Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    NIRS application as a screening tool for heat treatment of manure
    Derikx, Piet ; Heskamp, H.H. - \ 2019
    - p. 40 - 41.
    NIRS - heat treatment - screening tool - manure - NIRS - Screening tool - Heat treatment - Manure
    The high intensity of livestock production in the Netherlands gives rise to a surplus of minerals. Export of manure fractions is stimulated to reduce the local environmental stress. International transport of manure or manure derived products requires a sanitation step to prevent the distribution of any infectious disease. Heating the manure for one hour at 70 degrees Celsius is generally accepted as a practical guideline. Legal requirements are the absence of Salmonella spp and low counts for E.coli’s in the manure. To estimate these parameters sophisticated and time consuming sample taking and sample treatment are required. Results are only available after several days.
    In previous research is was shown NIRS measurements can be used to distinguish between heated and unheated manure (Derikx et al, 2017). Solid fractions, originating from both pig and cattle slurries after mechanical separation, were measured directly after separation and after heat treatment under well controlled laboratory conditions. Based on the results a mathematical model was built.
    As a follow up a field setup was constructed as a screening tool based on a handheld NIRS scanner in combination with an application on a smart phone. This combination provides the user with an easy to perform field inspection tool, providing on line results. Inspectors from The Dutch food and consumer product safety authority (NVWA) have gathered valuable experiences over a pilot period. With this, both the software application and the mathematical model have been improved. At this stage the results can only be used as a first screening . For official enforcement of the law, microbiological enumeration is still required. Future work will focus on improving the reliability of the screening results with the final goal on the long term to replace the microbiological procedures.
    Invited review: Nitrogen in ruminant nutrition: A review of measurement techniques
    Hristov, A.N. ; Bannink, A. ; Crompton, L.A. ; Huhtanen, P. ; Kreuzer, M. ; McGee, M. ; Nozière, P. ; Reynolds, C.K. ; Bayat, A.R. ; Yáñez-Ruiz, D.R. ; Dijkstra, J. ; Kebreab, E. ; Schwarm, A. ; Shingfield, K.J. ; Yu, Z. - \ 2019
    Journal of Dairy Science 102 (2019)7. - ISSN 0022-0302 - p. 5811 - 5852.
    environment - manure - metabolism - nitrogen - ruminant animal - technique

    Nitrogen is a component of essential nutrients critical for the productivity of ruminants. If excreted in excess, N is also an important environmental pollutant contributing to acid deposition, eutrophication, human respiratory problems, and climate change. The complex microbial metabolic activity in the rumen and the effect on subsequent processes in the intestines and body tissues make the study of N metabolism in ruminants challenging compared with nonruminants. Therefore, using accurate and precise measurement techniques is imperative for obtaining reliable experimental results on N utilization by ruminants and evaluating the environmental impacts of N emission mitigation techniques. Changeover design experiments are as suitable as continuous ones for studying protein metabolism in ruminant animals, except when changes in body weight or carryover effects due to treatment are expected. Adaptation following a dietary change should be allowed for at least 2 (preferably 3) wk, and extended adaptation periods may be required if body pools can temporarily supply the nutrients studied. Dietary protein degradability in the rumen and intestines are feed characteristics determining the primary AA available to the host animal. They can be estimated using in situ, in vitro, or in vivo techniques with each having inherent advantages and disadvantages. Accurate, precise, and inexpensive laboratory assays for feed protein availability are still needed. Techniques used for direct determination of rumen microbial protein synthesis are laborious and expensive, and data variability can be unacceptably large; indirect approaches have not shown the level of accuracy required for widespread adoption. Techniques for studying postruminal digestion and absorption of nitrogenous compounds, urea recycling, and mammary AA metabolism are also laborious, expensive (especially the methods that use isotopes), and results can be variable, especially the methods based on measurements of digesta or blood flow. Volatile loss of N from feces and particularly urine can be substantial during collection, processing, and analysis of excreta, compromising the accuracy of measurements of total-tract N digestion and body N balance. In studying ruminant N metabolism, nutritionists should consider the longer term fate of manure N as well. Various techniques used to determine the effects of animal nutrition on total N, ammonia- or nitrous oxide-emitting potentials, as well as plant fertilizer value, of manure are available. Overall, methods to study ruminant N metabolism have been developed over 150 yr of animal nutrition research, but many of them are laborious and impractical for application on a large number of animals. The increasing environmental concerns associated with livestock production systems necessitate more accurate and reliable methods to determine manure N emissions in the context of feed composition and ruminant N metabolism.

