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158 resultados, página 7 de 10

Application of ammonium to a N limited arable soil enriches a succession of bacteria typically found in the rhizosphere

Yendi Navarro-Noya Marco Luna_Guido Nele Verhulst Bram Govaerts Luc Dendooven (2022, [Artículo])

Crop residue management and tillage are known to affect the soil bacterial community, but when and which bacterial groups are enriched by application of ammonium in soil under different agricultural practices from a semi-arid ecosystem is still poorly understood. Soil was sampled from a long-term agronomic experiment with conventional tilled beds and crop residue retention (CT treatment), permanent beds with crop residue burned (PBB treatment) or retained (PBC) left unfertilized or fertilized with 300 kg urea-N ha-1 and cultivated with wheat (Triticum durum L.)/maize (Zea mays L.) rotation. Soil samples, fertilized or unfertilized, were amended or not (control) with a solution of (NH4)2SO4 (300 kg N ha-1) and were incubated aerobically at 25 ± 2 °C for 56 days, while CO2 emission, mineral N and the bacterial community were monitored. Application of NH4+ significantly increased the C mineralization independent of tillage-residue management or N fertilizer. Oxidation of NH4+ and NO2- was faster in the fertilized soil than in the unfertilized soil. The relative abundance of Nitrosovibrio, the sole ammonium oxidizer detected, was higher in the fertilized than in the unfertilized soil; and similarly, that of Nitrospira, the sole nitrite oxidizer. Application of NH4+ enriched Pseudomonas, Flavisolibacter, Enterobacter and Pseudoxanthomonas in the first week and Rheinheimera, Acinetobacter and Achromobacter between day 7 and 28. The application of ammonium to a soil cultivated with wheat and maize enriched a sequence of bacterial genera characterized as rhizospheric and/or endophytic independent of the application of urea, retention or burning of the crop residue, or tillage.

CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA AMMONIUM CROP RESIDUES WHEAT MAIZE TILLAGE SOIL

Precise irrigation water and nitrogen management improve water and nitrogen use efficiencies under conservation agriculture in the maize-wheat systems

Mahesh Gathala ML JAT (2023, [Artículo])

A 3-year field experiment was setup to address the threat of underground water depletion and sustainability of agrifood systems. Subsurface drip irrigation (SDI) system combined with nitrogen management under conservation agriculture-based (CA) maize-wheat system (MWS) effects on crop yields, irrigation water productivity (WPi), nitrogen use efficiency (NUE) and profitability. Grain yields of maize, wheat, and MWS in the SDI with 100% recommended N were significantly higher by 15.8%, 5.2% and 11.2%, respectively, than conventional furrow/flood irrigation (CT-FI) system. System irrigation water savings (~ 55%) and the mean WPi were higher in maize, wheat, and MWS under the SDI than CT-FI system. There was saving of 25% of fertilizer N in maize and MWS whereas no saving of N was observed in wheat. Net returns from MWS were significantly higher (USD 265) under SDI with 100% N (with no subsidy) than CT-FI system despite with higher cost of production. The net returns were increased by 47% when considering a subsidy of 80% on laying SDI system. Our results showed a great potential of complementing CA with SDI and N management to maximize productivity, NUE, and WPi, which may be economically beneficial and environmentally sound in MWS in Trans-IGP of South Asia.

