Soil organic matter: A review of research results

The role of soil OM is reviewed, with special reference to bean production. Soil physical properties, chemical properties, and biological effects are covered. The different interactions of soil management practices with soil OM, such as the implications of seasonal effects on decomposition, nutrient cycling in cereal- legume crops, minimization of losses of OM and nutrients, sources of OM, and management of crop residues, are also indicated. The benefits of composting are also reviewed; although few field trials on composting have been reported in Africa, the few research results obtained so far are summarized. Research needs for Africa, with particular reference to bean production, include (1) N and P balance studies in major cropping systems, (2) improved utilization of OM, (3) on-farm verification of management techniques with kraal or boma manure, (4) surveys of local sources of OM potentially for composting, (5) evaluation of different legumes and nonlegumes for green manuring and mulching, (6) determination of the effect of several OM sources on soil physicochemical properties, and (7) determination of the duration of surface-applied mulches. (CIAT

Crop improvement in Eastern and Southern Africa : Research Objectives and On-Farm Testing; a regional workshop held in Nairobi, Kenya, 20-22 July 1983

Meeting: Crop Improvement in Eastern and Southern Africa : Research Objectives and On-Farm Testing, 20-22 July 1983, Nairobi, K

Atlas of common bean (Phaseolus vulgaris L.) production in Africa

The Bean atlas is a comprehensive map of the bean growing areas in Africa. The first version was first published in 1998 and in paper format. For the last four years, PABRA has been developing the second edition, which shows dramatic changes in bean production areas across Africa, where some have expanded and others have shifted. The new atlas will be digital and available online soon. The new edition contains information from bean producing areas in Eastern, Southern and Western Africa and represents a total of 22 countries. It overlays bean producing areas with information on: bean varieties grown in those regions; ongoing seed production and dissemination work; local, national and international bean markets; market routes; information on end users, farmers and bean consumption; bean constraints, both Biotic and abiotic; and more

Production et recherche sur la banane en Afrique de l'Est et en Afrique centrale : actes du colloque régional tenu à Bujumbura, Burundi, 14-17 déc. 1983

Réunion: Production et recherche sur la banane en Afrique de l'Est et en Afrique centrale, 14-17 déc. 1983, Bujumbura, BIVersion anglaise disponible dans la Bibliothèque numérique du CRDI: Banana Production and Research in Eastern and Central Africa : proceedings of a regional workshop held in Bujumbura, Burundi, 14-17 Dec. 198

An Archaeological Survey on the Xoxocotlan Piedmont, Oaxaca, Mexico

Surface survey on the piedmont near the present village of Xoxocotlan, Oaxaca, Mexico, has revealed the pattern of prehistoric settlement around an irrigation canal that distributed water from a dammed reservoir located on the flanks of Monte Alban. Intensive systematic collection techniques have permitted quantitative statements to be made about the density of occupation and the contribution of the irrigation system to the food supply of Monte Alban

LSST: from Science Drivers to Reference Design and Anticipated Data Products

(Abridged) We describe here the most ambitious survey currently planned in the optical, the Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: probing dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. LSST will be a wide-field ground-based system sited at Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg$^2$ field of view, and a 3.2 Gigapixel camera. The standard observing sequence will consist of pairs of 15-second exposures in a given field, with two such visits in each pointing in a given night. With these repeats, the LSST system is capable of imaging about 10,000 square degrees of sky in a single filter in three nights. The typical 5$\sigma$ point-source depth in a single visit in $r$ will be $\sim 24.5$ (AB). The project is in the construction phase and will begin regular survey operations by 2022. The survey area will be contained within 30,000 deg$^2$ with $\delta<+34.5^\circ$, and will be imaged multiple times in six bands, $ugrizy$, covering the wavelength range 320--1050 nm. About 90\% of the observing time will be devoted to a deep-wide-fast survey mode which will uniformly observe a 18,000 deg$^2$ region about 800 times (summed over all six bands) during the anticipated 10 years of operations, and yield a coadded map to $r\sim27.5$. The remaining 10\% of the observing time will be allocated to projects such as a Very Deep and Fast time domain survey. The goal is to make LSST data products, including a relational database of about 32 trillion observations of 40 billion objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures available from https://www.lsst.org/overvie

The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment

The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since July 2014. This paper describes the second data release from this phase, and the fourteenth from SDSS overall (making this, Data Release Fourteen or DR14). This release makes public data taken by SDSS-IV in its first two years of operation (July 2014-2016). Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey (eBOSS); the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data driven machine learning algorithm known as "The Cannon"; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS website (www.sdss.org) has been updated for this release, and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020, and will be followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14 happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov 2017 (this is the "post-print" and "post-proofs" version; minor corrections only from v1, and most of errors found in proofs corrected

Sloan Digital Sky Survey IV: Mapping the Milky Way, Nearby Galaxies, and the Distant Universe

We describe the Sloan Digital Sky Survey IV (SDSS-IV), a project encompassing three major spectroscopic programs. The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is observing hundreds of thousands of Milky Way stars at high resolution and high signal-to-noise ratios in the near-infrared. The Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey is obtaining spatially resolved spectroscopy for thousands of nearby galaxies (median $z\sim 0.03$). The extended Baryon Oscillation Spectroscopic Survey (eBOSS) is mapping the galaxy, quasar, and neutral gas distributions between $z\sim 0.6$ and 3.5 to constrain cosmology using baryon acoustic oscillations, redshift space distortions, and the shape of the power spectrum. Within eBOSS, we are conducting two major subprograms: the SPectroscopic IDentification of eROSITA Sources (SPIDERS), investigating X-ray AGNs and galaxies in X-ray clusters, and the Time Domain Spectroscopic Survey (TDSS), obtaining spectra of variable sources. All programs use the 2.5 m Sloan Foundation Telescope at the Apache Point Observatory; observations there began in Summer 2014. APOGEE-2 also operates a second near-infrared spectrograph at the 2.5 m du Pont Telescope at Las Campanas Observatory, with observations beginning in early 2017. Observations at both facilities are scheduled to continue through 2020. In keeping with previous SDSS policy, SDSS-IV provides regularly scheduled public data releases; the first one, Data Release 13, was made available in 2016 July