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«International 17 Workshop th Nitrogen The was jointly organised by Teagasc and AFBI Printed by Print Depot Suggested citation Authors, 2012. Title ...»

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References Akimoto, F., Matsunami, A.; Kamata, Y., Kodama, I., Kitagawa, K.; Arai, N.; Higuchi, T.; Itoh, A. and Haraguchi, H.

2005. Cross-correlation analysis of atmospheric trace concentrations of N2O, CH4 and CO2 determined by continuous gas-chromatographic monitoring. Energy 30, 299-311.

Mørkved, P.T., Dörsch, P., Henriksen, T.M. and Bakken, L.R. 2006. N2O emissions and product ratios of nitrification and denitrification as affected by freezing and thawing. Soil Biology and Biochemistry 38, 3411-3420.

Ruser, R., Flessa, H., Russow, R., Schmidt, G., Buegger, F. and Munch, J.C. 2006. Emission of N2O, N2 and CO2 from soil fertilized with nitrate: effect of compaction, soil moisture and rewetting. Soil Biology and Biochemistry 38, 263Nitrogen Workshop 2012 Influence of soil amendment history on decomposition of recently applied organic amendments Nett, L.a, Ruppel, S.a, Ruehlmann, J.a, George, E.a, Fink, M.a a Leibniz-Institute of Vegetable and Ornamental Crops Großbeeren and Erfurt

1. Background & Objectives Long-term organic amendment, compared to the absent or solely mineral fertilization, can increase the microbial biomass content in soil (Gunapala and Scow, 1998), change the microbial community structure (Dambreville et al., 2006), and enhance the activities of certain enzymes (Carpenter-Boggs et al., 2000). However, it is not clear whether long-term amendment results in the modified decomposition rates of newly added organic matter. The literature does not give a consistent answer to this question (Fauci and Dick, 1994; Hadas et al., 1996; Mallory and Griffin, 2007). Hence, the objective of this study was to examine whether potential amendment history effects on decomposition of recently applied material depend on the amendment chemical characteristics.

2. Materials & Methods The soil was taken from a field experiment (Ruehlmann, 2006) where different amendment treatments had been applied to one original soil (loamy sand) since 1973: unfertilized control (HCO), solid farmyard manure (HFM), pine bark (HPB), and crop residues of the previous crop (HCR), referred to as amendment history treatments (prefix “H”). One composite samples of 24

subsamples was optained per treatment. These four soil materials were mixed in bulk with either:

nothing (RCO), farmyard manure (RFM), pine bark (RPB), or crop residues (RCR) at a rate equivalent to 2 mg C g−1 dry soil, hereafter referred to as recent amendment treatments (prefix “R”).

In a 147-day laboratory incubation experiment, net CO2-C release (∆CO2-C; 5 replications) and net changes in soil mineral N (∆SMN; 3 replications) and microbial biomass carbon (∆MBC; 3 replications) contents were determined.

3. Results & Discussion In the case of amendment history effects on the decomposition of recently added amendment, significant interactions between the factors amendment history and recent amendment were expected to be revealed in the two-way ANOVA. Such interactions were only detected in ∆SMN at day 3 and 78 (Table 1). In these cases, however, no consistent effect of amendment history on the decomposition of recently applied amendments was revealed by linear contrasts. Moreover, at day 147, the same trend (HCO HPB = HCR HFM; Tukey’s HSD) was exhibited in ∆SMN irrespective of recent amendment treatment (Table 1). This pattern was in concurrence with soil total N and C contents, initial microbial biomass C and initial soil mineral N (Fig. 1). These results were consistent with those of Hadas et al. (1996) and Langmeier et al. (2002), who found that differences in net N mineralization were mostly due to differences in N mineralization from previously existing soil organic matter. In ∆MBC and ∆CO2-C, there were no interactions between the two main factors at any of the measurement dates (Table 1). This was in accordance with results of Fauci and Dick (1994), who showed that the microbial biomass of the different soils did not respond differently to different recent amendment treatments. In conclusion, the results indicate that amendment history effects on the decomposition of recently applied amendments, if present, are too small to be relevant to fertilization practice. One explanation could be the capability of soil microorganisms to quickly respond to changes in substrate availability by adjusting both metabolic activity and microbial community structure.

–  –  –

Figure 1. Initial values of microbial biomass C (MBC) and soil mineral N (SMN) contents in μg g−1 dry soil.

Different letters above the columns indicate significant (p 0.05) differences between amendment history treatments in MBC (upper case) and in SMN (lower case), respectively.

