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1. Background & Objectives Nitrogen has the greatest influence of all elements on root quality. Sucrose production of sugar beet, grown with inadequate nitrogen, generally has a high sucrose percentage and low impurities, but root and sucrose production was limited (Azzazy., 2004). Too much N increases root impurities and reduces sucrose percentage and consequently limits refined sucrose production. (Beshit et al.,1995;
Pruvlovic et al., 2010). The objective of the study was to study the effect of integrated use of mineral and organic nitrogen on growth, yield and quality of sugar beet under two different plant densities. This was undertaken in order to maximize sugar beet yield and quality, minimize the deteriorative effect of high N rates on beet quality and minimize the pollution which resulting from mineral N application.
3. Results & Discussion Root yield and recoverable sugar yield in tons per hectare, as affected by nitrogen and compost rates and plant density as well as their interactions in 2008/09 and 2009/10 seasons, are illustrated in (Table 1-4). The effect of nitrogen rates on root and recoverable sugar yield were significantly over the two seasons. Least significant difference (L.S.D) at 5 % of nitrogen rate at 144 kg ha-1 was significantly lower than any other nitrogen rate. Nitrogen rate of 240 kg ha-1 was significantly higher than nitrogen rate of 192 kg ha-1 these result was in agreement with (Besheit; Mekki ;ElSayed.,1995; Azzazy., 2004).
The differences in yields induced by changing compost rates were significant in both seasons.
Table 3. Effect of organic nitrogen (compost) on yields of sugar beet in 2008/2009 and 2009/2010 seasons.
The influence of plant density was significant in both seasons.
Table 4. Effect of plant density on yields of sugar beet in 2008/2009 and 2009/2010 seasons.
All interactions were significant effect on root yield and recoverable sugar yield per hectare.
Conclusion Application of mineral nitrogen or organic nitrogen (compost) affect positively on growth behaviour of sugar beet that is finally increased root and sugar yields of sugar beet plants.
How does sheep grazing affect the greenhouse gas balance of a grazed steppe ecosystem?
Schönbach, P.a, Wolf, B.b, Wiesmeier, M.c, Dickhöfer, U.d, Wan, H.a, Gierus, M.a, Butterbach-Bahl, K.b, Susenbeth, A.d, Taube, F.a a Institute of Crop Science and Plant Breeding (Grass and Forage Science/Organic Agriculture), University of Kiel, Germany, b Institute for Meteorology and Climate cResearch, Karlsruhe Institute of Technology, Kreuzeckbahnstrasse 19, 82467 Garmisch-Partenkirchen, Germany, Lehrstuhl für Bodenkunde, Department für Ökologie und Ökosystemmanagement, Wissenschaftszentrum Weihenstephan für Ernährung, Landnutzung und Umwelt, Technische Universität München, 85350, Germany, d Institute of Animal Nutrition and Physiology, Christian-Albrechts-University, Hermann-Rodewald-Str. 9, 24118 Kiel, Germany
1. Background & Objectives Grasslands not only possess a major food resource for livestock farming, but also play a major role in the global fluxes of greenhouse gases (GHG), i.e. CO2, CH4, and N2O, and thus contribute to the increasing radiative forcing of the earth’s atmosphere. The present study quantifies GHG emissions in a common sheep farming system in semi-arid native grassland of Inner Mongolia for a range of sites, differing in grazing intensity.
2. Materials & Methods A partial life-cycle-assessment (LCA) method was used to conduct a whole-farm GHG balance (excluding pre- and post-farm processing steps). GHG fluxes were related to an area-based (ha) and a product-based (kg liveweight gain) functional unit, i.e. GHG balance (GHGB) and GHG intensity (GHGI), respectively. During 2005-2008, we measured carbon sequestration (change in soil organic carbon), CH4 oxidation (by closed-chamber method), and N2O production (by closed-chamber method) from grassland in a replicated series (at least two) of experimental sites. Measurements details on CO2, CH4 and N2Oare explained in Wolf et al. (2010), Chen et al. (2011) and Wiesmeier et al. (2012). The study was conducted in semi-arid, native grassland within the Xilin River catchment, Inner Mongolia Autonomous Region, P.R. China (43°38’ N, 116°42’ E). At the field level, GHG fluxes were measured at replicated controlled grazed sites differing in grazing intensity and at ungrazed (UG) successional sites. On average grazing plots were lightly (LG), moderately (MG), and highly (HG) stocked with 0.54±0.09, 1.15±0.02, and 1.91±0.05 sheep ha-1 year-1, respectively. Enteric CH4 production was estimated on the basis of herbage nutritive value and sheep’s digestible organic matter intake. Additionally, further GHG emissions from the manure management and the use of primary energy were quantified. GHGs were finally allocated to main (meat) and by-products (wool, dung) according to the economic option. Management effects on GHG fluxes were analysed by ANOVA using the Mixed Model of SAS (9.1). Multiple comparisons of means were made by Tukey’s Test.
