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Evaluación de un reactor biológico empacado con cubos de poliuretano para la remoción de materia orgánica y nutrientes

TANIA GUTIERREZ MACIAS Petia Mijaylova Nacheva (2017, [Conferencia])

El objetivo de este trabajo fue evaluar el uso de cubos de poliuretano como medio de soporte de la biopelícula en un reactor aerobio el cual operó de manera continua y flujo descendente durante un periodo de 90 días. Se aplicó una carga orgánica de 1.41 gDQO·m-3·d-1 con un tiempo de residencia hidráulica (TRH) de 4 h y se dio seguimiento al proceso determinando los siguientes parámetros: Demanda Química de Oxigeno (DQO), solidos suspendidos totales (SST) y solidos suspendidos volátiles (SSV), nitrógeno total (NT), nitrógeno amoniacal (N-NH4) y fósforo total (PT). Como resultado se observó que los microorganismos presentes en el agua residual, colonizaron el medio de soporte (cubos de poliuretano) en los primeros 30 días de operación del sistema, alcanzando una remoción de DQO de 50 %. En el transcurso del tiempo la remoción de DQO aumentó hasta lograr remociones máximas de 84 %. Las remociones obtenidas de SST y SSV fueron mayores de 83 %. La remoción de nutrientes registró valores de 50% NT, 95 % de N- NH4 y 29 % PT.

Reactores biológicos Materia orgánica INGENIERÍA Y TECNOLOGÍA

Precompoteo de residuos orgánicos y su efecto en la dinámica poblacional de Einsenia foetida

CARLOS MANUEL ACOSTA DURAN OFELIA SOLIS PEREZ OSCAR GABRIEL VILLEGAS TORRES Lina Cardoso (2013, [Artículo])

El compostaje y el vermicompostaje son técnicas que se utilizan para transformar los residuos sólidos orgánicos en abonos orgánicos (composta y vermicomposta, respectivamente) cuyas características físicas, químicas y biológicas inciden directamente en el mejoramiento del suelo y en el crecimiento de las plantas; sin embargo, durante el proceso, se liberan desechos que agreden al ambiente. El sustrato utilizado para alimentar a las lombrices debe pasar por un periodo previo de compostaje, conocido como precompostaje. El vermicompostaje produce un material en el que la mayoría de los nutrimentos se encuentran en mayor disponibilidad para la planta, comparados con el material resultante de un proceso de compostaje convencional. El precompostaje involucra un mayor tiempo y gasto de insumos, lo que puede incrementar el costo de la vermicomposta, por lo que es necesario establecer el tiempo necesario de precompostaje para que los residuos orgánicos puedan emplearse como sustrato en la producción de la lombriz Eisenia spp.

Residuos orgánicos Precompostaje Vermicomposta INGENIERÍA Y TECNOLOGÍA

Variabilidad estacional de la productividad primaria y su relación con la estratificación vertical en la bahía de La Paz, BCS

Seasonal variability of primary productivity and its relation to the vertical stratification in La Paz, BCS

RAFAEL CERVANTES DUARTE RUBEN ANTELMO MORALES PEREZ JOSE EDUARDO VALDEZ HOLGUIN (2003, [Artículo])

Se estimó la productividad primaria (pp) vía fluorescencia natural en la bahía de La Paz durante octubre de 1996, marzo, abril, mayo, junio, julio, septiembre, noviembre de 1997, y enero de 1998. simultáneamente a los registros de pp se realizaron perfiles verticales de temperatura (CTD) para determinar la estructura de la columna de agua, y de los cuales se estimó el índice de estratificación (_) de 0 a 100 m de profundidad. Durante primavera se observaron los valores promedio más altos de pp (16 mg C m-3 h-1) y valores bajos de _ (50 J m-3) que corresponden a una columna de agua casi homogénea. En contraste, en las subsecuentes estaciones (verano y otoño), la pp decreció a valores mínimos (2 y 5 mg C m-3 h-1), mientras que _ se incrementó significativamente (249 y 347 J m-3). Los resultados indican que existe una dependencia lineal de la pp y la mezcla en la columna de agua (r2 = 0.62, p<0.05) durante los meses de verano. Periodos con una alta estratificación tienden posiblemente a inhibir la fertilización de la capa superficial, mientras que una columna de agua bien mezclada facilita el proceso de fertilización. Por lo tanto, es evidente que en la Bahía de La Paz la estratificación asume un papel importante como mecanismo que controla la pp y explica parcialmente la variabilidad estacional observada en la bahía.

