Diversifying with grain legumes amplifies carbon in management-sensitive soil organic carbon pools on smallholder farms

Regis Chikowo Sieglinde Snapp (2023, [Artículo])

Crop diversification with grain legumes has been advocated as a means to increase agroecological resilience, diversify livelihoods, boost household nutrition, and enhance soil health and fertility in cereal-based cropping systems in sub-Saharan Africa and around the world. Soil organic carbon (SOC) is a primary indicator of soil health and there is limited data regarding SOC pools and grain legume diversification on smallholder farms where soils are often marginal. In Malawi, a range of legume diversification options are under investigation, including rotations and a doubled-up legume rotation (DLR) system in which two compatible legumes are intercropped and then rotated with a cereal. The impact of the DLR system on SOC has not yet been determined, and there is a lack of evidence regarding SOC status over a gradient of simple to complex grain legume diversified systems. We address this knowledge gap by evaluating these systems in comparison to continuous sole maize (Zea mays L.) at three on-farm trial sites in central Malawi. After six years of trial establishment, we measured SOC in bulk soils and aggregate fractions and in faster cycling SOC pools that respond more rapidly to management practices, including water extractable organic carbon (WEOC), particulate organic matter carbon (POM-C), potentially mineralizable carbon (C), and macroaggregate C. Cropping treatment differences were not seen in bulk SOC or total N, but they were apparent in SOC pools with a shorter turnover time. The DLR system of intercropped pigeonpea (Cajanus cajan (L.) Millsp.) and groundnut (Arachis hypogaea L.) rotated with maize had higher WEOC, POM-C, potentially mineralizable C, macroaggregate and microaggregate C values than continuous maize. Of the single legume rotations, the pigeonpea-maize rotation had more mineralizable C and microaggregate C compared to continuous maize, while the groundnut-maize rotation had similar C values to the maize system. Overall, this study shows the potential for crop rotations diversified with grain legumes to enhance C in management sensitive SOC pools, and it is one of the first reports to show this effect on smallholder farm sites.

Crop Diversification Water Extractable Organic Carbon CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA DIVERSIFICATION LEGUMES PARTICULATE ORGANIC MATTER SOIL ORGANIC CARBON

Studies of plant hydraulics and water relations in mexican environments: adaptation, physiology, and applications

Estudios sobre hidráulica y relaciones hídricas de plantas en ambientes mexicanos: adaptaciones, fisiología y aplicaciones

RODRIGO MENDEZ ALONZO Mark Olson Horacio Paz Casandra Reyes García CELENE MARISOL ESPADAS MANRIQUE CLARA TINOCO OJANGUREN Santiago Trueba (2022, [Artículo])

Given the outstanding global progress of research on the hydraulic pathway in plants, and its important role as an indicator of plant mortality risk, we reviewed: (1) the adaptive basis of hydraulic traits and their importance for overall plant function; (2) the number of primary scientific articles on plant hydraulics that have been produced in Mexico in the last 40 years, (3) research related to specific environments in Mexico, and (4) the possible applications of plant hydraulics to natural resource management. Our systematic review included 83 articles. The number of publications per year steadily increased over time, reaching its maximum in 2021. Veracruz and Yucatán are the states where the majority of scientific articles on plant hydraulics have been produced, but for most states less than two publications on this subject appeared in ca. 40 years, and none was found for Oaxaca and Chiapas, the most biodiverse states. In plant hydraulics, the most studied biome in Mexico was the tropical dry forest, followed by crops; trees were the most studied growth-form, followed by herbaceous crops and epiphytes. We point to the need of enhancing research in the interface between plant hydraulic function and remote sensing, as well as developing applications in adaptive forest management and ecological restoration. We hope that this review may ignite a national collaborative effort to quantify critical traits that could inform the hydraulic functioning of Mexican ecosystems, particularly in the underrepresented and highly diverse states of Mexico. © 2022 Sociedad Botanica de Mexico, A.C. All rights reserved.

