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1. Background & Objective Solid cattle manure is either applied directly from the barn to the field or stored for a certain period of time prior to land spreading. However, it is well-known that up to 50% of total nitrogen (N) can be lost during storage of solid manure (Eghball et al., 1997). This study aimed to examine the effects of two contrasting manure storage methods on N losses during storage and decomposition, N disappearance and herbage N recovery after land-spreading as compared with fresh manure.
2. Materials & Methods Fresh solid cattle manure (12.5 tonnes fresh wt.) was stored for 130 days in two ways: (i) as a composted heap with infrequent turning and (ii) as a sheeted heap under impermeable plastic cover (anaerobic storage). Total N losses were estimated by comparing their N contents relative to the raw ash fractions before and after storage. Thereafter, ~100 g (fresh wt.) of fresh (FR), composted (CO) and anaerobically stored (AN) manures were filled in litterbags (size 10 cm by 10 cm) of 4 mm mesh size, placed in three replicate blocks on the soil surface of a sandy grassland and removed after 15, 33, 63, 123 and 168 days. At each sampling, the leftover manure in the litterbags was oven-dried at 105°C for 24 hours, weighed, ground to pass a 1 mm sieve and analyzed for total N content. Possible soil contamination of manure in litterbags was estimated as described by Cusick et al. (2006). Manure dry matter (DM) and N disappearance patterns were fitted using the monocomponent model developed by Yang and Janssen (2000). In addition, herbage growing up to 15 cm around the litterbags and the controls, which consisted of non-decomposable pieces of wood (size 10 cm * 10 cm), was cut three consecutive times to a stubble height of 1 cm with a spinach knife after 47, 96 and 168 days. This enabled the calculation of the total apparent N recovery (ANR) from each manure type.
3. Results & Discussion During storage, total N losses were remarkably low from the anaerobic (10% of the initial) compared to that from the composted (46%) heap. Covering of the manure blocks air circulation, inhibits organic matter degradation and lowers internal heat production as well as pH, which ultimately leads to decreased N losses (Kirchmann, 1985). Fractions of manure DM and N that were remaining in the litterbags at each sampling event are presented in Figure 1a and 1b, respectively.
For all manures, DM and N disappearance rates were highest over the first 15 days. At the end of the growing season, the degree of manure DM and N disappearance was in the order (P 0.01): AN FR CO (Table 1). The increased values for the AN manure can be related to the presence of more readily degradable C and N compounds compared to the other two manures (Kirchmann, 1985). Of the total N disappeared from the litterbags, about 80% was apparently recovered in the aboveground herbage from both the FR and CO manures, whereas this fraction was 90% in the case of AN manure. This could be explained by its relatively higher mineral N content. Note that in this experiment the herbage harvesting height was close to ground level and therefore ANR values were higher than will be obtained by using ordinary cutting machines.
4. Conclusions This study clearly demonstrated that N losses can be markedly reduced (70%) by anaerobic storage of solid cattle manure. After application, this manure decomposes faster and more N is available for plant uptake compared to fresh and composted manures. This all resulted in a three times higher herbage uptake of the produced manure N relative to the compost treatment.
References Cusick, P.R., Powell, J.M., Kelling, K.A., Hensler, R.F. and Muňoz G.R. 2006. Dairy manure N mineralization estimates from incubations and litterbags. Biology and Fertility of Soils 43, 145-152.
Eghball, B., Power, J.F., Gilley, J.E. and Doran, J.W. 1997. Nutrient, carbon, and mass loss during composting of beef cattle feedlot manure. Journal of Environmental Quality 26, 189-193.
Kirchmann, H. 1985. Losses, plant uptake and utilization of manure nitrogen during a production cycle. Acta Agriculturae Scandinavica Supplementum, 24, pp. 77.
Yang, H.S. and Janssen, B.H. 2000. A mono-component model of carbon mineralization with a dynamic rate constant.
European Journal of Soil Science 51, 517-529.
Nitrogen Workshop 2012 Effects of urea fertilization with urease and nitrification inhibitors on ammonia volatilization and winter wheat yield Ni, K., Pacholski, A., Kage, H.
