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.

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Effects of maternal dietary nitrate supplementation on farrowing and placental characteristics, level of asphyxiation at birth and piglet vitality
Bosch, M. van den; Wijnen, H.J. ; Linde, I.B. van der; Wesel, A.A.M. van; Melchior, D. ; Kemp, B. ; Brand, H. van den; Clouard, C.M. - \ 2019
Theriogenology 129 (2019). - ISSN 0093-691X - p. 1 - 7.
nitrate - piglet vitality - placenta - farrowing - asphyxiation
We investigated whether maternal dietary nitrate supplementation, leading to nitric oxide (NO) formation, would affect duration of farrowing, levels of asphyxiation, vitality of piglets at birth and/or loss of potential viable piglets in the form of stillbirth and pre-weaning mortality. Data were collected from 190 crossbred (Yorkshire x Dutch Landrace) sows, which were allocated, balanced for parity, to six dietary nitrate levels (0, 0.03, 0.06, 0.09, 0.12 or 0.15% of nitrate). Sow received the lactational diet containing nitrate from approximately 7 days before farrowing until 5 days after farrowing. Blood acid-base parameters (pH, pO2, pCO2, BEecf, HCO3, sO2 and lactate) and nitrate concentration were determined in umbilical cord blood. The farrowing process was video recorded and later analysed for total duration of farrowing, piglet birth interval, piglet vitality was scored and piglet latency to stand right after birth. Placentas were collected after expulsion during and after farrowing. Placenta length and width were measured and placental color scores were assessed based on redness of the placenta. The probability of a higher vitality score of piglets (being more vital) linearly increased with increasing levels of maternal dietary nitrate. This higher vitality score however, was not reflected by changes in the blood acid-base parameters in umbilical cord blood, except for a tendency for a higher pO2 with increasing levels of nitrate, which could have been caused by a quicker onset of respiration or an increased blood flow to the piglets during birth. Placenta width increased with increasing levels of maternal dietary nitrate, but no effect on placenta length and redness was found. Neither duration of farrowing nor birth interval were affected by maternal dietary nitrate level. In conclusion, maternal nitrate supplementation may affect piglet vitality via vasodilatation (placental characteristics) rather than an increase in exercise efficiency (duration of farrowing).
Nitrate improves ammonia incorporation into rumen microbial protein in lactating dairy cows fed a low-protein diet
Wang, Rong ; Wang, Min ; Ungerfeld, Emilio M. ; Zhang, Xiu Min ; Long, Dong Lei ; Mao, Hong Xiang ; Deng, Jin Ping ; Bannink, André ; Tan, Zhi Liang - \ 2018
Journal of Dairy Science 101 (2018)11. - ISSN 0022-0302 - p. 9789 - 9799.
dissolved hydrogen - microbial protein - nitrate - rumen fermentation

Generation of ammonia from nitrate reduction is slower compared with urea hydrolysis and may be more efficiently incorporated into ruminal microbial protein. We hypothesized that nitrate supplementation could increase ammonia incorporation into microbial protein in the rumen compared with urea supplementation of a low-protein diet fed to lactating dairy cows. Eight multiparous Chinese Holstein dairy cows were used in a crossover design to investigate the effect of nitrate or an isonitrogenous urea inclusion in the basal low-protein diet on rumen fermentation, milk yield, and ruminal microbial community in dairy cows fed a low-protein diet in comparison with an isonitrogenous urea control. Eight lactating cows were blocked in 4 pairs according to days in milk, parity, and milk yield and allocated to urea (7.0 g urea/kg of dry matter of basal diet) or nitrate (14.6 g of NO3 /kg of dry matter of basal diet, supplemented as sodium nitrate) treatments, which were formulated on 75% of metabolizable protein requirements. Nitrate supplementation decreased ammonia concentration in the rumen liquids (−33.1%) and plasma (−30.6%) as well as methane emissions (−15.0%) and increased dissolved hydrogen concentration (102%), microbial N (22.8%), propionate molar percentage, milk yield, and 16S rRNA gene copies of Selenomonas ruminantium. Ruminal dissolved hydrogen was positively correlated with the molar proportion of propionate (r = 0.57), and negatively correlated with acetate-to-propionate ratio (r = −0.57) and estimated net metabolic hydrogen production relative to total VFA produced (r = −0.58). Nitrate reduction to ammonia redirected metabolic hydrogen away from methanogenesis, enhanced ammonia incorporation into rumen microbial protein, and shifted fermentation from acetate to propionate, along with increasing S. ruminantium 16S rRNA gene copies, likely leading to the increased milk yield.

