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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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3. Results & Discussion The performance of the winter wheat varied considerably between the two seasons. In 2009 the MT treatment had an increasing CNU as the season progressed with a significantly higher uptake than the P treatment at GS 65 and 75. However, cultivation system had no significant effect on grain yield or total N uptake at harvest. Due to poor crop establishment with MT in 2010, the P treatments had a higher CNU at GS 24, 28, 32 and 47. Although there was no difference in CNU at GS 65 or 70 the P treatments had a significantly higher grain yield and total N uptake than the MT at harvest. Straw incorporation had little effect in both seasons.

The Spring Barley also varied with season but not as extremely as the winter wheat. In 2009, the MT-Spring establishment method performed poorly compared to the other establishment methods with a significantly lower CNU at GS 55 and 85, and reduced total N uptake and grain yield at harvest. The plough-based system achieved the highest total N uptake and grain yield. All four establishment systems performed similar in 2010 with no significant difference in total N uptake or grain yield. In both years grain yields were moderate to low considering the normal yield potential at this location.

Nitrogen Workshop 2012

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4. Conclusion The N uptake pattern of both crops was influenced by establishment system. The effects however, were not consistent between years. These field experiments indicate that the performance of MT systems for winter wheat and spring barley establishment is season dependent and the plough-based system proved the most reliable establishment method.

References CAIR 2007. Conservation Agriculture Ireland report. www.geraghtyconsulting.com Morris N.L., Miller P.C.H., Orson J.H. and Froud-Williams R.J. 2010. The adoption of non-inversion tillage systems in the United Kingdom and the agronomic impact on soil, crops and the environment—A review Simon T., Javurek M., Mikanova O. and Vach M. 2009. The influence of tillage systems on soil organic matter and soil hydrophobicity.

Rasmussen K.J. 1999. Impact of ploughless soil tillage on yield and soil quality: A Scandinavian review.

Malhi S.S., Lemke R., Wang Z.H. and Chhabra Beldev S. 2006. Tillage, nitrogen and crop residue effects on crop yield, nutrient uptake, soil quality, and greenhouse gas emissions.

Meyer-Aurich A., Gandorfer M., Gerl G. and Kainz M. 2009. Tillage and fertilizer effects on yield, profitability and risk in a corn-wheat-potato-wheat rotation  

Nitrogen Workshop 2012

The effect of dicyandiamide addition to cattle slurry on rates of nitrification at a grassland site in Northern Ireland.

McGeough, K.L.a, Müller, C.b, Laughlin, R.L.a, Watson, C.J.a, Ernfors, M.c, Cahalan, E.b,c, Richards, K.G. c a Agri-Food and Biosciences Institute, Newforge Lane, Belfast, BT9 5PX, Northern Ireland b School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland c Teagasc, Johnstown Castle Environmental Research Centre, Co. Wexford, Ireland

1. Background & Objectives In order to comply with current European Union environmental legislation (Water Framework and Nitrates Directives) there is increased pressure to improve manure nitrogen efficiency. A potential strategy to reduce nitrogen losses through nitrate leaching and N2O emissions is the use of nitrification inhibitors. Dicyandiamide (DCD) is a nitrification inhibitor which slows down the conversion of NH4+ to NO3- and hence reduces NO3- leaching and the production of N2O. The objective of this study was to determine the effect of DCD on gross nitrogen transformations in a grassland field study following slurry application.

2. Materials & Methods A field study was conducted at the Agri-Food and Biosciences Institute, Hillsborough, Northern Ireland, to determine the effect of the nitrification inhibitor dicyandiamide (DCD) on gross N transformations after cattle slurry (CS) applications on three separate occasions (summer and autumn 2010 and spring 2011) using a 15N tracing model. Cattle slurry (33 tonnes ha-1) amended with KNO3 (65 kg N ha-1), with or without DCD (at 15% NH4+-N content of the CS) was surface applied to grassland with either the NH4+ or the NO3- pool labelled with 15N (14CS15NO3 or CS14NO3). The four treatments were arranged in a randomised block design with 4 replicates of each treatment. Soil (0-7.5cm cores) from the treatments was extracted with 2M KCl (2:1 v/w proportion of KCl to soil) on 12 occasions over a period of 4 weeks post application. On each occasion the concentration and 15N enrichment of the NH4+ and NO3- pools was determined. The N enrichment of the NO3--N and NH4+-N were determined by methods based on the generation of N2O for analysis by Isotope-Ratio Mass Spectrometry (Stevens and Laughlin, 1994; Laughlin et al., 1997). Gross soil N transformations were quantified with a 15N tracing model described by Müller et al. (2007) which considers six nitrogen pools and 12 nitrogen transformations (Figure 1).