    Manure management
    Buisonje, Fridtjof de - \ 2017
    From environmental nuisance to environmental opportunity: housefly larvae convert waste to livestock feed
    Zanten, H.H.E. van; Mollenhorst, H. ; Oonincx, D.G.A.B. ; Bikker, P. ; Meerburg, B.G. ; Boer, I.J.M. de - \ 2015
    Journal of Cleaner Production 102 (2015). - ISSN 0959-6526 - p. 362 - 369.
    life-cycle perspective - bio-energy - food - consequences - variability - digestion - scenarios - amazon - manure - land
    The livestock sector is in urgent need for more sustainable feed sources, because of the increased demand for animal-source food and the already high environmental costs associated with it. Recent developments indicate environmental benefits of rearing insects for livestock feed, suggesting that insect-based feed might become an important alternative feed source in the coming years. So far, however, this potential environmental benefit of waste-fed insects is unknown. This study, therefore, explores the environmental impact of using larvae of the common housefly grown on poultry manure and food waste as livestock feed. Data were provided by a laboratory plant in the Netherlands aiming to design an industrial plant for rearing housefly larvae. Production of 1 ton dry matter of larvae meal directly resulted in a global warming potential of 770 kg CO2 equivalents, an energy use of 9329 MJ and a land use of 32 m2, caused by use of water, electricity, and feed for flies, eggs and larvae. Production of larvae meal, however, also has indirect environmental consequences. Food waste, for example, was originally used for production of bio-energy. Accounting for these indirect consequences implies, e.g., including the environmental impact of production of energy needed to replace the original bio-energy function of food waste. Assuming, furthermore, that 1 ton of larvae meal replaced 0.5 ton of fishmeal and 0.5 ton of soybean meal, the production of 1 ton larvae meal reduced land use (1713 m2), but increased energy use (21,342 MJ) and consequently global warming potential (1959 kg CO2-eq). Results of this study will enhance a transparent societal and political debate about future options and limitations of larvae meal as livestock feed. Results of the indirect environmental impact, however, are situation specific, e.g. in this study food waste was used for anaerobic digestion. In case food waste would have been used for, e.g., composting, the energy use and related emission of greenhouse gases might decrease. Furthermore, the industrial process to acquire housefly larvae meal is still advancing, which also offers potential to reduce energy use and related emissions. Eventually, land scarcity will increase further, whereas opportunities exist to reduce energy use by, e.g., technical innovations or an increased use of solar or wind energy. Larvae meal production, therefore, has potential to reduce the environmental impact of the livestock sector.
    Biochar: An emerging policy arrangement in Brazil?
    Francischinelli Rittl, T. ; Arts, B.J.M. ; Kuyper, T.W. - \ 2015
    Environmental Science & Policy 51 (2015). - ISSN 1462-9011 - p. 45 - 55.
    network analysis - amazon region - soil - carbon - charcoal - availability - centrality - fertility - ferralsol - manure
    Biochar, the solid product of pyrolysis, has emerged as a new technology and policy tool to address various environmental challenges (climate change, food production and Agricultural waste management). The concept of biochar drew its inspiration from Amazonian practices that had led to the creation of Amazonian Dark Earth (ADE): fertile soils rich in (bio)char and human artefacts. In this article, we conceptualize biochar as an emerging policy arrangement, and examine it along the four dimensions of the Policy Arrangement Approach (PAA), which are actors, discourse, power and rules. We focus on Brazil as an important player in the international biochar debate. Our analysis shows that science experts are the predominant players in the network, while policy-makers, businessmen and farmers are marginally positioned. Experts from Embrapa occupy central positions and thus exercise most power in the network. Moreover, experts linked to ADE have lost prominence in the network. The reason for this is to be found in the shift from the ADE/ biochar to the biochar/technology discourse. The latter discourse includes different coalitions such as ‘climate change mitigation’, the ‘improvement of soil fertility’ and ‘improving crop residue management’. Although the biochar/climate coalition is dominant at the international level, it is far less prominent in Brazil. Nationally, it is particularly the discourses of ‘improvement of soil fertility’ and ‘improving crop residue management’ which have prompted actors’ relationships and practices. However, the biochar/technology discourse has not (yet) been formally institutionalized in Brazil. As a consequence, the country lacks an established biochar policy field.
