Some utilisation options for cattle dung as soil amendment and their effects in coarse-textured Ultisols and maize growth
Purpose Scarcity of effective manures frustrates the adoption of organic-based soil fertility management in tropical agriculture. Cattle dung (CD) is hugely generated but underutilised due to its high carbon-nitrogen ratio and low mineralisation rate compared with poultry droppings (PD), hence the need to enhance CD’s efficacy.
Method Effects of CD utilisation options on fertility of sandy-loam Ultisols and maize growth were assessed under glasshouse conditions. Four options, CD in its cured form (CD), CD-derived biochar (BC), CD water-soaked CD fermentate (FM) and CD+urea (CDU), were assessed against cured PD and NPK-15:15:15 as reference manure and fertilizer, respectively, using 5-kg potted soils watered to and maintained at field capacity. Organic amendments were added at 10-t-ha–1 equivalents before sowing except FM added alongside CDU’s urea at 250 kg ha–1 equivalent after sowing. Also, NPK-15:15:15 was added at 400 kg ha–1 equivalent after sowing.
Results After 9 weeks, BC, CDU and PD had similar effects on soil pH, organic matter, total N and available P which increased by 49-51%, 30-34%, 200-333% and 164-176%, respectively relative to the control. The BC always showed maize plants similar to the tallest ones in PD. Maize dry matter was the highest in CDU/PD (35.06-35.56 g pot–1) and the lowest in control (9.56 g pot–1). Residual effects showed that BC and PD maintained the increases in soil pH, while CDU/PD always showed tallest plants and enhanced dry matter over the rest except BC. Soil pH, Mg2+ and base saturation together caused 93% of treatments’ effects on dry matter.
Conclusion Converting CD to BC or supplementing it with urea (CDU) in coarse-textured tropical soils could have prolonged liming and/or biomass productivity-enhancing effects as PD.
- The effects of four cattle dung (CD) utilization options, with poultry-droppings manure and NPK fertilizer as reference amendments, were assessed for coarse-textured Ultisols.
- For this highly leached and hence acid soil, converting CD to biochar before use or fortifying it with urea produced similar effects on key soil fertility indices as compared to poultry-droppings manure.
- The CD-derived biochar had a prolonged positive effect on soil pH, while the urea-fortified CD enhanced maize growth as much as poultry-droppings manure did.
- Treatment effects on soil pH and the exchangeable bases (especially Mg2+) largely accounted for the variations in dry matter of maize.