Figure 1. 15N tracing model (Müller et al.

, 2007) (Nlab = labile soil organic N, Nrec = recalcitrant soil organic N, NH4+ads = adsorbed NH4+, NO3-sto = stored NO3-, MNlab = mineralisation of Nlab, MNrec = mineralisation of Nrec, INH4 = immobilisation of NH4+, INO3 = immobilisation of NO3-, ONrec = oxidation of Nrec to NO3-, ONH4 = oxidation of NH4+ to NO3-, DNO3 = dissimilatory reduction of NO3- to NH4+, RNH4a = release of adsorbed NH4+, and RNO3s = release of stored NO3-).

Nitrogen Workshop 2012

3. Results & Discussion Gross nitrification rates are shown in Figure 2. In the presence of DCD, the rate of ONH4 (autotrophic and heterotrophic oxidation of NH4+ to NO3-) showed a significant decrease (P0.001) of 99.9%, 81.9% and 90.1% in June 2010, October 2010 and March 2011 respectively. In comparison to rates of ONH4, the rates of ONrec (heterotrophic oxidation of organic-N to NO3-) were low. ONrec increased significantly (P0.001) from 0.064 µg N g-1 d-1 to 0.275 µg N g-1 d-1 when DCD was added in June 2010, and a significant increase (P0.05) from 0.066 µg N g-1 d-1 to 0.163 µg N g-1 d-1 was measured in October 2010. However, there was no significant change in ONrec when DCD was added in March 2011.


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Figure 2. Gross NH4+ nitrification rates (ONH4) and organic-N nitrification rates (ONrec) for CSNO3 with and without DCD applied to grassland soil in June 2010, October 2010 and March 2011.

LSD, least significant difference when comparing any two means for P=0.05.

4. Conclusion This study has demonstrated that NH4+ oxidation in cattle slurry was strongly inhibited by DCD on all three application dates. In contrast rates of heterotrophic nitrification of organic-N were low and DCD did not have an inhibiting effect. Overall, the percentage decrease in total nitrate production (ONH4 + ONrec) was calculated as 78%, 70% and 81% for June 2010, October 2010 and March 2011, respectively demonstrating that DCD was highly effective in slowing the rate of nitrate production under field conditions when CS was applied to a grassland soil.

References Laughlin, R.J., Stevens, R.J. and Zhuo, S. 1997. Determining nitrogen-15 in ammonium by producing nitrous oxide.

Soil Science Society of America Journal 61, 462-465.

Müller, C., Rütting, T., Kattge, J., Laughlin, R.J. and Stevens, R.J. 2007. Estimation of parameters in complex 15N tracing models by Monte Carlo sampling. Soil Biology and Biochemistry 39, 715-726.

Stevens, R.J. and Laughlin, R.J. 1994. Determining nitrogen-15 nitrite or nitrate by producing nitrous oxide. Soil Science Society of America Journal 58, 1108-1116.

Nitrogen Workshop 2012

The effect of mineral N fertiliser dose on nitrogen efficiency of silage maize Černý, J., Balík, J., Kulhánek, M., Vašák, F., Peklová, L., Sedlář, O., Shejbalová, Š.

Department of Agro-Environmental Chemistry and Plant Nutrition, Czech University of Life Sciences in Prague, Prague, Czech Republic

1. Background & Objectives Silage maize (Zea mays L.) is a crop, which is very responsive to N fertilisation and large amounts of N are generally applied to maize cultivations. The positive effects of nitrogen supply from mineral fertilizer or organic fertilizers on the yield of dry matter (DM) from maize are well documented (Schröder et al., 1998). Although maize has a high N use efficiency field balances still show considerable N surpluses due to excessive input of organic and mineral fertilisers, which are applied alone or in combination. Most of agricultural companies in the Czech Republic limit fertilization to usage of mineral nitrogen fertilizers and the amount of nutrients uptake by main and secondary products are often higher than the input of nutrients to soil in fertilizers. Adjusting N application rates to crop needs can improve N use efficiency and reduce N loses. The objective of this study is to evaluate effects of different application rates of mineral nitrogen fertilizers (MNF) on yield of silage maize and N uptake efficiency in long-term field experiment.

