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ratio but N amount and polyphenols were higher than in the coarse size fractions. As can be seen from Table 1, in the fine size fraction of yellow lupine, N microbial biomass has decreased by -36.8 mg.kg-1 while the sum of NH4+, NO3- and TONext increased by 18.7 mg.kg-1. Therefore, the difference (18.1 mg.kg-1) may be because of binding of proteins to polyphenol intermediates. The
correlation between polyphenol concentration and the sum of nitrogen changes was significant and positive (r =0.82) which confirm this hypothesis. It is interesting to note that other researchers also reported that plant tissues contain considerable amounts of phenolic compounds which can bind to enzymes and other proteins by non-covalent forces, including hydrophobic, ionic and hydrogen bonds, causing protein precipitation (Palm and Sanchez, 1991; Quideau et al., 2011). Following our experiment, the changes in soil N components during incubation from days 17-31 were compared with the changes from days 10-17. The decrease in NH4+ and of the sum of N changes in the coarse sizes of the three seed meals were greater than with the fine sizes (Table 2). Between days 17-31, the increase in soil NO3- content was lower than the NH4+ decrease. This may be because of immobilization of NO3- during nitrification of NH4+. Mineral N immobilization during this period was significantly correlated with the content of cellulose (r= 0.83*), cellulose + lignin (r=0.84*), cellulose + hemicelluloses (r=0.91*) and lignin + cellulose + hemicelluloses (r=0.92**). While the pathways by which lignin and hemicelluloses help to immobilize NO3- on cellulose is not clear, nevertheless, the cell wall cellulose is covalently cross-linked to hemicellulose and lignin. Li et al.
(2009) reported that N mineralization of lupin seed meals were negatively correlated with cellulose content (r = 0.73, p = 0.05) at 5°C, but that lignin and polyphenols had no effect on N mineralization due to their low content. Sabahi et al. (2009) have shown that accumulated N mineralization of legume seed meals at the end of an incubation experiment (61 days) significantly correlated with polyphenol and polyphenol:N ratio but not with cellulose. The effect of cellulose in N immobilization maybe short lived and unstable.
4. Conclusion From the results of this experiment, it appears that in cold condition such as winter, polyphenols can act as a stronger nitrification inhibitor than cellulose, hemicellulose and lignin, especially if its concentration is sufficiently high.
References Li, Z., Schulz, R., Müller, T. 2009. Short-term nitrogen availability from lupin seed meal as an organic fertilizer is affected by seed quality at low temperatures. Biological Agriculture and Horticulture, 26, 337–352.
Palm, C.A., Sanchez, P.A. 1991. Nitrogen release from the leaves of some tropical legumes as affected by their lignin and polyphenolic contents. Soil Biology and Biochemistry, 23, 83–88.
Quideau, S., Deffieux, D., Douat-Casassus, D., Pouysgu, L. 2011. Plant polyphenols: chemical properties, biological activities, and synthesis. Angewadte Chemie International Edition, 50, 586 – 621.
Sabahi, H., Schulz, R., Müller, T., Li Z. 2009. Nitrogen turnover of legume seed meals as affected by seed meal texture and quality at different temperatures. Archives of Agronomy and Soil Science 55, 6671- 682.
Nitrogen Workshop 2012
Potential for N2O emissions from volcanic grassland soils Cardenas, L.M.a, Scholefield, D.a, Hatch, D.J.a, Jhurreea, D.b, Clark, I.M.b, Hirsch, P.R.b Salazar, F.c, Rao-Ravella, S.a and Alfaro, M.c a Rothamsted Research, North Wyke, Okehampton, Devon EX20 2SB, UK b Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK c Instituto de Investigaciones Agropecuarias (INIA Remehue), Casilla 24-0, Osorno, Chile
1. Background & Objectives Grasslands are important ecosystems as they occupy large areas of the earth surface (about 40%, World Resources Institute, 2000). Their management involves a variety of practices affecting the soil physical structure, nutrient balance and the capacity of the soil to store C. Intensively managed grasslands have a major impact on water, soil and air quality. Nitrogen addition in the form of organic or inorganic fertiliser can cause losses to the environment, through leaching and to the atmosphere as nitrous oxide (N2O) and carbon dioxide (CO2), both greenhouse gases. Volcanic grassland soils in Chile, are not prone to leaching (Alfaro et al. 2008) and one of the possible pathways for N loss is N2O emission. The objective of this study was to investigate the potential for the formation of N2O of three Chilean soils and their relation to the presence of soil microbial communities.