Data from: Magnetite synthesis from ferrous iron solution at pH 6.8 in a continuous stirred tank reactor
Mos, Y.M. ; Bertens Zorzano, Karin ; Buisman, C.J.N. ; Weijma, J. - \ 2018
Continuous Stirred Tank Reactor (CSTR) - groundwater - iron removal - magnetite - nitrate - oxygen
Measurement data, calculations and pictures belonging to paper ‘Magnetite synthesis from ferrous iron solution at pH 6.8 in a continuous stirred tank reactor’
Effects of Stigeoclonium nanum, a freshwater periphytic microalga on water quality in a small-scale recirculating aquaculture system
Mohamed Ramli, Norulhuda ; Yusoff, Fatimah M. ; Giatsis, Christos ; Tan, Geok Yuan A. ; Verreth, Johan A.J. ; Verdegem, Marc C.J. - \ 2018
Aquaculture Research 49 (2018)11. - ISSN 1355-557X - p. 3529 - 3540.
ammonia - bacterial community - microalgae - nitrate - recirculating aquaculture system - Stigeoclonium nanum - water quality

Recirculating aquaculture systems (RAS) are becoming important for aquaculture due to land and water supply limitations and due to their low environmental impact. Bacteria are important in RAS as their role in nutrient recycling has been the main mechanism for waste removal in these systems. Besides bacteria, the presence of microalgae can benefit the water quality through the absorption of inorganic nitrogen (ammonium and nitrate) and phosphorus from the water. However, reports on the inclusion of microalgae in RAS are very scarce. The objective of this study was to determine the effect of microalgae on water quality (total ammonia nitrogen, nitrite, nitrate and phosphate) and bacterial composition in a freshwater small-scale RAS. A periphytic microalga, Stigeoclonium nanum, was used in this study. A rapid fingerprint analysis, denaturing gradient gel electrophoresis (DGGE), was used to determine the bacterial community composition in the water. The results showed that ammonia concentrations were not significantly different (p > 0.05) between RAS with microalgae (RAS+A) and RAS without microalgae (RAS-A). However, nitrite, nitrate and phosphate were significantly lower in the RAS+A than the RAS-A (p < 0.05). Pielou's evenness and Shannon diversity index of bacterial community between the treatments were not different (p > 0.05); however, the bacterial composition between the treatments was significantly different (p < 0.05).

Milieueffectrapportage van maatregelen zesde Actieprogramma Nitraatrichtlijn : Op planniveau
Groenendijk, P. ; Velthof, G.L. ; Schröder, J.J. ; Koeijer, T.J. de; Luesink, H.H. - \ 2017
Wageningen : Wageningen Environmental Research (Wageningen Environmental Research rapport 2842) - 109
nitraat - milieueffectrapportage - nederland - nitrate - environmental impact reporting - netherlands
Om aan de doelstellingen van de Nitraatrichtlijn te voldoen. wordt om de vier jaar een Actieprogramma geformuleerd waarin het rijksbeleid voor de komende vier jaar is aangegeven. In het 6e Actieprogramma wordt een aantal extra maatregelen doorgevoerd ten opzichte van het 5e Actieprogramma. In dit rapport worden de effecten van de extra maatregelen op het milieu (lucht, grondwater en oppervlaktewater) beschreven.