    Properties of anthropogenic soils in ancient run-off capturing agricultural terraces in the Central Negev desert (Israel) and related effects of biochar and ash on crop growth
    Asperen, H.L. van; Bor, A.M.C. ; Sonneveld, M.P.W. ; Bruins, H.J. ; Lazarovitch, N. - \ 2014
    Plant and Soil 374 (2014)1-2. - ISSN 0032-079X - p. 779 - 792.
    charcoal - productivity - manure - model
    In the Central Negev hills (Israel) many ancient terraced wadis exist, which captured run-off and caused gradual soil aggradation, which enabled agricultural practices. In these terraces, dark colored soil horizons were observed, containing charcoal, as can be found in Terra Preta soils, suggesting higher fertility compared to natural soils. The aim of our investigation was to investigate these anthropogenic soils and to study the effects of charcoal and ash addition on soil properties and crop growth. We investigated 12 soil profiles, focusing on possible differences between light and dark colored soil horizons. We also investigated the effects of amendment of charcoal and ash on the growth of wheat (Triticum Aestivum L.) in a 40-day pot experiment involving two water regimes. Results show that charcoal content in light and dark horizons were both low (<0.2 %), but significantly lower bulk densities were found in dark colored horizons. In the crop experiment, charcoal addition resulted in decreased crop growth, while, in the water deficit regime, ash addition resulted in increased crop growth. Considering the observed charcoal and the results from the crop experiment, we hypothesize that, in ancient run-off capturing agricultural systems, ash was purposefully added as fertilizer.
    Effect of application timing and grass height on the nitrogen fertilizer replacement value of cattle slurry applied with a trailing-shoe application system
    Lalor, S.T.J. ; Schroder, J.J. ; Lantinga, E.A. ; Schulte, R.P.O. - \ 2014
    Grass and Forage Science 69 (2014)3. - ISSN 0142-5242 - p. 488 - 501.
    ammonia-emission - soil compaction - animal slurry - pig slurry - manure - volatilization - yield - reduction - herbage
    This study investigated the effect of using a trailing-shoe system to apply cattle slurry, under different conditions of grass height (low [LG]: freshly cut sward [4–5 cm height] vs. high [HG]: application delayed by 7–19 d and applied to taller grass sward [4–11 cm] height) and month of application (June vs. April), on the nitrogen fertilizer replacement value (NFRV) and apparent N recovery (ANRS) of cattle slurry applied to grassland. NFRV was calculated using two methods: (i) NFRVN based on the apparent recovery of slurry-N relative to that of mineral-N fertilizer; and (ii) NFRVDM based on DM yield. The effect of applying slurry into HG swards, relative to LG swards, decreased the DM yield by 0·47 t ha-1 (P = 0·001), N uptake by 5 kg ha-1 (P = 0·05), ANRS by 0·05 kg kg-1 (P = 0·036), NFRVN by 0·05 kg kg-1 (P = 0·090) and NFRVDM by 0·11 kg kg-1 (P <0·001). It was concluded that the main factor causing these decreases with HG, compared with LG applications, was wheel damage affecting subsequent N uptake and growth of the taller grass sward.
    Soil biochar amendment in a nature restoration area: effects on plant productivity and community composition
    Voorde, T.F.J. van de; Bezemer, T.M. ; Groenigen, J.W. van; Jeffery, S.L. ; Mommer, L. - \ 2014
    Ecological Applications 24 (2014)5. - ISSN 1051-0761 - p. 1167 - 1177.
