Global assessment of soil phosphorus retention potential

Limited availability of P in soils to crops may be due to deficiency and/or severe P retention. Earlier studies that drew on large soil profile databases have indicated that it is not (yet) feasible to present meaningful values for "plant-available" soil P, obtained according to comparable analytical methods, that may be linked to soil geographical databases derived from 1:5 million scale FAO Digital Soil Map of the World, such as the 5 x 5 arc-minute version of the ISRIC-WISE database. Therefore, an alternative solution for studying possible crop responses to fertilizer-P applied to soils, at a broad scale, was sought. The approach described in this report considers the inherent capacity of soils to retain phosphorus (P retention), in various forms. Main controlling factors of P retention processes, at the broad scale under consideration, are considered to be pH, soil mineralogy, and clay content. First, derived values for these properties were used to rate the inferred capacity for P retention of the component soil units of each map unit (or grid cell) using four classes (i.e., Low, Moderate, High, and Very High). Subsequently, the overall soil phosphorus retention potential was assessed for each mapping unit, taking into account the P-ratings and relative proportion of each component soil unit. Each P retention class has been assigned to a likely fertilizer P recovery fraction, derived from the literature, thereby permitting spatially more detailed, integrated model-based studies of environmental sustainability and agricultural production at the global and continental level (< 1:5 million). Nonetheless, uncertainties remain high; the present analysis provides an approximation of world soil phosphorus retention potential.

Aeschyli Tragoediae quae supersunt ac desperditarum fragmenta /

Mode of access: Internet.

Green mountain annals, a tale of truth.

Wright I, 972.

Tragœdiæ quæ supersunt.

Greek text, Latin notes.

Lexicon Ciceronianum.

v.1. Index geographicus et historicus.--v.2-3. Index Latinitatis.--v.4. Index Graecolatinum, Index rerum, et index chronologicus.

Aeschyli Tragoediae quae supersunt ac deperditarum fragmenta /

Without the fragments, scholia, apparatus and lexicon; the scholia (v. 4) and fragments (v. 5) were published in 1821.

Tragoediae quae supersunt.

Marginal ms. notes by Rupert Brooke in vols. 1 and 2.

Théâtre choisi contenant Prométhée, Les sept chefs devant Thèbes, et Les Perses. Publié d'après le texte de Schütz, avec un index des mots les plus difficiles,

Mode of access: Internet.

M. Tulli Ciceronis Opera quae supersunt omnia ac deperditorum fragmenta /

Each volume also has special t.p.

Iurisprudentiae antehadrianae quae supersunt

Mode of access: Internet.

Acta sanctorum septembris ... /

Mode of access: Internet.

Acta Sanctorum septembris ... /

Mode of access: Internet.

Acta sanctorum septembris ex latinis & graecis, aliarumque gentium monumentis, servata primigenia veterum scriptorum phrasi, /

Mode of access: Internet.

Aeschyli Tragoediae qvae svpersvnt ac deperditarvm fragmenta /

Text in Greek.

Universal quantum computation with continuous-variable cluster states

We describe a generalization of the cluster-state model of quantum computation to continuous-variable systems, along with a proposal for an optical implementation using squeezed-light sources, linear optics, and homodyne detection. For universal quantum computation, a nonlinear element is required. This can be satisfied by adding to the toolbox any single-mode non-Gaussian measurement, while the initial cluster state itself remains Gaussian. Homodyne detection alone suffices to perform an arbitrary multimode Gaussian transformation via the cluster state. We also propose an experiment to demonstrate cluster-based error reduction when implementing Gaussian operations.