Continuous Cropping and Fertilization on Vertical Distribution of Major Nutrients, SOC Dynamics Through FT-IR Spectroscopy and Developing Soil Quality Indices Under Sandy Clay Loam Soil

Abstract

ABSTRACT Continuous application of farm yard manure and mineral fertilizer significantly affects the soil available nutrient and distribution of nutrients in soil. Balanced application of mineral fertilization (100% NPK) along with FYM @10 t ha−1 has significantly changed the soil labile C and recalcitrant pool. The study shows that integrated nutrient management has recorded the highest transmittance intensity of hydrophilic bond of carboxyl (1698–1701 cm−1) (3500–3200 cm−1 & 1400 cm−1) and aromatic (1650 cm−1), benzenes and alkenes (2922–2926 cm−1), disulfide (500–400 cm−1), and phosphorus esters (800–580 cm−1) bonds. Soil organic carbon (SOC), soil microbial biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN), labile and recalcitrant pools have observed higher in INM plots than super optimal (150% NPK), optimal (100% NPK), and with micronutrient (100% NPK +Zn). The addition of manure and mineral fertilizers has increased the SOC stocks and SOC sequestration. Soil quality indices were developed using principal component analysis and INM (T8) showed the highest soil quality index which has 10.2 (SQIA) and 10.6 (SQIW) percent higher response than super optimal dose (T3) and other optimal doses (T2, T4, T5 & T9) are on par which each other and lowest in control of intensive farming over four decades. The significant change in sustainable yield index (SYI) of finger millet and maize has observed in plot which received T8 followed by T3, and other optimal doses were least significant with each other and lowest in control plot.