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Registros recuperados: 9
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Challenges in modelling dissolved organic matter dynamics in agricultural soil using DAISY Organic Eprints
Gjettermann, B.; Styczen, M.; Hansen, H.C.B.; Vinther, F.P.; Hansen, S..
Because dissolved organic matter (DOM) plays an important role is terrestrial C-,N-and P-balances and transport of these three components to aquatic environments, there is a need to include it in models. This paper presents the concept of the newly developed DOM modules implemented in the DAISY model with focus on the quantification of DOM sorption/desorption and microbial-driven DOM turnover. The kinetics of DOM sorption/desorption is described by the deviation of the actual DOM concentration in solution from the equilibrium concentration, Ceq. The Ceq is soil specific and estimated from pedotransfer functions taking into account the soil content of organic matter, Al and Fe oxides. The turnover of several organic matter pools including one DOM pool are...
Tipo: Journal paper Palavras-chave: Soil.
Ano: 2008 URL: http://orgprints.org/21148/1/21148.pdf
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CN-SIM - a model for the turnover of soil organic matter. I: Long term carbon development Organic Eprints
Petersen, B.M.; Berntsen, J.; Hansen, S.; Jensen, L.S..
A computer model is presented that describes the flow of C and N in the soil. It employs a structure with conceptual compartments. Organic matter is represented by seven different compartments, two for added matter, two for soil microbial biomass, one for microbial residues, one for native organic matter, and one for inert organic matter. The latter pool probably represents both truly inert matter, and matter with a very slow turnover. This paper describes the parameterisation and performance of this model on selected long-term field data from United Kingdom, Sweden and Denmark. Statistical methods were employed to optimise parameters, and obtain proximate confidence intervals for these parameters. Very satisfactory simulations could be acquired, using the...
Tipo: Journal paper Palavras-chave: Nutrient turnover.
Ano: 2005 URL: http://orgprints.org/87/1/87.pdf
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CN-SIM - a model for the turnover of soil organic mattter. II: Short term carbon and nitrogen development Organic Eprints
Petersen, B.M.; Jensen, L.S.; Berntsen, J.; Hansen, S.; Pedersen, A.; Henriksen, T.M.; Sørensen, P.; Trinsoutrot, I..
A computer model is presented, which describes the transformations of C and N in the soil. The development has been divided into two interdependent tasks, the first being development of long-term SOC simulation capabilities, and the second being short-term simulations of C and N, as described in this paper. A number of existing, independent laboratory experiments, covering a range of amendments, have been used for this task. The amendments includes a variety of different crop residues and animal manure. These experiments have included measurements of 13C, 14C and 15N in various pools, and the model facilitates the simulation of these isotopes. Non-linear, automated optimisation procedures were utilised wherever feasible. The model generally yielded good...
Tipo: Journal paper Palavras-chave: Nutrient turnover.
Ano: 2005 URL: http://orgprints.org/88/1/88.pdf
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Effect of green manure management on barley yields and N-recovery Organic Eprints
Hansen, S.; Frøseth, R.B.; Bakken , A.K.; Riley, H.; Thorup-Kristensen, K.; Bleken, M.A..
Mulching of GM herbage can increase cereal yields compared to its removal. However, the same GM herbage removed for biogas production will provide biogas residue that can be used as spring fertilizer to cereals. This will improve N-recovery and reduce the risk for N pollution. Cooperation with existing biogas plants will be more efficient, as building small biogas plants are costly and challenging.
Tipo: Conference paper, poster, etc. Palavras-chave: Cereals; Pulses and oilseeds Composting and manuring Post harvest management and techniques.
Ano: 2013 URL: http://orgprints.org/24600/1/24600.pdf
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Embedded energy in dairy stables Organic Eprints
Koesling, M.; Hansen, S.; Fystro, G..
The calculation of the embedded energy (EE) of twenty barns shows that there is a considerable variation of EE per cow, where the lowest values were one fourth of the highest. Use of timber instead of concrete in walls had most effect to reduce the amount of EE. Cold barns can contribute to reduce the amount of EE, while the amount of EE is higher in free-stall than in tie-stall barns. While for an existing building the amount of EE is nearly fixed, calculating the anticipated amount for a new building can help to reduce energy use in agriculture and thus contribute to a more sustainable pro¬duction. Incorporating EE in planning new buildings should be of special importance for organic farming, since regulations demand more area per animal than in...
