Comparación de métodos para la determinación del carbono de la biomasa microbiana en suelos altoandinos del Perú

Universidad Nacional Agraria La Molina. Escuela de Posgrado. Maestría en SuelosActualmente, ha tomado mayor importancia la utilización de fracciones activas de carbono (C) como indicadores de calidad del suelo, debido a su rápida respuesta al manejo agronómico y estrategias para la conservación de suelos. Entre ellas, el Carbono de Biomasa Microbiana (Cbio) destaca por su dinamismo y corto tiempo de reciclaje, evidenciando los cambios en el sistema. Generalmente, en nuestro país su determinación sigue métodos tradicionales, presentando problemas de confiabilidad, subestimación, larga duración, riesgos para la salud y contaminación ambiental. El objetivo de la investigación fue determinar la factibilidad del empleo del analizador de C TOC-L Shimadzu, bajo las condiciones de trabajo del LASPAF-UNALM. Para dicho propósito, se determinó el efecto de realizar pretratamientos a las muestras, ajuste de humedad e incubación, y la refrigeración de extractos previo al análisis, una fase crítica del procesamiento. En una siguiente etapa, se compararon dos métodos tradicionales y la utilización del analizador de C en suelos contrastantes en la zona altoandina de Junín, con diferente Uso Actual de Tierra (UAT): suelos con cultivo de maca, en descanso o barbecho, pasto nativo y pastura. Así también, la relación con otros parámetros: Carbono Total (CT), Carbono Orgánico Total (COT), Nitrógeno Total (NT), tasas C:N y COT:N, y el Stock de Carbono Orgánico (COS Stock). En el análisis de resultados, se observó que el uso de pretratamientos no afectó significativamente la cuantificación del Cbio; sin embargo, sí la refrigeración de extractos. No se determinaron correlaciones significativas entre los métodos de determinación del Cbio. En cambio, el Cbio determinado con el analizador de C se mostró correlación con los otros parámetros mencionados anteriormente, demostrando su conveniencia de uso, a lo que se suma la rapidez de determinación, inocuidad para la salud humana y ser ambientalmente amigable.Recently, active carbon fractions use has become more important as indicators for soilquality; due to its rapid response to agronomic management and strategies for soilconservation. For example, Microbial Biomass Carbon (MBC) stands out for its dynamismand short recycling time, evidencing changes in the system. commonly, its determination in Peru follows traditional methods, presenting problems of reliability, underestimation, longduration, health risks and environmental pollution. The objective of this investigation wato determine the feasibility of using the TOC-L Shimadzu carbon analyzer, under theworking conditions of LASPAF-UNALM. The effect of pre-treatment of samples is a criticaphase of processing; for this purpose, humidity adjustment, incubation and cooling ofextracts prior to analysis was determined. Two traditional methods were compared with thuse of the carbon analyzer using contrasting soils in the Highlands of Junín, (soils with maccropland, fallow, native grassland and cultivated pasture). As well as other parameters such as: Total Carbon (TC), Total Organic Carbon (TOC), Total Nitrogen (TN), C: N ratio, COTN ratio and the Soil Organic Carbon Stock. Results showed that, the use of pre-treatmentsdid not significantly affect the quantification of MBC; however, refrigeration extracts had positive effect. There were no significant differences between MBC determination methods. On the other hand, a significant statistic correlation was found between MBC and thepreviously mentioned parameters, which demonstrates MBC method convenience of useand adds to the speed of determination, safety for human health and being environmentallyfriendly

Enmiendas orgánicas y su efecto en las propiedades de suelos alto andinos cultivados con papa nativa (Solanum goniocalyx Juz.et Buk.)