ADAPTATION DROUGHT VULNERABILITY ECOPHYSIOLOGY PLANT WATER RELATIONS SYSTEMATIC REVIEW BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA VEGETAL (BOTÁNICA) ECOLOGÍA VEGETAL ECOLOGÍA VEGETAL

Soil moisture content and maize grain yield under conventional and conservation agriculture practices - results of short term field tests in liselo, Namibia

Christian Thierfelder (2023, [Artículo])

This article focuses on the results from trials developed to monitor the short-term effects of conventionally tilled systems versus CA on soil quality and crop productivity under conditions of the major cropping systems in central, north-central and north-eastern regions of Namibia. Conventional tillage (CT), Minimum tillage (MT), Minimum tillage, mulch (MT-M), Minimum tillage, rotation (MT-R) and Minimum tillage, mulch and rotation (MT-MR) were the primary treatments tested. Significant differences (p≤0.000) among the treatments were observed in the 0-60 cm soil profiles where MT-M plots had the highest soil moisture content (39.8 mm, Standard Error of Mean 0.2815) over the study period. A significant difference (p=0.0206) in grain yield was observed in the second season with CT plots yielding the highest grain yield (3852.3 kg ha-1, standard error of mean 240.35). Results suggest that CA has the potential to increase water conservation and contribute to reduction of the risk of crop failure. Climate change driven degradation under conventional tillage necessitate alternative sustainable tillage methods. Conservation tillage methods and conservation agricultural practices that minimize soil disturbance while maintaining soil cover need to be adopted more locally as viable alternatives to conventional tillage.

Grain Yield Soil Moisture Content CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CONSERVATION AGRICULTURE CONVENTIONAL TILLAGE GRAIN YIELDS SOIL WATER CONTENT MAIZE

Low thermal conductivity solar domestic water heater

MIGUEL ANGEL PORTA GANDARA JOSE LUIS FERNANDEZ ZAYAS JUAN FRANCISCO VILLA MEDINA NORBERTO CHARGOY DEL VALLE (2022, [Artículo])

"Solar domestic water heaters (SWH) with thermosyphon circulation are the most common commercial applications of solar energy in Mexico. They are also becoming popular in the rest of the world, given their simplicity, good economic returns, and sustainability. Traditionally the solar collector, the piping, and the storage tank are built of copper and steel. However, wáter quality in many parts of the Mexican Northwest has high mineral contents and, when heated, results in early metal pitting corrosion of SWH parts. Short-lived water heaters are bad promoters of the technology. In this work, a SWH thermoplastic Chlorinated Polyvinyl Chloride (CPVC) is built and tested under real operating conditions in La Paz, BCS, Mexico. The optimal design is detected with the aid of a suitable numerical model. Results reveal that a full SWH-CPVC can be technically and economically convenient for the weather conditions of the Northwestern states of Mexico."

Low thermal conductivity solar water heater CPVC solar water heater Solar water heater cooper pitting corrosion Thermosiphon circulation INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA ELECTRÓNICA DISPOSITIVOS TERMOELÉCTRICOS DISPOSITIVOS TERMOELÉCTRICOS

Waterhole detection using a vegetation index in desert bighorn sheep (Ovis canadensis cremnobates) habitat

Jonathan Gabriel Escobar Flores (2019, [Artículo])

In arid ecosystems, desert bighorn sheep are dependent on natural waterholes, particularly in summer when forage is scarce and environmental temperatures are high. To detect waterholes in Sierra Santa Isabel, which is the largest area of desert bighorn sheep habitat in the state of Baja California, Mexico, we used the normalized difference vegetation index (NDVI) and normalized difference water index (NDWI) from Sentinel-2 satellite images. Waterhole detection was based on the premise that sites with greater water availability, where NDVI was higher, can be identified by their density of vegetation greenness. For the detected waterholes, we estimated the escape terrain (presence of cliffs or steep, rocky slopes) around each by the vector ruggedness measure to determine their potential use by desert bighorn sheep based on the animals’ presence as documented by camera traps. We detected 14 waterholes with the NDVI of which 11 were known by land owners and 3 were unrecorded. Desert bighorn were not detected in waterholes with high values of escape terrain, i.e., flat areas. Waterhole detection by NDVI is a simple method, and with the assistance and knowledge of the inhabitants of the Sierra, it was possible to confirm the presence each waterhole in the field. © 2019 Escobar-Flores et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Article, bighorn sheep, environmental aspects and related phenomena, environmental parameters, habitat, Mexico, nonhuman, normalized difference vegetation index, normalized difference water index, water availability, waterhole, animal, bighorn sheep, CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CIENCIAS AGRARIAS CIENCIA FORESTAL CIENCIA FORESTAL