Subsurface Drip Irrigation Nitrogen Management Irrigation Water Productivity Water Savings CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA IRRIGATION WATER NITROGEN-USE EFFICIENCY CONSERVATION AGRICULTURE MAIZE WHEAT

Potential impacts of Ukraine-Russia armed conflict on global wheat food security: A quantitative exploration

Khondoker Mottaleb Gideon Kruseman Sieglinde Snapp (2022, [Artículo])

Violent conflict is a major cause of acute food crises. In 2021, at least 155 million people in 10 countries were severely food insecure and eight of those countries were experiencing armed conflict. On February 24, 2022, an armed conflict between Russian Federation (Russia) and Ukraine escalated. As Russia and Ukraine are major wheat exporters, this will aggravate the already precarious food security situation in many developing countries by disrupting wheat production and export and by accelerating price hikes in import-dependent developing countries. This study examines the potential impacts of this ongoing armed conflict between Russia and Ukraine on wheat price, consumption, and calorie intake from wheat. In doing so, it applies the conditional mixed process estimation procedure using information collected from 163 countries and territories for the years 2016–2019 from online database of the Food and Agriculture Organization of the United Nations (FAO). The study shows that, on average, a 1% decrease in the global wheat trade could increase the producers' price of wheat by 1.1%, and a 1% increase in the producers' price could reduce the yearly per capita wheat consumption by 0.59%, daily calorie intake by 0.54% and protein intake by 0.64% in the sampled countries. Based on this, the study demonstrates that a 50% reduction in wheat exports by Russia and Ukraine could increase the producers’ price of wheat by 15%, which would induce a reduction in wheat consumption and dietary energy intake by at least 8%. Since wheat export has reduced from both Russia and Ukraine, to avoid a food crisis in developing countries, policies are suggested, including near term improvement of domestic wheat production by promoting improved agronomic practices to close yield gaps to meet a substantial portion of wheat self-sufficiency goals. In the long run, countries in Africa, East Asia and South America can explore expanding wheat into new land area. International donor agencies can play a key role in supporting the ongoing wheat research and development activities.

Export-Import CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA ARMED CONFLICTS CALORIES CONSUMPTION ELASTICITY FOOD SECURITY PRICES PRODUCTION WHEAT

Atlas para el manejo de riesgos en grandes obras hidráulicas por efecto de eventos meteorológicos extremos: primera etapa

ISAAC BONOLA ALONSO José Alfredo González Verdugo JOSE RAUL FLORES BERRONES JAVIER AVILES LOPEZ XIANGYUE LI LIU (2011, [Documento de trabajo])

Tabla de contenido: Introducción – Búsqueda y análisis de información – Objetivo del análisis multiespectral – Justificación – Introducción al análisis multiespectral – Metodología – Análisis analógico multiespectral de las imágenes de satélite empleadas – Estructuras volcánicas – Estructuras sedimentarias – Estructuras geomorfológicas sedimentarias – Reología – Reología de la sustancia actuante – Los índices estructurales genéticos de las rocas sedimentarias – Porosidad de las rocas carbonatadas – Deslizamiento de paredes montañosas y de tierras – Conclusiones y recomendaciones – Información relevante recopilada.

Introducción – Búsqueda y análisis de información – Objetivo del análisis multiespectral – Justificación – Introducción al análisis multiespectral – Metodología – Análisis analógico multiespectral de las imágenes de satélite empleadas – Estructuras volcánicas – Estructuras sedimentarias – Estructuras geomorfológicas sedimentarias – Reología – Reología de la sustancia actuante – Los índices estructurales genéticos de las rocas sedimentarias – Porosidad de las rocas carbonatadas – Deslizamiento de paredes montañosas y de tierras – Conclusiones y recomendaciones – Información relevante recopilada.

Construcciones hidráulicas Reología Desastres naturales Factores meteorológicos Informes de proyectos INGENIERÍA Y TECNOLOGÍA

The potential of UAV and very high-resolution satellite imagery for yellow and stem rust detection and phenotyping in Ethiopia

Gerald Blasch David Hodson Francelino Rodrigues (2023, [Artículo])

