Biochar improves diary pasture yields by alleviating P and K constraints with no influence on soil respiration or N2O emissions  

作　　者：Lukas van Zwieten Stephen Kimber Stephen Morris Lynne M.Macdonald Josh Rust Scott Petty Stephen Joseph Terry Rose 

机构地区：[1]NSW Department of Primary Industries,1243 Bruxner Highway,Wollongbar 2477,NSW,Australia [2]CSIRO Land and Water Agriculture and Food/Sustainable Agricultural Flagship,Urrbrae,SA 5064,Australia [3]School of Materials Science and Engineering,University of New South Wales,Kensington 2033,NSW,Australia [4]Southern Cross Plant Science,Southern Cross University,Lismore 2480,NSW,Australia [5]Centre for Organics Research,Southern Cross University,Lismore 2480,NSW,Australia

出　　处：《Biochar》2019年第1期115-126,共12页生物炭（英文）

摘　　要：Dairy pastures can be a major source of soil nitrous oxide(N_(2)O)emissions due to the combination of intensive nitrogen(N)fertiliser use and high soil water content,from either rainfall and/or irrigation.Biochar application is a promising approach to lower soil greenhouse gas emissions,particularly under high soil moisture conditions where denitrification is the primary N-transformation pathway.In a replicated field trial,we evaluated the effects of two contrasting biochars derived from poul-try litter and from hardwood on soil N_(2)O emissions,soil ammonium(NH4^(+))and nitrate(NO3^(−))status,pasture productivity and herbage nutrient content.A liming treatment to mimic the liming equivalence of the poultry litter biochar was used to separate any effects observed from changes in soil pH.To further separate the effects of biochars on soil N status,N_(2)O emissions and pasture N uptake,high and low N fertiliser doses(annual application of 672 kg N ha^(−1),336 kg N ha^(−1))were superimposed across all of the treatments.The N fertiliser dose had no significant impact on pasture yield.Application of poultry litter biochar resulted in significant increases in pasture productivity under both high and low N inputs.This was achieved by alleviating soil P,and possibly K nutritional constraints that are typical in Australian Ferralsols.Under the high N fertiliser dose,emissions of N_(2)O from the treatments and control were not significantly different(p>0.05)and ranged between 1.14 and 1.78 kg N_(2)O-N ha^(−1)across the 11-month study.The low N dose resulted in significantly lower emissions of N_(2)O of between 0.80 and 0.84 kg N_(2)O-N ha^(−1),but biochar had no significant effect on net emissions across the season.The lack of impact of biochar on N_(2)O emissions was attributed to the relatively dry conditions over the trial period resulting in nitrification being the most likely N-transformation pathway.During brief episodes of high soil moisture,peak emissions from the biochar plots were lower than from the co

关 键 词：FERRALSOL Autochamber methodology NITRIFICATION Urea Lime Poultry litter biochar Hardwood biochar Emission intensity 

分 类 号：S15[农业科学—土壤学]