Tipo: Conference paper, poster, etc. Palavras-chave: Dairy cattle; Buildings and machinery.
Ano: 2013 URL: http://orgprints.org/24558/1/24558.pdf
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Modelling long term carbon and radiocarbon development Organic Eprints
Petersen, B.M.; Berntsen, J.; Jensen, L.S.; Hansen, S..
In order to achieve predictive abilities for both short- and long-term simulations, SOM models should be developed on the basis of as large and diverse a data-set as possible. Many soil organic matter (SOM) models have parameters, where the criteria for estimating their values do not seem transparent, and few have been subject to a formal sensitivity analysis regarding the influence of parameter settings. One of the major problems in most SOM models is to estimate the soil content of very slowly decomposing or perhaps even inert organic matter ("refractory" SOM). In view of these possible limitations of present SOM models, the following model development criteria were chosen for this study: 1) use of a comprehensive data-set from both laboratory and...
Tipo: Conference paper, poster, etc. Palavras-chave: Soil biology.
Ano: 2003 URL: http://orgprints.org/4660/1/4660.doc
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Modelling short term carbon and nitrogen development Organic Eprints
Petersen, B.M.; Jensen, L.S.; Berntsen, J.; Hansen, S.; Pedersen, A..
Carbon (C) and nitrogen (N) transformations are highly interdependent, driven by the C metabolism. Though many details of the transformations of C and N forms in soil are well known, basic knowledge about the mechanisms determining substrate availability, and the chemical and physical properties determining the stabilisation of organic matter are still lacking. The soil biota furthermore constitutes an extremely complex food web, consisting of a vast number of bacteria, fungi and fauna species, each having their own feeding preferences and characteristic life cycle. A good quantitative description of the main processes involved is required. This involves both the long-term build-up and degradation of soil organic matter, and the more short-termed N...
Tipo: Conference paper, poster, etc. Palavras-chave: Soil biology.
Ano: 2003 URL: http://orgprints.org/4662/1/4662.doc
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Simulating soil fertility management effects on crop yield and soil nitrogen dynamics in field trials under organic farming in Europe Organic Eprints
Doltra, J.; Gallejones, P.; Olesen, J.E.; Hansen, S.; Frøseth, R.B.; Krauss, M.; Stalenga, J.; Jończyk, K.; Martínez-Fernández, A.; Pacini, G.C..
Soil fertility building measures should be explored at the short and long-term for an adequate evaluation of their impact on sustaining yields and of its environmental consequences in crop rotations under organic farming. For such a purpose, process-based crop models are potential useful tools to complement and upscale field observations under a range of soil and climatic conditions. Organic rotations differ in soil fertility dynamics in comparison to conventional farming but very few modelling studies have explicitly considered this specific situation. Here, we evaluate the FASSET model to predict the effects of different fertility management options in organic crop rotations on dry matter (DM) and nitrogen (N) yield, and soil N dynamics, including N2O...
Tipo: Journal paper Palavras-chave: Soil quality; Nutrient turnover; Soil tillage.
Ano: 2019 URL: http://orgprints.org/34308/1/doltra-etal-2019_FCR_Vol233_p1-11.pdf
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Sorption and fractionation of dissolved organic matter and associated phosphorus in agricultural soil Organic Eprints
Gjettermann, B.; Styczen, M.; Hansen, S.; Borggaard, O.K.; Hansen, H.C.B..
Molibility of dissolved organic matter (DOM) strongly affects the export of nitrogen (N) and phosphorus (P) from oils to surface waters. To study the sorption an mobility of dissolved organic C and P (DOC, DOP) in soil, the pH-dependent sorption of DOM to samples from Ap, EB, and Bt horizons from a Danish agircultural Humic Hapludult was investigated and a kinetic model applicable in field-scale model tested. Sorption experiments of 1 to 72 h duration were conducted at two pH levels (pH 5.0 and 7.0) and six initial DOC concentrtions (0-4.7 mmol L-1). Most sorption/desorption occurred during the first few hours. Dissolved organic carbon and DOP sorption decreased strongly with increased pH and desorption dominated at pH 7, especially for DOC. Due to...
Tipo: Journal paper Palavras-chave: "Organics" in general; Soil.
Ano: 2007 URL: http://orgprints.org/21007/4/21007.pdf
Registros recuperados: 9
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