Abbreviations:
ACP: acid phosphatase activity, ALP: alkaline phosphatase activity, AZO-Aztobacter counts, Na: available nitrogen,
Pa: available phosphorus, Ka: available
K, Sa: available sulphur, β-glu: β-glucosidase, BSR:
basal soil respiration. CZ: central zone, DAP: diammoinum phosphate,
DHA: dehydrogenase activity, EC: electrical conductivity, EZ: eastern
zone, FDA: fluorescein diacetate hydrolytic activity, MBC: microbial
biomass carbon, MBN: microbial biomass nitrogen, MDS: minimum data set,
NI: Nutrient index, SOC: soil organic carbon, SQI: soil quality index,S : sensitivity index, TC: total carbon, TCA: total culturable
actinomycetes counts, TCB: total culturable bacterial counts, TCF: total
culturable fungal counts, TYE: targeted yield equations, WZ: western
zone.
INTRODUCTION
India is the second largest sugarcane producer in the world with 18.7%
of world’s production during 2017 after Brazil, which is the largest
(37.0%) producer of the world (FAO, 2019). The increasing demand of
foodstuffs, animal feed, chemicals and industry are the major causes of
sugarcane expansion. Lisboa et al. (2011) stated that increasing demand
of bio-ethanol is the key driver of this quick increase. Since, it used
as a sustainable bio-energy sources, reduces emission of greenhouse
gases (GHGs), minimize unpredictability related to volatility of fossil
fuel prices (Black et al., 2012), and endowing a fixed income source for
farmers. Thus, sugarcane paramount a key role in Indian economy as ⁓50
million farmers’ and 5.0 lakhs skilled and unskilled workers are engaged
in its production and processing (Krishnakant et al., 2015).
In India, sugarcane cultivated ⁓ 45% and 55% of the total area in
tropical and sub-tropical conditions, respectively but vice-versa in its
production. Uttar Pradesh is the key sugarcane producing province under
subtropics has largest area (2.234 m ha), production (177.06 m t) and
average productivity (79.26 t ha-1) during 2017-18
(Cooperative sugar, 2021). As many as 30 district, in which
Muzaffarnagar, Meerut, Bijnor, Moradabad and Saharanpur, districts in
western zone (WZ), Bareilly, Shahjahanpur, Lakhimpur-Kheri and Sitapur
districts in central zone (CZ) and Kushinagar, Gonda, Balrampur, Basti,
Bahraich and Maharajganj in eastern zone (EZ) are considered as the main
cane producing district of Uttar Pradesh. WZ is considered as cane heart
land of the state due to highest cane production in India. Though, wide
yield variations existed across the cane production zones of Uttar
Pradesh despite having similar soil type (alluvial soils) might be due
to variations in nutrient management and edaphic factor. Rahman and Bee
(2019) observed 82.9, 72.0 and 66.9 Mg ha-1 and
Cooperative sugar (2021) reported 90.7, 86.8 and 77.8 Mg
ha-1 cane productivity of Muzaffarnagar,
Lakhimpur-kheri, and Kushinagar district during 2016-2017 and 2019-20,
respectively. Indeed, cane productivity has been increased significantly
during the decade due to inducting high yielding variety and advance
management practices, but yield variation remains is the cause of
concern in sub-tropical region (Uperti and Singh, 2017). Yet, the right
causes of cane yield variations are not confirmed. Albeit, there are
various reasons including increasing compactness, degrading soil
structure, nutrient losses through erosion, declining SOC, and
increasing multi-nutrient deficiency (Hartemink, 1998). In addition,
low-lying area affected with floods, surface runoff and water logging
during monsoon can be a major cause to suffer production and
productivity of sugarcane in EZ (Rahman and Bee, 2019). Imbalance
fertilization over the years can be another factor for variations in
cane yield, nutrient index and soil quality. Because, sugarcane is a
heavy nutrient feeder crop required 150–350 kg N; 60–100 kg
P2O5, and 60–120 kg K2O
ha-1 annually depending upon planting time, growing
condition and nutrient status in soil. However, sugarcane growers
largely using 150:60:60 kg N, P2O5 and
K2O ha-1 year-1across the sub-tropical zone from the decades despite changes of
fertility gradient (from medium to low or very low categories of
nutrients). Contrary to that, sugarcane removed about 208, 53 and
280 kg N, P, and K ha-1 year-1 for
producing 100 Mg ha-1 cane yields (Shukla et al.,
2017). Sugarcane mono-cropping over the years depleted 53, 56, 84 and
86% SOM, total N, Olsen P and exchangeable K, respectively than the
virgin land (0-30 cm depth). Chi et al. (2017) also suggested that
prolonged sugarcane cropping has detrimental effects on soil fertility,
but deterioration depends on soil types, surface runoff and water
logging (Satiro et al., 2017). Heavy mechanization in sugarcane also
caused adverse impact on soil compaction notably in top soils.