    nitrogen-fixation - activated carbon - charcoal - invasion - growth - performance - fertilizer - amazon - manure
    Biochar (pyrolyzed biomass) amendment to soils has been shown to have a multitude of positive effects, e.g., on crop yield, soil quality, nutrient cycling, and carbon sequestration. So far the majority of studies have focused on agricultural systems, typically with relatively low species diversity and annual cropping schemes. How biochar amendment affects plant communities in more complex and diverse ecosystems that can evolve over time is largely unknown. We investigated such effects in a field experiment at a Dutch nature restoration area. In April 2011, we set up an experiment using biochar produced from cuttings collected from a local natural grassland. The material was pyrolyzed at 400°C or at 600°C. After biochar or residue (non-pyrolyzed cuttings) application (10 Mg/ha), all plots, including control (0 Mg/ha) plots, were sown with an 18-species grassland mixture. In August 2011, we determined characteristics of the developed plant community, as well as soil nutrient status. Biochar amendment did not alter total plant productivity, but it had a strong and significant effect on plant community composition. Legumes were three times as abundant and individual legume plants increased four times in biomass in plots that received biochar as compared to the control treatment. Biomass of the most abundant forb (Plantago lanceolata) was not affected by biochar addition. Available phosphorous, potassium, and pH were significantly higher in soils that received biochar than in Control soils. The rate of biological nitrogen fixation and seed germination were not altered by biochar amendment, but the total amount of biological N fixed per Trifolium pratense (red clover) plant was more than four times greater in biochar-amended soil. This study demonstrates that biochar amendment has a strong and rapid effect on plant communities and soil nutrients. Over time these changes may cascade up to other trophic groups, including above- and belowground organisms. Our results emphasize the need for long-term studies that examine not only the short-term effects of biochar amendment, but also follow how these effects evolve over time and affect ecosystem functioning.
    Prediction of nitrogen use in dairy cattle: a multivariate Bayesian approach
    Reed, K.F. ; Moraes, L.E. ; Fadel, J.G. ; Casper, D.P. ; Dijkstra, J. ; France, J. ; Kebreab, E. - \ 2014
    Animal Production Science 54 (2014)12. - ISSN 1836-0939 - p. 1918 - 1926.
    cows - excretion - protein - management - metabolism - efficiency - ruminants - pollution - dietary - manure
    Quantification of dairy cattle nitrogen (N) excretion and secretion is necessary to improve the efficiency with which feed N is converted to milk N (ENU). Faecal and urinary N excretion and milk N secretion are correlated with each other and thus are more accurately described by a multivariate model that can accommodate the covariance between the three observations than by three separate univariate models. Further, by simultaneously predicting the three routes of excretion and taking advantage of the mass balance relationships between them, covariate effects on N partitioning from feed to faeces and absorbed N and from absorbed N to milk and urine N and animal ENU can be estimated. A database containing 1094 lactating dairy cow observations collated from indirect calorimetry experiments was used for model development. Dietary metabolisable energy content (ME, MJ/kg DM) increased ENU at a decreasing rate, increased the efficiency with which feed N was converted to absorbed N and decreased the efficiency with which absorbed N was converted to milk N. However, the parameter estimate of the effect of ME on post-absorption efficiency was not different from zero when the model was fitted to a data subset in which net energy and metabolisable protein were at or above requirement. This suggests the effect of ME on post-absorption N use is dependent on the energy status of the animal.
    Production-ecological modelling explains the difference between potential soil N mineralisation and actual herbage N uptake
    Rashid, M.I. ; Goede, R.G.M. de; Brussaard, L. ; Bloem, J. ; Lantinga, E.A. - \ 2014
    Applied Soil Ecology 84 (2014). - ISSN 0929-1393 - p. 83 - 92.
    winter-wheat fields - nitrogen mineralization - organic-matter - food webs - grassland soils - forest soils - community - manure - earthworms - management
    We studied two different grassland fertiliser management regimes on sand and peat soils: above-ground application of a combination of organic N-rich slurry manure and solid cattle manure (SCM) vs. slit-injected, mineral N-rich slurry manure, whether or not supplemented with chemical fertiliser (non-SCM). Measurements of field N mineralisation as estimated from herbage N uptake in unfertilised plots were compared with (i) potential N mineralisation as determined from a standard laboratory soil incubation, (ii) the contribution of groups of soil organisms to N mineralisation based on production-ecological model calculations, and (iii) N mineralisation calculated according to the Dutch fertilisation recommendation for grasslands. Density and biomass of soil biota (bacteria, fungi, enchytraeids, microarthropods and earthworms) as well as net plant N-uptake were higher in the SCM input grasslands compared to the non-SCM input grasslands. The currently used method in Dutch fertilisation recommendations underestimated actual soil N supply capacity by, on average, 102 kg N ha-1 (202 vs. 304 kg ha-1 = 34%). The summed production-ecological model estimate for N mineralisation by bacteria, fungi, protozoa, and enchytraeids was 87–120% of the measured potential soil N mineralisation. Adding the modelled N mineralisation by earthworms to potential soil N mineralisation explained 98–107% of the measured herbage N uptake from soil. For all grasslands and soil biota groups together, the model estimated 105% of the measured net herbage N uptake from soil. Soil biota production-ecological modelling is a powerful tool to understand and predict N uptake in grassland, reflecting the effects of previous manure management and soil type. The results show that combining production ecological modelling to predict N supply with existing soil N tests using aerobic incubation methods, can add to a scientifically based improvement of the N fertilisation recommendations for production grasslands.
