Decomposition rate of organic fertilizers: effect on yield, nitrogen availability and nitrogen stock in the soil

The nitrogen of organic fertilizers does not fully mineralize within a season, and hence will partly become available in later years. This effect is taken into account for the first year but generally not in later fertilizer applications. If it would be taken into account, fertilizer use could be more efficient. This study is an analysis of a 13-year field trial where crop yield was measured in 13 fertilizer treatments which differ in total N applied and decomposition rate. This is complemented with a model study in which mineralization and soil nitrogen content were calculated. We intended to show step by step that the use of fertilizers with a low decomposition rate, relative to fertilizers with a high decomposition rate, lead in the course of years to an increase in soil organic nitrogen, an increased nitrogen mineralization and availability and that this results in increased yields. Some of the results in these four steps in our work give support to this, but there are more factors at play. We show that when using, for example, deep stable manure, after some years the available nitrogen may for 50% or more be derived from manure applied in former years. This makes clear that, at least in agricultural systems that use a substantial amount of organic fertilizers, it is worthwhile taking this delayed mineralization into account

The Inner Quality Concept for food, based on life processes

How can we adequately express the quality of food produced by organic agriculture? To answer this research question, we defined a concept of ‘inner quality’ (formerly called ‘vital quality’) based on the life processes growth and differentiation, and their integration. Growers use management methods to influence life processes in their crops, thus optimising the quality of the final product. Traders and consumers can recognise certain product properties as being the result of these life processes. Here, we present a course of validation for the quality concept, together with appropriate quality parameters. The process of validation has been completed in part for two experimental crops, apple and carrot. This quality concept can provide a holistic context for the interpretation of individual food quality parameters as developed by different laboratories

Bewertung von Bodenfruchtbarkeit, Stickstoffhaushalt und Ertrag.

Dieser Bericht ist die Übersetzung der Publikation "Planty Organic 5 jaar: evaluatie van bodem-vruchtbaarheid, stikstofhuishouding en productie", die um ein kurzes Kapitel über die nach der Veröffentlichung gewonnenen Ergebnisse der Jahre 2017 und 2018 ergänzt wurde. Vom ursprünglichen Bericht lag bereits eine englische Fassung vor. Der Jahresbericht 2017 wurde in niederländischer Sprache publiziert; der Jahresbericht 2018 ("Planty Organic – voortgang 2018") ist, ebenfalls als niederländische Datei, auf www.louisbolk.nl zu finden. Der ursprüngliche Bericht wurde vollständig und unverändert übersetzt. Zusätzlich wurde ein Schlusskapitel angehängt, Kapitel 8, in dem der Frage nachgegangen wird, ob sich die in der Bewertung der Jahre 2012 – 2016 angedeuteten Entwicklungstendenzen bezüglich Boden und Pflanzen in den Jahren 2017 und 2018 fortgesetzt haben

An early warning indicator for atmospheric blocking events using transfer operators

The existence of persistent midlatitude atmospheric flow regimes with time-scales larger than 5-10 days and indications of preferred transitions between them motivates to develop early warning indicators for such regime transitions. In this paper, we use a hemispheric barotropic model together with estimates of transfer operators on a reduced phase space to develop an early warning indicator of the zonal to blocked flow transition in this model. It is shown that, the spectrum of the transfer operators can be used to study the slow dynamics of the flow as well as the non-Markovian character of the reduction. The slowest motions are thereby found to have time scales of three to six weeks and to be associated with meta-stable regimes (and their transitions) which can be detected as almost-invariant sets of the transfer operator. From the energy budget of the model, we are able to explain the meta-stability of the regimes and the existence of preferred transition paths. Even though the model is highly simplified, the skill of the early warning indicator is promising, suggesting that the transfer operator approach can be used in parallel to an operational deterministic model for stochastic prediction or to assess forecast uncertainty

The principle of a virtual multi-channel lock-in amplifier and its application to magnetoelectric measurement system

This letter presents principles and applications of a virtual multi-channel lock-in amplifier that is a simple but effective method to recover small ac signal from noise with high presison. The fundamentals of this method are based on calculation of cross-correlation function. Via this method, we successfully built up a magnetoelectric measurement system which can perform precise and versatile measurements without any analog lock-in amplifier. Using the virtual multi-channel lock-in amplifier, the output of the magnetoelectric measurement system is extensively rich in magnetoelectric coupling behaviors, including coupling strength and phase lag, under various dc bias magnetic field and ac magnetic field.Comment: 11 pages, 6 figures. To be submitted to Rev. Sci. Instr

In Conversation with Mubin Shaikh: From Salafi Jihadist to Undercover Agent inside the "Toronto 18" Terrorist Group

This interview with former undercover agent Mubin Shaikh can help academics and security practitioners understand the key role played and the challenges faced by covert human intelligence sources within domestic terrorist groups. The interview highlights the identity crisis, the personal factors, and the allure of jihadi militancy that initially drove Shaikh to join a Salafi jihadist group. It investigates Shaikh’s process of disengagement from the Salafi jihadist belief system and his rediscovery of a moderate, inclusive, and benevolent form of Islam. It explores his work as an undercover agent for the Canadian Security Intelligence Service, the Royal Canadian Mounted Police, and the Integrated National Security Enforcement Team responsible for disrupting domestic terrorist groups. The “Toronto 18” terrorist cell, the key role played by undercover agents in preventing terrorist action, and the challenges posed by entrapment are also discussed

Effect meerjarige toepassing groenbemester en organische mest op bodemkwaliteit bij continuteelt maïs : 2e rapport project Zorg voor Zand

In 2005 is onderzoek gedaan naar het effect van meerjarige toepassing van groenbemester en organische bemesting op diverse bodemkwaliteitskenmerken bij continuteelt van snijmaïs op zandgrond. De conclusie is dat het effect op de bodemkwaliteit en gewasopbrengst van organische bemesting wat groter was dan van groenbemester. De biologische activiteit werd nauwelijks beïnvloed door beide behandelingen