Landbouwpraktijk en waterkwaliteit in Nederland: toestand (2012-2014) en trend (1992-2014)
Fraters, B. ; Hooijboer, A.E.J. ; Vrijhoef, A. ; Claessens, J. ; Kotte, M.C. ; Rijs, G.B.J. ; Denneman, A.I.M. ; Bruggen, C. van; Daatselaar, C.H.G. ; Begeman, H.A.L. ; Bosma, J.N. - \ 2016
Bilthoven : Rijksinstituut voor Volksgezondheid en Milieu (RIVM rapport 2016-0076) - 191 p.
oppervlaktewaterkwaliteit - grondwaterkwaliteit - mestbeleid - landbouw en milieu - nitraat - eutrofiëring - bemesting - monitoring - waterverontreiniging - surface water quality - groundwater quality - manure policy - agriculture and environment - nitrate - eutrophication - fertilizer application - water pollution
Stikstof en fosfaat zijn essentiële stoffen in mest die landbouwbedrijven gebruiken om de productie te bevorderen. Teveel stikstof en fosfaat is echter schadelijk. Het verschil tussen de aan- en afvoer van stikstof naar en van landbouwbedrijven in Nederland, het zogeheten stikstofoverschot, is tussen 1992 en 2014 gehalveerd. Het fosfaatoverschot is nagenoeg verdwenen. De nitraatconcentraties in het water op landbouwbedrijven zijn gedaald en de kwaliteit van het oppervlaktewater is verbeterd. Ten opzichte van de vorige monitoringronde (2008-2011) zijn de verbeteringen in de waterkwaliteit echter beperkt. De nutriëntenconcentraties zullen naar verwachting wel blijven dalen, maar de gewenste situatie zal in het grondwater niet overal worden bereikt. Ook zal de kwaliteit van het oppervlaktewater veelal onvoldoende blijven. Dit blijkt uit een inventarisatie van de grond­ en oppervlaktewaterkwaliteit en de landbouwpraktijk.
Use of long-term monitoring data to derive a relationship between nitrogen surplus and nitrate leaching for grassland and arable land on well-drained sandy soils in the Netherlands
Fraters, Dico ; Leeuwen, Ton van; Boumans, Leo ; Reijs, Joan - \ 2015
Acta Agriculturae Scandinavica Section B-Soil and Plant Science 65 (2015)suppl.2. - ISSN 0906-4710 - p. 144 - 154.
nitrate - nitrogen leaching fraction - regional scale approach - root zone leaching - sandy soils - upper groundwater

The decrease in nitrogen (N) use in agriculture led to improvement of upper groundwater quality in the Sand region of the Netherlands in the 1991–2009 period. However, still half of the farms exceeded the European nitrate standard for groundwater of 50 mg/l in the 2008–2011 period. To assure that farms will comply with the quality standard, an empirical model is used to derive environmentally sound N use standards for sandy soils for different crops and soil drainage conditions. Key parameters in this model are the nitrate-N leaching fractions (NLFs) for arable land and grassland on deep, well-drained sandy soils. NLFs quantify the fraction of the N surplus on the soil balance that leaches from the root zone to groundwater and this fraction represents N available for leaching and denitrification. The aim of this study was to develop a method for calculating these NLFs by using data from a random sample of commercial arable farms and dairy farms that were monitored in the 1991–2009 period. Only mean data per farm were available, which blocked a direct derivation of NLFs for unique combinations of crop type, soil type and natural soil drainage conditions. Results showed that N surplus leached almost completely from the root zone of arable land on the most vulnerable soils, that is, deep, well-drained sandy soils (95% confidence interval of NLF 0.80–0.99), while for grassland only half of the N surplus leached from the root zone of grassland (0.39–0.49). The NLF for grassland decreased with 0.015 units/year, which is postulated to be due to a decreased grazing and increased year-round housing of dairy cows. NLFs are positively correlated with precipitation surplus (0.05 units/100 mm for dairy farms and 0.10 units/100 mm for arable farms). Therefore, an increase in precipitation due to climate change may lead to an increase in leaching of nitrate.

Nitraat voeren: methaan en N-kringloop
Sebek, L.B. - \ 2015
Nieuwsbrief Koeien & Kansen (2015)42. - p. 2 - 2.
nitraat - methaanremmers - agrarische bedrijfsvoering - innovatie adoptie - melkproductie - melkveehouderij - broeikasgassen - nitrate - methane inhibitors - farm management - innovation adoption - milk production - dairy farming - greenhouse gases
De Marke loopt voor met milieukundige innovaties. Het proefbedrijf implementeert bewezen innovaties om milieukundige winst te halen. Het voeren van nitraat is daarvan een voorbeeld. Daarmee wordt de grootste bron van broeikasgasemissie op het melkveebedrijf, methaan, flink verminderd.
