Evaluations of environmental factors responses and emission factor of N2O and NO fluxes from agricultural soils by the hierarchical Bayesian model with lognormal probability distribution
Kazuya Nishina, Hiroko Akiyama, Shigeto Sudo, Seiichi Nishimura, Kazuyuki Yagi National Institute of Agro-Environmental Sciences, Japan E-mail address; [email protected] ([email protected]) Agricultural soils are the major source of nitrous oxide (N2O) and nitric oxide (NO). Because N fertilizer strongly stimulates these N oxide gases emission derived from both nitrification and denitrification processes in soils. However, many researchers pointed out that the strength of N oxide gases from agricultural soils still has a large uncertainty in the global budget. One of the reasons is due to a methodological limitation of a closed chamber method, which is spatial resolution and its representativeness (Mosier et al., 1998). According to previous reports, the spatial variations of N oxide fluxes from soils seemed to be inherently high dispersion and skewed distribution, which could not be approximated to normal distribution (Fig. 1). Therefore, to analyze and adjust the parameters by the ensemble averaged N2O flux cause bias in the estimation. Nishina et al. (2009) proposed the application of hierarchical Bayes (HB) model framework to N2O flux from forest soils, by which the N2O flux was assumed as lognormal distribution and with random variable to cope with not independent data among the replications. In this study, we applied HB model to daily N2O and NO fluxes from NIAES lysimeter field with Urea application treatment (see detail in Akiyama et al., 2002). Our simple Bayesian hierarchical model aimed (i) to quantify the response of N2O and NO fluxes against the environmental factors and nitrogen fertilization effect and by then, (ii) to estimate N2O and NO fluxes and their emission factor more accurately with uncertainty. The HB model revealed the responses of N2O and NO flux to the N fertilizer, soil temperature and water filled pore space (WFPS) (Fig. 2), which is estimated by taking account in variability as lognormal distribution. See detail the observed flux and the hierarchical Bayes model in the presentation.  A. R. Mosier, 1998, Biol. Fert. Soils, 27, 221-229.  K. Nishina et al., 2009, Biogeocehm., 96, 163-175.  H. Akiyama et al., 2002, Nutr. Cycle. Agroecosys. , 63, 219-230.
Fig 1, Schematic illustration of the variations in N oxide flux (4 replicates). Middle circle with bar
indicate mean with S. D., which can be calculated from both side of values (it’s not absolutely
precise). Left (right) values generated from normal (lognormal) distribution (line see aside).
Fig 2. Response functions of N2O flux (a) and NO flux (b) calculated from posterior
distributions. Top; fertilization resnponse, Middle; soil temperature response, Bottom;
WFPS response. Dashed line indicated the functions calculated from posterior median.
It has been estimated that 100,000 tonnes of extraterrestrial material Every year the Earth is showered by reach the Earth’s surface every year. It extraterrestrial material falling from can be anything from fine dust to space. The Museum’s mineralogy and metallic masses weighing many tonnes. petrology collections include a small Extraterrestrial material t
[Regd. No. TN/CCN/467/2009-11. [Price: Rs. 6.40 Paise. TAMIL NADU GOVERNMENT GAZETTE Part III—Section 1(a) General Statutory Rules, Notifications, Orders, Regulations, etc., issued by Secretariat Departments. NOTIFICATIONS BY GOVERNMENT CONTENTS Tamil Nadu Water (Prevention and Control of Pollution) Rules, 1983—Tamil Nadu State Legal Services Authority Rules, 1997—