Nicholas Clarke
Seniorforsker
Biografi
Sammendrag
In agricultural production, it is crucial to increase the availability of phosphorus (P) in cultivated soil to solve the P limitation. Arbuscular mycorrhizal fungi (AMF) have been proven to promote crop nutrient absorption effectively, while biochar can lead to improvements in soil properties. However, the possible synergistic effect of AMF and biochar on P uptake by crops as well as its underlying mechanisms are unclear. In this study, we conducted a pot experiment to explore the effects of biochar and AMF (Glomus etunicatum) on the community of rhizospheric phosphate-solubilizing microorganisms (PSMs) of maize (Zea mays L. Xianyu-335) using metagenomic methods. The experiment used 0 mg P2O5 g·kg−1 soil (P0) and 30 mg P2O5 g·kg−1 soil (P30) application rates. Each P application rate included 0 (NC), 20 g·kg−1 biochar (BC) addition, inoculation AMF, and without AMF treatments (NM) for a total of eight treatments. During the experiment, both the P uptake and the biomass of maize were measured. The study found that the combination of AMF and biochar significantly increased the mycorrhizal colonization rate of maize roots, regardless of P application level. It was observed that the P uptake by maize was significantly increased when exposed to a combination of AMF and biochar. The increase in P uptake in P0 treatments was 67% higher than the sum of the effects of biochar and AMF inoculation alone. The increase was only 35% higher in P30 treatments, demonstrating a substantially higher interactive effect under P0 than under P30 conditions. The AM-BC treatments significantly increased the abundance of Streptomyces, Bacillus, and Pseudomonas, genera that are known to contain PSMs. In addition, the abundance of genes related to P-cycling (gcd, phoD, and ugpQ) in PSMs increased significantly by 1.5–1.8 times in AM-BC treatments compared with NM-BC and AM-NC treatments under P0 conditions. This increase was significantly and positively correlated with the P uptake. Overall, the results suggest that biochar can help AMF colonize the roots, increasing the functional roles of PSMs in the rhizosphere, which in turn promotes P uptake and biomass in maize. This study provides a new way to improve P-use efficiency and reduce the need for P-fertilizer application in agricultural production.
Forfattere
Peter Waldner Tiina M. Nieminen Elena Vanguelova Nathalie Cools Carmen Iacoban Katrin Meusburger Nicholas Clarke Kai Schwärzel Anita Zolles Anna Andreetta Antti-Jussi Lindroos Bruno de Vos Holger Sennhenn Reulen Zoran Galic Panos Michopoulus Henning MeesenburgSammendrag
Det er ikke registrert sammendrag
Sammendrag
Effekten av skogbruk på eutrofibelastningen i Oslofjorden er anslått basert på tilførsler av løst uorganisk nitrogen (DIN). Dette anslaget er beheftet med en rekke usikkerheter som kan forbedres ved å bl.a. samle inn flere data om effekten av skogsdrift på vann, samt forbedre anslag over årlig hogstareal. Våre anslag antyder at tap av nitrogen fra skogsdrift til Oslofjorden ligger på nivå med tapet fra spredt avløp og bebyggelse. På side 6 finnes et utvidet sammendrag. The effect of forestry on the eutrophic pressure of the Oslo Fjord has been estimated based on fluxes of DIN (dissolved inorganic nitrogen). This estimate is subject to many uncertainties that can be improved by, among other things, collecting more data on the effect of forestry on water, as well as improving estimates of annual logging area. Our estimate suggests that losses of nitrogen to the Oslo Fjord from forestry are in the same range as losses from households not connected to sewage treatment plants and from settlements.