Las papas nativas tienen creciente aceptación en el mercado nacional e internacional; sin embargo, ante un bajo rendimiento es común la utilización de agroquímicos, lo que acarrea contaminación ambiental, riesgos para la salud e incremento de los costos de producción; ante ello, el uso de enmiendas orgánicas constituye una relevante alternativa. El estudio se realizó en el distrito de Uchuraccay (Ayacucho, Perú), en tres pisos altitudinales: zona alta (4150 msnm.), media (4050 msnm.) y baja (4002 msnm.). Tres enmiendas orgánicas fueron aplicadas (guano de islas, compost y estiércol de ovino) utilizando dos variedades de papa nativa (Amarilla Tumbay y Peruanita). Se encontró que las enmiendas orgánicas incrementaron la humedad gravimétrica, en un 42%, 67% y 55%, en las zonas alta, media y baja, respectivamente; las poblaciones de bacterias, hongos y actinomicetos aumentaron en un 14%, 11% y 10%, respectivamente. Además, la capacidad de intercambio catiónico (CIC), se elevó en un 88%, 100% y 60%, en las zonas alta, media y baja, respectivamente. Estos alcances resaltan la importancia de realizar mayores estudios, en el efecto de la aplicación de enmiendas orgánicas, para la mejora de la fertilidad de los suelos en zonas andinas

Manual de producción de enmiendas orgánicas para restablecer la fertilidad del suelo

La gran cantidad de residuos generados como parte del proceso productivo agrícola, hacen necesario un mejor manejo de estos, a fin de incorporar nutrientes al suelo, lo cual representa una gran oportunidad. Es en este contexto se desarrolla el “Manual de producción de enmiendas orgánicas para restablecer la fertilidad del suelo”, el cual presenta información científica y práctica relevante para la producción de enmiendas de fácil fabricación, ofreciendo alternativas eficientes y de bajo costo que pueden ser aplicables por los pequeños agricultores

Cultivos de cobertura asociados a quinua (Chenopodium quinoa Willd) en el Altiplano peruano: Reducción de la erosión, mejora de la salud del suelo y rendimiento agrícola

The Peruvian Altiplano presents increasing fertility losses, being susceptible to natural erosion. For many years, conventional agricultural management has generated losses of the topsoil and deterioration of soil properties, impacting in crop yields and deepening the degradation of this vulnerable ecosystem. The aim of this research was to determine the benefits of cover crops against erosion, soil health and quinoa yield. The trial was carried out in Huancarani and Cahualla towns, Mañazo district, Puno; with a randomized complete block design (RCBD) with four treatments: without cover and with clover (Medicago hispida G.), vetch (Vicia villosa) and mulch covers. We evaluated the physical, chemical, and biological characteristics of soil, the biomass of the cover crops and the quinoa yield. The results showed that the treatments with clover, mulch and vetch covers reduced soil erosion by 59.61%, 51.87% and 49.50%, respectively. Likewise, the use of clover and vetch covers increased organic carbon (29.71% and 31.16%), nitrogen (36.94% and 48.65%), and available phosphorus with clover cover (26.11%). Finally, clover cover associated with quinoa increased the yield of quinoa grain by 17% and reduced soil erosion significantly. These results show that cover crops have great potential for restoring soil health and improving yield.El Altiplano peruano presenta pérdidas crecientes de fertilidad, siendo a su vez susceptible a una erosión natural. Durante muchos años, un manejo agrícola convencional ha generado pérdidas de la capa superficial del suelo y deterioro de sus propiedades, teniendo gran impacto en el rendimiento de los cultivos y profundizando la degradación de este ecosistema vulnerable. El propósito de esta investigación fue evaluar el uso de cultivos de cobertura frente a la erosión, salud del suelo y rendimiento del cultivo de quinua. El ensayo se realizó en las localidades Huancarani y Cahualla, distrito Mañazo, provincia y región Puno. Se utilizó un diseño experimental de bloques completos al azar (DBCA) con cuatro tratamientos: sin cobertura y con coberturas de trébol (Medicago hispida G.), vicia (Vicia villosa) y mulch. Los resultados mostraron que la quinua asociada con coberturas de trébol, mulch y vicia redujeron la erosión del suelo en 59,61%, 51,87% y 49,50%, respectivamente. Asimismo, el uso de coberturas de trébol y vicia aumentó el carbono orgánico (+29,71% y 31,16%) y nitrógeno (+36,94% y 48,65%), y con el trébol, el fósforo disponible (+26,11%). Finalmente, la cobertura de trébol aumentó en 17% el rendimiento de la quinua en grano y redujo significativamente la erosión del suelo. Estos resultados muestran que los cultivos de cobertura presentan gran potencial para el restablecimiento de la salud del suelo y mejora en el rendimiento