    Nitrous oxide (N2O) emissions from biotrickling filters used for ammonia removal at livestock facilities
    Melse, R.W. ; Mosquera Losada, J. - \ 2014
    Water Science and Technology 69 (2014)5. - ISSN 0273-1223 - p. 994 - 1003.
    activated-sludge - liquid fraction - water-treatment - nitric-oxide - air - nitrification - operations - manure
    Recently several manufacturers of nitrifying biotrickling filters for ammonia (NH3) removal at animal houses have started to add a denitrification step to the installation, aiming to reduce the amount of discharge water by conversion of NH3 to nitrogen gas (N2). The aim of this research was to quantify the possible formation of nitrous oxide (N2O), which is a potent greenhouse gas, in three of these farm-scale installations. Furthermore, the removal efficiency of NH3 and odor was determined. All installations were successful in reducing the amount of discharge water. The average NH3 removal efficiency for the three locations was 85, 71 and 86%, respectively. However, a significant part of the NH3 removed from the inlet air was not converted to N2 but to N2O, which is a potent greenhouse gas. The part of the inlet NH3-N that was converted to N2O-N amounted to 17, 66 and 24%, respectively. The high N2O production might have been caused by a too low scarcity of biodegradable carbon/N ratio for complete denitrification. The average odor removal efficiency was 21, 32 and 48%, respectively. Further research is necessary to explore how process conditions can be adjusted and controlled in order to reduce the production and emission of N2O from these types of systems.
    Effects of nursery management practices on morphological quality attributes of tree seedlings at planting: The case of oil palm (Elaeis guineensis Jacq.)
    Akpo, E. ; Stomph, T.J. ; Kossou, D. ; Omore, A.O. ; Struik, P.C. - \ 2014
    Forest Ecology and Management 324 (2014). - ISSN 0378-1127 - p. 28 - 36.
    container size - pot size - growth - fertilization - irrigation - substrate - purposes - manure - benin - field
    Even though oil palm production is associated with forest clearance and environmental degradation, it is also considered a potential carbon sink. For oil palm to fulfil its potential role in environmental sustainability, high quality seedlings are required. Nursery managers in Benin who produce oil palm seedlings for owners of small farms ignored recommended practices and developed their own. To evaluate the efficacy of their nursery management practices in terms of seedling growth, 2 experiments were conducted. Three polybag sizes (5 L, 8 L, and 15 L) in combination with 4 types of soil substrates and 3 fertiliser treatments were implemented in both experiments in a factorial design. Biomass (shoot, root, shoot-to-root ratio) and allometric (seedling height, number of leaves, length of most developed leaf, root-collar diameter) variables were measured 8 or 6 months after transplanting. Polybag size was the main factor determining oil palm seedling growth in both experiments. Applying 10 g fertiliser once a month was harmful to seedling survival with lethal effects in 5 L polybags. Arable soil with animal manure in 8 L polybags without any fertiliser supply sustained seedling growth well; this practice seemed to be the best balance between quality and production cost although 15 L polybags produced the best seedlings. Growth variables were highly correlated. Height and root-collar diameter constitute good candidates to estimate seedling biomass production non-destructively. The treatment effects on total biomass produced were similar for the 2 experiments. Given the observed large effects of polybag size on seedling growth, our findings suggest that fertiliser addition or substrate selection cannot overrule container size effects; the latter should be considered carefully for (forest and crop) tree seedling production in nurseries.