Institute of Crop Science and Plant Breeding, Christian-Albrechts-University, Kiel, Germany
1. Background & Objectives The worldwide use of urea as nitrogen fertilizer has increased more than four fold since the 1960s, currently accounting for more than 50% of global agricultural nitrogen input (Gilbert et al., 2006). After application, urea nitrogen can be lost through ammonia volatilization. Due to the rising concerns about the economic and environmental impacts of ammonia volatilization, new urea fertilizers, combined with urease or nitrification inhibitors have been developed to reduce ammonia emission or nitrate leaching. Further in situ testing is still required to quantify the actual reduction of losses under different soil and weather conditions.
Therefore, a field study was carried out under the climatic conditions of Northern Germany to quantify the effects of different urea fertilizers on ammonia emissions as well as N-uptake and yield of winter wheat.
2. Materials & Methods The field experiment was conducted during the winter wheat season on Hohenschulen experimental farm of Christian-Albrechts-University in Kiel, North Germany in 2011. The treatments consisted of five commercial nitrogen fertilizer products, Calcium ammonium nitrate (CAN), Common granular urea (Piagran 46®), urea combined with urease inhibitor (Piazur®), urea combined with nitrification inhibitor (Alzon 46®), urea combined with urease/ nitrification inhibitor with the same nitrogen application rate, 200 kg N ha-1. The application of urea combined with nitrification inhibitors were split in two doses (EC 23, EC 37), and the other fertilizers were applied three times (EC 23, EC 31, EC 49). All treatments were replicated (n = 4). Ammonia emissions were measured in all replications by a calibrated passive sampling method (CPS), a combination of Drager tube method (Pacholski et al.,
2006) and standard comparison method (Vandre and Kaupenjohann, 1998). The detailed description and validation of the method is presented in Gericke et al. (2011). Winter wheat biomass and yields were determined by hand harvest (5 rows x 50 cm) before combine harvest in August.
showed a significant interaction effect between urease and nitrification inhibitors on ammonia volatilization. However, due to very dry weather in April and May, NH3 losses after the 2nd application of urea and urea with urease inhibitor where very low as compared to moister conditions which possibly biased the differences between total NH3 losses after application of the tested fertilizers. Wheat grain yield varied between 7.85 and 9.01 t ha-1. There was no effect on grain yield between N fertilized treatments under the presented application rate with a tendency of lower yields under higher NH3 emissions (Figure 1a). However, a significant effect of fertilizer types on N uptake was observed (CAN, U+UI, U+NI+UI U, U+NI CK).
The higher N-uptake in the CAN treatment compared to the urea treatments, even with low NH3 losses, can probably be accounted for by the higher NO3--N availability under dry soil conditions as compared to NH4+-N, the product of urea hydrolysis. The relationship between NH3 loss and total nitrogen uptake could be described as a linear equation, which indicates a negative relationship between NH3 emission and crop nitrogen uptake (Figure 1b).
Figure 1. Grain yield (a), and relationship between cumulative NH3 loss and total nitrogen N uptake (b).
Different letters represent significant difference at P0.05, and multiple comparison was carried out by HSD test
4. Conclusion Our study showed that the application of urea combined with urease inhibitor significantly reduced NH3 emissions as compared to conventional urea, whereas nitrification inhibitors alone stimulated ammonia volatilization without significantly decreasing wheat grain yield.
These higher emissions as compared to urea without inhibitors can probably be accounted for by different soil and weather conditions at the different application dates. The combined use of urease/nitrification inhibitor applied in only 2 doses showed the lowest NH3 loss and high grain yield. This was the best economic and environmental result amongst the urea fertilizers treatments, similar or even superior to that of the CAN application (3 doses).
We appreciate the support of this study by SKW Stickstoffwerke Piesteritz GmbH.
References Gericke, D., Pacholski, A. and Kage, H. 2011. Measurement of ammonia emissions in multi-plot field experiments. Biosystems Engineering 108, 164-173.
Glibert, P.M., Harrison, J., Heil, C. and Seitzinger, S. 2006. Escalating worldwide use of urea - a global change contributing to coastal eutrophication. Biogeochemistry 77, 441-463.
Pacholski, A., Cai, G.X., Nieder, R., Richter, J., Fan, X.H., Zhu, Z.L. and Roelcke, M. 2006. Calibration of a simple method for determining ammonia volatilization in the field - comparative measurements in Henan Province, China. Nutrient Cycling in Agroecosystems 74, 259-273.
Vandre, R. and Kaupenjohann, M. 1998. In situ measurement of ammonia emissions from organic fertilizers in plot experiments. Soil Science Society of America Journal 62, 467-473.
Nitrogen Workshop 2012 Efficacy of 15N nitrogen in fertilization of mixtures of cereals and pea Rutkowska, A.