2. Materials & Methods Soils were two andisols and an ultisol (Osorno, Chiloé and Cudico respectively) collected in April 2007 and July 2008 from three grassland locations in the South of Chile. The soils pH was 5.8, 5.6 and 5.2 organic matter was 170, 270 and 140 g kg-1; organic C was 9.9, 15.7 and 8.1 %.for Osorno, Chiloé and Cudico respectively. The soils were air dried, sieved (2 mm) and mixed to be incubated for 15 days in aerobic conditions for the measurement of N2O emissions (Carneiro et al., 2010). The soils (400 g dry soil) were compacted to a bulk density (BD) of about 1.2 (Cudico) and 0.64 g cm-3 (andisols) in Kilner jars with modified lids that incorporated a rubber septum for extracting gas samples. The following four treatments were superimposed: water only; water + N; water + C and water + N + C. N was applied as KNO3 at a rate of 200 kg N ha-1 (equivalent to 167 mg N kg soil-1 for Cudico and 313 mg N kg soil-1 for the andisols), based on the equivalent amount of soil occupying the 0-10 cm depth under field conditions. Three replicates were prepared for each soil and each treatment to give a total of 36 jars. C was applied as glucose at a rate of 600 kg C ha-1 (equivalent to 500 mg C kg soil-1 for Cudico and 938 mg C kg soil-1 for the andisols). The final soil moisture content, after amendments were applied, was equivalent to 90% of the water holding capacity (WHC) or about 80% water filled pore space (WFPS) which created conditions conducive for denitrification. N2O emissions were measured by gas chromatography daily for 8 days after the application of the amendment and then on days 11 and 15. Abundance of bacterial denitrification (nirK, nirS, nosZ) and 16S rRNA genes in the soils was determined by extracting DNA from each of three replicate samples of each soil before incubation and analysing in duplicate using qPCR.
3. Results & Discussion Emissions of N2O appeared in all soils in the N and N+C treatments about three days after the amendment application with cumulative fluxes for the whole incubation period of up to 20.9 mg N kg-1 dry soil (see Table 1).
For each soil, there was no difference in the N2O emissions between the two treatments (N and N+C) (P= 0.08; 0.48 and 0.31 for Chiloé, Cudico and Osorno, respectively). The interaction of soil with treatments was not significant (P 0.05). The denitrifier communities in all soils appeared to
4. Conclusions This study showed that under optimum conditions there is a large potential for N losses via emissions of N2O after addition of N fertiliser in these volcanic soils likely due to their high carbon content. The microbial analyses showed that there is larger potential for denitrification in the two soils that showed significantly larger N2O emissions, Osorno and Cudico.
References Alfaro M, Cárdenas L, Salazar F, Hatch D. and Ramírez L. 2009. Low nitrogen leaching losses in andisoils, advances in the processes involved. Proceedings of the 16th Nitrogen Workshop, Connecting different scales of nitrogen use in agriculture. Grignani C et al (ed) 28 de junio al 1 de julio, Turin, Italia. pp:115-116 Carneiro, J., Cardenas, L.M., Hatch, D.J., Trindade, H., Scholefield, D., Clegg, C.D. and Hobbs P. 2010. A laboratory study on the effect of pre-treatment with a nitrification inhibitor (Dicyandiamide) on an arable soil fertilized with ammonium sulphate. Environ Chem Lett 8, 237-246 World Resources Institute, 2000, in http://www.fao.org/index.php?id=24781
Nitrogen Workshop 2012
Prediction of mineral nitrogen content in deeper layers of soil in Lithuania based on its concentration in surface layers Staugaitis,G., Arbaciauskas, J., Mazvila, J., Vaisvila Z., Adomaitis, T., Sasnauskaite, L., Staugaitiene, R., Mazeika, R.
