Substitution of manure source and aerator in nursery media on sandy loam topsoil and their fertility indices 4\xa0months after formulation

Abstract

PurposeIn soil-based nursery media, topsoil, poultry droppings and sawdust conventionally provide anchorage, nutrients and aeration, respectively. Considering poultry droppings’ scarcity and sawdust’s inertness nutrient-wise, more readily available organic wastes should be explored as substitutes. Here, we evaluated the effect of such substitution on media fertility, aimed at seeking alternatives to the conventional practice.MethodsIn a topsoil-manure-aerator volume ratio of 3:2:1, poultry droppings was substituted with pig slurry (slurry) or cattle dung (dung) as manure and sawdust with rice-husk dust (huskdust) as aerator, giving seven soil-based media including reference medium (topsoil+droppings+sawdust) and the control (topsoil+topsoil+topsoil). They were watered regularly and analysed for fertility parameters 4 months later.ResultsReference had the highest pH (8.60) and topsoil + dung + huskdust/control the lowest (6.83). Substituting sawdust with huskdust enhanced pH, organic matter and Mg2+ in droppings/dung-amended media (topsoil+droppings+huskdust/topsoil+dung+huskdust) unlike slurry-amended ones where it too reduced total nitrogen (0.19 vs 0.11%). The substitution also enhanced available phosphorus in topsoil+droppings+huskdust (117.50 mg kg−1) and topsoil+dung+huskdust (71.50 mg kg−1) but reduced K+ in the latter where it too had moderating effects on Na+. Reference surpassed topsoil+slurry+huskdust for Ca2+, but was surpassed by topsoil+droppings+huskdust for Mg2+. Reference/topsoil+droppings+huskdust and topsoil+slurry+huskdust/control showed highest and lowest CEC, respectively. Excluding pH, topsoil+dung+huskdust and topsoil+slurry+sawdust were, notably, consistently similar. Overall, droppings-amended > dung-amended > slurry-amended media and, for available phosphorus only, sawdust-aerated < huskdust-aerated media.ConclusionBased on fertility status 4 months after blending, topsoil+droppings+huskdust could serve as alternative to the conventional nursery medium, or topsoil+dung+huskdust where near-neutral pH is preferred to increased phosphorus/cations release.