3. Results & Discussion Increasing grazing intensity significantly increased the emission of GHGs (Table 1). While successional UG sites act as significant sinks, grazed sites emitted large amounts of GHGs. GHGB of the HG management system was the strongest source of GHG emissions. Per kg of liveweight gain, GHG intensity (GHGI) was highest and lowest at HG and LG, respectively (Table 1). GHGB was predominantly determined by soil organic carbon changes and field fluxes and, to a lesser extent, by enteric CH4 production. The manure management and the use of primary energy marginally contributed to the emission of GHGs (Figure 1). Grazing exclusion, as practiced in the UG treatment, led to a significant sequestration of atmospheric CO2, whereas grazing depleted the soil organic carbon stock, i.e. a significant net emission of CO2. Therefore, a reduction in grazing intensity has a large potential as a GHG mitigation strategy.
4. Conclusion The grazing-induced depletion of soil organic carbon through increasing grazing intensity and the corresponding emission of CO2 dominated the GHG balance. Grazing exclusion, as practiced in the UG treatment, has large GHG mitigation potential through CO2 sequestration. In contrast, grazing results in a significant release of GHGs, mainly due to losses in soil organic carbon.
References Chen, W., Wolf, B., Zheng, X., Yao, Z., Butterbach-Bahl, K., Bruggemann, N., Liu, C., Han, S. and Han X. 2011.
Annual methane uptake by temperate semiarid steppes as regulated by stocking rates, aboveground plant biomass and topsoil air permeability. Global Change Biol 17 (9), 2803-2816 Wiesmeier, M., Kreyling, O., Steffens, M., Schönbach, P., Wan, H., Taube, F. and Kögel-Knabner I. 2012. Short-term degradation of semiarid grasslands—results from a controlled grazing experiment in Northern China J. Plant Nutr. Soil Sci., 1-9 Wolf, B, Zheng, X, Brueggemann, N, Chen, W, Dannenmann, M, Han, X, Sutton, M, Wu, H, Yao, Z. and ButterbachBahl K 2010. Grazing-induced reduction of natural nitrous oxide release from continental steppe. Nature 464 (7290), 881-884
Influence of different nitrogen fertilizers on forage maize yield and quality García, M.I., Báez, D., Louro, A., Castro, J.
INGACAL-CIAM, Xunta de Galicia, Apdo. de correos 10, 15080 A Coruña, Spain.
1. Background & Objectives Galicia is the primary milk production region of Spain. The production is associated with a feed management system based on own-grown crops (maize and grass silage) and concentrates. Atlantic European project Green Dairy found that nitrogen surplus was very high with 349 kg·ha-1 (García et al., 2007). In this context of excessive use of nitrogen on farms there are commercial interests in selling slow-release fertilizers and fertilizers with nitrification inhibitors, with a higher cost than traditional mineral fertilizers. Furthermore, at this time, farmers´ economic margins are decreasing due to rising input prices and drop of milk price. The potential benefit of using new fertilizers in forage maize has not been tested in Galicia. The aim of this study was to determine their influence on forage maize yield and quality and to compare with traditional mineral and organic fertilizers.