2. Materials & Methods The experiment, established in 1992, was carried out on the experimental field of the Czech University of Life Sciences Prague in Czech Republic (50°7'40"N, 14°22'33"E). The climate is dry temperate, drought periods may occur, mainly in late spring and summer. The soil is Chernozem with loamy texture (Černý et al., 2010). Silage maize has been continuously cultivated since the beginning of the experiment. The treatments were compared in a split-plot design. The size of experimental plots was 46 m2. The trial comprised 5 treatments: no fertilization (control), four mineral N rates (calcium ammonium nitrate) (60, 120, 180, 240 kg N ha-1) prior to crop sowing. No other nutrients and liming were used since the beginning of the experiment. The N content of the aboveground biomass was estimated using a Kjeldahl procedure. Efficiency of N fertilizer N was calculated according to the difference method (Dobermann, 2007; Nannen et al., 2011) considering the DM yield and N uptake by the maize: i) nitrogen utilization efficiency (NUE, kg kg-1) as the ratio between yield and total N uptake; ii) agronomic efficiency of applied N (AEN, kg kg-1) as the ratio of (yield at Nx – yield at N0) and applied N at Nx, iii) recovery efficiency of applied N (REN, %) as the ratio of (uptake at Nx – uptake at N0) and applied N at Nx, iv) physiological efficiency of applied N (PEN, kg kg-1) as the ratio of (yield at Nx – yield at N N0) and (uptake at Nx – uptake at N0).

3. Results & Discussion All results for this research are presented as average from 1997 to 2008 experimental years. The average dry mater (DM) yields were 11.2–14.8 t ha-1. The lowest yield was determined in the control variant, the highest yield in the variant 240 kg N ha-1. In some years, however, 240 kg N hadid not increase the yield compared to the amount of 180 kg N ha-1. Average nitrogen uptakes were 88–185 kg N ha-1, when the average N contents in DM were 0.8–1.25 %. From this result it is evident that the amount of 240 kg of N per hectare did not increase the content of nitrogen in the dry matter of the silage maize more distinctly when compared with the variant 180 kg N ha-1.

Similar to Nannen et al. (2011), in variants 180 kg N ha-1 and 240 kg N ha-1 the uptake of nitrogen was estimated lower compared with the amount of N, which was at the beginning of the growing season applied in fertilizer (Figure 1).

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NUE was relatively stable value during the evaluated period and range between 80.53 and 124.86 kg N ha-1. The highest value of AEN was calculated for the amount of 60 kg N ha-1 and 120 kg N ha-1. The lowest AEN was calculated for the application of 240 kg of N ha-1. The highest values of REN were calculated in the variant 120 kg N ha-1 and they were decreasing with higher amount of N applied, which corresponds with the lower use of the applied N. The average values of REN in all variants were calculated from 40.51 to 57.49 %. The highest value of PEN (55.27 kg kg-1) was found out for the amount of 60 kg N ha-1 and the PEN value decreased with an increasing amount of N (Table 1).

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4. Conclusion Higher DM yield, N content and N uptake by silage maize were with the increasing N dose, but the best use of nitrogen from MNF had been reached by a nitrogen rate of 60 and 120 kg ha-1.

References Černý, J., Balík, J., Kulhánek, M., Čásová, K. and Nedvěd, V. 2010. Mineral and organic fertilization efficiency in long-term stationary experiments. Plant Soil and Environment 56, 28-36.

Dobermann, A.R. 2007. Nutrient use efficiency – measurement and management. IFA International Workshop on Fertilizer Best Management Practices, 7-9 March, 2007, Brussels, Belgium.

Nannen, D.U., Herrmann, A., Loges, R., Dittert, K. and Taube, F. 2011. Recovery of mineral fertiliser N and slurry N in continuous silage maize using the 15N and difference methods. Nutrient Cycling in Agroecosystems 89, 269-280.

Schröder, J.J., Neeteson, J.J., Withagen, J.C.M. and Noij, I.G.A.M. 1998. Effects of N application on agronomic and environmental parameters in silage maize production on sandy soils. Field Crops Research 58, 55-67.

Acknowledgement This research was supported by the Ministry of Agriculture of the Czech Republic, project No. QH 91081 Nitrogen Workshop 2012 The impact of crop rotation and N fertilization on the growth and yield of winter wheat Vári E., Pepó P.

Institute of Crop Science, Faculty of Agricultural and Food Sciences and Environmental Management, Centre for Agricultural and Applied Economic Sciences, University of Debrecen, Hungary

1. Background & Objectives According to Lönhardné and Kismányoky (1992) and Lönhard and Németh (1988), N fertilization significantly increased leaf area index (LAI) and leaf area duration (LAD) in winter wheat and the leaf area index determined the yield. Petr et al. (1985) found that the yield of cereals was increased leaf area index up to a certain limit. According to Pepó (2002), fertilization is one of the major technological elements of wheat production, because it has a direct or indirect impact on all other technological elements. Pepó (2009) found that the optimum fertilizer doses vary between N150PK in biculture and N50-150+PK in triculture depending upon the year and the water supply.

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