Cultivos de cobertura asociados a quinua (Chenopodium quinoa Willd) en el Altiplano peruano: Reducción de la erosión, mejora de la salud del suelo y rendimiento agrícola

El Altiplano peruano presenta pérdidas crecientes de fertilidad, siendo a su vez susceptible a una erosión natural. Durante muchos años, un manejo agrícola convencional ha generado pérdidas de la capa superficial del suelo y deterioro de sus propiedades, teniendo gran impacto en el rendimiento de los cultivos y profundizando la degradación de este ecosistema vulnerable. El propósito de esta investigación fue evaluar el uso de cultivos de cobertura frente a la erosión, salud del suelo y rendimiento del cultivo de quinua. El ensayo se realizó en las localidades Huancarani y Cahualla, distrito Mañazo, provincia y región Puno. Se utilizó un diseño experimental de bloques completos al azar (DBCA) con cuatro tratamientos: sin cobertura y con coberturas de trébol (Medicago hispida G.), vicia (Vicia villosa) y mulch. Los resultados mostraron que la quinua asociada con coberturas de trébol, mulch y vicia redujeron la erosión del suelo en 59,61%, 51,87% y 49,50%, respectivamente. Asimismo, el uso de coberturas de trébol y vicia aumentó el carbono orgánico (+29,71% y 31,16%) y nitrógeno (+36,94% y 48,65%), y con el trébol, el fósforo disponible (+26,11%). Finalmente, la cobertura de trébol aumentó en 17% el rendimiento de la quinua en grano y redujo significativamente la erosión del suelo. Estos resultados muestran que los cultivos de cobertura presentan gran potencial para el restablecimiento de la salud del suelo y mejora en el rendimiento

Enmiendas orgánicas y su efecto en las propiedades de suelos alto andinos cultivados con papa nativa (Solanum goniocalyx Juz.et Buk.)

Native potatoes have rising acceptance in the national and international market. However, the use of agrochemicals is common due to a low yield, which entails environmental contamination, health risks and an increase in production costs. In response, the use of organic amendments is a relevant alternative. This study was carried out in the district of Uchuraccay (Ayacucho, Peru), in three different altitudes: high (4150 masl.), medium (4050 masl.) and low (4002 masl.). We applied three organic amendments (guano islands, compost and sheep manure) in two varieties of native potato (Amarilla Tumbay and Peruanita). The organic amendments increased the gravimetric humidity, up to 76%, 205% and 149%, in the high, medium and low sites, respectively; likewise, the populations of bacteria, fungi and actinomycetes reported an increase, up to 14%, 12% and 10 %, respectively. Further, the amendments increased the cation exchange capacity (CEC), up to 88%, 100% and 60%, in the high, medium and low sites, respectively. These scopes realize the importance of further studies on the effect of applying organic amendments to improve soil fertility in the Andean highlandsLas papas nativas tienen creciente aceptación en el mercado nacional e internacional; sin embargo, ante un bajo rendimiento es común la utilización de agroquímicos, lo que acarrea contaminación ambiental, riesgos para la salud e incremento de los costos de producción; ante ello, el uso de enmiendas orgánicas constituye una relevante alternativa. El estudio se realizó en el distrito de Uchuraccay (Ayacucho, Perú), en tres pisos altitudinales: zona alta (4150 msnm.), media (4050 msnm.) y baja (4002 msnm.). Tres enmiendas orgánicas fueron aplicadas (guano de islas, compost y estiércol de ovino) utilizando dos variedades de papa nativa (Amarilla Tumbay y Peruanita). Se encontró que las enmiendas orgánicas incrementaron la humedad gravimétrica, en un 42%, 67% y 55%, en las zonas alta, media y baja, respectivamente; las poblaciones de bacterias, hongos y actinomicetos aumentaron en un 14%, 11% y 10%, respectivamente. Además, la capacidad de intercambio catiónico (CIC), se elevó en un 88%, 100% y 60%, en las zonas alta, media y baja, respectivamente. Estos alcances resaltan la importancia de realizar mayores estudios, en el efecto de la aplicación de enmiendas orgánicas, para la mejora de la fertilidad de los suelos en zonas andinas

