Modelling root distribution and nitrogen uptake

Plant soil and atmosphere models are commonly used to predict crop yield and environmental consequence. Such models often include complex modelling modules for water movement, soil organic matter turnover and, above ground plant growth. However, the root modelling in these models are often very simple, partly due to a limited access to experimental data. We present a two-dimensional model for root growth and proliferation. The model focuses on annual crops, and attempt to model root growth of the crops and its significance for N uptake from different parts of the soil volume

A model analysis on nitrate leaching under different soil and climate conditions and use of catch crops

The use of crops and catch crops with deep rooting can strongly improve the possibility of retaining nitrate-N that will otherwise be leached to the deeper soil layers and end up in the surrounding environment. But will it always be an advantage for the farmer to grow a catch crop? This will depend on factors such as soil mineral nitrogen level, soil water holding capacity, winter precipitation, rooting depth and N demand of the scceeding crop. These factors interact, and it can be very difficult for farmers or advisors to use this information to decide whether growing a catch crop will be beneficial. To analyse the effect of catch crops under different Danish soil and precipitation conditions, we used the soil, plant and atmosphere model Daisy

Simulating Root Density Dynamics and Nitrogen Uptake -Field Trials and Root Model Approach in Denmark

Plant soil and atmosphere models are commonly used to predict crop yield and associated environmental consequences. Such models often include complex modelling of water movement, soil organic matter turnover and above ground plant growth. However, the root modelling in these models is often very simple, partly due to a limited access to experimental data. Here we propose a root model developed to describe root growth, root density and nitrogen uptake. The model focuses on annual crops, and attempts to model root growth of different crop species and row crops and its significance for nitrogen uptake from different parts of the soil volume

Simulating Root Density Dynamics and Nitrogen Uptake – Can a Simple Approach be Sufficient?

The modeling of root growth in many plant–soil models is simple and with few possibilities to adapt simulated root proliferation and depth distribution to that actually found with different crop species. Here we propose a root model, developed to describe root growth, root density and nitrogen uptake. The model focuses on annual crops, and attempts to model root growth of different crop species and row crops and its significance for nitrogen uptake from different parts of the soil volume

Assessment of risks related to agricultural use of sewage sludge, pig and cattle slurry

In April 2017, the Organic Business Development Team released a report with 25 recommendations for the Minister of Environment and Food (Det økologiske erhvervsteam 2017). Among these was a recommendation that organic farmers should have opportunities for utilizing nutrients from treated domestic wastewater for nutrient recycling. A prerequisite for future use of nutrients from treated wastewater is, that quality requirements are met and that application can be explained to (and accepted by) consumers. In partial fulfilment of this, the business team identified a need for a scientific overview of the risks of using nutrients from treated municipal wastewater in relation to other authorized fertilizer sources – e.g. conventional animal manures. Thus, it was assumed that a comparative approach to assess potential risk of using sewage sludge and conventional manures, could usefully inform decision makers in the future regulation of organic farming systems. Dependent on the result of the scientific investigation, the Organic Business Development Team foresaw that Denmark could chose to work to expand Annex 1 of the EU Ecology Regulation, to allow the organic farmers to use nutrients from municipal wastewater or other acceptable derived sludge products. Mobilization of support for this should be done by the Ministry of Environment and Food in collaboration with the Organic Farming Industry. Thus, based on available literature, this report aims at creating an overview of the environmental and human risks associated with application of pig and cattle slurry as well as sewage sludge to agricultural soils. The risk evaluation was performed for the following compound groups: Metals, Chlorophenyls, Dioxins, Furans, Halogenated aliphatic and aromatic hydrocarbons (HAH), Linear alkylbenzenesulfonates (LAS), Polyaromatic hydrocarbons (PAH), Polybrominated diphenyl ethers (PBDE), Polychlorinated biphenyls (PCB), Poly- and perfluorinated alkylated substances (PFAS), Phenols, Phosphate-triesters VII, Phthalates, Polychlorinated naphtalenes (PCN), Polychlorinated alkanes (PCA), Triclosan, Triclocarban, Medicines, Estrogens, Antibiotic resistance genes. Additionally the fertilizer potential of the two nutrient sources was characterized and compared

Calibration of the Mass-Temperature Relation for Clusters of Galaxies Using Weak Gravitational Lensing

The main uncertainty in current determinations of the power spectrum normalization, sigma_8, from abundances of X-ray luminous galaxy clusters arises from the calibration of the mass-temperature relation. We use our weak lensing mass determinations of 30 clusters from the hitherto largest sample of clusters with lensing masses, combined with X-ray temperature data from the literature, to calibrate the normalization of this relation at a temperature of 8 keV, M_{500c,8 keV}=(8.7 +/- 1.6) h^{-1} 10^{14} M_sun. This normalization is consistent with previous lensing-based results based on smaller cluster samples, and with some predictions from numerical simulations, but higher than most normalizations based on X-ray derived cluster masses. Assuming the theoretically expected slope alpha=3/2 of the mass-temperature relation, we derive sigma_8 = 0.88 +/-0.09 for a spatially-flat LambdaCDM universe with Omega_m = 0.3. The main systematic errors on the lensing masses result from extrapolating the cluster masses beyond the field-of-view used for the gravitational lensing measurements, and from the separation of cluster/background galaxies, contributing each with a scatter of 20%. Taking this into account, there is still significant intrinsic scatter in the mass-temperature relation indicating that this relation may not be very tight, at least at the high mass end. Furthermore, we find that dynamically relaxed clusters are 75 +/-40% hotter than non-relaxed clusters.Comment: 8 pages, 4 figures, revised version submitted to Ap