer was
found to be superior over imbalanced fertilization (N and NP) with respect to soil
quality, system productivity and sustainability. All the soil chemical properties
measured during crop growth stages (pH, available phosphorus, available K and soil
organic carbon) responded consistently to management over time and hence their
measurement at any time of crop growth can serve as an indicator to soil quality.
Labile organic carbon, dehydrogenase activity, hot water soluble boron, soil pH,
exchangeable Ca, soil pH and bulk density were identified as the key indicators of soil
quality under soybean-wheat cropping system .
Description
SOIL QUALITY ASSESSMENT UNDER LONG TERM
FERTILIZER EXPERIMENT IN RED AND LATERITIC
SOILS OF RANCHI