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This study presents a global scale analysis of cropping intensity, crop duration and fallow land extent computed by using the global dataset on monthly irrigated and rainfed crop areas MIRCA2000. MIRCA2000 was mainly derived from census data and crop calendars from literature. Global cropland extent was 16 million km2 around the year 2000 of which 4.4 million km2 (28%) was fallow, resulting in an average cropping intensity of 0.82 for total cropland extent and of 1.13 when excluding fallow land. The lowest cropping intensities related to total cropland extent were found for Southern Africa (0.45), Central America (0.49) and Middle Africa (0.54), while highest cropping intensities were computed for Eastern Asia (1.04) and Southern Asia (1.0). In remote or arid regions where shifting cultivation is practiced, fallow periods last 3–10 years or even longer. In contrast, crops are harvested two or more times per year in highly populated, often irrigated tropical or subtropical lowlands where multi-cropping systems are common. This indicates that intensification of agricultural land use is a strategy that may be able to significantly improve global food security. There exist large uncertainties regarding extent of cropland, harvested crop area and therefore cropping intensity at larger scales. Satellite imagery and remote sensing techniques provide opportunities for decreasing these uncertainties and to improve the MIRCA2000 inventory.
Making agriculture sustainable is a global challenge. In the European Union (EU), the Common Agricultural Policy (CAP) is failing with respect to biodiversity, climate, soil, land degradation as well as socio‐economic challenges.
The European Commission's proposal for a CAP post‐2020 provides a scope for enhanced sustainability. However, it also allows Member States to choose low‐ambition implementation pathways. It therefore remains essential to address citizens' demands for sustainable agriculture and rectify systemic weaknesses in the CAP, using the full breadth of available scientific evidence and knowledge.
Concerned about current attempts to dilute the environmental ambition of the future CAP, and the lack of concrete proposals for improving the CAP in the draft of the European Green Deal, we call on the European Parliament, Council and Commission to adopt 10 urgent action points for delivering sustainable food production, biodiversity conservation and climate mitigation.
Knowledge is available to help moving towards evidence‐based, sustainable European agriculture that can benefit people, nature and their joint futures.
The statements made in this article have the broad support of the scientific community, as expressed by above 3,600 signatories to the preprint version of this manuscript. The list can be found here (https://doi.org/10.5281/zenodo.3685632).
A free Plain Language Summary can be found within the Supporting Information of this article.
À guisa de conclusão, e de acordo com Morais e Correia (1993), as causas da crise que vivem as populações pastoris e agropastoris do Sul de Angola que, inclusivamente as põem em risco de extinção, são os fracos apoios nos serviços de produção animal, a degradação da captação e retenção da água e a liberalização do comércio. Daí que, ao invés de se fazer dos Ovimbundu bode expiatório de alguns dos males que afectam esses grupos, dever-se-ia, como é óbvio, reforçar as capacidades locais, visando promover uma melhor adaptação dos Muíla, Kuvale e outros grupos da região para integrá-los, da melhor maneira, no contexto social e económico vigente em Angola. Isso não é apenas uma acção humanitária, mas o respeito dos direitos das populações marginalizadas e que necessitam também de se sentiram cidadãos. Por outras palavras: uma questão de Direitos Humanos.
Spinnen und Weberknechte (Arachnida: Araneae, Opiliones) in Agrarlandschaften Nordostdeutschlands
(2006)
Große Gebiete Norddeutschlands sind durch offene Ackerlandschaften geprägt, die überwiegend intensiv genutzt werden. Durch die Liberalisierung des Welthandels und den damit verbundenen Abbau der Flächenförderung muss nach Alternativen zur bisherigen Nutzung gesucht werden. Offene Ackerlandschaften haben jedoch neben ihrer traditionellen Funktion für die Landwirtschaft auch einen großen Wert für die Belange der Wasserwirtschaft, des Naturschutzes und der Erholung. Bei der notwendigen Umorientierung in der Nutzung sollten diese Funktionen in Zukunft wesentlich stärker berücksichtigt werden. Eine besondere Bedeutung kommt dabei den ökologischen Leistungen der Ackerlandschaften zu, die bisher noch kaum untersucht wurden. Das Projekt EASE (finanziert vom BMBF, Projektträger DLR) soll dazu beitragen, die Voraussetzung für die zielführende Definition und Förderung ökologischer Leistungen im Ackerbau zu schaffen (vgl. HAMPICKE et al. 2005). Dazu werden extensive Bewirtschaftungsmethoden für ertragsarme und damit auflassungsbedrohte Ackerstandorte entwickelt, welche hinsichtlich ihres Faktoreinsatzes, ihrer Ertragshöhe und ihrer Artenausstattung Ähnlichkeit mit der traditionellen Bewirtschaftung vor dem Intensivierungsschub seit den 60er Jahren besitzen. Wichtige Kriterien sind dabei eine Reduzierung der Nutzungsintensität verbunden mit einem Verzicht auf Maximalerträge und Senkung der Kosten, bedarfsgerechte Nährstoff zufuhr bei Minimierung des Austrags und weitestgehender Verzicht auf chemische Pflanzenschutzmittel. Durch optimale Einbindung