2. Materials & Methods The nitrogen fertilizers experiment was carried out in the Agricultural Research Centre of Mabegondo (CIAM) in 2008, 2009 and 2010. They were established in different sites with soils of similar characteristics. Trials using a randomized block design with three replicates were established. Different fertilizers were compared: T1 (0 kg·ha-1 of N), T2 (Mineral fertilizer 15-15urea), T3 (Entec 20-10-10 with DMPP ), T4 (20-12-8/20-8-6/20-7-9 with DCD), T5 (20-10with DURAMON technology ), T6 (D-Coder 14-7-12 /15-8-5/18-5-5), T7 (Urea), T8 (Injected cattle slurry) and T9 (Injected pig slurry) with the same amount of nitrogen (200 kg·haapplied before sowing, only T2 was fractionated in 125 kg·ha-1 before sowing and 75 kg·ha-1 for the top dressing. Amounts of P and K were levelled between different fertilizers. Forage maize variety DKC3745 was sown in May. Yield and quality were measured at harvest. The data were analyzed using the MSTAT statistical package for analysis of variance.
3. Results & Discussion In 2008 fresh yield did not show significant differences between treatments, only the control T1 had lower yield than T4 and T7. In 2009 the control treatment T1 had a significantly lower yield than all other treatments and among these T4 highlighted with the highest fresh yield. In 2010 differences were not significant. In 2008, 2009 and 2010 dry matter percentage differed significantly between treatments. Slurry treatments had the highest values due to a shorter growing season (Table 1).
Table 1. Fresh and dry yield (kg·ha-1) of forage maize for the three-year experiment.
4. Conclusion Traditional mineral and organic fertilizers showed, in Galicia soil and climate conditions, similar behaviour in yield and nutritional value to slow-release fertilizers and fertilizers with nitrification inhibitors as indicated Ruitjer (2009): when fertilizers are applied according to good practice it is questionable whether slow release fertilizers and fertilizers with DMPP perform better.
References Báez, D., Coutinho, J. and Trindade, H. 2004. Efecto del sistema de laboreo, tipo de abonado y uso de inhibidores de la nitrificación en la producción de maíz forrajero. XLIV Congreso de la SEEP, 541-545.
Carrasco, I. and Villar, J.M. 2001. Field evaluation of DMPP as a nitrification inhibitor in the area irrigated by the Canal d´Urgell (Northeast Spain), In: W.J. Horst et al. (eds.), Plant nutrition-food security and sustainablity of agroecosystems, Kluwer Academic Publisher, Holland, 756-757.
Díez-López, J.A., Hernaiz, P., Arauzo, M. and Carrasco, I. 2008. Effect of a nitrification inhibitor (DMPP) on nitrate leaching and maize yield during two growing seasons. Spanish Journal of Agricultural Research 6(2), 294-303.
Nelson, D.W., Huber, D. 1992. Nitrification inhibitors for corn production. Iowa State University, U. Extension, pp. 6.
García, M.I., Castro, J., Novoa, R., Báez, D. and López, J. 2007.Improving nitrogen mineral balance and conversion rate in dairy farms in Galicia (Spain). XV Nitrogen Workshop, Lérida (Spain), 401-403.
Pasda, G., Hähndel, R. and Zerulla, W. 1997. Effect of fertilizers with the new nitrification inhibitor DMPP on yield and quality of agricultural and horticultural crops. Biology and Fertility of Soils 34, 85-97.
Ruijter, F.J., 2009. Fertilizers in field vegetables. XVI Nitrogen Workshop, 249-250.
Nitrate metabolism in leaves of lettuce plants grown in floating system with different nitrate concentrations Podetta, N., Ferrante, A., Dept. Plant Production, Università degli Studi di Milano, Italy
1. Background & Objectives The nitrate content in leaves of vegetables represents an important quality parameter.
Epidemiological studies showed a positive correlation between nitrate intake and gastrointestinal cancer incidence in humans. Since nitrates are constitutively present in drinking water and largely used as meat preservatives, the EU imposed thresholds for the commercialization of leafy vegetables. EU countries apply this regulation differently and to a limited number of species. In Italy the nitrate content limits have only been imposed for lettuce, spinach and rocket. Many factors influence the nitrate accumulation in leaves. In practice, fertilization plays and important role, even if each species may have a different behaviour. In floating systems, the plant roots are directly in the nutrient solution and nitrate concentration may influence the assimilation pathway and plant performance. The aim of this work was to investigate if different nitrate concentrations affected the nitrate accumulation in lettuce baby leaf.