In Vitro Activities of Levofloxacin and Comparable Agents against Middle Ear Fluid, Nasopharyngeal, and Oropharyngeal Pathogens Obtained from Costa Rican Children with Recurrent Otitis Media or Failing Other Antibiotic Therapy

This study analyzes the in vitro activities of levofloxacin and other commonly used antimicrobials against middle ear fluid, nasopharyngeal, and oropharyngeal pathogens obtained from children with otitis media at risk of having a resistant pathogen. Levofloxacin proved to be very active against these pathogens and had intermediate activity against Streptococcus pyogenes

General and abdominal adiposity and hypertension in eight world regions: a pooled analysis of 837 population-based studies with 7·5 million participants

International audienceSummaryBackground Adiposity can be measured using BMI (which is based on weight and height) as well as indices of abdominal adiposity. We examined the association between BMI and waist-to-height ratio (WHtR) within and across populations of different world regions and quantified how well these two metrics discriminate between people with and without hypertension.MethodsWe used data from studies carried out from 1990 to 2023 on BMI, WHtR and hypertension in people aged 20–64 years in representative samples of the general population in eight world regions. We graphically compared the regional distributions of BMI and WHtR, and calculated Pearson’s correlation coefficients between BMI and WHtR within each region. We used mixed-effects linear regression to estimate the extent to which WHtR varies across regions at the same BMI. We graphically examined the prevalence of hypertension and the distribution of people who have hypertension both in relation to BMI and WHtR, and we assessed how closely BMI and WHtR discriminate between participants with and without hypertension using C-statistic and net reclassification improvement (NRI).FindingsThe correlation between BMI and WHtR ranged from 0·76 to 0·89 within different regions. After adjusting for age and BMI, mean WHtR was highest in south Asia for both sexes, followed by Latin America and the Caribbean and the region of central Asia, Middle East and north Africa. Mean WHtR was lowest in central and eastern Europe for both sexes, in the high-income western region for women, and in Oceania for men. Conversely, to achieve an equivalent WHtR, the BMI of the population of south Asia would need to be, on average, 2·79 kg/m² (95% CI 2·31–3·28) lower for women and 1·28 kg/m² (1·02–1·54) lower for men than in the high-income western region. In every region, hypertension prevalence increased with both BMI and WHtR. Models with either of these two adiposity metrics had virtually identical C-statistics and NRIs for every region and sex, with C-statistics ranging from 0·72 to 0·81 and NRIs ranging from 0·34 to 0·57 in different region and sex combinations. When both BMI and WHtR were used, performance improved only slightly compared with using either adiposity measure alone.InterpretationBMI can distinguish young and middle-aged adults with higher versus lower amounts of abdominal adiposity with moderate-to-high accuracy, and both BMI and WHtR distinguish people with or without hypertension. However, at the same BMI level, people in south Asia, Latin America and the Caribbean, and the region of central Asia, Middle East and north Africa, have higher WHtR than in the other regions

Diminishing benefits of urban living for children and adolescents’ growth and development

