Variation of trace metal minerals among different soil orders under different land use systems falling in Malwa region of Punjab in North-western India

Background

Trace metal deficiency has become a major constraint on the productivity and sustainability of soils. Agriculture becomes more complex, advanced and intensive farming systems develop, however, the deficiency of trace metal are more frequent and extensive in different systems.

Methods

This study investigated the variation of trace metal minerals in soil profiles of diverse land use systems (LUSs), i.e. agriculture, horticulture and forestry, falling under three dominant soil orders (Entisol, Inceptisol and Aridisol) in Malwa region of Punjab. Through comprehensive analyses, we explore the intricate relationships between soil characteristics, land use practices, and the distribution of key trace metals—namely zinc (Zn), copper (Cu), iron (Fe) and manganese (Mn).

Results

The mean values of DTPA-extractable trace metal from soil profiles of different land uses varied from 1.75 to 2.09, 1.64–2.32, 1.18–1.69 mg kg⁻¹ for Zn; 0.59–1.02, 0.59–0.99, 0.64–0.92 mg kg⁻¹ for Cu; 12.12–16.49, 9.84–16.05, 7.94–11.56 mg kg⁻¹ for Fe; 7.82–9.99, 4.66–9.39, 6.51–7.46 mg kg⁻¹for Mn in soil orders Entisol, Inceptisol and Aridisol, respectively. The concentration of trace metals in different soil orders follows the pattern of ntisol>Inceptisol>Aridisol. In contrast, there is a considerable amount of variation and no discernible pattern in the distribution of trace metals under various LUSs in each soil order. Several LUSs were examined, and agriculture land use system (ALUS) had the greatest Fe and Mn content, while the horticulture land use system (HLUS) had the highest Zn and Cu content. The Irrespective of soil orders and LUSs, the concentration of trace metals decreased as soil depth increased. Diverse LUSs and management practices have a substantial impact on the physico-chemical characteristics of soils, which in turn influence the availability of trace metals. According to the Pearson correlation studies, trace metals were positively associated with soil OC and negatively associated with soil pH, electrical conductivity (EC), and calcium carbonate (CaCO₃) and there was also a positive correlation between DTPA-Zn, Cu, Fe, and Mn in the investigated soils. The results of the principal component analysis (PCA) revealed that soil CaCO₃ and organic carbon (OC) content were the most variable soil parameters influencing crop trace metal availability in different soil orders and land use systems.

Conclusion

The findings contribute to a nuanced understanding of the dynamic interplay between soil properties and land use, providing valuable insights for sustainable agricultural practices and environmental management in the region.