    Assessing environmental consequences of using co-products in animal feed
    Zanten, H.H.E. van; Mollenhorst, H. ; Vries, J.W. de; Middelaar, C.E. van; Kernebeek, H.R.J. van; Boer, I.J.M. de - \ 2014
    The International Journal of Life Cycle Assessment 19 (2014)1. - ISSN 0948-3349 - p. 79 - 88.
    bio-energy - digestion - impact - rumen - perspective - absorption - manure - tract - model
    The livestock sector has a major impact on the environment. This environmental impact may be reduced by feeding agricultural co-products (e.g. beet tails) to livestock, as this transforms inedible products for humans into edible products, e.g. pork or beef. Nevertheless, co-products have different applications such as bioenergy production. Based on a framework we developed, we assessed environmental consequences of using co-products in diets of livestock, including the alternative application of that co-product. We performed a consequential life cycle assessment, regarding greenhouse gas emissions (including emissions related to land use change) and land use, for two case studies. Case 1 includes increasing the use of wheat middlings in diets of dairy cattle at the expense of using it in diets of pigs. The decreased use of wheat middlings in diets of pigs was substituted with barley, the marginal product. Case 2 includes increasing the use of beet tails in diets of dairy cattle at the expense of using it to produce bioenergy. During the production of biogas, electricity, heat and digestate (that is used as organic fertilizer) were produced. The decrease of electricity and heat was substituted with fossil fuel, and digestate was substituted with artificial fertilizer. Using wheat middlings in diets of dairy cattle instead of using it in diets of pigs resulted in a reduction of 329 kg CO2 eq per ton wheat middlings and a decrease of 169 m(2) land. Using beet tails in diets of dairy cattle instead of using it as a substrate for anaerobic digestion resulted in a decrease of 239 kg CO2 eq per ton beet tails and a decrease of 154 m(2) land. Emissions regarding land use change contributed significantly in both cases but had a high uncertainty factor, +/- 170 ton CO2 ha(-1). Excluding emissions from land use change resulted in a decrease of 9 kg CO2 eq for case 1 'wheat middlings' and an increase of 50 kg CO2 eq for case 2 'beet tails'. Assessing the use of co-products in the livestock sector is of importance because shifting its application can reduce the environmental impact of the livestock sector. A correct assessment of the environmental consequences of using co-products in animal feed should also include potential changes in impacts outside the livestock sector, such as the impact in the bioenergy sector.
    Whole-farm nitrogen cycling and intensification of crop-livestock systems in the highlands of Madagascar: An application of network analysis
    Alvarez, S. ; Rufino, M.C. ; Vayssières, J. ; Salgado, P. ; Tittonell, P.A. ; Tillard, E. ; Bocquier, F. - \ 2014
    Agricultural Systems 126 (2014). - ISSN 0308-521X - p. 25 - 37.
    soil fertility management - nutrient balances - exploring diversity - efficiencies - resource - manure - flows - kenya - conservation - agriculture
    Food insecurity, soil fertility depletion and strong competition for biomass are commonly observed in smallholder crop-livestock systems. The objective of this study was to explore options to improve farm-level nitrogen cycling, productivity and economic performance through the analysis of N flows within four contrasting crop-livestock farm systems of Madagascar highlands. Farms were conceptualized as networks where the compartments were the household and their farming activities, all connected by N flows. Indicators assessing network size and cycling, and the organization and diversity of the N flows, were compared with system productivity, food self-sufficiency, and gross margins for the current situation and under four scenarios of intensification (i) dairy production increased by increasing N inputs as supplementary feed; (ii) crop production increased by increasing N inputs as mineral fertilizer; (iii) manure management improved to increase N conservation during storage and application to soils; (iv) a combination of the two most economically attractive scenarios (i and iii). The four case study farms represent local diversity differing widely in terms of network size, with total annual system N throughput ranging from 113 to 1037kgN per capita, and in terms of N cycling, from 3 to 41kgN per capita per year. They differed less in terms of external dependence, from 0.26 to 0.41kgN kgN-1. Improving N conservation through improved manure management (scenario iii) had a positive impact on gross margin, and this in combination with increased concentrate supply (scenario iv) led to increases in whole-farm N use efficiencies from 2% to 50%, in N cycling from 9% to 68% and in food self-sufficiency from 12% to 37% across farm types. Gross margin was the most sensitive indicator to changes in management. Intensification through scenario iv had the highest impact on farm productivity, gross margin, food self-sufficiency, and environment sustainability (N use efficiency, capacity of the soil to stock N)
    Relationship between soil properties and the bias of N2O reduction by acetylene inhibition technique for analyzing soil denitrification potential
    Qin, S.P. ; Yuan, H.J. ; Dong, W.X. ; Hu, C.S. ; Oenema, O. ; Zhang, Y.M. - \ 2013
    Soil Biology and Biochemistry 66 (2013). - ISSN 0038-0717 - p. 182 - 187.