krautiger sowie dauerhafter Zwischenstrukturen (Hecken, Feldraine, Sölle, Schutzstreifen, Brachen) soll eine wirksame Verbesserung der Lebensraumsituation offenlandbewohnender Lebensgemeinschaften bewirkt werden. Als Zielgruppen zur Überprüfung wurden u.a. Arthropoden der Bodenoberfläche gewählt (Laufkäfer, Spinnen, Kurzflügler). Spinnen gehören in der Agrarlandschaft zu den potentiellen Gegenspielern schädlicher Insekten. In Getreidefeldern dominieren über weite Teile Europas hinweg Arten aus der Familie Linyphiidae und Lycosidae. Spinnen sind nicht von einzelnen Pflanzen- oder Tierarten abhängig, sondern sie sind eng an biotische (Raumstruktur der Vegetationsschicht) und abiotische Faktoren (Mikroklima) gebunden. Demzufolge reagieren sie schnell und stark auf die Veränderungen dieser Umweltparameter und bieten somit sehr gute Indikatoreigenschaften (z.B. NÄHRIG & HARMS 2003). Was Spinnen zu geeigneten Untersuchungsobjekten macht, ist die hohe räumliche Auflösung der ermittelten Daten. Im Gegensatz zu Wirbeltieren nämlich zeigen wirbellose Arthropoden schon auf relativ kleinen Untersuchungsflächen Wechselwirkungen zwischen Tier und Habitat an. Ziel dieser Arbeit ist die Darstellung der charakteristischen Dominanzstrukturen und die Biodiversitäts-Entwicklung der Spinnen und Weberknechte auf den Fruchtfolgeflächen innerhalb von drei Fangjahren (2001 bis 2003).
Plant diversity change for cities and their surroundings is well documented. For rural areas such studies are difficult as literature data are mostly insufficient. We reconstructed phytodiversity change in the Feldatal community (Germany, Hesse) by comparison of historical herbarium collections (1945–1976, Hans Hupke) with a recent floristic survey (2012). The study area is a rural area typical for Central Europe, dominated by agriculture and forestry and with a stable human population. Floristic diversity decreased (683 to 497 species; 31% of the total flora), principally by disappearance of species of unimproved grassland, fields and villages. The small number of newly documented species (33 spp.; 5% of total flora) comprises mostly naturalized ornamentals and salt tolerant species along roads. Plant diversity change of the last decades in rural landscapes in Central Europe was mainly dependent on the intensification of agriculture.
Artificial drainage of agricultural land, for example with ditches or drainage tubes, is used to avoid water logging and to manage high groundwater tables. Among other impacts it influences the nutrient balances by increasing leaching losses and by decreasing denitrification. To simulate terrestrial transport of nitrogen on the global scale, a digital global map of artificially drained agricultural areas was developed. The map depicts the percentage of each 5’ by 5’ grid cell that is equipped for artificial drainage. Information on artificial drainage in countries or sub-national units was mainly derived from international inventories. Distribution to grid cells was based, for most countries, on the "Global Croplands Dataset" of Ramankutty et al. (1998) and the "Digital Global Map of Irrigation Areas" of Siebert et al. (2005). For some European countries the CORINE land cover dataset was used instead of the both datasets mentioned above. Maps with outlines of artificially drained areas were available for 6 countries. The global drainage area on the map is 167 Mio hectares. For only 11 out of the 116 countries with information on artificial drainage areas, sub-national information could be taken into account. Due to this coarse spatial resolution of the data sources, we recommended to use the map of artificially drained areas only for continental to global scale assessments. This documentation describes the dataset, the data sources and the map generation, and it discusses the data uncertainty.
U.S. retail food price increases in recent years may seem large in nominal terms, but after adjusting for inflation have been quite modest even after the change in U.S. biofuel policies in 2006. In contrast, increases in the real prices of corn, soybeans, wheat and rice received by U.S. farmers have been more substantial and can be linked in part to increases in the real price of oil. That link, however, appears largely driven by common macroeconomic determinants of the prices of oil and agricultural commodities rather than the pass-through from higher oil prices. We show that there is no evidence that corn ethanol mandates have created a tight link between oil and agricultural markets. Rather increases in food commodity prices not associated with changes in global real activity appear to reflect a wide range of idiosyncratic shocks ranging from changes in biofuel policies to poor harvests. Increases in agricultural commodity prices in turn contribute little to U.S. retail food price increases, because of the small cost share of agricultural products in food prices. There is no evidence that oil price shocks have caused more than a negligible increase in retail food prices in recent years. Nor is there evidence for the prevailing wisdom that oil-price driven increases in the cost of food processing, packaging, transportation and distribution are responsible for higher retail food prices. Finally, there is no evidence that oil-market specific events or for that matter U.S. biofuel policies help explain the evolution of the real price of rice, which is perhaps the single most important food commodity for many developing countries.