Nutriënten verwijderen uit lozingswater en hergebruiken als meststof
Os, E.A. van; Klein, P. ; Niekerk, O. van; Ruijven, J.P.M. van; Staaij, M. van der - \ 2015
glastuinbouw - emissie - bemesting - milieueffect - stikstof - filters - nitraat - fosfaat - greenhouse horticulture - emission - fertilizer application - environmental impact - nitrogen - nitrate - phosphate
De glastuinbouwsector heeft met de overheid afgesproken naar een (nagenoeg) nul-emissie in 2027 toe te werken. Hiervoor zijn emissienormen voor stikstof afgesproken die steeds verder worden verscherpt. Behalve stikstof kunnen er in het lozingswater andere nutriënten, gewasbeschermingsmiddelen (GBM), zout, pathogenen en groeiremmers zitten. Om toch drainwater te kunnen lozen zijn Horticoop en Optima Agrik (ZA) de ontwikkeling gestart om een apparaat te maken dat nitraat en fosfaat uit het lozingswater verwijderd terwijl het restproduct weer als meststof kan worden gebruikt.
Optimization of blue mussel (Mytilus edulis) seed culture using recirculation aquaculture systems
Blanco Garcia, A. ; Kamermans, P. - \ 2015
Aquaculture Research 46 (2015)4. - ISSN 1355-557X - p. 977 - 986.
toxicity - ammonia - nitrite - nitrate - growth - flow
By introducing recirculation aquaculture systems (RAS) in the nursery phase of the blue mussel (Mytilus edulis) (17–18 mm), we aimed at a similar growth and survival and a similar water quality compared to the commonly used flow-through systems (FTS). To calculate water flow and size of the biofilter, a series of experiments were done to determine clearance rate (9.26 mL min-1), pseudo faeces threshold (60 000 cells Pavlova lutheri mL-1), nitrogen production (0.00065 mg TAN h-1 ind-1 and 1.6 × 10-5 mg NO2–N h-1 ind-1) and oxygen consumption (0.03 ± 0.01 mg O2 h-1 ind-1). RAS showed no significant differences in water quality (0.06 mg TAN L-1; 7.7 mg O2 L-1) and growth performance of mussel seed specific growth rate (SGR = 5% day-1) after the experimental period of 4 weeks compared with FTS. The low water refreshment, 10% per day, as well as the constant chlorophyll concentrations (9.76 ± 1.06 µg L-1), suggests the potential of RAS as culture system for mussel seed.
Schram, Edward - \ 2014
fisheries - aquaculture - water quality - feed intake - pike perch - silurus glanis - eels - fishes - diversity - nitrate - ammonia
Correction of the Vimoke–Taylor Concept Representing Drains in a Numerical Simulation Model
Heinen, M. - \ 2014
Vadose Zone Journal 13 (2014)10. - ISSN 1539-1663 - 9 p.
flood-irrigated field - hydraulic conductivity - water-flow - subsurface drains - preferential flow - soil - transport - equation - nitrate
Proper prediction of drain discharge using the single node Vimoke and Taylor approach in a numerical simulation model requires an additional correction factor. This correction factor was calibrated and dependent on node size, drain radius and the way of averaging the hydraulic conductivity. For a transient situation the additional correction factor resulted in higher groundwater levels and lower drain discharges. Drains are special internal or boundary conditions in numerical simulation models. Instead of approximating them by a hole surrounded by a very dense grid of finite elements, the single node or single element approach based on the theory of Vimoke and Taylor proposed in 1962 offers a good alternative. Several authors have suggested that the Vimoke and Taylor constant to adapt the hydraulic conductivity of the element representing the drain should be changed by a certain factor. However, different correction factors have been given. Here this correction factor is derived for a control volume finite element numerical simulation model for different ratios of the size of the control volume representing the drain and the effective drain radius. It is shown that this relationship is dependent on the way the hydraulic conductivity is averaged at the interfaces between the neighboring control volumes. The relationships were obtained by optimization against an analytical solution for a steady-state, saturated situation. By applying the additional correction to a hypothetical transient situation for four soil types it was shown that the application of the additional correction factor resulted in 3 to 13% lower drain discharges compared to uncorrected simulations. Consequently, higher groundwater levels of on average 2 to 4 cm were obtained when applying the additional correction. For situations where exact predictions of drain discharge are needed, typically when solute transport is considered, it is advised to make use of the additional correction. Model specific correction factors may be required.