References Carpenter-Boggs L., Kennedy A.C. and Reganold J.P. 2000. Organic and biodynamic management: Effects on soil biology. Soil Science Society of America Journal 64, 1651-1659.

Dambreville C., Hallet S., Nguyen C., Morvan T., Germon J.C. and Philippot L. 2006. Structure and activity of the denitrifying community in a maize-cropped field fertilized with composted pig manure or ammonium nitrate. FEMS Microbiology Ecology 56, 119-131.

Fauci M.F. and Dick R.P. 1994. Soil microbial dynamics: Short-term and long-term effects of inorganic and organic nitrogen. Soil Science Society of America Journal 58, 801-806.

Gunapala N. and Scow K.M. 1998. Dynamics of soil microbial biomass and activity in conventional and organic farming systems. Soil Biology & Biochemistry 30, 805-816.

Hadas A., Kautsky L. and Portnoy R. 1996. Mineralization of composted manure and microbial dynamics in soil as affected by long-term nitrogen management. Soil Biology & Biochemistry 28, 733-738.

Langmeier M., Frossard E., Kreuzer M., Mader P., Dubois D. and Oberson A. 2002. Nitrogen fertilizer value of cattle manure applied on soils originating from organic and conventional farming systems. Agronomie 22, 789-800.

Mallory E.B. and Griffin T.S. 2007. Impacts of soil amendment history on nitrogen availability from manure and fertilizer. Soil Science Society of America Journal 71, 964-973.

Ruehlmann J. 2006. The box plot experiment in Grossbeeren after six rotations: Effect of fertilization on crop yield.

Archives of Agronomy and Soil Science 52, 313–319.

Nitrogen Workshop 2012

Influence of N deposition and atmospheric O3 concentration on N2O and NO emissions from Mediterranean pastures.

Sanchez-Martin, L.a, de la Cruz Lopez, A.a, Garcia-Torres, L.a, Calvete, H.b, García, H.b, Gonzalez, I.b, Bermejo, V. b, Vallejo, A.a a ETSI Agrónomos, Technical University of Madrid, Ciudad Universitaria. 28040 Madrid, Spain.

b Ecotoxicity of Air Pollution, CIEMAT, Madrid, Spain.

1. Background & Objectives Pastures are among the most important ecosystems in Europe considering their high biodiversity and their coverage in the European territory (8 %). Previous studies have shown that in the last decades, tropospheric ozone (O3) produced primarily by atmospheric pollution, and nitrogen (N) deposition, significantly affect these ecosystems altering their structure and composition (Sanz et al., 2007). The greenhouse gas nitrous oxide (N2O) and the photochemical oxidant nitric oxide (NO) have increased during recent years, mostly as a result of management of natural and agricultural soils. The magnitude of these emissions, promoted by nitrification and denitrification processes, depends on substrate availability (mineral N), climate and soil properties. However, the effect that the combination of both tropospheric ozone and nitrogen deposition has on nitrogen emissions in a Mediterranean pasture ecosystem is largely unknown. Our objective was to quantify the N2O and NO emissions from a Mediterranean pasture for three different levels of N deposition under different ozone concentrations.

2. Materials & Methods The experiment was carried out from April to June 2011 in “La Higueruela/CSIC” field station located in Toledo (Spain). An Open Top Chamber (OTC) technique was used to establish the different O3 concentrations: [unfiltered air (ANF), unfiltered air + 40 ppb of ozone (AFU), unfiltered air + 60 ppb of ozone (AFU+) and control plots without OTC (AC)]. Six plant species, representative of a typical annual pasture, were sown inside the chambers and given four applications of N fertilizer (NH4NO3), with one application every 15 days. Different rates of fertilizer were applied to simulate different levels of atmospheric N deposition (0, 20 and 40 kg N ha‐1 corresponding to the treatments N-0, N-20 and N-40, respectively). Emissions of N2O were measured by the static chamber technique and analysed by gas chromatography (Sanchez-Martin et al., 2010) and a flow through system was used to measure NO emissions by chemiluminescence (Roelle et al., 1999). Soil parameters such as WFPS, mineral N and temperature were also measured (Sanchez-Martin et al., 2010).

3. Results & Discussion Total N2O emissions were not affected by different rates of N deposition (Figure 1a). According to Skiba et al. (1998) it is necessary to exceed the threshold of 40 kg N ha‐1 y‐1 if the soil was not previously exposed to high rates of N inputs. Some negative N2O fluxes were observed, especially for the treatments which were exposed to ambient concentrations of ozone (ANF and AC), which also shows that there was no effect of the OTC.