    nitrous-oxide reduction - pseudomonas-aeruginosa - cultures - catchment - oxidation - sediments - nitrate - manure - assay - no
    The acetylene inhibition technique (AIT) has been widely used to measure soil denitrification potential (SDP), but has been criticized also for underestimating the actual SDP due to limitations of the AIT. Possible effects of soil properties on the bias of the AIT-derived SDP have not been thoroughly investigated yet. The study presented here therefore aimed at quantifying the relationships between soil texture and nutrient contents and the bias of AIT-derived SDP. A total of 26 soils with a wide range of clay and nutrient contents were incubated according to the standard procedure of AIT for assaying SDP. Incubation flasks were made anaerobic by gas substitution with pure helium (99.999%). Changes in the N-2 and N2O concentrations in the He headspace were measured using gas chromatography. The emission rates of N2O and N-2 were calculated to quantify the bias of the AIT-derived SDP (expressed as the percentage of the actual SDP that was not accounted for by AIT). The results showed that the bias ranged from 8 to 98%. The bias was negatively correlated (P <0.05) with the clay, silt, organic matter and nutrient contents of the soils. These results indicate that the bias of the AIT-derived SDP was higher in low-fertility soils than in fertile soils. We recommend that soil properties are taken into account when interpreting results of AIT-derived SDP values. (C) 2013 Elsevier Ltd. All rights reserved.
    Characterization of Colloidal Phosphorus Species in Drainage Waters from a Clay Soil Using Asymmetric Flow Field-Flow Fractionation
    Regelink, I.C. ; Koopmans, G.F. ; Salm, C. van der; Weng, L.P. ; Riemsdijk, W.H. van - \ 2013
    Journal of Environmental Quality 42 (2013)2. - ISSN 0047-2425 - p. 464 - 473.
    environmental-samples - phosphate adsorption - organic phosphorus - surface runoff - sandy soils - manure - netherlands - separation - transport - minerals
    Phosphorus transport from agricultural land contributes to eutrophication of surface waters. Pipe drain and trench waters from a grassland field on a heavy clay soil in the Netherlands were sampled before and after manure application. Phosphorus speciation was analyzed by physicochemical P fractionation, and the colloidal P fraction in the dissolved fraction (
    Short-term extractability of sulfadiazine after application to soils
    Müller, T. ; Rosendahl, I. ; Focks, A. ; Siemens, J. ; Klasmeier, J. ; Matthies, M. - \ 2013
    Environmental Pollution 172 (2013). - ISSN 0269-7491 - p. 180 - 185.
    sulfonamide antibiotics - test-plot - manure - residues - fate - bioavailability - environment - extraction - transport - pathways
    The long-term environmental fate of the veterinary antibiotic sulfadiazine (SDZ) in soils is determined by a reversible sequestration into a residual fraction and an irreversible formation of non-extractable residues (NER), which can be described as first-order rate processes. However, the concentration dynamics of the resulting fractions of SDZ in soil show an unexplained rapid reduction of extractability during the first 24 h. We therefore investigated the short-term extractability of SDZ in two different soils under different SDZ application procedures over 24 h: with and without manure, for air-dried and for moist soils. In all batches, we observed an instantaneous loss of extractability on a time scale of minutes as well as kinetically determined sequestration and NER formation over 24 h. Data evaluation with a simple kinetic model led to the conclusion that application with manure accelerated the short-term formation of NER, whereas sequestration was very similar for all batches.
    Identification and dynamic modeling of biomarkers for bacterial uptake and effect of sulfonamide antimicrobials
    Richter, M.K. ; Focks, A. ; Siegfried, B. ; Rentsch, D. ; Krauss, M. - \ 2013
    Environmental Pollution 172 (2013). - ISSN 0269-7491 - p. 208 - 215.