Agricultura, agua y cambio climático en zonas áridas de México

SALVADOR EMILIO LLUCH COTA JUAN ALBERTO VELAZQUEZ ZAPATA César Nieto Delgado (2022, [Artículo])

"En este artículo se expone cómo a pesar de que la ciencia y la tecnología han permitido aumentar históricamente la productividad agrícola, hoy día existen grandes retos derivados del cambio climático y la crisis global de abastecimiento de agua. Se comentan algunas medidas de adaptación y manejo del recurso agua, con algunas referencias a nuestra realidad nacional, y se argumenta cómo el enfoque de Nexo, que implica la toma de decisiones sobre el uso del recurso agua de forma transectorial, representa una alternativa de adaptación al cambio climático."

Cambio climático, agricultura, agua, Nexo, adaptación Climate change, agriculture, water, nexus, adaptation CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO CLIMATOLOGÍA CLIMATOLOGÍA REGIONAL CLIMATOLOGÍA REGIONAL

Evaluación de la intrusión salina utilizando el método electromagnético transitorio (TEM) y análisis de iones mayores e isótopos estables del agua en el acuífero La Misión, B.C., México

Saline intrusion assessment using transient electromagnetic method (TEM) and analysis of major ions and stable isotopes of water in La Mision aquifer, B.C., Mexico

Yesica Guadalupe Cabrera Sillas (2023, [Tesis de maestría])

El acuífero La Misión constituye una fuente importante de abastecimiento de agua en la zona semiárida de Ensenada, Baja California, México. La explotación intensiva del acuífero puede haber desarrollado el deterioro de la calidad del agua subterránea, y con ello el avance del agua de mar. El presente estudio se centra en la evaluación de la posible intrusión salina en el acuífero costero La Misión a partir de técnicas geofísicas e hidrogeoquímicas. De acuerdo con investigaciones anteriores, se plantea la hipótesis de que el acuífero está afectado por procesos de mezcla de agua de mar principalmente en la franja costera. El estudio geofísico comprende 11 sondeos Transitorios Electromagnéticos (TEM). Además, se recolectaron 18 muestras de agua subterránea en temporada de secas y lluvias, donde se analizaron isótopos estables (δ18O y δ2H) y los principales iones mayores (Na+, K+, Ca2+, Mg2+, Cl-, HCO3, CO32- y SO42-). La inversión de datos geofísicos en 1D revela dos acuíferos en la zona de estudio; 1) el acuífero de depósitos de arena aluvial saturado superficial con un rango de resistividad de 2.1-5.5 Ωm y un espesor <80 m (UH2); 2) el segundo pertenece a un acuífero semiconfinado compuesto por limolitas y areniscas con resistividades de 13.8 a 21.4 Ωm (UH4). Los resultados hidroquímicos muestran que los principales tipos de aguas subterráneas son Ca-Cl, mixtas y Na-Cl. Además, las diversas relaciones iónicas confirmaron el proceso de intercambio iónico inverso donde el Ca2+ y el Mg2+ en la matriz del acuífero se han reemplazado por Na+ en sitios favorables. El cálculo del índice de saturación de minerales indica que las muestras de agua subterránea están saturadas con respecto a los minerales de carbonato. Por lo tanto, estos resultados sugieren que el acuífero costero La Misión está sujeto a la influencia continua de la mezcla de agua de mar, disolución de minerales carbonatados ayudado por la interacción agua-roca, y los procesos de intercambio iónico. Considerando que éstos son los factores determinantes que están controlando la evolución del agua subterránea en esta zona.