Contrary to some studies (Kanerva et al., 2006; Bhatia et al., 2011), increasing tropospheric ozone (AFU+) increased N2O emissions. On the other hand, NO emissions were mainly affected by the different levels of N deposition but not the O3 concentrations (Figure 1b). According to Kanerva et al. (2007), the impact of elevated O3 on the production and consumption of trace gases is not well

Nitrogen Workshop 2012

understood and has not been assessed in natural or semi-natural grasslands. To date, very few studies have looked at the combined affects of N and O3 on below-ground processes that may be important for the global atmospheric budgets of these gases, especially in climates with extreme seasonal weather variations such as the Mediterranean climate.

–  –  –

Figure 1. Total N2O (a) and NO (b) emissions from different O3 and N treatments at the end of the experimental period.

4. Conclusion Deposition of atmospheric N significantly increased NO emissions, although there were no significant differences between the values for different deposition rates.

By contrast, N2O emissions were not affected by N deposition but emissions increased when atmospheric O3 concentration reached 60-80 ppb.

Moderately enhanced O3 concentrations and N deposition rates appear to alter N2O and NO emissions but longer measurement periods are required to verify these interactions in Mediterranean pasture ecosystems.

References Bhatia, A., Ghosh, A., Kumar, V., Tomer, R., Singh, S.D. and Pathak, H. 2011. Effect of elevated tropospheric ozone on methane and nitrous oxide emission from rice soil in north India. Agriculture, Ecosystems and Environment 144, 21Kanerva, T. 2006. Below‐ground processes in meadow soil under elevated ozone and carbon dioxide ‐ Greenhouse gas fluxes, N cycling and microbial communities. Thesis. University of Helsinki, Faculty of Biosciences, Department of Biological and Environmental Sciences and MTT, Agrifood Research Finland Kanerva, T., Regina, K., Rämo, K., Ojanperä, K. and Manninen, S., 2007. Fluxes of N2O, CH4 and CO2 in a meadow ecosistem exponed to elevated ozone and carbon dioxide for three years. Environmental Pollution 145, 818‐828 Roelle, P., Aneja, V. P., O’Connor, J., Robarge, W., Kim, D. and Levine, J. S. 1999. Measurement of nitrogen oxide emissions from an agricultural soil with a dynamic chamber system. Journal of Geophysical research 104, 1609-1619.

Sanz, J., Bermejo, V., Gimeno, B.S., Elvira, S. and Alonso, R. 2007. Ozone sensitivity of the Mediterranean terophyte Trifolium striatum is modulated by soil nitrogen content. Atmospheric Environment 41, 8952‐8962.

Sanchez-Martin, L., Sanz-Cobena, A., Meijide, A., Quemada, M. and Vallejo, A. 2010. The importance of the fallow period for N2O and CH4 fluxes and nitrate leaching in a Mediterranean irrigated agroecosystem. European Journal of soil Science 61, 710-720.

Skiba, U., Sheppard, L., Pitcairn, C.E.R., Leith, I., Crossley, A., van Dijk, S., Kennedy. V.H. and Fowler, D. 1998. Soil nitrous oxide and nitric oxide emissions as indicators of the exceedance of critical loads of atmospheric N deposition in seminatural ecosystems. Environmental Pollution 102, S1, 457-461

Nitrogen Workshop 2012

Influence of soil water status and compaction on N2O and N2 emissions from 15N-labelled synthetic urine.

Harrision-Kirk, T.a, Thomas, S.M.a, Beare, M.H.a, Clough, T.J.b, van der Weerden, T.J.c, Meenken, E.D.a a New Zealand Institute for Plant & Food Research, Private Bag 4704, Christchurch 8140, New Zealand.

b Department of Soil and Physical Sciences, PO Box 7647, Lincoln University, Canterbury, New Zealand.

c AgResearch Invermay, Private Bag 50034, Mosgiel, New Zealand.

1. Background & Objectives Animal excreta deposition is New Zealand’s largest source of nitrous oxide (N2O) emissions, representing 50% of direct N2O emissions (de Klein et al., 2003). Denitrification is considered the main process of N2O production from these pasture soils. Soil water status is a key determinant of these emissions as it influences air-filled porosity and oxygen diffusion into and through the soil.

Soil compaction is an important factor affecting these processes. The aim of this research was to develop a better understanding of the role that soil physical characteristics and changing soil water status during drainage play in regulating both N2 and N2O emissions from urine patches, using 15Nlabelled synthetic urine. This knowledge will be used to develop practical tools for predicting when there is greatest risk of N2O emissions from urine patches.

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