title: Soil and foliar nutrient and nitrogen isotope composition (δ(15)N) at 5 years after poultry litter and green waste biochar amendment in a macadamia orchard.
abstract: This study aimed to evaluate the improvement in soil fertility and plant nutrient use in a macadamia orchard following biochar application. The main objectives of this study were to assess the effects of poultry litter and green waste biochar applications on nitrogen (N) cycling using N isotope composition (δ(15)N) and nutrient availability in a soil-plant system at a macadamia orchard, 5 years following application. Biochar was applied at 10 t ha(-1) dry weight but concentrated within a 3-m diameter zone when trees were planted in 2007. Soil and leaf samples were collected in 2012, and both soil and foliar N isotope composition (δ(15)N) and nutrient concentrations were assessed. Both soil and foliar δ(15)N increased significantly in the poultry litter biochar plots compared to the green waste biochar and control plots. A significant relationship was observed between soil and plant δ(15)N. There was no influence of either biochars on foliar total N concentrations or soil NH4 (+)-N and NO3 (-)-N, which suggested that biochar application did not pose any restriction for plant N uptake. Plant bioavailable phosphorus (P) was significantly higher in the poultry litter biochar treatment compared to the green waste biochar treatment and control. We hypothesised that the bioavailability of N and P content of poultry litter biochar may play an important role in increasing soil and plant δ(15)N and P concentrations. Biochar application affected soil-plant N cycling and there is potential to use soil and plant δ(15)N to investigate N cycling in a soil-biochar-tree crop system. The poultry litter biochar significantly increased soil fertility compared to the green waste biochar at 5 years following biochar application which makes the poultry litter a better feedstock to produce biochar compared to green waste for the tree crops.
authors.affiliation: Environmental Futures Research Institute, School of Natural Sciences, Griffith University, Nathan, Brisbane, Queensland, 4111, Australia, s.hosseini-bai@griffith.edu.au.
authors.forename: Shahla Hosseini
authors.initials: SH
authors.lastname: Bai
authors.forename: Cheng-Yuan
authors.initials: CY
authors.lastname: Xu
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Xu
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Blumfield
authors.forename: Haitao
authors.initials: H
authors.lastname: Zhao
authors.forename: Helen
authors.initials: H
authors.lastname: Wallace
authors.forename: Frédérique
authors.initials: F
authors.lastname: Reverchon
authors.forename: Lukas
authors.initials: L
authors.lastname: Van Zwieten
mesh_terms: D000383:Agriculture / Q000379:methods*; D000818:Animals; D002606:Charcoal; D005308:Fertilizers; D039106:Macadamia / Q000737:chemistry / Q000254:growth & development*; D008372:Manure; D009587:Nitrogen Isotopes / Q000032:analysis*; D010758:Phosphorus / Q000378:metabolism; D018515:Plant Leaves / Q000737:chemistry*; D011200:Poultry; D012987:Soil / Q000737:chemistry*; D013997:Time Factors
chemical_list: D005308:Fertilizers; D008372:Manure; D009587:Nitrogen Isotopes; D012987:Soil; C540010:biochar; D002606:Charcoal; D010758:Phosphorus