Materia orgánica Producción primaria La Paz Fluorescencia natural BIOLOGÍA Y QUÍMICA

Influence of conservation agriculture-based production systems on bacterial diversity and soil quality in rice-wheat-greengram cropping system in eastern Indo-Gangetic Plains of India

Anup Das virender kumar Peter Craufurd Andrew Mcdonald Sonam Sherpa (2023, [Artículo])

Introduction: Conservation agriculture (CA) is gaining attention in the South Asia as an environmentally benign and sustainable food production system. The knowledge of the soil bacterial community composition along with other soil properties is essential for evaluating the CA-based management practices for achieving the soil environment sustainability and climate resilience in the rice-wheat-greengram system. The long-term effects of CA-based tillage-cum-crop establishment (TCE) methods on earthworm population, soil parameters as well as microbial diversity have not been well studied. Methods: Seven treatments (or scenarios) were laid down with the various tillage (wet, dry, or zero-tillage), establishment method (direct-or drill-seeding or transplantation) and residue management practices (mixed with the soil or kept on the soil surface). The soil samples were collected after 7 years of experimentation and analyzed for the soil quality and bacterial diversity to examine the effect of tillage-cum-crop establishment methods. Results and Discussion: Earthworm population (3.6 times), soil organic carbon (11.94%), macro (NPK) (14.50–23.57%) and micronutrients (Mn, and Cu) (13.25 and 29.57%) contents were appreciably higher under CA-based TCE methods than tillage-intensive farming practices. Significantly higher number of OTUs (1,192 ± 50) and Chao1 (1415.65 ± 14.34) values were observed in partial CA-based production system (p ≤ 0.05). Forty-two (42) bacterial phyla were identified across the scenarios, and Proteobacteria, Actinobacteria, and Firmicutes were the most dominant in all the scenarios. The CA-based scenarios harbor a high abundance of Proteobacteria (2–13%), whereas the conventional tillage-based scenarios were dominated by the bacterial phyla Acidobacteria and Chloroflexi and found statistically differed among the scenarios (p ≤ 0.05). Composition of the major phyla, i.e., Proteobacteria, Actinobacteria, and Firmicutes were associated differently with either CA or farmers-based tillage management practices. Overall, the present study indicates the importance of CA-based tillage-cum-crop establishment methods in shaping the bacterial diversity, earthworms population, soil organic carbon, and plant nutrient availability, which are crucial for sustainable agricultural production and resilience in agro-ecosystem.

Metagenomics Bacterial Diversity Rice-Wheat-Greengram CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CONSERVATION AGRICULTURE DNA SEQUENCES EARTHWORMS METAGENOMICS SOIL QUALITY AGROECOSYSTEMS

Estimating lime requirements for tropical soils: Model comparison and development

Fernando Aramburu Merlos João Vasco Silva Frédéric Baudron Robert Hijmans (2023, [Artículo])

Acid tropical soils may become more productive when treated with agricultural lime, but optimal lime rates have yet to be determined in many tropical regions. In these regions, lime rates can be estimated with lime requirement models based on widely available soil data. We reviewed seven of these models and introduced a new model (LiTAS). We evaluated the models’ ability to predict the amount of lime needed to reach a target change in soil chemical properties with data from four soil incubation studies covering 31 soil types. Two foundational models, one targeting acidity saturation and the other targeting base saturation, were more accurate than the five models that were derived from them, while the LiTAS model was the most accurate. The models were used to estimate lime requirements for 303 African soil samples. We found large differences in the estimated lime rates depending on the target soil chemical property of the model. Therefore, an important first step in formulating liming recommendations is to clearly identify the soil property of interest and the target value that needs to be reached. While the LiTAS model can be useful for strategic research, more information on acidity-related problems other than aluminum toxicity is needed to comprehensively assess the benefits of liming.