Consequently, reduce soil aeration, soil resistance and infiltration
rates and increases runoff and soil erosion in Brazil (Macedo, 2007).
Thus, cumulative effects of these factors affect microbial life in soils
(i.e. bacterial, fungal, actinomycetes, and nematodes counts)
(Hartemink, 2008). Holt & Mayer (1998) observed that long-term
sugarcane cultivation had low enzymes’ activity than natural habitats
and pasture. Although, it varied with management practices such as
unfertilized/fertilized, burnt/green harvesting, trash removal/trash
mulching and tillage level employed (Yadav et al., 2009; Stirling et
al., 2010; Castioni et al., 2018).
Soil quality may be defined as the capacity of a soil to function within
ecosystem boundaries to sustain biological productivity, maintain
environmental quality, and promote plant and animal health (Doran and
Parkin, 1994a). Recently, it utilized by various researchers as a tool
for assessing the suitability of management practices implies in a soil,
and indices have been developed to grade and compare soil conditions
over time and or between different locations (Nortcliff, 2002). Various
methods such as soil management assessment framework (Masto et al.,
2007) , Fuzzy association rule (Yue-Ju et al., 2010), dynamic
variability of soil quality methods (Larson & Pierce, 1994), nutrient
index (Amara et al., 2017), soil health cards and test kit (Ditxler &
Tugei, 2002) have been employed by researchers for soil quality
assessment. Among these methods, soil quality index has been most
extensively applied due to its quantitative flexibility and suitability
for different types of soil and its coordination among the physical,
chemical and biological attributes. Hence, soil quality indices are
using at large scale to assess the impact of long-term management
practices in particular crop production on the soil at a district;
regional and provincial scale (Gong et al., 2015). Soil quality markers
are vital component that incorporate soil function, and reflect
environmental differences at large scale liable to influence soil
quality. Though, lacking in consensus on which soil marker is useful for
soil quality monitoring. For instance, Rahmanipour et al. (2014) had
chosen soil erodibility, chromium and cobalt contents as quality
indicators to assess soil quality, but were not found in other research.
Liu et al. (2015) included some biological indicators like as acid
phosphatase, and total counts of bacteria and AM fungi in minimum data
set. However, soil pH, Pa, Ka, soil
structure and SOC were considered as ideal soil quality indicators for
the sugarcane production in Brazil (Cherubin et al., 2016). deFreitas et
al. (2018) also reported that total sand, clay, micro-porosity,
magnesium, calcium, soil pH, and organic matter considered as a
sensitive soil quality indicators for sugarcane and native forest grown
in northeastern São Paulo state, Brazil.
Certain soil environments have been shown to produce ultra-high
sugarcane yields (i.e., >100 t ha-1).
Although, it is unaware to which extent soil physical, chemical and
biological properties contribute to create yield differences between the
area under ultra-high yields and average yields within the same soil
order (Bigott et al., 2019). Although, the study was meager to assess
causes of yield variation and long-term impact of sugarcane
mono-cropping on nutrient index, microbial activity and soil quality
across the cane producing zones of Uttar Pradesh. Hence, this study was
undertaken to (i) assess the chemical and biological properties of soil
on different cane producing zones of Uttar Pradesh, (ii) evaluate the
effects of soil attributes on nutrient index, soil quality and
sensitivity measurement differ among the high, average and lower
yielding areas and (iii) suggest the doses of balance fertilizer for
different cane producing zones of Uttar Pradesh.