Vol. 9, Special Issue 12, Part B (2025)

The study conducted Research cum Instructional Farm IGKV, Nutrients play a crucial role in maximizing crop productivity and their supply is predominantly met through chemical fertilizers such as urea, DAP and muriate of potash. However, the current challenges in the availability and escalating cost of these fertilizers necessitate exploring alternative nutrient sources. In this context, a field experiment was conducted during kharif 2024-25 at the Research-cum-Instructional Farm, College of Agriculture, Indira Gandhi Krishi Vishwavidyalaya, Raipur (Chhattisgarh), to evaluate the potential of different organic manures as substitutes for chemical fertilizers in sustaining crop productivity and improving soil fertility under rice cultivation. The experiment was laid out in a Randomized Block Design comprising seven treatments with four replications. The treatments included: T₁-Control, T₂-100% RDF (100:60:40 kg N:P:K ha^-1), T₃-100% FYM (24t ha^-1), T₄-100% Vermicompost (10t ha^-1), T₅-100% Poultry manure (10t ha^-1), T₆-100% Kitchen waste compost (10 t ha^-1) and T₇-100% Cow dung (24 t ha^-1).
The results of one season indicated that the application of 100% RDF (T₂) was most effective in enhancing growth, yield attributes, yield, nutrient uptake, nutrient use efficiencies and economic returns. The treatment T₂ recorded the highest total tillers hill⁻¹ (9.6), effective tillers hill⁻¹ (6.5), grains panicle⁻¹ (127), panicle length (23.55 cm), panicle weight (4.50 g), grain yield (61.62 q ha⁻¹), straw yield (78.12 q ha⁻¹), harvest index (44.11%) and yield increase over control (189%). The maximum test weight (18.48 g) was observed in T₇ (Cow dung). Nutrient uptake was also significantly higher under T₂, with N, P and K uptake values of 105.04, 18.46 and 163.00 kg ha⁻¹, respectively. Similarly, the highest partial factor productivity, agronomic efficiency and recovery efficiency for N, P and K were observed under T₂.
Regarding soil properties, organic manure treatments showed positive effects on soil health. Treatments with poultry manure (T₅), cow dung (T₇), FYM (T₃) and vermicompost (T₄) maintained favorable soil pH (7.20), EC (0.33 dS m⁻¹) and organic carbon (0.60%). Available N (212.00 kg ha⁻¹), P (18.95 kg ha⁻¹) and K (440.21 kg ha⁻¹) were highest under T₆, T₂ and T₃, respectively. Micronutrient availability was also enhanced under organic manures, with Fe (12.36 ppm) and Mn (7.36 ppm) highest in T₄, Cu (1.38 ppm) in T₅ and Zn (0.65 ppm) in T₃. Correlation analysis revealed that available N was the most critical factor influencing rice yield. The highest benefit-cost ratio (2.93) was recorded in T₂, followed by T₃ (2.77). Overall, the study concluded that while 100% organic manure applications could not match the yield levels obtained with RDF, they played a significant role in sustaining and improving soil nutrient status.