Effect of zinc-enriched organic manures on zinc composition in wheat and zinc pools in a vertisols of central India

Aim: The study was conducted at Jawaharlal Nehru Krishi Vishwa Vidyalaya, Jabalpur, Madhya Pradesh, India, to evaluate the effect of zinc-enriched organic manures on wheat yield, zinc uptake, and the distribution of zinc pools in soil. The research aimed to identify integrated nutrient management strategies that enhance wheat productivity and micronutrient availability in zinc-deficient soils.
Methods: A pot experiment was conducted to assess the impact of various combinations, organic manures (farm yard manure (FYM), Vermicompost (VC), and Poultry manure (PM)), Zinc (Zn), and Zinc-Solubilizing Bacteria (ZSB). For enrichment: incubation of 10 t FYM, 5 t VC, and 2.5 t PM ha-1 with Zn at 2.5 or 5.0 kg ha-1, and with or without ZSB. Parameters chlorophyll content (SPAD and pigment concentration), yield attributes, and nutrient uptake by wheat, were recorded. The soil nutrient availability, DTPA-extractable micronutrients, and pools of Zn were assessed.
Results:
The results indicated that the application of 10 t ha-1enriched FYM with 5.0 kg Zn ha-1 and ZSB (Pseudomonas aeruginosa) showed the highest SPAD reading (40), chlorophyll “a” (1.15 mg g-1), chlorophyll “b” (0.67 mg g-1), total chlorophyll (1.82 mg g-1 at 35 DAS), spike length (7.53 cm), number of grains (19) spikelets-1, grain weight (2.90 g pot-1), dry matter production (11.18 g pot-1) and Zn content and uptake by wheat. Zn-enriched poultry manure enhanced Zn and Cu availability, while Zn-enriched farm yard manure significantly improved soil NPK content and micronutrient availability. Application of enriched poultry manure with 2.5 kg Zn ha-1 and ZSB showed the highest uptake of Cu and Mn, while enriched poultry manure with 5.0 kg Zn ha-1 recorded the highest Fe uptake.
Conclusion: The application of enriched organic manures (FYM, VC, and PM) with Zn and ZSB significantly increased the availability and uptake of Zn, Cu, Fe, and Mn by wheat. Application of 2.5.0 t ha-1 enriched poultry manure with 5.0 kg Zn ha-1 and 2.5 t ha-1 enriched poultry manure with 2.5 kg Zn ha-1 and ZSB were particularly effective in increasing total and plant-available Zn pools in the soil. The findings highlight the importance of enrichment of organic manures with Zn and ZSB in improving micronutrient bioavailability, sustaining soil fertility, and enhancing wheat productivity in zinc-deficient soils.