Exchangeable Acidity Aluminum Saturation Calcium Carbonate Equivalent CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CHEMICOPHYSICAL PROPERTIES LIMES TROPICAL ZONES ACID SOILS ALUMINIUM BASE SATURATION CALCIUM CARBONATE

Agricultural lime value chain efficiency for reducing soil acidity in Ethiopia

Moti Jaleta (2023, [Artículo])

Soil acidity is challenging agricultural production in Ethiopia. Above 43% of the farmland is under soil acidity problem and it leads to low crop yields and production losses. Ag-lime is widely considered as an effective remedy for amending soil acidity. This study assesses the current structure of ag-lime value chain and its functionality focusing on central parts of Ethiopia where lime is produced and channeled to acidity affected areas. The study uses Ethiopia as a case study and applies qualitative methods such as key informant interviews and focus group discussions to collect data from different actors in the ag-lime value chain. Key findings indicate that both public and private ag-lime producing factories are operating below their capacity. Due to limited enabling environments, the engagement of private sector in ag-lime value chain is minimal. In addition, farmers have a good awareness of soil acidity problem on their farms, and its causes and mitigation strategies in all regions. However, the adoption of ag-lime by smallholders was minimal. Overall, the current structure of the ag-lime value chain appears fragmented and needs improvement. Addressing soil acidity challenge through efficient ag-lime value chain could narrow lime supply-demand mismatches and increase widespread adoption by farmers to enhance crop productivity and food security in acidity-prone areas of the country.

CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA LIMES PRODUCTION COSTS VALUE CHAINS SOIL PH

Expanding the WOFOST crop model to explore options for sustainable nitrogen management: A study for winter wheat in the Netherlands

João Vasco Silva Pytrik Reidsma (2024, [Artículo])

Nitrogen (N) management is essential to ensure crop growth and to balance production, economic, and environmental objectives from farm to regional levels. This study aimed to extend the WOFOST crop model with N limited production and use the model to explore options for sustainable N management for winter wheat in the Netherlands. The extensions consisted of the simulation of crop and soil N processes, stress responses to N deficiencies, and the maximum gross CO2 assimilation rate being computed from the leaf N concentration. A new soil N module, abbreviated as SNOMIN (Soil Nitrogen for Organic and Mineral Nitrogen module) was developed. The model was calibrated and evaluated against field data. The model reproduced the measured grain dry matter in all treatments in both the calibration and evaluation data sets with a RMSE of 1.2 Mg ha−1 and the measured aboveground N uptake with a RMSE of 39 kg N ha−1. Subsequently, the model was applied in a scenario analysis exploring different pathways for sustainable N use on farmers' wheat fields in the Netherlands. Farmers' reported yield and N fertilization management practices were obtained for 141 fields in Flevoland between 2015 and 2017, representing the baseline. Actual N input and N output (amount of N in grains at harvest) were estimated for each field from these data. Water and N-limited yields and N outputs were simulated for these fields to estimate the maximum attainable yield and N output under the reported N management. The investigated scenarios included (1) closing efficiency yield gaps, (2) adjusting N input to the minimum level possible without incurring yield losses, and (3) achieving 90% of the simulated water-limited yield. Scenarios 2 and 3 were devised to allow for soil N mining (2a and 3a) and to not allow for soil N mining (2b and 3b). The results of the scenario analysis show that the largest N surplus reductions without soil N mining, relative to the baseline, can be obtained in scenario 1, with an average of 75%. Accepting negative N surpluses (while maintaining yield) would allow maximum N input reductions of 84 kg N ha−1 (39%) on average (scenario 2a). However, the adjustment in N input for these pathways, and the resulting N surplus, varied strongly across fields, with some fields requiring greater N input than used by farmers.

