2.3. Computation of mineral fertilizers
Since, wide variations in soil fertility across the cane producing
zones, a workable targeted yield equation (TYE) for plant (FN = 7.37 T–
1.95 SN, FP2O5 = 0.96 T–2.21 SP and
FK2O =3.36 T– 0.83 SK) and ratoon crop (FN = 5.91
T–1.83 SN, FP2O5 = 0.64 T–1.85 SP and
FK2O =2.33 T–0.60 SK) were used for balance
fertilization in different cane producing zones by employing initial
soil test value and defined targeted cane yield. A wonder sugarcane
variety (Co 0238) which covered larger area (alluvial soil) in Uttar
Pradesh was used for developing TYE during 2016–17 and 2017-18 by
considering nutrient required to achieve per Mg cane yield, utilization
efficiencies of nutrients available in soil and those applied through
inorganic fertilizers were considered for developing TYE (Ramamoorthy &
Velayutham 1971).
where, FN, FP2O5 and
FK2O are mineral fertilizers N,
P2O5 and K2O (kg
ha−1); SN, SP and SK are initial soil test values
estimated before planting. To make symmetry,
P2O5 and K2O were
converted into P and K by applying factor 2.29 and 1.20, respectively.
T-targeted cane yield (Mg ha−1). N,
P2O5 and K2O fertilizers
were calculated on the basis of above equations for balance
fertilization.