Soil bulk density and moisture content influence relatieve gas diffusivity and the reduction of nitrogen-15 nitrous oxide
Klefoth, R.R. ; Clough, T.J. ; Oenema, O. ; Groenigen, J.W. van - \ 2014
Vadose Zone Journal 13 (2014)11. - ISSN 1539-1663 - 8 p.
nitrifier denitrification - n2o emission - grassland soil - subsoil - nitrate - water - fate - availability - consumption - diversity
Soil bulk density and moisture influence N2O movement and its reduction. This isotope study shows the sensitivity reduction of N2O, a greenhouse gas, to soil physical properties and their effect on gas diffusion. Increasing soil bulk density and water content promoted N2O reduction. Nitrous oxide is a greenhouse gas and contributes to stratospheric ozone depletion. Soil physical conditions may influence N2O reduction and subsequent N2O emissions. We studied how soil water-filled pore space (WFPS) and soil bulk density (¿b) affect N2O reduction and surface fluxes. Columns were repacked with soil and arranged in a factorial design at three levels of WFPS (60, 75, and 90%) and three levels of soil ¿b (0.94, 1.00, 1.07 Mg m-3). Over 19 d, 15N-enriched N2O was introduced at the base of the soil columns and N2O fluxes were measured. Relative gas diffusivities (Dp/Do) were also calculated. Soil ¿b and WFPS interacted to affect the recovery of N2O-15N and the antecedent inorganic-N contribution to surface fluxes. Reduction rates of N2O-15N ranged from 0.15 to 0.47 mg N2O-N g-1 soil d-1. Calculated Dp/Do values correlated (P <0.01) with soil NH4+–N (r = -0.73), NO3-–N (r = 0.93), cumulative N2O-N flux (r = 0.76), and N2O-N 15N enrichment (r = 0.80) and were affected by a soil WFPS × soil ¿b interaction. Soil N transformations and the net surface N2O flux is dependent on the soil’s Dp/Do, and WFPS alone does not suffice to discriminate between N2O emission sources. Consequently, the soil surface N2O flux may be comprised of N2O originating from deeper soil layers transported upward and/or from production in the topsoil.
Diversity of crop development traits and nitrogen use efficiency among potato cultivars grown under contrasting nitrogen regimes
Ospina Nieto, C.A. ; Lammerts Van Bueren, E. ; Allefs, J.J.H.M. ; Engel, B. ; Putten, P.E.L. van der; Linden, C.G. van der; Struik, P.C. - \ 2014
Euphytica 199 (2014)1-2. - ISSN 0014-2336 - p. 13 - 29.
solanum-tuberosum l. - yield response - root-system - dry-matter - nitrate - fertilization - management - quality - index - plant
Potato (Solanum tuberosum L.) requires abundant nitrogen (N) to perform well and has low nitrogen use efficiency (NUE). We assessed phenotypic variation among 189 potato cultivars for NUE and the association between NUE and ecophysiological variables describing canopy development (CDv), under high and low N input. In 2009 and 2010, 189 cultivars were grown with N supply (soil N + fertiliser N) of 75 or 180 kg N/ha at Bant, the Netherlands. CDv was assessed weekly as the percentage of soil covered by green potato leaves (%SC). Data were analysed using a model that described CDv as a function of thermal time, based on the Beta function and estimates of cardinal temperatures. Nitrogen significantly affected model-derived, biologically relevant, curve-fit parameters for each cultivar. The t 1 (i.e., thermal time required to reach maximum soil cover (Vx)) was higher at low than at high N. Other parameters were higher at high than at low N, especially Vx and the period over which it was maintained. Nitrogen also affected tuber dry matter yield, tuber size and weight distributions, N content and N uptake but not tuber dry matter percentage. The total area under the %SC curve was highly correlated with yield in both years. Cultivars performing well under high N also performed well under low N. There was large variation in NUE component traits among cultivars; maturity type partially explained this variation. Variables of the CDv model captured this variation, N effects on light interception and its correlation with yield.