Institute of Soil Science and Plant Cultivation – National Research Institute in Puławy
1. Background & Objectives Natural farming conditions in Poland are poor, due to prevalence of light, acid soils with low content of available P, K, Mg and unfavorable climate. Thus legume growing in mixtures with cereals is characteristic of Polish agriculture. The purpose of mixing legumes and cereals is to optimize the use of spatial, temporal and physical resources both above- and below ground.
However, fertilization of mixtures in order to provide the cereal with nitrogen is questionable since high levels of available N depress atmospheric N fixation by legumes, and can lead to ground water pollution or losses in surface runoff as well as greenhouse gas emissions. The objective of this pot experiment was to determine the efficacy of mineral fertilizers on yield and quality of wheat, barley and oats in mixtures with field peas and estimation of 15N derived from mineral fertilizers by the mixtures under four percentages of peas in mixture: 33, 57, 75 and 88% of cereals.
2. Materials & Methods Nitrogen fertilizer (15NH415NO3) was applied at the rates: 0,3, 0,6, 0,9 and 1,2 g N/pot, accordingly to cereal (winter, barley and oats) percentage in the mixtures: 33% (2 cereal plants + 4 pea plants), 57% (4 cereal plants + 3 pea plants), 75% (6 cereal plants + 2 pea plants) and 88% (8 cereal plants + 1 pea plant). Total amount of fertilizers was subdivided into 0.3 g N/pot doses of which the first was applied before sowing and subsequent rates at10 day intervals. The experiment was conducted in three replicates. After harvest dry mass of above ground biomass was evaluated.
3. Results & Discussion The highest seed yields of the mixtures were obtained in treatments with a wheat component.
However, barley was the least competitive crop for peas (average 52% of the mixture seed yield) in comparison with wheat (60%) and oats (64%). Generally, nitrogen fertilization ensured yield stability, but the highest protein yield was associated with the highest proportion of cereals (Figure 1 – 4).
The quantity of 15N derived from fertilizers by cereals – peas mixtures increased together with N rate (or cereal contribution in the mixture) and amounted to 16% to 58% of total N taken up by the mixtures. The oats – pea mixture took up the lowest amount of total nitrogen but recovered the highest quantity of 15N from fertilizers. In treatment 0,3g N/pot, N biologically fixed by pea plants and N from soil, taken up by wheat-peas mixture reached 1,28 g, by barley-peas mixture -1,60 g and by oats – peas one – 1,19 g. Respectively, in treatment 1,2 g N/pot, the extra N consisted 0,7 g on the average (Figure 5 – 8).
4. Conclusions Nitrogen fertilization at the rates fitted to cereal proportion in the mixture ensured yield stability, however, in respect of protein yield (with except of wheat) the most beneficial mixture composition was 33% cereal plants and 67 % peas. The coefficient of 15N utilization by the mixtures (including root mass) was very high, decreasing through the N rates and ranging from 92 (0,3 g N/pot) to 76% (1,2 g N/pot).
References Hardarson, G, Danso, S.K.A., Zapata, F. and Reichardt, K. 1991. Measurements of nitrogen fixation in fababean at different N fertilizer rates using 15N isotope dilution and “A- value” methods. Plant Soil 131, 161-168.
Lauk, R. and Lauk, E. 2008. Pea-oat intercrops are superior to pea-wheat and pea-barley intercrops. Acta Agriculturae Scandinavica, Section B - Soil & Plant Science 58 (2), 139-144.
Noworolnik, K. and Dworakowski, T. 2010. Yield of barley, pea and oat-pas mixtures depending on nitrogen rate and soil condition. Acta Scientarum Polonica, Agricultura 9(3), 53-60.
Papastylianou, I. 1990. Response of pure stands and mixtures of cereals and legumes to nitrogen fertilization and residual effect on subsequent barley. The Journal of Agriculture Science 115, 15-22.
Zapata, F., Danso, S. K. A. and Hardarson, G. 1987. Time course of nitro gen fixation in field-grown soybean using nitrogen – 15methodology. Agronomy Journal 79, 172-176 Nitrogen Workshop 2012 Emissions of ammonia and nitrous oxide from liquid and solid fractions of treated pig slurry Velthof, G.L.a, Hummelink, Ea. Oenema, O.a a Alterra, Part of Wageningen UR, P.O. Box 47, 6700 AA Wageningen, The Netherlands