3.2. Nutrient index of different sugarcane zones
The NI ranking was used to assess the long-term sugarcane mono-cropping
impact on nutrient pattern changes (Table 4). The NI of SOC altered from
medium to low category (<1.67) in CZ and WZ, but EZ maintained
at medium level (1.69). Lower NI (<1.67) of Nawas recorded entire the cane producing zones under the study, being the
highest was in CZ (1.04) than that of EZ and WZ (1.00). NI of
Pa and Ka was falls under medium
category (1.67-2.33) in CZ and WZ, whereas lower level was existed in
EZ. The medium NI category of Sa was maintained only in
WZ but EZ (1.51) and CZ (1.38) showed <1.67. The NI of Zn was
recorded in medium level which ranged between 1.67−2.33 in EZ and CZ,
whereas WZ soils had lower NI levels of Zn (1.66). The NI level of Cu,
Fe and Mn were highest (>2.33) across the cane producing
zones of Uttar Pradesh, except NI of Fe was maintained at medium level
in WZ. Overall, the higher mean NI value was observed in CZ (2.19)
followed by EZ (1.98) and WZ (1.97).