Very high (spatial and temporal) resolution satellite (VHRS) and high-resolution unmanned aerial vehicle (UAV) imagery provides the opportunity to develop new crop disease detection methods at early growth stages with utility for early warning systems. The capability of multispectral UAV, SkySat and Pleiades imagery as a high throughput phenotyping (HTP) and rapid disease detection tool for wheat rusts is assessed. In a randomized trial with and without fungicide control, six bread wheat varieties with differing rust resistance were monitored using UAV and VHRS. In total, 18 spectral features served as predictors for stem and yellow rust disease progression and associated yield loss. Several spectral features demonstrated strong predictive power for the detection of combined wheat rust diseases and the estimation of varieties’ response to disease stress and grain yield. Visible spectral (VIS) bands (Green, Red) were more useful at booting, shifting to VIS–NIR (near-infrared) vegetation indices (e.g., NDVI, RVI) at heading. The top-performing spectral features for disease progression and grain yield were the Red band and UAV-derived RVI and NDVI. Our findings provide valuable insight into the upscaling capability of multispectral sensors for disease detection, demonstrating the possibility of upscaling disease detection from plot to regional scales at early growth stages.

Very High Resolution Imagery Disease Detection Methods Early Growth Stages CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA UNMANNED AERIAL VEHICLES STEM RUST PHENOTYPING HIGH-THROUGHPUT PHENOTYPING WHEAT

The water crisis in the south-central region of the Chihuahua State and the 1997 UN Convention

Jorge Arturo Salas Plata Mendoza Thelma J. Garcia (2022, [Artículo, Artículo])

The present writing focuses on the water crisis in the south-central part of Chihuahua State in the year 2020. Recent literature points to the drought, excess demand for the vital liquid and overpopulation of this region, among other issues, as the causes of the emergency. This paper argues that the reasons mentioned above are not causes, but effects of an economic policy of capital valorization and accumulation, which go far beyond the carrying capacity of the ecosystems and their capacity to regulate the polluting processes. The obsolescence of the water treaties between Mexico and the US make it necessary to consider other alternatives such as the 1997 UN Convention on water.

Chihuahua water crisis hydro-agricultural crisis carrying capacity expansive growth 1997 UN Convention Ecological Economics crisis del agua crisis hidroagrícola capacidad de carga crecimiento expansivo Convención de la ONU de 1997 Economía Ecológica CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA

Índices de seguridad hídrica (ISH)

José Manuel Rodríguez Varela Velitchko Tzatchkov Petronilo Edilburgo Cortez Mejía ARIZABETH SAINOS OSCAR JESUS LLAGUNO GUILBERTO LUCIANO SANDOVAL YOVAL DAVID ORTEGA GAUCIN EDGAR YURI MENDOZA CAZARES SALVADOR NAVARRO BARRAZA (2017, [Documento de trabajo])

El objetivo del proyecto fue establecer a nivel municipal índices de seguridad hídrica de accesibilidad y disponibilidad a los servicios de agua potable y saneamiento; seguridad y calidad del agua ante fenómenos de inundaciones, sequías y de contaminación del recurso agua. Para lo cual, con base en una revisión del estado del arte, se identificaron al menos nueve definiciones de seguridad hídrica. Se identificaron varias metodologías internacionales y nacionales para medir la seguridad hídrica, incluyendo la del Programa Nacional Hídrico (PNH) con ocho indicadores en los que se incluyen dos índices. Se decidió trabajar sobre siete indicadores: 1) el índice global de acceso a los servicios básicos de agua (IGASA) del PNH; 2) el índice de vulnerabilidad a la sequía; 3) abatimientos de aguas subterráneas con métodos indirectos, como el experimento de recuperación de gravedad y clima; 4) vulnerabilidad social; 5) indicador municipal de seguridad hídrica; 6) índice global de seguridad hídrica a nivel estatal; y 7) un indicador de gestión del agua. Se analizó la metodología del Índice Global de Seguridad Hídrica, para poder aplicarla, lo cual se hizo a nivel estatal con datos 2015, principalmente de la CONAGUA, así como datos internacionales en la componente de administración.

Seguridad hídrica Factores meteorológicos Ciudades Abastecimiento de agua Calidad del agua CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA