«International 17 Workshop th Nitrogen The was jointly organised by Teagasc and AFBI Printed by Print Depot Suggested citation Authors, 2012. Title ...»
Montemurro et al. (2007) did not detect differences in yields of winter wheat between the fertilizer treatments N120+PK and N180+PK.
2. Materials & Methods The experiments were carried out at the Látókép experimental station of the University of Debrecen on chernozem soil in a long term winter wheat experiment in the season of 2010/2011 in triculture (pea-wheat-maize) and biculture (wheat-maize) at three fertilization levels (control, N50+P35K40, N150+P105K120). The wheat variety used in the long-term trial was GK Csillag. The leaf area index was determined using the instrument SunScan Canopy Analysis Systems (SS1). Leaf area duration (LADLAI) was also calculated, which is the area under the LAI curve over time. LADLAI quantitatively expresses the length of time over which the stand maintains the photosynthetically active leaf area (Berzsenyi, 2000).
3. Results & Discussion The leaf area per 1 m2 ground surface was calculated and its dynamics was plotted (Figure 1). After maize forecrop, N fertilization had a significant effect on leaf area index dynamics and its maximum up to the treatment N150+PK. In triculture, a similar trend was observed, significant differences were found between the three fertilization treatments. In both crop rotations, the maximum leaf area index was measured at flowering-grain filling in winter wheat stands.
Considerably higher leaf area index was measured in triculture than in biculture (2.2 in the control;
4.1 m2 m2 in the treatment N150+PK).
Biculture Triculture 5,0 5,0 Leaf area index (m 2/m 2)
4,0 4,0 3,0 3,0 2,0 2,0 1,0 1,0
Figure 1. Dynamics of LAI-values of winter wheat in a bi- and triculture crop-rotation system (Debrecen, 2011.
) In triculture, yields were 2088-4615 kg·ha-1 higher than in biculture at the same fertilization levels.
After maize, the differences between the control and the fertilization level of N150+PK were
Nitrogen Workshop 2012
considerably higher than after pea as a forecrop. When studying the effect of fertilization, it can be stated that the yields significantly increased with increasing fertilization levels (Figure 2) and the maximum yield of winter wheat was obtained in the treatment N150+PK in both crop rotations (7442 and 9830 kg·ha-1).
Nitrogen Workshop 2012 The interactions among the nitrogen supply and the physiological parameters and yield of winter wheat genotypes Szabó É., Pepó P.
Institute of Crop Sciences, 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 Houles et al. (2007), more precise results can be obtained about the nitrogen uptake of winter wheat if SPAD and leaf area index (LAI) values are examined together. Vidal et al. (1999) found a close correlation between SPAD values, nitrogen uptake and yield. Sugár and Berzsenyi (2010) found that in dry years, LAI was mainly influenced by nitrogen supply. Fois et al. (2009) claimed that nitrogen supply has a determining effect on yield in the case of winter wheat. As a result of higher nitrogen doses, larger leaf area is formed and the nitrogen content of foliage is also higher. Ziadi et al. (2010) found a tight positive correlation between nitrogen doses and SPAD values. Cartelat et al. (2005) found strong correlation between the SPAD values of winter wheat leaves and their chlorophyll content was r=0.91.
2. Materials & Methods We have tested two winter wheat genotypes, GK Öthalom, which has been grown for a long time and a new, modern variety, Pannonikus. Four repetitions were set up in a small plot long-term experiment in a split plot design in the season of 2010/2011. The experimental soil was calcareous chernozem. In the treatments, three fertilization levels were studied, the control, N=60 kg ha-1, with P2O5=45 kg ha-1 and K2O=53 kg ha-1and its twofold dosage were applied. The chlorophyll content of the wheat leaves and the leaf area index (LAI) were measured with a portable Konica-Minolta SPAD 502Plus instrument and a portable SunScan Canopy Analysis Systems (SS1) instrument, respectively. Measurements were performed on five occasions during the season.
20,0 10,0 0,0 2011.04.18 2011.05.03 2011.05.23 2011.06.14 2011.06.20 2011.04.18 2011.05.03 2011.05.23 2011.06.14 2011.06.20
The effect of fertilizer doses was even more obvious in the case of the leaf area index (LAI) (Figure 2). The increasing nitrogen doses significantly increased the leaf area index in both varieties, the LAI was higher and the decreasement was also more moderate for both fertilizer treatments for the variety Pannonikus due to its better fertilizer response.
3,0 2,0 1,0 0,0 2011.04.18 2011.05.03 2011.05.23 2011.06.14 2011.06.20 2011.04.18 2011.05.03 2011.05.23 2011.06.14 2011.06.20
Figure 2. Interactions among the fertilization, the genotype and the leaf area index of winter wheat varieties.
4. Conclusion According to our results, it can be stated that the fertilizer treatments significantly increased the SPAD values and the leaf area index (LAI) of winter wheat genotypes with increasing nitrogen doses. The higher chlorophyll content and the larger assimilating surface contributed to the achievement of higher yields. The more modern variety, Pannonikus had better results both in its physiological parameters and yields due to its better fertilizer response.
References Cartelat A., Cerovic,Z.G.-Goulas,Y.-Meyer, S.-Lelarge, C.-Prioul, L.-Barbottin, A.-Jeuffroy, M.H.-Gate, P.-Agati, G.Moya, I. (2005): Optically assessed contents of leaf polyphenolics and chlorophyll as indicators of nitrogen deficiency in wheat (Triticum aestivum L.). Field Crops Research.
Fois S., Motzo R. and Giunta F. 2009. The effect of nitrogenous fertiliser application on leaf traits in durum wheat in relation to grain yield and development. Field Crops Research. 110. 69-75 Houles V., Guerif M. and Marya B. 2007. Elaboration of a nitrogen nutrition indicator for winter wheat based on leafarea index and chlorophyll content for making nitrogen recommendations. European Journal of Agronomy. 27, 1-11 Sugár E. And Berzsenyi Z. 2010. Growth dynamics and yield of winter wheat varieties grown at diverse nitrogen levels.
Acta Agronomica Hungarica 58, 121-126 Vidal, I., Longeri L. and H´etier J.M. 1999. Nitrogen uptake and chlorophyll meter measurements in Spring Wheat.
Nutrient Cycling in Agroecosystems 55, 1-6 Ziadi N., Bélanger G., Lefebver L., Tremblay N., Cambouris A.N., Nolin M. C. and Parent L.É. 2010. Plant-based diagnostic tool for evaluating wheat nitrogen status. Crop Science 50, 2580-2589 The work/publication is supported by the TÁMOP-4.2.2/B-10/1-2010-0024 project. The project is co-financed by the European Union and the European Social Fund.
Nitrogen Workshop 2012 Using bromide as tracer to study the horizontal and vertical movement of nitrate under field conditions Almadni, M., Stockdale, E.A., Cooper, J.M.
School of Agriculture, Food and Rural Development, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK.
1. Background & Objectives Porous ceramic cups are widely used for the extraction of soil solution for monitoring of nitrate leaching from arable land despite their acknowledged weaknesses. Bromide and chloride have both been widely used as a conservative tracer of nitrate movement, but this has dominantly focussed on following the vertical movement of nitrate through the soil profile (Lord and Shepherd, 1993;
Webster et al., 1993). Under field conditions in some soils, lateral (horizontal) movement may also be an important component of the total nitrate movement (Waddell and Weil, 2006). Hence for any site it is important to understand the hydrological pathways leading to nitrate leaching and to assess the relative importance of both vertical and horizontal components of nitrate transport, especially where plot scale N balances are to be estimated. The aim of these field studies was to better understand the hydrological pathways of nitrate leaching in a large agronomic field experiment thus allowing better parameterisation of models used to estimate nitrate leaching.
2. Materials & Methods Two experiments have been carried out using bromide as tracer during spring 2011 and overwinter 2011-2012. Porous ceramic (suction) cups were used to obtain soil solution samples during drainage and soil coring approaches were used to determine overall recovery. The field experiments were situated at Newcastle University’s Nafferton Experimental Farm, Northumberland, UK under natural soil conditions. The soil is a surface water gley with a sandy loam topsoil. The 30 suction cups were installed at 30 and 60 cm (15 suction cups for each depth) in three replicate plots/areas under grass ley. Each group of suction cups (at either 30 or 60 cm) was arranged in a circle (1m radius) with one suction cup installed in the centre (source) and the 4 remaining cups equally spaced on the perimeter of the circle. For each circle the first cup on the perimeter was placed directly downslope of the centre (downslope). There was 3m between the two groups of suction cups.
Initial soil samples were collected to determine soil water content and the background concentration of bromide. Bromide was extracted from soil (1:5 ratio) using de-ionised water. 300kg ha-1 of bromide (as NaBr) was applied to the soil surface within a circular plot (0.5 m diameter) centred on the central porous cup. Soil solutions were collected from the porous cups weekly (80kPa suction for 2 hours) until the soil had dried so that solution samples could not be obtained. At the end of this period soil cores (0-90 cm) were collected close to the locations of the porous cups and also at an intermediate positions downslope of the application (3 samples 0.75 m from source) and one sample outside the perimeter (1.25 m beyond the downslope). These cores were divided (0-30, 30-60 and 60-90 cm); water content was determined and bromide extracted with de-ionised water. All bromide concentration in soil extracts and soil solution samples were determined by ion chromatography.
3. Results & Discussion Soil solution data collected in the spring 2011 experiment showed that bromide moved downwards through the soil profile after application in March. At the end of this short experiment 36% of the applied bromide was recovered immediately below the source with 23% in 0-30 cm, 6.5% in 30-60 cm and 6.4% in 60-90 cm. At the source, soil solution samplers showed vertical movement of bromide during the experiment with the highest bromide concentration measured in the second
Nitrogen Workshop 2012
week after application at 30 cm depth (Figure 1). The peak bromide concentrations at 60 cm were lower and were not measured until the final sampling, there may have been some bromide concentration at this depth as the soil dried out. Downslope (0.5 m beyond any direct surface application of bromide), bromide was detected in the soil solution after 2 weeks at both 30 and 60 cm depths. While bromide concentrations at 30 cm were very significantly lower than those at the source; there was much less difference between bromide concentrations at 60 cm, suggesting that there may have been significant lateral movement of bromide within the soil profile. The primary result from this scoping study indicated that surface applied bromide could move both horizontally and vertically to 60 cm from March to May even in the presence of grass. Hence the second experiment overwinter 2011-12 was designed to investigate bromide movement during the main drainage period and consider the implications for the estimation of nitrate leaching in these soils.
Data are still being processed and full bromide recovery together with residence times will be calculated.
Figure 1. Mean concentration of bromide in soil solutions (mg l-1; with SD in brackets) obtained with porous ceramic cups installed at 30 and 60 cm depth on 5 occasions following application of bromide in March 2011
a) immediately beneath a bromide application (source) and b) 0.5 m from the plot edge in a downslope direction (downslope).
4. Conclusion For any site the relative importance of both vertical and horizontal components of nitrate movement should be determined. Most simple models of nitrate leaching do not take account of horizontal flow pathways; the preliminary data given here indicate that this is likely to be a major weakness where such models are used to estimate residence times and the environmental impacts of land management.
References Lord, E.I. and Shepherd, M.A. 1993. Developments in the use of porous ceramic cups for measuring nitrate leaching.
Journal of Soil Scienc, 44, 435-449.
Waddell, J.T. and Weil, R.R. 2006. Effects of fertilizer placement on solute leaching under ridge tillage and no tillage.
Soil and Tillage Research 90, 194-204.
Webster, C.P., Shepherd, M.A., Goulding, K.W.T. and Lord, E. 1993. Comparisons of methods for measuring the leaching of mineral nitrogen from arable land, Journal of Soil Science 44, 49-62.
Nitrogen Workshop 2012 Winter wheat nitrogen demand under different soil conditions Anna-Karin Krijger Rural Economy and Agricultural Society of Skaraborg, PO Box 124, 532 22 Skara, Sweden
1. Background & Objectives The aim with this study was to explore the effects of soil nitrogen (N) supplying capacity under different growing conditions on optimum N fertilization level to improve the efficiency in use of added N to crops. Nitrogen fertilization experiments in barley and wheat over several years have shown large variations in optimum N fertilization between sites with similar yields (Gruvaeus, 2008). A major cause of variation was differences in N supply from the soil. Wetterlind (2010) showed that the optimal N dose varied greatly between years and location and even within the farm or the fields. Both the yield and soil N supply needs to be taken into account to estimate the optimum N fertilization level. Using zero-N subplots to estimate N supply on the site, and estimating biomass and N-content with an N-sensor in the BBCH 37 growth stage may improve optimization of N fertilization level.