The Misión aquifer is an important source of water supply in the semi-arid zone of Ensenada, Baja California, Mexico. Intensive exploitation of the aquifer may have developed groundwater quality deterioration, and the advance of seawater. The present study focuses on the evaluation of possible saline intrusion in the coastal aquifer of La Misión, using geophysical and hydrogeochemical techniques. Based on previous research, it is hypothesized that the aquifer is affected by seawater mixing processes mainly in the coastal strip. The geophysical survey comprises 11 Transient Electromagnetic soundings (TEM). In addition, a total of 18 groundwater samples were collected in dry and post rainy season, where stable isotopes (δ18O and δ2H) and the main major ions (Na+, K+, Ca2+, Mg2+, and Cl-, HCO3-, CO32- and SO42-) were analyzed. One-dimensional inversion geophysical data reveals two aquifers in the study area. 1) the shallow saturated alluvial sand deposit aquifer with a resistivity range of 2.1-5.5 Ωm and a thickness <80 m (UH2). 2) the second belongs to a semi-confined aquifer composed of siltstones and sandstones with resistivities of 13.8 to 21.4 Ωm (UH4). Hydrochemical results show that the main groundwater types are Ca-Cl, mixed and Na-Cl. In addition, the various ionic ratios confirmed the reverse ion exchange process where Ca2+ and Mg2+ in the aquifer matrix have been replaced by Na+ at favorable sites. Calculation of the mineral saturation index indicates that the groundwater samples are saturated with respect to carbonate minerals. Therefore, these results suggest that the coastal Mission aquifer is subject to the continuous influence of seawater mix, dissolution of carbonate minerals aided by water-rock interaction, and ion exchange processes. Considering these processes, the important determining factors that are controlling the evolution of groundwater in this zone.

Agua subterránea, resistividad, interacción agua-roca, índice de saturación, salinidad. Groundwater, resistivity, water-rock interaction, saturation index, salinity. CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO GEOFÍSICA GEOMAGNETISMO Y PROSPECCIÓN MAGNÉTICA GEOMAGNETISMO Y PROSPECCIÓN MAGNÉTICA

Utilización de aguajes por el borrego cimarrón (Ovis canadensis cremnobates) y análisis de calidad del agua en Sierra Santa Isabel, Baja California, México

Watering sites use by bighorn sheep (Ovis canadensis cremnobates) and water quality analysis in Sierra Santa Isabel, Baja California, Mexico

Jonathan Gabriel Escobar Flores SERGIO ALVAREZ CARDENAS Sara Cecilia Díaz Castro Aradit Castellanos Vera Jorge Torres Rodriguez MARIANA DELGADO FERNANDEZ (2016, [Artículo])

"Se analizó la utilización de aguajes por el borrego cimarrón en la Sierra Santa Isabel, Baja California, México durante la temporada de sequía de 2011 y 2013 y el periodo de lluvias e inicio de la temporada de sequía del 2015. Asimismo, se estudió la calidad del agua, con base en siete parámetros fisicoquímicos. Se obtuvieron 260 registros fotográficos de borregos cimarrones, donde hembras, añeros y corderos representaron el 73%. En el periodo de lluvias, en dos de los aguajes se obtuvieron valores de conductividad de 1.31 µS/cm2 y 1.92 µS/cm2, y de sólidos disueltos totales de l0.65 ppt y 0.95 ppt, indicando un bajo contenido de sales en el agua. Los valores de oxígeno disuelto mayores a 6.4 ppm, dureza del agua menor a 100 ppm y PH entre 6.5 y 8.5, sugieren que el agua tiene condiciones óptimas para ser bebida por los borregos cimarrones. Los aguajes con mayor utilización por los borregos fueron El Zamora (n = 120) y El Cordero (n = 67), donde se registraron las mejores condiciones de calidad de agua en este estudio. El mayor registro de hembras y añeros, asociado a condiciones óptimas de calidad del agua, confirman la importancia de los aguajes para la crianza y reclutamiento del borrego cimarrón."