Identifying nitrogen-efficient potato cultivars for organic farming
Tiemens-Hulscher, M. ; Lammerts Van Bueren, E. ; Struik, P.C. - \ 2014
Euphytica 199 (2014)1-2. - ISSN 0014-2336 - p. 137 - 154.
late blight - growth - yield - model - management - nitrate - plant
In organic farming, nitrogen efficiency of potato might vary among cultivars, even within the same maturity type. We therefore analysed in depth the response to nitrogen of a diverse set of cultivars, grown at different locations (differing in soil type and management) and in four years (differing in temperature and rainfall patterns). Yield increased with an increase in nitrogen supply and with growing later cultivars if the crop cycle lasted long enough. When crops had to be flamed to prevent spread of late blight, late cultivars yielded less than early cultivars, especially under high nitrogen. By measuring the fraction of soil covered by green leaves throughout the growing season and using a model, we analysed canopy development in detail and related nitrogen and genotype sensitive model parameters to tuber yield. In one year with early, temporary drought, model prediction was poor. We observed that cultivars that rapidly established a high maximum soil cover, maintained that maximum for long and senesced slowly, could sustain high yields. When late-blight infection was late, these (mid)-late cultivars showed high agronomic nitrogen use efficiency, but were not (always) high in nitrogen uptake efficiency, accumulation of nitrogen in the tubers or nitrogen utilisation efficiency. When late-blight infection started early, early or mid-late cultivars that rapidly established a high maximum soil cover under low nitrogen availability gave best performance. In most years, early canopy development is responsive to nitrogen, shows genetic variation, and is significantly related to early tuber yield. Nitrogen-efficient cultivars suitable for organic production should have rapid early canopy development, a high agronomic nitrogen use efficiency and nitrogen utilisation efficiency, but a low nitrogen concentration in the tubers.
Hoe giftig zijn ammonia en nitraat voor snoekbaars?
Schram, E. ; Roques, J.A.C. ; Kuijk, T. van; Abbink, W. ; Heul, J.W. van der; Vries, P. de; Bierman, S.M. ; Vis, J.W. van de; Flik, G. - \ 2014
Aquacultuur 29 (2014)1. - ISSN 1382-2764 - p. 12 - 17.
snoekbaars - recirculatie aquacultuur systemen - aquacultuur - nitraat - ammoniak - voeropname - pike perch - recirculating aquaculture systems - aquaculture - nitrate - ammonia - feed intake
In intensieve recirculatiesystemen lopen vissen het risico blootgesteld te worden aan ammonia en nitraat. Hoe hoog mogen de nitraat- en ammoniaconcentratie zijn zonder dat dit negatieve effecten heeft op de vissen? IMARES onderzocht dit in samenwerking met de Radboud Universiteit Nijmegen en de Universiteit van Amsterdam voor juveniele snoekbaars. Conclusie: de ammonia (NH3) concentratie moet onder de 0.05 mg NH3-N/I gehouden worden. Van nitraat lijken juveniele snoekbaarzen zelfs bij 358 mg NO3-N/I nog weinig hinder te ondervinden.
N2O consumption by low-nitrogen soil and its regulation by water and oxygen
Wu, D.M. ; Dong, W.X. ; Oenema, O. ; Wang, Y.Y. ; Trebs, I. ; Hu, C.S. - \ 2013
Soil Biology and Biochemistry 60 (2013). - ISSN 0038-0717 - p. 165 - 172.
