Assessment of soil fertility levels under horticultural land use soils of Kaushambi District of Uttar Pradesh, India

Abstract

The present study assessed the physico-chemical properties and nutrient status of soils under horticultural land-use systems in Manjhanpur and Sirathu blocks of Kaushambi district across three soil depths (0-15, 15-30, and 30-60 cm). Soil reaction in both regions ranged from slightly to moderately alkaline, with mean pH values increasing gradually with depth (7.32 to 7.51 in Manjhanpur; 7.33 to 7.51 in Sirathu). Electrical conductivity remained low across all depths (0.34 to 0.49 dS/m in Manjhanpur; 0.34 to 0.48 dS/m in Sirathu), indicating non-saline conditions. Organic carbon content declined with depth, showing higher accumulation in surface layers (0.36 to 0.33% in Manjhanpur and 0.39 to 0.40% in Sirathu), reflecting the effect of organic matter inputs and biological activity. Exchangeable Ca, Mg, and Na increased with soil depth in both blocks, with higher mean Ca (2.26-2.57 meq/100 g) and Mg (0.66-0.73 meq/100 g) observed in deeper horizons. Primary nutrient concentrations also followed a depth-wise decreasing trend. In Manjhanpur, mean nitrogen decreased from 200.44 to 175.97 kg/ha with increasing depth, while phosphorus (16.48 to 14.29 kg/ha) and potassium (201.26 to 171.35 kg/ha) showed similar reductions. Comparable patterns were recorded in Sirathu, where nitrogen declined from 186.13 to 162.91 kg/ha, phosphorus from 14.95 to 12.87 kg/ha, and potassium from 208.94 to 177.53 kg/ha. Sulphur levels were higher in surface soils of both regions, ranging from 11.03 to 7.22 kg/ha in Manjhanpur and 11.79 to 7.97 kg/ha in Sirathu. Micronutrient availability (Fe, Mn, Cu, Zn, and B) exhibited significant spatial and vertical variability but consistently decreased with depth. In Manjhanpur surface soils, mean Fe, Mn, Cu, Zn, and B were 9.55, 8.18, 0.79, 0.73, and 0.68 mg/kg respectively, declining notably in subsurface layers. Similarly, Sirathu showed higher micronutrient levels at 0-15 cm (Fe 8.68 mg/kg; Mn 8.05 mg/kg; Cu 0.77 mg/kg; Zn 0.71 mg/kg; B 0.67 mg/kg) compared with deeper horizons. Overall, the study highlights that horticultural soils of both blocks are moderately fertile, alkaline, non-saline, and characterized by decreasing organic carbon and nutrient content with soil depth. These findings underscore the need to adopt depth-specific nutrient management and soil conservation strategies to sustain productivity under horticultural land-use systems.