Mackay, J.Macdonald, L.Smernik, R.Cavagnaro, T.2017-06-212017-06-212017Soil Biology and Biochemistry, 2017; 107:50-590038-07171879-3428http://hdl.handle.net/2440/106138As phosphorus (P) fertilisers become increasingly expensive there is a need to find innovative ways to supply crops with P. Organic amendments (OA) can contain high concentrations of total P, although the P is present in various forms. We aimed to determine the forms of P and carbon (C) in a range of OA and the effect of these OA on soil microbial biomass, P release, arbuscular mycorrhizal (AM) colonisation, and plant P uptake. Four OA were investigated: two chicken litters (CHK-STR and CHK-SD, one with straw bedding and one with sawdust bedding), a pig litter (PIG-STR) and a municipal waste compost (COMP). An incubation experiment and a plant growth experiment were conducted in which OA and INORG-P were supplied at 15 mg P kg−1 soil and a zero P control was included. All OA had high P concentrations and did not result in an increase in the soil microbial biomass C. There were few temporal changes in available P throughout the incubation experiment suggesting that solubilisation and/or mineralisation of P occurred at a similar rate as conversion of P to unusable forms. Of the OA, PIG-STR had the largest proportion of orthophosphate P and bicarbonate extractable P, and it provided the most P to plants. While CHK-STR had a higher proportion of orthophosphate P and bicarbonate extractable P than CHK-SD, both CHK-STR and CHK-SD provided plants with similar amounts of P. This could be because CHK-SD had a higher proportion of phytate, which can be rapidly mineralised to orthophosphate, and/or because plants in the CHK-SD had higher rates of arbuscular mycorrhizal (AM) colonisation compared with CHK-STR. This study provides new insights into plant and microbial responses to OA which could help in the development of sustainable food production systems.en© 2016 Elsevier Ltd. All rights reserved.Phosphorus; organic amendments; diffusive gradients in thin films (DGT); microbial biomass carbon; nuclear magnetic resonance spectroscopy; wheatJournal article003006111710.1016/j.soilbio.2016.12.0080003952135000062-s2.0-85007500084283213Smernik, R. [0000-0001-6033-5855]Cavagnaro, T. [0000-0002-9922-5677]