Crop Growth Models WOFOST CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CROPS NITROGEN-USE EFFICIENCY WINTER WHEAT SOIL WATER

Impact of manures and fertilizers on yield and soil properties in a rice-wheat cropping system

Alison Laing Akbar Hossain (2023, [Artículo])

The use of chemical fertilizers under a rice-wheat cropping system (RWCS) has led to the emergence of micronutrient deficiency and decreased crop productivity. Thus, the experiment was conducted with the aim that the use of organic amendments would sustain productivity and improve the soil nutrient status under RWCS. A three-year experiment was conducted with different organic manures i.e. no manure (M0), farmyard manure@15 t ha-1 (M1), poultry manure@6 t ha-1(M2), press mud@15 t ha-1(M3), rice straw compost@6 t ha-1(M4) along with different levels of the recommended dose of fertilizer (RDF) i.e. 0% (F1), 75% (F2 and 100% (F3 in a split-plot design with three replications and plot size of 6 m x 1.2 m. Laboratory-based analysis of different soil as well as plant parameters was done using standard methodologies. The use of manures considerably improved the crop yield, macronutrients viz. nitrogen, phosphorus, potassium and micronutrients such as zinc, iron, manganese and copper, uptake in both the crops because of nutrient release from decomposed organic matter. Additionally, the increase in fertilizer dose increased these parameters. The system productivity was maximum recorded under F3M1 (13,052 kg ha-1) and results were statistically identical with F3M2 and F3M3. The significant upsurge of macro and micro-nutrients in soil and its correlation with yield outcomes was also observed through the combined use of manures as well as fertilizers. This study concluded that the use of 100% RDF integrated with organic manures, particularly farmyard manure would be a beneficial resource for increased crop yield, soil nutrient status and system productivity in RWCS in different regions of India.

CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA ORGANIC FERTILIZERS YIELDS SOIL PROPERTIES RICE WHEAT CROPPING SYSTEMS

Adsorción y mineralización de atrazina y relación con parámetros de suelos del DR 063 Guasave, Sinaloa

LUIS CARLOS GONZALEZ MARQUEZ ANNE MARGRETHE HANSEN HANSEN (2009, [Artículo])

Se investigó el efecto de los parámetros del suelo en la atenuación natural de atrazina en muestras de suelo del distrito de riego 063 (DR 063). Se evaluó la adsorción y la mineralización del herbicida aplicando las guías recomendadas por la Organización para la Cooperación y el Desarrollo Económico y utilizando atrazina con trazador radiactivo. Las isotermas de adsorción del herbicida fueron lineales y los coeficientes obtenidos están en el intervalo de los valores reportados en la literatura para adsorción de atrazina en suelos agrícolas. La mineralización del herbicida fue relativamente lenta, lo cual es un indicador de la falta de microorganismos degradadores de este herbicida en las muestras de suelo, debido, probablemente, a que no ha sido aplicado en años recientes. Las muestras de suelo fueron caracterizadas por su contenido de arena, limo, arcilla, materia orgánica, nitratos y amonio, así como el pH, la conductividad eléctrica y la profundidad del suelo. El análisis de correlación entre la atenuación natural de atrazina y estas propiedades del suelo muestran una relación negativa entre la adsorción y la profundidad del suelo, así como entre la mineralización de atrazina y el contenido de materia orgánica, la concentración de amonio y la conductividad eléctrica. Esto significa que la atrazina es más móvil, debido a la menor adsorción del herbicida a mayor profundidad y la mayor persistencia con el incremento de la concentración de tales componentes. Estos resultados permitirán formular escenarios más realistas sobre la lixiviación de atrazina en suelos agrícolas.

Atenuación natural Región agrícola Materia orgánica Fertilizantes INGENIERÍA Y TECNOLOGÍA