Soil and Plant Responses to Phosphorus Inputs from Different Phytase-Associated Animal Diets
Date
2022-01-05
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Publisher
MDPI
Abstract
The over-supplementation of animal feeds with phosphorus (P) within livestock-production
systems leads to high rates of P excretion and thus to high P loads and losses, which negatively
impact the natural environment. The addition of phytase to pig and poultry diets can contribute
to reducing P excretion; however, cascading effects of phytase on plant–soil systems remain poorly
understood. Here, we addressed how three different diets containing various levels of exogenous
phytase, i.e., (1) no-phytase, (2) phytase (250 FTU), and (3) superdose phytase (500 FTU) for pigs
(Sus scrofa domesticus) and broilers (Gallus gallus domesticus) might affect P dynamics in two different
plant–soil systems including comfrey (Symphytum uplandicum) and ryegrass (Lolium perenne). We
found that differences in phytase supplementation significantly influenced total P content (%) of
broiler litter and also pig slurry (although not significantly) as a result of dietary P content. P Use
Efficiency (PUE) of comfrey and ryegrass plants was significantly higher under the intermediate
‘phytase’ dose (i.e., commercial dose of 250 FTU) when compared to ‘no-phytase’ and ‘superdose
phytase’ associated with pig slurry additions. Soil P availability (i.e., water soluble P, WSP) in both
comfrey and ryegrass mesocosms significantly decreased under the intermediate ‘phytase’ treatment
following pig slurry additions. Dietary P content effects on P losses from soils (i.e., P leaching)
were variable and driven by the type of organic amendment. Our study shows how commercial
phytase levels together with higher dietary P contents in pig diets contributed to increase PUE and
decrease WSP thus making the plant–soil system more P conservative (i.e., lower risks of P losses).
Our evidence is that dietary effects on plant–soil P dynamics are driven by the availability of P forms
(for plant uptake) in animal excretes and the type of organic amendment (pig vs. broiler) rather than
plant species identity (comfrey vs. ryegrass).
Description
Publication history: Accepted - 4 January 2022; Published - 5 January 2022.
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Article
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Keywords
agricultural value chain, circularity, mixed crop-livestock system, phosphorus cycling
Citation
Fornara, D., Ball, E.M.E., Mulvenna, C., Reyer, H., Oster, M., Wimmers, K., Damgaard Poulsen, H. and Rosemarin, A. (2022) ‘Soil and Plant Responses to Phosphorus Inputs from Different Phytase-Associated Animal Diets’, Agronomy. MDPI AG. doi:10.3390/agronomy12010130