    escherichia-coli - dihydropteroate synthase - agricultural soils - waste-water - manure - sulfadiazine - antibiotics - growth - sulfamethoxazole - pharmaceuticals
    The effects of sulfathiazole (STA) on Escherichia coli with glucose as a growth substrate was investigated to elucidate the effect-based reaction of sulfonamides in bacteria and to identify biomarkers for bacterial uptake and effect. The predominant metabolite was identified as pterine-sulfathiazole by LC-high resolution mass spectrometry. The formation of pterine-sulfathiazole per cell was constant and independent of the extracellular STA concentrations, as they exceeded the modeled half-saturation concentration of 0.011 µmol L-1. The concentration of the dihydrofolic acid precursor para-aminobenzoic acid (pABA) increased with growth and with concentrations of the competitor STA. This increase was counteracted for higher STA concentrations by growth inhibition as verified by model simulation of pABA dynamics. The EC value for the inhibition of pABA increase was 6.9 ± 0.7 µmol L-1 STA, which is similar to that calculated from optical density dynamics indicating that pABA is a direct biomarker for the SA effect.
    Effects of slurry from sulfadiazine- (SDZ) and difloxacin- (DIF) medicated pigs on the structural diversity of microorganisms in bulk and rhizosphere soil
    Reichel, R. ; Rosendahl, I. ; Peeters, E.T.H.M. ; Focks, A. ; Groeneweg, K.J.I. ; Bierl, R. - \ 2013
    Soil Biology and Biochemistry 62 (2013). - ISSN 0038-0717 - p. 82 - 91.
    microbial-community structure - gradient gel-electrophoresis - organic-matter - antibiotic sulfadiazine - agricultural soils - arable soils - manure - nitrogen - bacteria - impact
    Conventional farming still consumes considerable amounts of antibiotics such as sulfadiazine (SDZ) or difloxacin (DIF) to protect livestock from infectious diseases. Consequently, slurries from medicated animals are applied to arable soils. Antibiotics, co-applied with pig slurry, are increasingly reported to change soil microbial community structures in un-rooted bulk soil. The effects in rhizosphere soil, as well as the medication-derived direct and indirect effects of an altered slurry composition are poorly investigated. We evaluated the response of microorganisms to slurry of SDZ- and DIF-medicated pigs in a 63-d mesocosm experiment, considering the natural complexity of a typical agricultural pig slurry amendment and developing Zea mays L. root systems. Slurry-derived fecal bacteria were still present in mesosocosm soil 14 days after amendment. Medication with DIF and SDZ further altered the molecular-chemical pattern of the pig slurry, confounding the precise antibiotic effect. This has to be considered when investigating antimicrobial effects under ecological relevant conditions. Effects on the microbial community in mesocosm bulk soil widely matched results from previous studies on directly spiked soil. Effects were also found in the mesocosm rhizosphere soil, but not more pronounced than in bulk soil. This was also verified under laboratory conditions after application of artificially SDZ-spiked control slurry.
    Measuring gas emissions from livestock buildings: A review on uncertainty analysis and error sources
    Calvet, S. ; Gates, R.S. ; Zhang, G. ; Estelles, F. ; Ogink, N.W.M. ; Pedersen, S. ; Berckmans, D. - \ 2013
    Biosystems Engineering 116 (2013)3. - ISSN 1537-5110 - p. 221 - 231.
    measuring ammonia emissions - fattening pig house - ventilation rate - carbon-dioxide - broiler houses - air-flow - rates - poultry - manure - performance
    Measuring gaseous and particulate emissions from livestock houses has been the subject of intensive research over the past two decades. Currently, there is general agreement regarding appropriate methods to measure emissions from mechanically ventilated buildings. However, measuring emissions from naturally ventilated buildings remains an elusive target primarily because there is no reference method for measuring building ventilation rate. Ventilation rates and thus building emissions estimates for naturally ventilated buildings are likely to contain greater errors compared with those from mechanically ventilated buildings. This work reviews the origin and magnitude of errors associated with emissions from naturally ventilated buildings as compared to those typically found in mechanical ventilation. Firstly, some general concepts of error analysis are detailed. Then, typical errors found in the literature for each measurement technique are reviewed, and potential sources of relevant systematic and random errors are identified. The emission standard uncertainty in mechanical ventilation is at best 10% or more of the measured value, whereas in natural ventilation it may be considerably higher and there may also be significant unquantifiable biases. A reference method is necessary to obtain accurate emissions estimates, and for naturally ventilated structures this suggests the need for a new means of ventilation measurement. The results obtained from the analysis of information in this review will be helpful to establish research priorities, and to optimize research efforts in terms of quality of emission measurements.
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