spruce forest soil - aerobic denitrification - oxide - fluxes - emissions - exchange - n-2 - no - bacteria - nitrate
Soils can be a source and sink for atmospheric nitrous oxide (N2O). Consumption of N2O has been reported for anoxic soils and sediments rich in organic matter and depleted in nitrates (NO3-), and also for some dry, oxic soils. However, the mechanisms and controls of N2O consumption in dry soil are not clear. Here, we report on a field study in China (Taihang mountain region, Shijiazhuang), in which N2O uptake by a sandy loam soil was measured for the greater part of the season (from April to October in 2011), and on four incubation experiments, in which we tried to reveal the roles of water content and oxygen (O-2) concentrations on N2O consumption. Flux measurements in the field were made bi-weekly on unfertilized cropped land with static flux chambers (5 replicates) for 6 months. The results show that N2O-N fluxes ranged from -26.0 to -726.6 mu g m(-2) h(-1). Consumption of N2O was largest when the soil was dry (5-20% soil water filled pore space). In the incubation experiments, N2O consumption and N-2 production were measured in (an)aerobic soil with soil moisture content ranging from 1% to 50% (wt/wt) and with N2O addition, using a thermostatic, robotized incubation system. Under anaerobic conditions, N2O was rapidly consumed at water content of >10% (wt/wt). However, a significant consumption also occurred at 1% soil moisture. Under aerobic conditions, N2O consumption increased with increasing soil moisture content, but significant consumption was still measured at 2% moisture. Sterilization of oxic soil completely blocked N2O consumption, suggesting that the consumption had a biological nature. In conclusion, the steady N2O consumption measured in the field was confirmed by the laboratory experiments, but the relationship with soil moisture content was reversed. Further studies are required to understand this apparent anomaly.
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.
Global inventory of closed-off Tidal basins and developments after the closure
Schultz, B. ; Hayde, L.G. ; Sang-Hyun, P. ; Tanaka, K. - \ 2013
Irrigation and Drainage 62 (2013)Suppl. 1. - ISSN 1531-0353 - p. 107 - 123.
porous ceramic cups - deep drainage - clay soil - tillage - nitrate - vertosols - systems
Closed-off tidal basin reclamation represents a special type of reclamation. In several countries enclosing dams have been built to close off estuaries, shallow seas, or lagoons, and lands up to 5~6¿m - MSL (below mean sea level) have been reclaimed in the former tidal basins. Although these areas were generally primarily reclaimed for agriculture, a second-stage development may have taken place where parts of these lands were transferred to urban and industrial use. The originally saline water in the created reservoirs was transformed to fresh water that may be used for irrigation, domestic and/or industrial water supply. In several of these reservoirs there are water quality problems, primarily due to pollution in upstream parts of the river basins. In 2007 the Enclosing Dam of the Zuiderzee Scheme in the Netherlands had existed for 75¿years. This occasion was used to conduct a global inventory of closed-off tidal basin reclamation on which this paper is based. The study shows that closed-off tidal basin reclamation concerns 25 schemes with a total area of 738 000¿ha, of which 337 000¿ha have been reclaimed and 401 000¿ha freshwater reservoirs have been created. This paper presents a summarized overview. Attention is paid to safety, land use and changes in it, development of water quality in the reservoirs, as well as to land subsidence and possible impacts of climate change, like rise in mean sea level. In time this may have implications for safety of the deep polders, the management of the reservoirs as well as for the sustainable development of tidal areas in the future. These items are presented for four major tidal reclamation schemes: the Zuiderzee Scheme in the Netherlands, the Saemangeum Scheme in South Korea, the Kuttanad Region in India and the Hachirogata Scheme in Japan
Nieuwe technieken, nog meer reductie
Haan, M.H.A. de; Hilhorst, G.J. ; Vegte, D.Z. van der; Booij, A. - \ 2013
Veeteelt 30 (2013)11. - ISSN 0168-7565 - p. 36 - 37.
melkveehouderij - broeikasgassen - innovaties - proefboerderijen - mestverwerking - methaan - emissie - rundveevoeding - voersamenstelling - nitraat - onderzaaien - grassen - dairy farming - greenhouse gases - innovations - experimental farms - manure treatment - methane - emission - cattle feeding - feed formulation - nitrate - undersowing - grasses
Gras crushen, mest raffineren, toevoegmiddelen voor voer en kuil; op praktijkcentrum De Marke in het Gelderse Hengelo worden verschillende innovatietechnieken uitgeprobeerd om de broeikasgassen verder te verminderen. Praktijkrijp zijn ze nog niet.
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