Agrochemical Research Laboratory of the Lithuanian Research Centre for Agriculture and Forestry, Kaunas, Lithuania
1. Background & Objectives Since 1985, aiming to increase nitrogen fertilizer utilization efficiency and to reduce environmental pollution with nitrogen compounds, the mineral nitrogen (Nmin.) method was employed for making recommendations on crop nitrogen fertilization in Lithuania (Pliupelyte et al., 1986). Research evidence suggests that Nmin. present in 0-60 cm soil layer at winter wheat vegetation resumption stage correlated with the yield of winter wheat best with winter wheat yield, for spring barley – in spring before fertilization (Staugaitis et al., 2007). Since 2006, in order to assess nitrogen fertilizer use efficiency, soil samples for determination of Nmin. concentration have been taken down to the 90 cm depth not only in spring, but also in autumn, at the end of October – beginning of November (Staugaitis et al., 2008). The objective of this study was to find out if it is possible to predict N availability in the deeper soil layers based on N concentration determined in surface layers.
2. Materials & Methods The studies were conducted in 2006-2009 in different regions of Lithuanian major soil typological units of various textures. Soil samples were collected from 20x20 m plots: in spring – within the first or second ten days of April (before nitrogen fertilization) and in autumn – within the last ten days of October or first ten days of November from 0-30, 30-60 and 60-90 cm layers of soil.
Colometry method was employed for measuring of Nmin content in soil samples (N-NO3 – using hydrazine sulphate and sulphanilamide; N-NH4 – using sodium phenolate and sodium hypochlorite). Statistical analysis was performed using the computer program STATISTICA (Clewer, Scarisbric, 2001).
3. Results & Discussion Evidence presented in Table 1 suggests that the ratio between Nmin. concentration in deeper layers of soil and that in surface layer tended to be smaller when conditional Nmin. concentration in 0-30 cm layer of soil increased.
Correlation between Nmin. concentrations in deeper and surface soil layers was best expressed by linear equation (Table 2). Correlative relations were strong and significant, thus the concentration of Nmin. in deeper soil layers can be calculated using the available data on Nmin. concentration in surface layer of soil.
Differences between the parameters of correlation equations calculated for different soil nitrogen status groups are small, therefore Nmin. concentration in deeper soil layers can be calculated based on its concentration in the surface layer using average parameters of the linear equation for all soils of mineral origin.
4. Conclusion Soils were grouped according to the nitrogen content in 0-30 cm soil layer, then simple linear equations were developed for the calculation of Nmin. concentrations in deeper layers of soil. It is possible to calculate the Nmin. concentrations in deeper layers of soil with sufficient accuracy for all soils of mineral origin without grouping them. In most cases, the correlations determined were very strong and significant.
References Clewer A.G. and Scarisbrick D.H. 2001. Practical statistics and experimental design for plant and crop science.
– New York, USA,– pp. 331.
Pliupelyte E., Lazauskas S., Matusevicius K. and Vaisvila Z. 1986. The dependence of winter wheat yieldand the efficacy of nitrogen fertilizers on the amount of mineral nitrogen in soil in Lithuanias coditions. Agrochimija 10, 44-51 (in Russian).
Staugaitis G., Vaisvila Z., Mazvila J., Arbaciauskas J., Adomaitis T. and Fullen M.A. 2007. Role of soil mineral nitrogen for agricultural crops: Nitrogen nutrition diagnostics in Lithuania. Archives of Agronomy and Soil Science 53, 3, 253-261.
Staugaitis G., Mazvila J., Vaisvila Z., Arbaciauskas J., Dalangauskiene A. and Adomaitis T. 2008. Mineral nitrogen in Lithuanian soils. Zemes ukio mokslai. 15, 3, 59-66.
Nitrogen Workshop 2012 Regulatory effect of soil properties on N2O emission from wheat-growing season in five soils: field and pot experiment Lebender, U., Senbayram M.
Research Center Hanninghof, Yara International, Dülmen, Germany
1. Background & Objectives Soils are a major source of N2O emission and the two biological processes (nitrification and denitrification) are responsible for its production. Chemical and physical properties of soils such as texture and total carbon (C) are important variables which control the formation of N2O from these processes. However, the impact of these variables on regulatory mechanisms of N2O formation is still poorly understood. The first objective of this study is to compare five German soil types for their N2O emission during the wheat-growing season under field conditions. In addition to the field experiment, the potential denitrification and respiration rate of the soils have been tested in incubation experiments under standardized anoxic conditions.