Depth-wise Distribution of Soil Nutrients under Different Cropping Systems in Eastern Rajasthan, India

The availability of nutrients for crops is significantly impacted by various cropping systems and nutrient management techniques. Ten common cropping systems—pearl millet-wheat, pearl millet-mustard, pearl millet-chickpea, sesame-chickpea, pearl millet-fennel, groundnut-wheat, maize-chickpea, maize-wheat, tomato-cabbage, and sesame-mustard—were thoroughly evaluated in four districts (Karauli, Sawai Madhopur, Bharatpur, and Dholpur) in Eastern Rajasthan, a semi-arid region of India. In order to measure depthwise differences in soil macronutrients (N, P, K, S) and micronutrients (Zn, Cu, Fe, Mn), 360 soil samples (12 per system over three depths: 0–15, 15–30, and 30–45 cm) were taken in April 2024 after Rabi crop harvest. The Maize-Chickpea) system had the highest available nitrogen (N) 432.75 kg ha^-1, 373.80 kg ha^-1 and 277.48 kg ha^-1 at 0-15 cm, 15-30 cm and 30-45 cm depth, while both the groundnut-wheat (27.70 kg ha^-1) and maize-chickpea (25.25 kg ha^-1) systems had higher available phosphorus (P) levels compared to pearl millet–fennel (14.56 kg ha^-1). Nutrient concentrations generally declined with depth, yet legume-based systems excelled: maize-chickpea and groundnut-wheat achieved peak available N and P, driven by biological N fixation and enhanced organic matter turnover. Pulse-based systems substantially outperformed cereal based systems rotations in nutrient retention and SOC buildup. These findings underscore crop diversification—especially legume integration—as vital for boosting soil fertility in semi-arid agroecosystems, supporting sustainable agriculture.