"Water used by bighorn sheep during the 2011 and 2013 dry seasons and the rainy season and drought of 2015 in the Sierra Santa Isabel of the State of Baja California, Mexico was analyzed for seven physicochemical parameters. At four watering sites, 260 photographs of sheep were obtained. Females, yearlings, and lambs accounted for 73% of the photographs. In the rainy season at two watering sites, conductivity was 1.31 µS/cm2 and 1.92 µS/cm2 and total dissolved solids was 0.65 and 0.95 ppt, indicating low salt content and safe for bighorn sheep. The watering sites with greater use by bighorn sheep were El Zamora (n = 120) and El Cordero (n = 67), which also had the best water quality. The frequent use by females and yearlings of the two sites with optimal water quality support the belief that watering sites for lambing and recruitment of bighorn sheep is important."

Baja California, borrego cimarrón, calidad del agua, cámaras trampa. Baja California, bighorn sheep, water quality, camera traps. BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA ANIMAL (ZOOLOGÍA) MAMÍFEROS MAMÍFEROS

Freshwater exchanges and surface salinity in the Colombian basin, Caribbean Sea

Emilio Beier (2017, [Artículo])

Despite the heavy regional rainfall and considerable discharge of many rivers into the Colombian Basin, there have been few detailed studies about the dilution of Caribbean Surface Water and the variability of salinity in the southwestern Caribbean. An analysis of the precipitation, evaporation and runoff in relation to the climate variability demonstrates that although the salt balance in the Colombian Basin overall is in equilibrium, the area south of 12N is an important dilution sub-basin. In the southwest of the basin, in the region of the Panama-Colombia Gyre, Caribbean Sea Water is diluted by precipitation and runoff year round, while in the northeast, off La Guajira, its salinity increases from December to May by upwelling. At the interannual scale, continental runoff is related to El Niño Southern Oscillation, and precipitation and evaporation south of 12°N are related to the Caribbean Low Level Jet. During El Niño years the maximum salinification occurs in the dry season (December-February) while in La Niña years the maximum dilution (or freshening), reaching La Guajira Coastal Zone, occurs in the wet season (September-November). © 2017 Beier et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

sea water, fresh water, Article, Caribbean, dilution, dry season, El Nino, environmental parameters, evaporation, freshwater exchange, geographic distribution, molecular weight, oscillation, precipitation, river basin, salinity, seasonal variation, s CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO OCEANOGRAFÍA OCEANOGRAFÍA

Dipole-wind interactions under gap wind jet conditions in the Gulf of Tehuantepec, Mexico: A surface drifter and satellite database analysis

MAURO WILFRIDO SANTIAGO GARCIA (2019, [Artículo])

Gap wind jets (Tehuano winds) trigger supersquirts of colder water and mesoscale asymmetric dipoles in the Gulf of Tehuantepec (GT). However, the effects of successive gap wind jets on dipoles and their effects inside eddies have not yet been studied. Based on the wind fields, geostrophic currents, and surface drifter dispersion, this research documented three dipoles triggered and modified by Tehuano winds. Once a dipole develops, successive gap wind jets strengthen the vortices, and the anticyclonic eddy migrates southwestward while the cyclonic eddy is maintained on the east side of the GT. During the wind relaxation stage, the cyclonic eddy may propagate westward, but due to the subsequent re-intensification of the Tehuano winds, the vortex could break down, as was suggested by surface drifter dispersion pattern and geostrophic field data. The effect of the Tehuano winds was evaluating via eddy-Ekman pumping. Under Tehuano wind conditions, Ekman downwelling (upwelling) inside the anticyclonic (cyclonic) eddies may reach ~ -2.0 (0.5) m d-1 and decrease as the wind weakens. In the absence of Tehuano winds, Ekman downwelling inside the anticyclonic eddy was ~ 0.1 (-0.1) m d-1. The asymmetry of downwelling and upwelling inside eddies during Tehuano wind events may be associated with Tehuano wind forcing. © 2019 Santiago-García et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

article, dipole, leisure, Mexico, cold, ecosystem, factual database, geographic mapping, hurricane, Mexico, satellite imagery, season, water flow, wind, sea water, Cold Temperature, Cyclonic Storms, Databases, Factual, Ecosystem, Geographic Mapping, CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO OCEANOGRAFÍA OCEANOGRAFÍA