A controlled experiment to verify the effect of magnesium fertilizers on soil pH and available soil nutrients in acid soil of Nilgiris, India

An incubation experiment was conducted in laboratory conditions for 60 days to observe the impact of different Magnesium fertilizers on soil chemical properties, i.e. pH, available nitrogen, phosphorus, potassium, and DTPA extractable micronutrient cations. A complete factorial complete randomized block design (FCRD)with two replications and six levels was selected as the experimental layout. The levels included were (L0) Absolute control (L1) soil + Mg @ 10 kg ha-1, (L2) soil + Mg @ 20 kg ha-1, (L3) soil + 30 kg ha-1, (L4) soil + 40 kg ha-1, (L5) soil + 50 kg ha-1. Findings revealed that applying magnesium fertilizers to soil significantly (p ≤ 0.05) affects soil parameters. The impacts of magnesium fertilization on soil pH altered with sources and incubation period. The application of CaMg(CO3)2 @ 50 kg ha-1 recorded significantly (p ≤ 0.05) higher soil pH (5.67) as compared to MgCO3 @ 50 kg ha-1 that increased the pH up to 5.57 due to the impact of carbonate ion whereas MgSO4.7H2O decreased the soil up to 4.80 because of dissolution of SO42- ions to the soil solution.  Applying CaMg(CO3)2 significantly (p ≤ 0.05) influenced soil available N, P, K, Fe, Mn, and Cu content which is due to the decrease in acidity, which indirectly enhanced the nutrient availability.  The positive effects persisted throughout the experimental duration, indicating the potential long-term benefits of magnesium fertilization in acid soil management. This study contributes to the current body of knowledge by providing novel insights into applying magnesium fertilizers as an effective strategy for addressing soil acidity and improving nutrient availability in acid soil