Mineralogical composition of soils under rice-based cropping systems in Shiwalik Foothills of Northwest India

Abstract Understanding the evolution of soil mineralogy under rice-based cropping systems is essential for maintaining soil health, boosting agricultural productivity, and ensuring long-term sustainability. To explore this, we examined the response of different rice-based cropping systems (e.g. rice–wheat, rice-potato-melon system, rice-potato-mungbean, rice-potato-maize and rice-peas-maize) on mineralogy composition in the Kandi region of Punjab. Among rice-based cropping systems, the rice–wheat system exhibited the highest soil pH (8.17), while the rice-potato-melon system had the lowest (7.23). The rice-potato-mungbean system recorded the highest available potassium (227.5 mg kg⁻ 1 ), and the rice-peas-maize system showed the highest soil organic carbon (1.12 g kg⁻ 1 ). Across all systems, quartz was dominant in the sand-sized fraction, followed by mica and feldspar. In the clay-sized fraction, feldspar and quartz were the predominant minerals accounting for 66% and 68%, respectively among different cropping. Illite and Kaolinite were present in lower proporation and contributed about 21% and 11%, respectively. In contrast, sand fraction was composed of quartz (~ 90%), followed by feldspar (~ 6%), mixed-layer minerals (~ 4%) and mica (~ 1%) irrespective of cropping systems. Illite content peaked at 25% in the rice–wheat system and decreased progressively in rice-potato-maize (24%), rice-peas-maize (21%), rice-potato-mungbean (20%), and rice-potato-melon (18%) systems. Mineralogical analysis revealed that higher pH and electrical conductivity (EC) corresponded with lower quartz and higher illite and potassium content in the clay fraction. Correlation studies indicated that increases in pH, EC and organic carbon significantly influenced sand mineral composition by decreasing quartz and increasing mixed-layer minerals. These variations were primarily controlled by the characteristics of the alluvial parent material rather than landform or cropping system differences.