Optimal growth and development in childhood and adolescence is crucial for lifelong health and well-being1–6. Here we used data from 2,325 population-based studies, with measurements of height and weight from 71 million participants, to report the height and body-mass index (BMI) of children and adolescents aged 5–19 years on the basis of rural and urban place of residence in 200 countries and territories from 1990 to 2020. In 1990, children and adolescents residing in cities were taller than their rural counterparts in all but a few high-income countries. By 2020, the urban height advantage became smaller in most countries, and in many high-income western countries it reversed into a small urban-based disadvantage. The exception was for boys in most countries in sub-Saharan Africa and in some countries in Oceania, south Asia and the region of central Asia, Middle East and north Africa. In these countries, successive cohorts of boys from rural places either did not gain height or possibly became shorter, and hence fell further behind their urban peers. The difference between the age-standardized mean BMI of children in urban and rural areas was <1.1 kg m–2 in the vast majority of countries. Within this small range, BMI increased slightly more in cities than in rural areas, except in south Asia, sub-Saharan Africa and some countries in central and eastern Europe. Our results show that in much of the world, the growth and developmental advantages of living in cities have diminished in the twenty-first century, whereas in much of sub-Saharan Africa they have amplified

Worldwide trends in underweight and obesity from 1990 to 2022: a pooled analysis of 3663 population-representative studies with 222 million children, adolescents, and adults

Background: Underweight and obesity are associated with adverse health outcomes throughout the life course. We estimated the individual and combined prevalence of underweight or thinness and obesity, and their changes, from 1990 to 2022 for adults and school-aged children and adolescents in 200 countries and territories. Methods: We used data from 3663 population-based studies with 222 million participants that measured height and weight in representative samples of the general population. We used a Bayesian hierarchical model to estimate trends in the prevalence of different BMI categories, separately for adults (age ≥20 years) and school-aged children and adolescents (age 5-19 years), from 1990 to 2022 for 200 countries and territories. For adults, we report the individual and combined prevalence of underweight (BMI &lt;18·5 kg/m2) and obesity (BMI ≥30 kg/m2). For school-aged children and adolescents, we report thinness (BMI &lt;2 SD below the median of the WHO growth reference) and obesity (BMI &gt;2 SD above the median). Findings: From 1990 to 2022, the combined prevalence of underweight and obesity in adults decreased in 11 countries (6%) for women and 17 (9%) for men with a posterior probability of at least 0·80 that the observed changes were true decreases. The combined prevalence increased in 162 countries (81%) for women and 140 countries (70%) for men with a posterior probability of at least 0·80. In 2022, the combined prevalence of underweight and obesity was highest in island nations in the Caribbean and Polynesia and Micronesia, and countries in the Middle East and north Africa. Obesity prevalence was higher than underweight with posterior probability of at least 0·80 in 177 countries (89%) for women and 145 (73%) for men in 2022, whereas the converse was true in 16 countries (8%) for women, and 39 (20%) for men. From 1990 to 2022, the combined prevalence of thinness and obesity decreased among girls in five countries (3%) and among boys in 15 countries (8%) with a posterior probability of at least 0·80, and increased among girls in 140 countries (70%) and boys in 137 countries (69%) with a posterior probability of at least 0·80. The countries with highest combined prevalence of thinness and obesity in school-aged children and adolescents in 2022 were in Polynesia and Micronesia and the Caribbean for both sexes, and Chile and Qatar for boys. Combined prevalence was also high in some countries in south Asia, such as India and Pakistan, where thinness remained prevalent despite having declined. In 2022, obesity in school-aged children and adolescents was more prevalent than thinness with a posterior probability of at least 0·80 among girls in 133 countries (67%) and boys in 125 countries (63%), whereas the converse was true in 35 countries (18%) and 42 countries (21%), respectively. In almost all countries for both adults and school-aged children and adolescents, the increases in double burden were driven by increases in obesity, and decreases in double burden by declining underweight or thinness. Interpretation: The combined burden of underweight and obesity has increased in most countries, driven by an increase in obesity, while underweight and thinness remain prevalent in south Asia and parts of Africa. A healthy nutrition transition that enhances access to nutritious foods is needed to address the remaining burden of underweight while curbing and reversing the increase in obesity. Funding: UK Medical Research Council, UK Research and Innovation (Research England), UK Research and Innovation (Innovate UK), and European Union